Recent advances in bioprinting techniques: approaches, applications and future prospects
© The Author(s) 2016
Received: 2 June 2016
Accepted: 5 September 2016
Published: 20 September 2016
Bioprinting technology shows potential in tissue engineering for the fabrication of scaffolds, cells, tissues and organs reproducibly and with high accuracy. Bioprinting technologies are mainly divided into three categories, inkjet-based bioprinting, pressure-assisted bioprinting and laser-assisted bioprinting, based on their underlying printing principles. These various printing technologies have their advantages and limitations. Bioprinting utilizes biomaterials, cells or cell factors as a “bioink” to fabricate prospective tissue structures. Biomaterial parameters such as biocompatibility, cell viability and the cellular microenvironment strongly influence the printed product. Various printing technologies have been investigated, and great progress has been made in printing various types of tissue, including vasculature, heart, bone, cartilage, skin and liver. This review introduces basic principles and key aspects of some frequently used printing technologies. We focus on recent advances in three-dimensional printing applications, current challenges and future directions.
KeywordsTissue engineering 3D bioprinting Artificial organs
The loss or failure of organs and tissues is a difficult and costly problem in healthcare. The limited supply of organs globally  has motivated research on tissue engineering, particularly the design of a cell-scaffold-microenvironment to promote the regeneration of various types of tissue, e.g., skin , cartilage , bone , tendon  and cardiac tissue .
Scaffolds are considered the key element for tissue regeneration because they provide the necessary mechanical support and a physical structure for the transplanted cells to attach, grow and maintain their physiological functions. A suitable scaffold, such as a bone scaffold for tissue engineering, must have favorable biocompatibility or cytocompatibility to provide a surface for cells to adhere, proliferate, differentiate and secrete extracellular matrix (ECM). ECM contains abundant bioactive molecules, including glycosaminoglycans, collagen, fibronectin and cytokines. Pore size and interconnectivity also play important roles in cell adhesion and migration, vascularization and new tissue ingrowth [7–11]. Thus, a fully satisfactory scaffold must simultaneously support the growth of different cell types and tissues, each with specific mechanical properties, chemical gradients, cell populations, and geometric structures. However, conventional fabrication methods [12, 13] used for manufacturing three-dimensional (3D) scaffolds, such as electrospinning, fiber deposition, freeze-drying, gas foaming, and salt leaching, lack precise control of internal structural features and topology. Therefore, techniques for the accurate fabrication of multifunctional scaffolds are needed. These complex design constraints limit the effectiveness of many current traditional methods, particularly when attempting to repair clinically relevant injuries, organs, and other complex tissues.
3D bioprinting technology has attracted increasing attention based on its immense potential in the manufacture of tissue-engineering compounds. This review focuses on the key elements of 3D bioprinting technology used to fabricate very precise scaffolds and the applications of printing-specific modeling used in patient preoperative planning and the production of artificial tissues or organs for implantation. The article also discusses challenges and potential future directions.
Bioprinting technologies and their applications
Characteristics of bioprinting processes
Low-viscosity suspension of living cells; biomolecules; growth factors
Fast (<10,000 droplets/s)
Wide availability; low cost; high resolution; high printing speed; ability to introduce concentration gradients in 3D constructs
Poor vertical structure clogging characteristics; thermal and mechanical stress to cells; limited printable materials (liquid only)
Hydrogel; melt; cells; proteins and ceramic materials; solutions, pastes, or dispersions of low to high viscosity; PLGA; tricalcium phosphate (TCP); collagen and chitosan; collagen-alginate-silica composites coated with HA; and agarose with gelatin
Numerous materials that can be printed with any dimensions; mild conditions (room temperature); use of cellular spheroids; direct incorporation of cells; and homogenous distribution of cells
Limited mechanical stiffness; critical timing of gelation time; specific matching of the densities of the material and the liquid medium to preserve shapes; low resolution and viability
Hydrogel, media, cells, proteins and ceramic materials of varying viscosity
Nozzle-free, noncontact process; cells are printed with high activity and high resolution; high control of ink droplets and precise delivery
High cost; cumbersome and time consuming; requires a metal film and thus is subject to metallic particle contamination
Light-sensitive polymer materials; curable acrylics and epoxies
Fast (<40,000 mm/s)
Solid freeform and nozzle-free technology; highest fabrication accuracy; compatibility with an increasing number of materials; light-sensitive hydrogels can be printed layer-by-layer
Applicable to photopolymers only; lack of biocompatible and biodegradable polymers; harmful effects from residual toxic photo-curing reagents; possibility of harm to DNA and human skin by UV
Scientists have made great progress in patterning molecules, cells and organs by inkjet printing. Molecules such as DNA have been successfully printed , facilitating studies of cancer pathogenesis and treatment. In addition, thermal inkjet printing has been demonstrated to be biocompatible with Chinese hamster ovary (CHO) cells and rat embryonic motoneurons . Less than 8 % of CHO cells were lysed in the printing process, indicating that mammalian cells can be successfully printed by inkjet bioprinting and retain their functions, with good prospects for creating living tissue structures or organs. Further developments in bioprinting technology have resulted in advancements in the printing of functional blood vessels and heart valves. In 2015, Jana and Lerman studied the bioprinting of cardiac valves to solve clinical transplantation shortages. Cardiac constructs are complex and important, particularly the four valves of the heart. Although heart valves have been successfully printed, the functional requirements of elasticity and physiological conditions remain to be fulfilled . Similarly, in 2014, Duan B examined printing of blood vessels and observed drawbacks similar to those observed for bioprinted heart valves. Hydrogels, the main biomaterials used in inkjet bioprinting, are too soft to withstand normal physiological conditions [30, 31]. Thus, to successfully print organs that maintain good biological function in vivo, new biological materials that are more suitable for the human body must be developed to match the mechanical and biological properties of native organs.
Pressure-assisted bioprinting and its applications
Pressure-assisted bioprinting (PAB) is based on extrusion to create desired 3D patterns and constructs. The biomaterials used for printing are usually solutions, pastes, or dispersions  that are extruded by coordinating the motion of pneumatic pressure or plunger- or screw-based pressure in the form of a continuous filament through a microscale nozzle orifice or a microneedle onto a stationary substrate. After layer-by-layer application, complete 3D patterns and constructs are eventually formed (Fig. 2c).
The advantages of PAB technology include room temperature processing, direct incorporation of cells and homogenous distribution of cells. PAB has been applied to the printing of cell and organs with confirmed retention of activity. Bioprinted cells include mouse pre-osteoblasts, human mesenchymal stem cells, endothelial cells, and osteogenic progenitors. Bioprinted cells have been used to repair ovine calvarial defects . The feasibility of multicellular bioprinted constructs incorporating goat multipotent stromal cells (MPSCs) and endothelial progenitor cells with retention of heterogeneous cell organization in the subcutaneous tissue of immunodeficient mice and production extracellular matrix has been demonstrated. The multipotent stromal cells in the multicellular bioprinted constructs differentiated into bone structures, and the endothelial progenitor cells differentiated into blood vessels. These results support the ability of multicellular bioprinted grafts to retain activity in vivo [34, 35].
Laser-assisted bioprinting (LAB) uses a laser as the energy source to deposit biomaterials onto a substrate. This technique usually consists of three parts: a pulsed laser source, a ribbon coated with liquid biological materials that are deposited on the metal film, and a receiving substrate . The lasers irradiate the ribbon, causing the liquid biological materials to evaporate and reach the receiving substrate in droplet form. The receiving substrate contains a biopolymer or cell culture medium to maintain cellular adhesion and sustained growth after transfer of cells from the ribbon (Fig. 2d). LAB mainly uses nanosecond lasers with UV or near-UV wavelengths as energy sources to print hydrogels, cells, proteins and ceramic materials [36, 37]. The resolution varies from pico- to micro-scale features and is affected by many factors: the thickness of the biological materials on the film, their rheological properties, the energy of the laser pulse, the wettability of the substrate, and the printing speed and organization of the structure [38, 39].
