Fig. 1
Analysis of Assay Upper and Lower Limits of Detection Using VSVG Vector. Serial dilutions of an empty VSVG viral vector were analyzed using ddPCR and the upper limit of assay was determined to be 1 × 104 copies per microliter and the lower limit was 0.13 copies per microliter. a The vector concentrations are indicated on the X-axis and ranged from \(1\) to \(1 \times 10^{4}\) copies per microliter. The measured vector copy number is shown on the Y- axis. The number of copies input for each resulting observation is shown on the X-axis. Axes are in log–log scale. The line of best fit displayed is a log–log line with a slope of 1.083, a y-intercept of − 1.381 and an R2 value of 0.9907. For inputs of \(1 \times 10^{5}\) copies per microliter or higher, the Quantasoft software failed to return a measured value. b The vector concentrations are indicated on the X-axis and ranged from \(0.13\) to \(5 \times 10^{4}\) copies per microliter. The measured vector copy number is shown on the Y- axis. The number of copies input for each resulting observation is shown on the X-axis. Axes are in log–log scale. The line of best fit displayed is a log–log line with a slope of 1.038, a y-intercept of − 0.4816 and an R2 value of 0.9994