Fig. 3: Soft PDMS surfaces as substrates for neuronal cell growth.

Neuronal cells were plated on soft PDMS surfaces and followed over time. At fixed times, growth was stopped, cells immobilized and examined by fluorescence microscopy. Image shows how cell number and layout is affected by substrate elasticity: cell-growth is hampered on substrates with larger values of elasticity (\(1.88{MPa}\), rigth) compared to substrates with smaller ones (0.55 MPa, left) (a). The number of neuronal cells \(N\) measured on substrates \(24\,h\) from incubation illustrates that \(N\) shows a nearly inverse relationship with \(E\) in the \(0.55-2.65{MPa}\) interval (b). The negative correlation between N and E is exhibited for all considered times of incubation – 24 (c) \(48\) (d) 72 (e) and 96 h (f). Diagrams illustrate how the number of cells varies as a function of substrate elasticity (time) for all the times of the analysis (substrate elasticity) (g, h). Data in Fig. 3b–f are represented by mean ± standard deviation (sample size\(\sim\)50 for each data point). Data in Fig. 3g, h are quantitatively described by a whisker box plot, where the lower and upper boundary corresponds to the 25% and 75% quartiles of the distribution, while the central band marks the median value (sample size\(\sim\)50 for each data point).