Researchers have demonstrated the feasibility of using laser-based technology to print cells, for example, human dermal fibroblasts, mouse C2C12 myoblasts, bovine pulmonary artery endothelial cells (BPAECs), breast cancer (MCF-7) cells and rat neural stem cells [39–41]. In 2013, Michael et al.  successfully created Graftskin skin substitutes by utilizing LAB technology, a landmark event in the field of laser-assisted bioprinting. Fibroblasts and keratinocytes were used as the cell sources to fabricate the skin constructs, which were subsequently transplanted into the skin folds of nude mice to perform an in vivo evaluation. Eleven days later, the graft adhered well to the tissue around the skin wound. The keratinocytes proliferated and differentiated well and grew to the skin stratum corneum and basal layer. Compared with other bioprinting technologies, LAB has unique advantages, including a nozzle-free, non-contact process, the printing of cells with high activity and high resolution, and the control of ink droplets and precise delivery characteristics. Ink bubble dynamics, shear stress and laser pulse energy all play important roles in the bioprinting process [43–45].
Stereolithography (STL) technology is a solid freeform, nozzle-free technology that was developed in the late 1980s . A liquid, photo-sensitive polymer formulation is solidified upon illumination. STL uses digital micromirror arrays to control the light intensity to polymerize light-sensitive polymer materials. This technique is mainly applied to fabricate structures from curable acrylics and epoxies. The number of photocrosslinkable polymers is increasing, and multiple resins can be used for one structure . Digital light projection controls the printing process in this top-down system. Compared with other solid freeform techniques, STL has the highest fabrication accuracy, and an increasing number of materials can be used in this process. Furthermore, STL can print light-sensitive hydrogels layer-by-layer, and the total printing time depends only on the thickness of the structure .
However, in addition to these advantages, there are numerous restrictions, such as the lack of proper biocompatible and biodegradable polymers, harmful effects from residual toxic photocuring reagents, the inability to completely remove the supporting structure and the inability to form horizontal gradients in the constructs . UV-sensitive photoinitiators were once used, although UV is harmful to cellular DNA and causes skin cancer. In 2015, Wang  investigated the use of customized visible light in a STL system, including a commercial beam projector and bioinks, a mixture of PEGDA, methacrylated gelatin (GelMA), and eosin Y-based photoinitiator. They first described the detailed protocol of the visible light-based STL system and revealed the necessity of an infrared ray (IR)-filtering water filter to the system. Their experimental results with NIH 3T3 cells demonstrated that this system with customized visible light could support the bioprinting of visible light-curable hydrogels with 50-μm resolution and high cell viability (∼85 %) for at least 5 days.
Key points of bioprinting
The goal of tissue engineering is to fabricate 3D artificial tissues or organs composed of a scaffold, cells and a microenvironment that mimics the real environment of the human body. As a highly effective and accurate method to fabricate artificial tissue in vitro, printing achieves these three necessary components. This section will discuss the applications and limitations of the materials used in bioprinting, including biomaterials, cells and cell factors.
Parameters of biomaterials
In general, biomaterials can be categorized into a large variety of hydrogel, metallic, ceramic, polymeric and composite materials. The physical characteristics of biomaterials determines the optimal printing type. For example, low-viscosity materials are more attractive for bioprinting because cells can grow well in the low-pressure environment . Other material properties, such as pore size and interconnectivity, also influence the encapsulated cells .
The biocompatibility of biomaterials is the first parameter to be considered when fabricating scaffolds and significantly limits the number of suitable materials. Scaffold materials must accommodate the encapsulated cells and the recipient’s body. Thus, the implant must be cytocompatible and support cell growth, attachment, proliferation and migration but safe for the host and not cause severe inflammation or immunologic rejection.
Hydrogels are attractive materials for bioprinting because they are an enormous three-dimensional network of polymer chains holding a mass of water. For the processing of physical hydrogels, a polymer network is expected to form from the physical junctions between hydrogel macromolecules. The use of some photo-initiators and monomers during hydrogel crosslinking affects cell viability depending on radical concentration and the length of exposure . However, more complex, functional and biocompatible hydrogels can be fabricated using bioprinting technology. Wüst et al.  reported the use of different amounts of HA to print a tunable alginate-gelatin hydrogel composite with a two-step crosslinking procedure. Human mesenchymal stem cells (hMSCs) were subsequently mixed with the hydrogel, and cell viability was detected. Approximately 85 % of the cells were still viable after 3 days of in vitro culture. This experiment demonstrated that adding HA to the hydrogel in different concentrations enhances mechanical properties to match hard tissue reconstruction with no reduction in cell viability.
Porosity and interconnectivity
Pore shape, volume, size and geometry all directly affect the behavior of cells after adhesion to the scaffold. Different pore sizes in matrices can affect extracellular matrix development and are strictly correlated with cellular organization, collagen I assembly, and mineralization . Porosity and interconnectivity play important roles in the ingrowth of surrounding tissues. Open and interconnected pores can allow oxygen and nutrients to be transported into the interior and eliminate the waste generated by cellular metabolism.
Domingos et al.  performed a systematic analysis of 3D-printed scaffolds to determine the effects of pore size and geometry on hMSC viability. Three different filament distances (550, 650 and 750 μm) and filament patterns (0°/90°, 0°/60°/120° and 0°/45°/90°/135°) were designed to obtain complex internal geometries. Cells encapsulated in the structure with larger filament distances and fewer deposition angles behaved more actively. The results indicated the following: (1) cell adhesion, viability and proliferation were strongly influenced by the pore size and shape, whereby large quadrangular pores enhanced hMSC viability and proliferation; (2) cell morphology did not seem to be affected by pore topology, as demonstrated by the investigation of the shape factor.
Characteristics of human cortical and cancellous bones
Pore size (μm)
Compressive strength (MPa)
Young’s modulus (GPa)
3D-printed ceramic materials for tissue engineering
Porosity and compressive strength
32–52 % and 2–10 MPa
Increased mechanical strength and cellular proliferation
High compressive modulus and good drug delivery performance
70 % and 7 MPa
Enhanced cell attachment and osteogenic activity
34 % and 47 MPa
resulting in improved mechanical properties and good cell affinity
Laser-aided gelling (LAG)
Sr–Mg doped TCP
Increased osteons and, consequently, an enhanced network of blood vessel formation and osteocalcin expression
55 % and 0.88 MPa
Osteoconduction and osteointegration in vivo
HSP bioceramic (hollow-struts-packed)
65–85 % and ~5 MPa
Significantly improved cell attachment and proliferation; promotion of formation of new bone tissue in the center of the scaffolds
A modified coaxial 3D printing
Most material components of bioink are derived from current materials used in tissue engineering and limit the application of printed scaffolds. In addition to good biocompatibility, high porosity and matching mechanical properties, the ideal material must have appropriate hydrophilicity, pH neutrality, and degradability without the formation of toxic macromolecules. Future development of manufacturing technology will enable printing of biofunctional scaffolds that perfectly mimic the extracellular matrix to provide cells with a microenvironment for adhesion, proliferation and directional differentiation.
Classification and ink formulations
A wide range of biomaterial inks which categorize polymers, ceramics, hydrogels and composites have been developed in the printing technology . Compared to polymer and ceramic, hydrogel inks have received much more attention, and significant progress have already been made to design novel ink formulations. A new 3D bioprinting technique called freeform reversible embedding of suspended hydrogels (FRESH) has been introduced by Feinberg AW . The innovation of this technology is what deposits and crosslinks one kind of hydrogel inks into another that can be considered as a support carrier. It has been successfully applied in the printing of human femurs, branched coronary arteries, trabeculated embryonic hearts and human brains .
