Figure 2. Membrane capacitance of HG21-cultured hESC and physical properties of HG21.

(a) Gelcode blue staining of 1-D polyacrylamide gel electrophoresis of proteins incorporated and retained in HG21 after incubation with mTeSR1 at 37 °C, followed by washing with PBS at 37 and 15 °C. Seven bands, ranging in size from ~17–188 kDa, were apparent under both conditions but less abundant in the latter. (b) Quantification of mean stained protein band intensity (±s.d; n=4) normalized to background confirmed significant reduction in the retention of most bands (2–7) in HG21 upon temperature reduction (Student’s t-test, ***P<0.001; **P<0.01). (c) Long-term culture on HG21 does not significantly alter cell membrane biophysical properties from those observed for cells cultured on Matrigel (MG). Distribution and average cell membrane capacitance values for RH1 populations on HG21 and MG, as measured by dielectrophoresis. No significant difference was observed between cells grown on MG versus HG21 after 20 passages (two-tailed t-test, null hypothesis; P=0.8338). (d) Change in relative thickness of HG21 as a function of temperature in response to actual (2 and 4 kPa) and extrapolated (0 kPa) compressive forces, confirming swelling of HG21 at lower temperatures. NS, not significant.