Single-Cell Response to the Rigidity of Semiconductor Nanomembranes on Compliant Substrates

Area of Science:

• Biomedical engineering
• Materials science
• Cell biology

Background:

• Single-crystalline semiconductor nanomembranes (NMs) on compliant substrates are vital for biomedical applications.
• Understanding cellular responses to the mechanical properties of these substrates is crucial but limited.

Purpose of the Study:

• To investigate how NIH-3T3 fibroblast cells sense and respond to varying thicknesses of silicon nanomembranes (Si NMs) on polydimethylsiloxane (PDMS) substrates.
• To elucidate the relationship between NM thickness, cellular behavior, and mechanical substrate properties.

Main Methods:

• Performed proliferation assays, cytoskeleton analysis, and focal adhesion (FA) studies on cells cultured on 20 nm and 220 nm Si/PDMS substrates.
• Utilized bulk silicon as a reference and employed a shear-lag mechanical model for analysis.

Main Results:

• NM thickness significantly impacts cell proliferation, cytoskeleton organization, cell spreading, and FA formation.
• Cells on 220 nm Si/PDMS exhibited responses similar to bulk silicon (well-spread, organized cytoskeleton, and FAs).
• Cells on 20 nm Si/PDMS showed spherical morphology with negligible cytoskeleton organization and FAs.

Conclusions:

• Cellular sensing of mechanical properties is thickness-dependent for Si NMs on PDMS.
• Findings highlight the critical role of NM thickness in dictating cell-substrate interactions, informing the design of flexible electronics for biomedical use.