The lack of diversity in “biomaterial inks” became barriers to the widespread applications of 3D printing. UV light, chemical cross-linking, and high temperatures in the materials machining negatively impact most biologically activities. However, utilizing cellularized matrix gels lacked initial mechanical strength. The balance between structural strength and biocompatible processing is hard to satisfy scientists . In the future, more bioactive and more mechanically stable must be developed to ultimately serve as the “bioink” for bioprinting tissue constructs.
Cell printing is the key element for the printing of tissue and organs. However, the choice of bioink materials is limited by the stringent printing conditions. The stiffness, functional groups, and surface morphology of biomaterials have a significant impact on cellular behavior. Cells are usually encapsulated in biodegradable hydrogels that mimic a tissue-like environment for building bioprinted ink . The characteristics of hydrogels can protect the inner cells from the shear force generated in the printing process and maintain their bio-functions, such as the self-renewal ability and multi-lineage differentiation potency of stem cells. The cytocompatibility of laser-assisted cell printing technology with cells post-deposition was recently demonstrated, and this technique has been widely used for its high resolution and accuracy in single-cell deposition.
Viability of post-printed cells
CHO and embryonic motoneuron cells  were first successfully deposited into pre-defined patterns in 2005. That study emphasized the need to study the biocompatibility of the inkjet printing process and the ability to encapsulate cells into bioink. The results were satisfactory, and less than 8 % cell death was observed. Researchers  have successfully constructed HepG2-loaded GelMA hydrogels exhibiting high cell viability of greater than 95 % for at least 8 days. These achievements demonstrated the possibility of bioprinting complex, cell-laden hydrogel tissue constructs. Cells embedded in the hydrogels may remain in a non-proliferating state . Neufurth et al. used the calcium salt of polyphosphate (polyp-Ca2+-complex) as a second layer on top of an inner sodium alginate hydrogel surface, which strongly promoted cell proliferation and enhanced the hydrogel mechanical strength.
Bioprinted cells maintain their proliferation and differentiation abilities in vitro, an important step in the development of tissue constructs. Lorber et al.  reported that adult rat RGCs (retinal ganglion cells) and glia could be successfully printed by a piezoelectric inkjet printing method. No significant differences in cell survival and outgrowth were observed between the non-printed control group and the printed group. Additionally, coating a glial substrate first and then printing RGCs on top enhanced the functional activity of the cells. Future goals include printing other cells of the retina, particularly the light-sensitive photoreceptors, with exciting implications for the printing of a functional retina.
Bioprinting stem cells
Stem cells, including embryonic stem cells (ESCs), BMSCs and ASCs, can be printed and patterned by precise deposition of picoliter (pl) volumes of fluid or laser-aided accurate localization. An important concern in stem cell printing is that the activity of stem cells, including proliferation and pluripotency, may change during the printing process. Levato et al.  encapsulated MSCs in gelatin methacrylamide-gellan gum bioinks that combined bioprinting with microcarrier technology. This bioprinting approach allowed cells to be deposited internally with 90 % viability after 3 days, and the cells were induced to osteogenic differentiation, with increased expression of bone markers such as ALP and OCN. MSCs were submerged in perfluorotributylamine (C12F27N) as a hydrophobic high-density fluid to be printed in the desired shape . A printed vascular bifurcation maintained its shape and dimensions for more than 6 months.
In the laser-assisted field, MSCs  were printed based on laser-induced forward transfer (LIFT) for the construction of scaffold-free autologous grafts. The seed cells survived the complete printing procedure and maintained their ability to proliferate and continue differentiating into the osteogenic lineage. Laser-induced jet formation and jet dynamics were explored using time-resolved imaging . Slow jets were unperturbed, with increased stability and retention of stem cells with very high viability and high resolution. Ultraviolet (UV) light used in traditional laser-assisted printing technology might be damaging to the cellular DNA. Lin et al.  reported a visible light-based projection STL system that successfully incorporated hASCs in hydrogel scaffolds.
As bioprinting technology has developed, single-cell deposition onto two-dimensional (2D) and into 3D environments has been used to explore cell behavior and monitor responses to growth, physical stimulation, cytokines and metabolite factors at the cellular level. A single-cell throughput system was also utilized to explore stem cell characteristics . Based on the microdroplet throughput, the authors isolated and patterned single cells from heterogeneous cell suspensions. The printed cells maintained high viability of greater than 95 %, and 11 stem cell markers (including Kit and Notch1) were collected and analyzed from the genomic information. In Ma et al.’s work , researchers utilized a laser-patterned method to control MSC alignment to create a parallel-aligned morphology and studied cardiogenic differentiation and contractile function. Single-cell arrays have been widely utilized in neural networks. Dinh et al.  constructed compartmentalized brain models with single-cell precision based on microfluidic methods.
Significant progress has been made in controlling printing conditions to ensure minimal damage to cells and adequately mimic the extracellular environment. However, to print tissue structures, different cell types must be placed in specific locations, and stem cell differentiation must be controlled to produce the desired cell types . Organ printing remains a long-term goal, and micro-organ printing has more potential in clinical applications. For example, islet cells with secretory capacity account for only 2 % of pancreas cells. Printing these functional cells and reintroducing them into patients may allow patients without a complete pancreas to continue producing insulin.
The extracellular microenvironment or niche provides various stimuli, such as physical, chemical and biological factors, to direct cell adhesion, proliferation and differentiation. Obvious effects on cell behavior have been confirmed by directly designing the surface morphology of scaffolds .
Biological molecules, including proteins and nucleic acids, have been successfully deposited with bioprinting technologies such as inkjet printing . An advantage of inkjet printing is the ability to control the concentration gradient of internal ingredients using different bioink densities .
Growth factors such as BMP2, epidermal growth factor (EGF) and fibroblast growth factor 2 (FGF-2) have also been measured by molecular patterning. To print 3D artificial tissues, studies of 2D molecular arrays may provide clues about the function of growth factors in their niche.
Advanced applications of bioprinted tissues and organs
Applications and directions of bioprinting organs
Bioprinted tissues and organs
3D printing technology
Optimizing vascular geometry and cell viability and function
Predicting flow rates, oxygen tension, and the diffusion of molecules in the vascular environment
Improving resolution for printing small vessels
Increasing available bioink materials
Increasing bioprinting speed
Printing valvular interstitial cells into scaffolds with high speed and good viability (~100 %) over 21 days
Printing hydrogel-based valve-shaped structures
Developing types of materials with good flexibility and elasticity
Printing scaffolds that provide a framework for cells to attach, proliferate and function and to be integrated with the surrounding tissue
Accurately controlling pore geometry, cell viability and mechanical properties
Investigating printed materials with osteoinductive or osteoconductive proteins
Triggering vascularization in the repaired region
Printing biological livers for liver transplantation in patients with liver resection
Constructing artificial liver tissue for the detection of drug toxicities and other medical and biological testing
Constructing 3D functional liver tissue with a substantial capillary-like network
Fabricating skin substitutes to repair skin wounds
Studying the pathophysiology of skin diseases
Fabricating more complex human skin models with secondary and adnexal structures
Improving LAB technology to achieve automation for bioprinting skin
Blood vessel and heart printing
As the mode of transport for nutrition and metabolic waste, functional blood vessels play important roles in cardiovascular diseases  and the construction of artificial organs, particularly these with a rich blood supply. Advances in developmental biology and iconography have enabled significant progress in printing vasculature in vitro. However, due to the unique functions and specific structures of the vasculature in different tissues, creating a vascular system remains a critical, unmet challenge.
Bioprinting enables the fabrication of network structures using hydrogels or other materials as bioink. Bertassoni et al.  successfully bioprinted a vascular network with GelMA, which improved metabolic transportation, cellular viability and the formation of endothelial monolayers. Kolesky et al.  successfully co-printed multiple materials with cells and vasculature using thermally reversible gelation to fabricate complex tissues.
