Mechanical and Electronic Cell-Chip Interaction of APTES-Functionalized Neuroelectronic Interfaces

Area of Science:

• Neuroscience
• Materials Science
• Biomedical Engineering

Background:

• Neuroelectronic interfaces are crucial for neural recording and stimulation.
• Self-assembled monolayers (SAMs) are used to modify surface properties.
• (3-aminopropyl)triethoxysilane (APTES) is a common SAM for surface functionalization.

Purpose of the Study:

• To investigate the impact of APTES SAM coating on neuroelectronic interface properties.
• To elucidate the mechanisms behind enhanced signal transfer in APTES-coated interfaces.
• To assess the effects of APTES coating on cell viability and mechanical coupling.

Main Methods:

• Coating platinum electrodes with APTES SAMs.
• Electrochemical impedance spectroscopy to measure interface properties.
• Microscopy to observe cell morphology and development on coated substrates.
• Analysis of cell-substrate mechanical coupling.

Main Results:

• APTES SAMs slightly reduced electrode-electrolyte interface impedance (approx. 13%).
• APTES coating significantly enhanced mechanical clamping of cells to the substrate.
• Stronger mechanical coupling correlated with improved signal transfer, likely due to reduced signal loss.
• Enhanced cell adhesion led to decreased cell viability after 9 days in vitro (DIV 9).

Conclusions:

• The primary driver for large signal transfer in APTES-coated interfaces is enhanced mechanical coupling, not just reduced impedance.
• The positively charged amino group in APTES SAMs facilitates tighter cell-substrate interaction.
• The short lifetime of cells on rigid APTES-coated substrates highlights a trade-off between signal enhancement and cell health.
• Future strategies should explore soft substrates or alternative molecular coatings to improve long-term cell viability.