Functional Behavior of the Primary Cortical Neuronal Cells on the Large Surface of TiO₂ and SnO₂ Based Biosensing Device

In this study, we report the fabrication of poly-L-lysine (PLL) coated large surface TiO
₂
and SnO
₂
based biosensing devices to analyze the influence of the functional behaviour of primary cortical neuronal cells. Through frequency-dependent impedance study, we observed an increase in the impedance values initially most likely due to cell adhesion, proliferation and differentiation processes leading to an increase in both the single-cell mass as well as overall cellular mass; however, it got decreased eventually with the progression of various other cellular functions including neural activity, synapse formation and neuron-neuron communication. Typically, formation and regulation of the neuronal junction i.e., synapses noticeably affected the functional behaviour of the fabricated biosensing device by increasing the neuronal communication and thereby improving the flow of current by altering the thin film resistance and capacitance. Further, the neuro-electrical phenomenon is validated by fitting the experimental impedance data to an equivalent electrical circuit model. A significant shift in the Nyquist plot was also observed visually, which indicates that this alternation is primarily due to change in characteristic behaviour of the fabricated biosensing device. Hence, we anticipate that the fabricated PLL coated large surface TiO
₂
and SnO
₂
based biosensing device can serve as a promising tool to monitor the influence of the functional behaviour of neuronal cells.