In the printing of cardiac valves, tissue-engineered valve scaffolds are generally focused on the rebuilding of the aortic valve . Researchers have performed extensive studies of printing aortic valve structures with hydrogels [30, 31, 83]. Cell-laden, valve-shaped structures were printed with a high cell survival rate (greater than 90 %). However, bioink materials are deficient in flexibility and elasticity, and their mechanical characteristics still do not meet clinical needs.
Bone and cartilage tissue printing
Bone and cartilage regeneration is the most mature field utilizing printing technology because the composition of hard tissues is uncomplicated and is mainly composed of inorganic elements. A variety of biomaterials have been produced to construct bone and cartilage scaffolds by many manufacturing approaches, including gas foaming [84, 85], salt leaching [86, 87] and freeze drying [88, 89]. However, the structural and mechanical properties of artificial scaffolds can be more accurately controlled by 3D bioprinting than by other technologies.
A cement powder system was recently fabricated containing HA and TCP as the ideal composition for human bone replacement to repair large defects . The dimensional accuracy of the bioprinted scaffolds was greater than 96.5 %. In Gao’s work , hMSCs and nanoparticles of bioactive glass (BG) and HA were co-printed to control the spatial placement of cells. hMSCs encapsulated in this compound exhibited high cell viability (86.62 ± 6.02 %) and compressive modulus (358.91 ± 48.05 kPa) after 21 days in culture. In Park et al. work , HA and Col-1 hydrogels printed as tissue-mimetic structures were investigated independently to elucidate their effects on the behavior of chondrocytes and osteoblasts. Chondrocytes on HA hydrogels and osteoblasts on Col-1 hydrogels maintained better proliferative capacity and cell function than chondrocytes on Col-1 hydrogels and osteoblasts on HA hydrogels.
Bioprinting has been a popular technology for the creation of cartilage tissue engineering scaffolds from a variety of materials, ranging from ceramics to nanomaterials. Markstedt et al.  developed a printable bioink using a combination of nanofibrillated cellulose and alginate with human chondrocytes as living soft tissue. The mixture exhibited excellent shear-thinning behavior and cell viability of 86 % after 7 days of 3D culture. The high plasticity of the ink allowed shapes resembling cartilage tissues, such as an ear and a meniscus, to be printed successfully.
Although printable scaffolds have been extensively applied in bone and cartilage tissue engineering, bioinks with suitable physical properties are still needed.
Skin protects the body from attack by foreign substances and maintains the integrity of the body. Many chronic diseases and burn wounds cause irreversible damage to skin, and thus bioprinting technology is particularly critical in the preparation of skin substitutes for transplantation to repair damaged skin.
The LAB technique has been applied to the printing of bio-skin. Michael et al.  successfully created skin substitutes using LAB technology and transplanted them to skin wounds of nude mice. Eleven days later, the graft was able to adhere well to the tissue around the skin wound, and the cells in the graft were able to proliferate and differentiate. In 2014, Lee et al. used keratinocytes and fibroblasts as materials to bioprint skin tissue. The resulting skin tissue had representative morphology and biology. The skin bioprinted by 3D technology was able to maintain its shape and had high flexibility, reproducibility and culture throughput. In addition, cells that cause skin diseases can be added to the biomaterials, and skin tissue printed with pathogenic cells can be used to study the pathophysiology of skin diseases .
Liver tissue printing
Compared to other organs, the liver has strong regeneration ability. Patients who require liver transplantation can receive lobes of liver from a healthy donor  or can also wait for their own liver tissue to regenerate. However, healthy donors are in short supply, and the regeneration period for self-liver tissue is long. Therefore, bioprinting of liver tissue by tissue engineering is particularly important.
Many researchers have studied liver bioprinting. Primary hepatocytes and stem cell-derived hepatocytes have been used as the bioink to bioprint liver tissue . Although the cells lose a certain amount of activity and functionality in the printing process, liver tissue containing both cell types can be sustained for a period of time. In contrast to traditional printing technologies, 3D printing technology can provide the exact size and shape of the liver suitable for the needs of patients with liver resection . Recently, a new technique has been used to maintain cell activity and functionality for longer times . The technique utilizes bioprinting technology to form structures called “canaliculi” that are similar to the liver hepatic cord. The primary hepatocytes and the “canaliculus” structures are cultured together in the collagen matrix. Then, a biomimetic ECM system evaluates the activity and functionality of the primary hepatocytes on different ECM-based hydrogels . After the activity and functionality of the primary hepatocytes have been confirmed, the cells can be maintained for 4 weeks. Further increases in cellular activity would facilitate expanded applications of bioprinted liver tissue. Chang et al.  also demonstrated that multilayered tissues can be used as in vitro 3D liver models. This multilayered tissue contained rat and human hepatocytes, and the multilayered cellular architecture could be used as a liver analog to help detect drug toxicities and for other medical and biological testing. Thus, 3D bioprinted livers can be used not only for liver resection in patients and other liver surgeries but also for simulated liver experiments in vitro.
The use of biological printing for the liver would have profound impact. Although some achievements have been made, hurdles must still be overcome, including cost and time, and the mechanical properties of printed liver tissue must be highly consistent with that of the native liver.
Limitations of and future directions for bioprinting
Different types of 3D printing are utilized for applications that range from studies of cellular behavior to investigations of tissue pharmacodynamics or toxicological mechanisms. Although 3D printers have high precision and reproducibility, printing organs and functional tissues with entire structures still requires assembly layer-by-layer with “bio-glue.” The main technological barriers are suitable bioinks with good biocompatibility and mechanical strength that can be used to achieve biological function. Hydrogels and ceramics have been used for soft and hard tissue engineering, respectively [50, 55, 100]. Meanwhile, personalized 3D printing technology will lead to a series of regulatory hurdles referring to the specified printed product supervision. However, it is urgent for the management establishing and perfecting relevant laws and regulations to guarantee sustainable development of 3D printing technology. Studies in the near future will likely bring great progress in printing micro-organs, such as pancreas islet tissues that function in the absence of the complete pancreas structure, which will benefit hundreds of millions of diabetic patients around the globe. Chang  successfully fabricated micro-livers that were utilized for testing drug metabolism.
As printing technology develops, additional biomimetic, tissue engineered organs will be created. Decreases in reestablishment time and cost should also be addressed before bioprinting of organs can be applied in the clinic.
Bioprinting technology has drawn more and more attention as a fabrication methodology for producing scaffolds, cells, tissues and organs. It has advantages in precise control, repeatability and individual design, yet many challenges remains for building complex tissues including multiple cell types in a spatial structure. More importantly, bioink materials development, resolution enhancement and vascularization are necessary to apply bioprinting technology clinically.
computer-aided design/computer-aided manufacturing
Chinese hamster ovary
multipotent stromal cells
selective laser sintering
hydroxyapatite/poly (l-lactic acid)
human mesenchymal stem cells
embryonic stem cells
laser-induced forward transfer
epidermal growth factor
fibroblast growth factor 2
freeform reversible embedding of suspended hydrogels
JL and MC contributed to gathering the data relevant for this review. XF and HZ drafted and revised the manuscript. JL prepared the figures. MC participated in the design of tables. All authors read and approved the final manuscript.
The authors thank all those who participated in the revision of this review.
The authors declare that they have no competing interests.
Availability of data and materials
Data sharing not applicable to this article as no datasets were generated or analysed during the current study.
This work was sponsored by National High Technology Research and Development Program (863 Program) (2015AA020311); SJTU Medical & Engineering Cross Fund (YG2014MS03); Shanghai Science Committee Basic Research Leading Project (No. 13JC1403800).
Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
- Huang JMY, Millis JM. Government policy and organ transplantation in China. Lancet. 2008;372:1937–8.PubMedView ArticleGoogle Scholar
- Zhang Q, Johnson JA, Dunne LW, Chen Y, Iyyanki T, Wu Y, Chang EI, Branch-Brooks CD, Robb GL, Butler CE. Decellularized skin/adipose tissue flap matrix for engineering vascularized composite soft tissue flaps. Acta Biomater. 2016;35:166–84.PubMedView ArticleGoogle Scholar
- Futrega K, Palmer JS, Kinney M, Lott WB, Ungrin MD, Zandstra PW, Doran MR. The microwell-mesh: a novel device and protocol for the high throughput manufacturing of cartilage microtissues. Biomaterials. 2015;62:1–12.PubMedView ArticleGoogle Scholar
- Shamaz BH, Anitha A, Vijayamohan M, Kuttappan S, Nair S, Nair MB. Relevance of fiber integrated gelatin-nanohydroxyapatite composite scaffold for bone tissue regeneration. Nanotechnology. 2015;26:405101.PubMedView ArticleGoogle Scholar
- Lee CH, Lee FY, Tarafder S, Kao K, Jun Y, Yang G, Mao JJ. Harnessing endogenous stem/progenitor cells for tendon regeneration. J Clin Invest. 2015;125:2690–701.PubMedPubMed CentralView ArticleGoogle Scholar
- Thankam FG, Muthu J. Alginate-polyester comacromer based hydrogels as physiochemically and biologically favorable entities for cardiac tissue engineering. J Colloid Interface Sci. 2015;457:52–61.PubMedView ArticleGoogle Scholar
- Rouwkema J, Rivron NC, van Blitterswijk CA. Vascularization in tissue engineering. Trends Biotechnol. 2008;26:434–41.PubMedView ArticleGoogle Scholar
- Jones AC, Arns CH, Hutmacher DW, Milthorpe BK, Sheppard AP, Knackstedt MA. The correlation of pore morphology, interconnectivity and physical properties of 3D ceramic scaffolds with bone ingrowth. Biomaterials. 2009;30:1440–51.PubMedView ArticleGoogle Scholar
- Hollister SJ, Maddox RD, Taboas JM. Optimal design and fabrication of scaffolds to mimic tissue properties and satisfy biological constraints. Biomaterials. 2002;23:4095–103.PubMedView ArticleGoogle Scholar
- Lee J, Cuddihy MJ, Kotov NA. Three-dimensional cell culture matrices: state of the art. Tissue Eng Part B Rev. 2008;14:61–86.PubMedView ArticleGoogle Scholar
- Leong KF, Chua CK, Sudarmadji N, Yeong WY. Engineering functionally graded tissue engineering scaffolds. J Mech Behav Biomed Mater. 2008;1:140–52.PubMedView ArticleGoogle Scholar
- Zong X, Bien H, Chung CY, Yin L, Fang D, Hsiao BS, Chu B, Entcheva E. Electrospun fine-textured scaffolds for heart tissue constructs. Biomaterials. 2005;26:5330–8.PubMedView ArticleGoogle Scholar
- Moroni L, de Wijn JR, van Blitterswijk CA. 3D fiber-deposited scaffolds for tissue engineering: influence of pores geometry and architecture on dynamic mechanical properties. Biomaterials. 2006;27:974–85.PubMedView ArticleGoogle Scholar
- Derby B. Printing and prototyping of tissues and scaffolds. Science. 2012;338:921–6.PubMedView ArticleGoogle Scholar
- Powers MK, Lee BR, Silberstein J. Three-dimensional printing of surgical anatomy. Curr Opin Urol. 2016;26:283–8.PubMedView ArticleGoogle Scholar
- Cui X, Breitenkamp K, Lotz M, D’Lima D. Synergistic action of fibroblast growth factor-2 and transforming growth factor-beta1 enhances bioprinted human neocartilage formation. Biotechnol Bioeng. 2012;109:2357–68.PubMedPubMed CentralView ArticleGoogle Scholar
- Poldervaart MT, Wang H, van der Stok J, Weinans H, Leeuwenburgh SC, Oner FC, Dhert WJ, Alblas J. Sustained release of BMP-2 in bioprinted alginate for osteogenicity in mice and rats. PLoS ONE. 2013;8:e72610.PubMedPubMed CentralView ArticleGoogle Scholar
- Arslan-Yildiz A, Assal RE, Chen P, Guven S, Inci F, Demirci U. Towards artificial tissue models: past, present, and future of 3D bioprinting. Biofabrication. 2016;8:014103.PubMedView ArticleGoogle Scholar
- Lee SY, Kim HJ, Choi D. Cell sources, liver support systems and liver tissue engineering: alternatives to liver transplantation. Int J Stem Cells. 2015;8:36–47.PubMedPubMed CentralView ArticleGoogle Scholar
- Boland T, Xu T, Damon B, Cui X. Application of inkjet printing to tissue engineering. Biotechnol J. 2006;1:910–7.PubMedView ArticleGoogle Scholar
- Cui X, Dean D, Ruggeri ZM, Boland T. Cell damage evaluation of thermal inkjet printed Chinese hamster ovary cells. Biotechnol Bioeng. 2010;106:963–9.PubMedView ArticleGoogle Scholar
- Murphy SV, Atala A. 3D bioprinting of tissues and organs. Nat Biotechnol. 2014;32:773–85.PubMedView ArticleGoogle Scholar
- Cui X, Boland T, D’Lima DD, Lotz MK. Thermal inkjet printing in tissue engineering and regenerative medicine. Recent Pat Drug Deliv Formul. 2012;6:149–55.PubMedPubMed CentralView ArticleGoogle Scholar
- Jana S, Lerman A. Bioprinting a cardiac valve. Biotechnol Adv. 2015;33:1503–21.PubMedView ArticleGoogle Scholar
- Nakamura M, Kobayashi A, Takagi F, Watanabe A, Hiruma Y, Ohuchi K, Iwasaki Y, Horie M, Morita I, Takatani S. Biocompatible inkjet printing technique for designed seeding of individual living cells. Tissue Eng. 2005;11:1658–66.PubMedView ArticleGoogle Scholar
- Saunders RE, Gough JE, Derby B. Delivery of human fibroblast cells by piezoelectric drop-on-demand inkjet printing. Biomaterials. 2008;29:193–203.PubMedView ArticleGoogle Scholar
- Seetharam R, Sharma SK. Purification and analysis of recombinant proteins. Biotechnology and Bioprocessing, vol 12. CRC Press; 1991.
- Okamoto T, Suzuki T, Yamamoto N. Microarray fabrication with covalent attachment of DNA using bubble jet technology. Nat Biotechnol. 2000;18:438–41.PubMedView ArticleGoogle Scholar
- Xu T, Jin J, Gregory C, Hickman JJ, Boland T. Inkjet printing of viable mammalian cells. Biomaterials. 2005;26:93–9.PubMedView ArticleGoogle Scholar
- Duan B, Hockaday LA, Kang KH, Butcher JT. 3D bioprinting of heterogeneous aortic valve conduits with alginate/gelatin hydrogels. J Biomed Mater Res A. 2013;101:1255–64.PubMedView ArticleGoogle Scholar
- Hockaday LA, Kang KH, Colangelo NW, Cheung PY, Duan B, Malone E, Wu J, Girardi LN, Bonassar LJ, Lipson H, et al. Rapid 3D printing of anatomically accurate and mechanically heterogeneous aortic valve hydrogel scaffolds. Biofabrication. 2012;4:035005.PubMedPubMed CentralView ArticleGoogle Scholar
- Chia HN, Wu BM. Recent advances in 3D printing of biomaterials. J Biol Eng. 2015;9:4.PubMedPubMed CentralView ArticleGoogle Scholar
- Chien KB, Makridakis E, Shah RN. Three-dimensional printing of soy protein scaffolds for tissue regeneration. Tissue Eng Part C Methods. 2013;19:417–26.PubMedView ArticleGoogle Scholar
- Fedorovich NE, Schuurman W, Wijnberg HM, Prins HJ, van Weeren PR, Malda J, Alblas J, Dhert WJ. Biofabrication of osteochondral tissue equivalents by printing topologically defined, cell-laden hydrogel scaffolds. Tissue Eng Part C Methods. 2012;18:33–44.PubMedView ArticleGoogle Scholar
- Fedorovich NE, Wijnberg HM, Dhert WJ, Alblas J. Distinct tissue formation by heterogeneous printing of osteo- and endothelial progenitor cells. Tissue Eng Part A. 2011;17:2113–21.PubMedView ArticleGoogle Scholar
- Catros S, Fricain JC, Guillotin B, Pippenger B, Bareille R, Remy M, Lebraud E, Desbat B, Amedee J, Guillemot F. Laser-assisted bioprinting for creating on-demand patterns of human osteoprogenitor cells and nano-hydroxyapatite. Biofabrication. 2011;3:025001.PubMedView ArticleGoogle Scholar
- Trombetta R, Inzana J, Schwarz EM, Kates SL, Awad HA. 3D printing of calcium phosphate ceramics for bone tissue engineering and drug delivery. Ann Biomed Eng. 2016. doi:10.1007/s10439-016-1678-3.
