Substrate Stiffness Modulates Cell-Network Topology in Human-Derived Neurons

Area of Science:

• Biomedical Engineering
• Neuroscience
• Materials Science

Background:

• Substrate properties critically influence neuronal cell behavior.
• Polydimethylsiloxane (PDMS) is widely used in neural tissue engineering scaffolds.
• Understanding mechanical cues is vital for optimizing neural cultures.

Purpose of the Study:

• To investigate the effect of substrate stiffness on human induced pluripotent stem cell (hiPSC)-derived neuronal cultures.
• To analyze neuronal adhesion, outgrowth, and network connectivity on soft versus stiff PDMS.
• To determine the role of mechanical compliance in neuronal development.

Main Methods:

• Culturing hiPSC-derived neurons on soft (∼12 kPa) and stiff (∼1.5 MPa) PDMS substrates.
• Utilizing confocal imaging to assess Neural Cell Adhesion Molecule (NCAM) expression.
• Employing network topology analysis to evaluate neuronal connectivity metrics.

Main Results:

• Higher NCAM expression and enhanced neuronal adhesion/outgrowth were observed on soft PDMS at 10 days in vitro (DIV).
• Soft PDMS substrates facilitated increased neuronal clustering and reduced path length.
• Network topology analysis revealed higher small-worldness on soft PDMS, indicating more efficient neural network connectivity.

Conclusions:

• Substrate compliance is a crucial factor in promoting neuronal development and network formation.
• Soft PDMS scaffolds offer superior support for hiPSC-derived neuronal cultures compared to stiff ones.
• These findings provide essential insights for designing advanced scaffolds in neural engineering applications.