High-Density Redox Amplified Coulostatic Discharge-Based Biosensor Array.

Area of Science:

• Biomedical Engineering
• Electrical Engineering
• Materials Science

Background:

• High-density biosensor arrays are crucial for advanced biomedical applications like point-of-care disease screening.
• Conventional electrochemical biosensing methods struggle with miniaturization due to complex, sensitive readout circuits required for sub-pA current measurements.
• Scaling down readout circuits for high-density arrays remains a significant challenge in current biosensor technology.

Purpose of the Study:

• To develop a high-density 4,096-pixel electrochemical biosensor array integrated into a 180 nm CMOS chip.
• To overcome the limitations of existing readout circuits for miniaturization and complexity in high-density biosensing.
• To demonstrate the array's capability for detecting specific biomarkers in complex biological samples.

Main Methods:

• Implementation of a 4,096-pixel electrochemical biosensor array using 180 nm CMOS technology.
• Utilization of a coulostatic discharge sensing technique combined with interdigitated electrode geometry.
• Integration of a 13 aA low-leakage readout circuit directly beneath each interdigitated microelectrode (biopixel).

Main Results:

• Achieved a high sensor density comparable to state-of-the-art arrays without complex sensor post-processing.
• Interdigitated electrodes demonstrated a maximum amplification factor of 10.5× via redox cycling compared to planar electrodes.
• Successfully detected anti-Rubella and anti-Mumps antibodies in human serum samples.

Conclusions:

• The developed 4,096-pixel CMOS biosensor array offers a scalable solution for high-density electrochemical sensing.
• The coulostatic discharge technique and interdigitated electrodes effectively reduce readout circuit complexity and size.
• This technology holds promise for advanced point-of-care diagnostics and multiplexed disease screening.