- Guillemot F, Souquet A, Catros S, Guillotin B. Laser-assisted cell printing: principle, physical parameters versus cell fate and perspectives in tissue engineering. Nanomedicine. 2010;5:507–15.PubMedView ArticleGoogle Scholar
- Guillemot F, Souquet A, Catros S, Guillotin B, Lopez J, Faucon M. Highthroughput laser printing of cells and biomaterials for tissue engineering. Acta Biomater. 2010;6:2494–500.PubMedView ArticleGoogle Scholar
- Barron JA, Wu P, Ladouceur HD, Ringeisen BR. Biological laser printing: a novel technique for creating heterogeneous 3-dimensional cell patterns. Biomed Microdevices. 2004;6:139–47.PubMedView ArticleGoogle Scholar
- Ringeisen BR, Kim H, Barron JA, Krizman DB, Chrisey DB, Jackman S, Auyeung RY, Spargo BJ. Laser printing of pluripotent embryonal carcinoma cells. Tissue Eng. 2004;10:483–91.PubMedView ArticleGoogle Scholar
- Michael S, Sorg H, Peck CT, Koch L, Deiwick A, Chichkov B, Vogt PM, Reimers K. Tissue engineered skin substitutes created by laser-assisted bioprinting form skin-like structures in the dorsal skin fold chamber in mice. PLoS ONE. 2013;8:e57741.PubMedPubMed CentralView ArticleGoogle Scholar
- Serra P, Duocastella M, Fernández-Pradas JM, Morenza JL. Liquids microprinting through laser-induced forward transfer. Appl Surf Sci. 2009;255:5342–5.View ArticleGoogle Scholar
- Patrascioiu A, Fernández-Pradas JM, Palla-Papavlu A, Morenza JL, Serra P. Laser-generated liquid microjets: correlation between bubble dynamics and liquid ejection. Microfluidics Nanofluidics. 2014;16:55–63.View ArticleGoogle Scholar
- Ali M, Pages E, Ducom A, Fontaine A, Guillemot F. Controlling laser-induced jet formation for bioprinting mesenchymal stem cells with high viability and high resolution. Biofabrication. 2014;6:045001.PubMedView ArticleGoogle Scholar
- Melchels FP, Feijen J, Grijpma DW. A review on stereolithography and its applications in biomedical engineering. Biomaterials. 2010;31:6121–30.PubMedView ArticleGoogle Scholar
- Wang Z, Abdulla R, Parker B, Samanipour R, Ghosh S, Kim K. A simple and high-resolution stereolithography-based 3D bioprinting system using visible light crosslinkable bioinks. Biofabrication. 2015;7:045009.PubMedView ArticleGoogle Scholar
- Khatiwala C, Law R, Shepherd B, Dorfman S, Csete M. 3D cell bioprinting for regenerative medicine research and therapies. Gene Ther. 2012;7:1–19.Google Scholar
- Tasoglu S, Demirci U. Bioprinting for stem cell research. Trends Biotechnol. 2013;31:10–9.PubMedView ArticleGoogle Scholar
- Nicodemus GD, Bryant SJ. Cell encapsulation in biodegradable hydrogels for tissue engineering applications. Tissue Eng Part B Rev. 2008;14:149–65.PubMedPubMed CentralView ArticleGoogle Scholar
- Wust S, Godla ME, Muller R, Hofmann S. Tunable hydrogel composite with two-step processing in combination with innovative hardware upgrade for cell-based three-dimensional bioprinting. Acta Biomater. 2014;10:630–40.PubMedView ArticleGoogle Scholar
- Matsiko A, Gleeson JP, O’Brien FJ. Scaffold mean pore size influences mesenchymal stem cell chondrogenic differentiation and matrix deposition. Tissue Eng Part A. 2015;21:486–97.PubMedView ArticleGoogle Scholar
- Domingos M, Intranuovo F, Russo T, De Santis R, Gloria A, Ambrosio L, Ciurana J, Bartolo P. The first systematic analysis of 3D rapid prototyped poly(epsilon-caprolactone) scaffolds manufactured through BioCell printing: the effect of pore size and geometry on compressive mechanical behaviour and in vitro hMSC viability. Biofabrication. 2013;5:045004.PubMedView ArticleGoogle Scholar
- Lou T, Wang X, Song G, Gu Z, Yang Z. Structure and properties of PLLA/beta-TCP nanocomposite scaffolds for bone tissue engineering. J Mater Sci Mater Med. 2015;26:5366.PubMedView ArticleGoogle Scholar
- Nadeem D, Smith CA, Dalby MJ, Meek RM, Lin S, Li G, Su B. Three-dimensional CaP/gelatin lattice scaffolds with integrated osteoinductive surface topographies for bone tissue engineering. Biofabrication. 2015;7:015005.PubMedView ArticleGoogle Scholar
- Yao Q, Wei B, Guo Y, Jin C, Du X, Yan C, Yan J, Hu W, Xu Y, Zhou Z, et al. Design, construction and mechanical testing of digital 3D anatomical data-based PCL-HA bone tissue engineering scaffold. J Mater Sci Mater Med. 2015;26:5360.PubMedView ArticleGoogle Scholar
- Leonardi E, Ciapetti G, Baldini N, Novajra G, Verne E, Baino F, Vitale-Brovarone C. Response of human bone marrow stromal cells to a resorbable P(2)O(5)-SiO(2)-CaO-MgO-Na(2)O-K(2)O phosphate glass ceramic for tissue engineering applications. Acta Biomater. 2010;6:598–606.PubMedView ArticleGoogle Scholar
- Jose RR, Rodriguez MJ, Dixon TA, Omenetto F, Kaplan DL. Evolution of Bioinks and Additive Manufacturing Technologies for 3D Bioprinting. ACS Biomater Sci Eng 2016. doi:10.1021/acsbiomaterials.6b00088.
- Hinton TJ, Jallerat Q, Palchesko RN, Park JH, Grodzicki MS, Shue HJ, Ramadan MH, Hudson AR, Feinberg AW. Three-dimensional printing of complex biological structures by freeform reversible embedding of suspended hydrogels. Sci Adv. 2015;1:e1500758.PubMedPubMed CentralView ArticleGoogle Scholar
- Duffy RMSY, Feinberg AW. Understanding the role of ECM protein composition and geometric micropatterning for engineering human skeletal muscle. Ann Biomed Eng. 2016;44:2076–89.PubMedView ArticleGoogle Scholar
- Guvendiren M, Molde J, Soares RMD, Kohn J. Designing biomaterials for 3D printing. ACS Biomater Sci Eng; 2016. doi:10.1021/acsbiomaterials.6b00121.
