Neuronal cell biocompatibility and adhesion to modified CMOS electrodes

Area of Science:

• Materials Science
• Biomedical Engineering
• Neuroscience

Background:

• Complementary Metal Oxide Semiconductor (CMOS) integrated circuits offer advantages for biosensors and neural implants.
• Unmodified aluminum CMOS electrodes can corrode in physiological environments, limiting their use.
• Developing robust and biocompatible electrode interfaces is critical for neural interfacing.

Purpose of the Study:

• To investigate a low-cost nanoporous alumina electrode modification for CMOS circuits.
• To assess the biocompatibility and cell adhesion properties of nanoporous alumina with neuronal cells.
• To determine the effect of pore pitch on cell adhesion and potential for electrical coupling.

Main Methods:

• Fabrication of nanoporous alumina electrodes by modifying CMOS metallization.
• Culturing NG108-15 mouse neuroblastoma x rat glioma hybrid cells on alumina substrates.
• Utilizing a novel cell detachment centrifugation assay to quantify long-term cell adhesion.
• Comparing cell vitality and adhesion on alumina with varying pore pitches (17 nm, 69 nm, 206 nm) against unmodified aluminum.

Main Results:

• Porous alumina is biocompatible with NG108-15 cells, showing no adverse effects on cell vitality.
• The inter-pore distance (pore pitch) did not influence cell vitality.
• Porous alumina substrates with a large pore pitch (206 nm) significantly enhanced long-term cell adhesion compared to unmodified aluminum.
• Smaller pore pitches (17 nm and 69 nm) resulted in less favorable surfaces for cell adhesion.

Conclusions:

• Nanoporous alumina is a promising, biocompatible material for CMOS-based neural electrode interfaces.
• Optimizing pore pitch is essential for achieving robust cell adhesion and tight junctions, critical for effective electrical coupling.
• The 206 nm pore pitch demonstrates superior performance for neuronal cell adhesion, suggesting its potential for advanced biosensor and implant applications.