Effects of PDMS curing ratio and 3D micro-pyramid structure on the formation of an in vitro neural network

An in vitro neural network can provide a model to investigate the signaling processes that regulate the body functions. Using polydimethylsiloxane (PDMS) multilayer micro-structures to construct a neural network, the bonding between the layers can be improved by modulation of the curing ratio. In this study, we found that as the curing ratio increased from 10:1 to 10:4, the contact angle decreased from 111.69° to 102.08° and the surface energy and roughness increased. For adhesion and proliferation, the hippocampal primary neural cells preferred a PDMS surface with a 10:1 curing ratio to other surfaces. In addition, 3D PDMS micro-pyramid array allows the primary hippocampal neuron to pattern a network without any surface treatment and the network was verified by immunocytochemistry. These results may suggest the optimum PDMS curing ratio to apply in constructing a cell device for in vitro neural network formation as well as the potential of 3D structure fabrication which allows us to construct neural network without any surface treatment.