- Bertassoni LE, Cardoso JC, Manoharan V, Cristino AL, Bhise NS, Araujo WA, Zorlutuna P, Vrana NE, Ghaemmaghami AM, Dokmeci MR, Khademhosseini A. Direct-write bioprinting of cell-laden methacrylated gelatin hydrogels. Biofabrication. 2014;6:024105.PubMedPubMed CentralView ArticleGoogle Scholar
- Neufurth M, Wang X, Schroder HC, Feng Q, Diehl-Seifert B, Ziebart T, Steffen R, Wang S, Muller WE. Engineering a morphogenetically active hydrogel for bioprinting of bioartificial tissue derived from human osteoblast-like SaOS-2 cells. Biomaterials. 2014;35:8810–9.PubMedView ArticleGoogle Scholar
- Lorber B, Hsiao WK, Hutchings IM, Martin KR. Adult rat retinal ganglion cells and glia can be printed by piezoelectric inkjet printing. Biofabrication. 2014;6:015001.PubMedView ArticleGoogle Scholar
- Levato R, Visser J, Planell JA, Engel E, Malda J, Mateos-Timoneda MA. Biofabrication of tissue constructs by 3D bioprinting of cell-laden microcarriers. Biofabrication. 2014;6:035020.PubMedView ArticleGoogle Scholar
- Duarte Campos DF, Blaeser A, Weber M, Jakel J, Neuss S, Jahnen-Dechent W, Fischer H. Three-dimensional printing of stem cell-laden hydrogels submerged in a hydrophobic high-density fluid. Biofabrication. 2013;5:015003.PubMedView ArticleGoogle Scholar
- Gruene M, Deiwick A, Koch L, Schlie S, Unger C, Hofmann N, Bernemann I, Glasmacher B, Chichkov B. Laser printing of stem cells for biofabrication of scaffold-free autologous grafts. Tissue Eng Part C Methods. 2011;17:79–87.PubMedView ArticleGoogle Scholar
- Lin H, Zhang D, Alexander PG, Yang G, Tan J, Cheng AW, Tuan RS. Application of visible light-based projection stereolithography for live cell-scaffold fabrication with designed architecture. Biomaterials. 2013;34:331–9.PubMedView ArticleGoogle Scholar
- Moon S, Kim Y-G, Dong L, Lombardi M, Haeggstrom E, Jensen RV, Hsiao L-L, Demirci U. Drop-on-demand single cell isolation and total RNA analysis. PLoS ONE. 2011;6:e17455.PubMedPubMed CentralView ArticleGoogle Scholar
- Ma Z, Liu Q, Yang H, Runyan RB, Eisenberg CA, Xu M, Borg TK, Markwald R, Wang Y, Gao BZ. Laser patterning for the study of MSC cardiogenic differentiation at the single-cell level. Light Sci Appl. 2013;2:e68.View ArticleGoogle Scholar
- Dinh ND, Chiang YY, Hardelauf H, Baumann J, Jackson E, Waide S, Sisnaiske J, Frimat JP, van Thriel C, Janasek D, et al. Microfluidic construction of minimalistic neuronal co-cultures. Lab Chip. 2013;13:1402–12.PubMedView ArticleGoogle Scholar
- Roth EA, Xu T, Das M, Gregory C, Hickman JJ, Boland T. Inkjet printing for high-throughput cell patterning. Biomaterials. 2004;25:3707–15.PubMedView ArticleGoogle Scholar
- Campbell PG, Miller ED, Fisher GW, Walker LM, Weiss LE. Engineered spatial patterns of FGF-2 immobilized on fibrin direct cell organization. Biomaterials. 2005;26:6762–70.PubMedView ArticleGoogle Scholar
- Skardal A, Zhang J, Prestwich GD. Bioprinting vessel-like constructs using hyaluronan hydrogels crosslinked with tetrahedral polyethylene glycol tetracrylates. Biomaterials. 2010;31:6173–81.PubMedView ArticleGoogle Scholar
- Beyersdorf F. Three-dimensional bioprinting: new horizon for cardiac surgery. Eur J Cardiothorac Surg. 2014;46:339–41.PubMedView ArticleGoogle Scholar
- Sawkins MJ, Mistry P, Brown BN, Shakesheff KM, Bonassar LJ, Yang J. Cell and protein compatible 3D bioprinting of mechanically strong constructs for bone repair. Biofabrication. 2015;7:035004.PubMedView ArticleGoogle Scholar
- Markstedt K, Mantas A, Tournier I, Martinez Avila H, Hagg D, Gatenholm P. 3D bioprinting human chondrocytes with nanocellulose-alginate bioink for cartilage tissue engineering applications. Biomacromolecules. 2015;16:1489–96.PubMedView ArticleGoogle Scholar
- Bernhard JC, Isotani S, Matsugasumi T, Duddalwar V, Hung AJ, Suer E, Baco E, Satkunasivam R, Djaladat H, Metcalfe C, et al. Personalized 3D printed model of kidney and tumor anatomy: a useful tool for patient education. World J Urol. 2016;34:337–45.PubMedView ArticleGoogle Scholar
- Skardal A, Mack D, Kapetanovic E, Atala A, Jackson JD, Yoo J, Soker S. Bioprinted amniotic fluid-derived stem cells accelerate healing of large skin wounds. Stem Cells Transl Med. 2012;1:792–802.PubMedPubMed CentralView ArticleGoogle Scholar
- Go AS, Mozaffarian D, Roger VL, Benjamin EJ, Berry JD, Borden WB, Bravata DM, Dai S, Ford ES, Fox CS, Franco S, Fullerton HJ, Gillespie C, Hailpern SM, Heit JA, Howard VJ, Huffman MD, Kissela BM, Kittner SJ, Lackland DT, Lichtman JH, Lisabeth LD, Magid D, Marcus GM, Marelli A, Matchar DB, McGuire DK, Mohler ER, Moy CS, Mussolino ME, Nichol G, Paynter NP, Schreiner PJ, Sorlie PD, Stein J, Turan TN, Virani SS, Wong ND, Woo D, Turner MB, American Heart Association Statistics Committee and Stroke Statistics Subcommittee. Heart disease and stroke statistics—2013 update: a report from the American Heart Association. Circulation. 2012;127:e6–245. doi:10.1161/CIR.0b013e31828124ad.
- Bertassoni LE, Cecconi M, Manoharan V, Nikkhah M, Hjortnaes J, Cristino AL, Barabaschi G, Demarchi D, Dokmeci MR, Yang Y, Khademhosseini A. Hydrogel bioprinted microchannel networks for vascularization of tissue engineering constructs. Lab Chip. 2014;14:2202–11.PubMedPubMed CentralView ArticleGoogle Scholar
- Kolesky DB, Truby RL, Gladman AS, Busbee TA, Homan KA, Lewis JA. 3D bioprinting of vascularized, heterogeneous cell-laden tissue constructs. Adv Mater. 2014;26:3124–30.PubMedView ArticleGoogle Scholar
- Duan B, Kapetanovic E, Hockaday LA, Butcher JT. Three-dimensional printed trileaflet valve conduits using biological hydrogels and human valve interstitial cells. Acta Biomater. 2014;10:1836–46.PubMedView ArticleGoogle Scholar
- Chen W, Zhou H, Tang M, Weir MD, Bao C, Xu HH. Gas-foaming calcium phosphate cement scaffold encapsulating human umbilical cord stem cells. Tissue Eng Part A. 2012;18:816–27.PubMedView ArticleGoogle Scholar
- Thein-Han W, Xu HH. Prevascularization of a gas-foaming macroporous calcium phosphate cement scaffold via coculture of human umbilical vein endothelial cells and osteoblasts. Tissue Eng Part A. 2013;19:1675–85.PubMedPubMed CentralView ArticleGoogle Scholar
- Kim TG, Chung HJ, Park TG. Macroporous and nanofibrous hyaluronic acid/collagen hybrid scaffold fabricated by concurrent electrospinning and deposition/leaching of salt particles. Acta Biomater. 2008;4:1611–9.PubMedView ArticleGoogle Scholar
- Mehrabanian M, Nasr-Esfahani M. HA/nylon 6,6 porous scaffolds fabricated by salt-leaching/solvent casting technique: effect of nano-sized filler content on scaffold properties. Int J Nanomedicine. 2011;6:1651–9.PubMedPubMed CentralGoogle Scholar
- Gercek I, Tigli RS, Gumusderelioglu M. A novel scaffold based on formation and agglomeration of PCL microbeads by freeze-drying. J Biomed Mater Res A. 2008;86:1012–22.PubMedView ArticleGoogle Scholar
- Alizadeh M, Abbasi F, Khoshfetrat AB, Ghaleh H. Microstructure and characteristic properties of gelatin/chitosan scaffold prepared by a combined freeze-drying/leaching method. Mater Sci Eng C Mater Biol Appl. 2013;33:3958–67.PubMedView ArticleGoogle Scholar
- Castilho M, Moseke C, Ewald A, Gbureck U, Groll J, Pires I, Tessmar J, Vorndran E. Direct 3D powder printing of biphasic calcium phosphate scaffolds for substitution of complex bone defects. Biofabrication. 2014;6:015006.PubMedView ArticleGoogle Scholar
- Gao G, Schilling AF, Yonezawa T, Wang J, Dai G, Cui X. Bioactive nanoparticles stimulate bone tissue formation in bioprinted three-dimensional scaffold and human mesenchymal stem cells. Biotechnol J. 2014;9:1304–11.PubMedView ArticleGoogle Scholar
- Park JY, Choi JC, Shim JH, Lee JS, Park H, Kim SW, Doh J, Cho DW. A comparative study on collagen type I and hyaluronic acid dependent cell behavior for osteochondral tissue bioprinting. Biofabrication. 2014;6:035004.PubMedView ArticleGoogle Scholar
- Lee V, Singh G, Trasatti JP, Bjornsson C, Xu X, Tran TN, Yoo SS, Dai G, Karande P. Design and fabrication of human skin by three-dimensional bioprinting. Tissue Eng Part C Methods. 2014;20:473–84.PubMedView ArticleGoogle Scholar
- Zein NN, Hanouneh IA, Bishop PD, Samaan M, Eghtesad B, Quintini C, Miller C, Yerian L, Klatte R. Three-dimensional print of a liver for preoperative planning in living donor liver transplantation. Liver Transpl. 2013;19:1304–10.PubMedView ArticleGoogle Scholar
- Bale SS, Vernetti L, Senutovitch N, Jindal R, Hegde M, Gough A, McCarty WJ, Bakan A, Bhushan A, Shun TY, et al. In vitro platforms for evaluating liver toxicity. Exp Biol Med. 2014;239:1180–91.View ArticleGoogle Scholar
- Ikegami T, Maehara Y. Transplantation: 3D printing of the liver in living donor liver transplantation. Nat Rev Gastroenterol Hepatol. 2013;10:697–8.PubMedView ArticleGoogle Scholar
- Nakao Y, Kimura H, Sakai Y, Fujii T. Bile canaliculi formation by aligning rat primary hepatocytes in a microfluidic device. Biomicrofluidics. 2011;5:22212.PubMedView ArticleGoogle Scholar
- Skardal A, Smith L, Bharadwaj S, Atala A, Soker S, Zhang Y. Tissue specific synthetic ECM hydrogels for 3D in vitro maintenance of hepatocyte function. Biomaterials. 2012;33:4565–75.PubMedPubMed CentralView ArticleGoogle Scholar
- Chang R, Emami K, Wu H, Sun W. Biofabrication of a three-dimensional liver micro-organ as an in vitro drug metabolism model. Biofabrication. 2010;2:045004.PubMedView ArticleGoogle Scholar
- Zhu MZJ. Three-dimensional printing of cerium-incorporated mesoporous calcium-silicate scaffolds for bone repair. J Mater Sci. 2016;51:836–44.View ArticleGoogle Scholar
- Chang RC, Emami K, Jeevarajan A, Wu H, Sun W. Microprinting of liver micro-organ for drug metabolism study. Methods Mol Biol. 2011;671:219–38.PubMedView ArticleGoogle Scholar
- Chien KB, Aguado BA, Bryce PJ, Shah RN. In vivo acute and humoral response to three-dimensional porous soy protein scaffolds. Acta Biomater. 2013;9:8983–90.PubMedView ArticleGoogle Scholar
- Haberstroh K, Ritter K, Kuschnierz J, Bormann KH, Kaps C, Carvalho C, Mulhaupt R, Sittinger M, Gellrich NC. Bone repair by cell-seeded 3D-bioplotted composite scaffolds made of collagen treated tricalciumphosphate or tricalciumphosphate-chitosan-collagen hydrogel or PLGA in ovine critical-sized calvarial defects. J Biomed Mater Res B Appl Biomater. 2010;93:520–30.PubMedView ArticleGoogle Scholar
- Lim TC, Chian KS, Leong KF. Cryogenic prototyping of chitosan scaffolds with controlled micro and macro architecture and their effect on in vivo neo-vascularization and cellular infiltration. J Biomed Mater Res A. 2010;94:1303–11.PubMedGoogle Scholar
- Fielding GA, Bandyopadhyay A, Bose S. Effects of silica and zinc oxide doping on mechanical and biological properties of 3D printed tricalcium phosphate tissue engineering scaffolds. Dent Mater. 2012;28:113–22.PubMedView ArticleGoogle Scholar
- Gao L, Li C, Chen F, Liu C. Fabrication and characterization of toughness-enhanced scaffolds comprising beta-TCP/POC using the freeform fabrication system with micro-droplet jetting. Biomed Mater. 2015;10:035009.PubMedView ArticleGoogle Scholar
- Chang CH, Lin CY, Liu FH, Chen MH, Lin CP, Ho HN, Liao YS. 3D printing bioceramic porous scaffolds with good mechanical property and cell affinity. PLoS ONE. 2015;10:e0143713.PubMedPubMed CentralView ArticleGoogle Scholar
- Tarafder S, Dernell WS, Bandyopadhyay A, Bose S. SrO- and MgO-doped microwave sintered 3D printed tricalcium phosphate scaffolds: mechanical properties and in vivo osteogenesis in a rabbit model. J Biomed Mater Res B Appl Biomater. 2015;103:679–90.PubMedView ArticleGoogle Scholar
- Cox SC, Thornby JA, Gibbons GJ, Williams MA, Mallick KK. 3D printing of porous hydroxyapatite scaffolds intended for use in bone tissue engineering applications. Mater Sci Eng C Mater Biol Appl. 2015;47:237–47.PubMedView ArticleGoogle Scholar
- Luo Y, Zhai D, Huan Z, Zhu H, Xia L, Chang J, Wu C. Three-dimensional printing of hollow-struts-packed bioceramic scaffolds for bone regeneration. ACS Appl Mater Interfaces. 2015;7:24377–83.PubMedView ArticleGoogle Scholar
- Paulsen SJ, Miller JS. Tissue vascularization through 3D printing: will technology bring us flow? Dev Dyn. 2015;244:629–40.PubMedView ArticleGoogle Scholar
- Bose SVS, Bandyopadhyay A. Bone tissue engineering using 3D printing. Mater Today. 2013;16:496–504.View ArticleGoogle Scholar
- Xia Y, Zhou P, Cheng X, Xie Y, Liang C, Li C, Xu S. Selective laser sintering fabrication of nano-hydroxyapatite/poly-epsilon-caprolactone scaffolds for bone tissue engineering applications. Int J Nanomedicine. 2013;8:4197–213.PubMedPubMed CentralGoogle Scholar
- Lee JW, Choi YJ, Yong WJ, Pati F, Shim JH, Kang KS, Kang IH, Park J, Cho DW. Development of a 3D cell printed construct considering angiogenesis for liver tissue engineering. Biofabrication. 2016;8:015007.PubMedView ArticleGoogle Scholar