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Development of Microelectrode Arrays Using Electroless Plating for CMOS-Based Direct Counting of Bacterial and HeLa
IEEE Transactions on Biomedical Circuits and Systems
|November 13, 2015
Summary
Researchers developed novel electroless plated microelectrode arrays for high-sensitivity direct bacteria and cell counting. This advancement enables smaller electrodes and faster circuits for improved pathogen detection.
Area of Science:
- Biomedical Engineering
- Microfabrication
- Biosensing Technology
Background:
- Direct pathogen counting requires microelectrodes sized for target cells and high-sensitivity amperometry circuits.
- Existing microelectrode fabrication methods face limitations in achieving bacteria-sized dimensions.
- High-speed, low-noise amperometry circuits are crucial for accurate measurements with small electrodes.
Purpose of the Study:
- To develop novel, high-density, electroless plated microelectrode arrays for CMOS-based direct bacteria and HeLa cell counting.
- To address the challenges of fabricating bacteria-sized microelectrodes and developing sensitive, high-speed amperometry circuits.
Main Methods:
- Improved self-aligned electroless plating technique to reduce microelectrode dimensions to 1.2 μm × 2.05 μm.
- Fabrication of test chips using a 0.6-μm CMOS process with varying sensor array sizes (1024x1024, 4x4, 16x16).
- Integration of a current buffer in the amperometry circuit to mitigate potential fluctuation and enhance sensitivity.
- Development and verification of trench structures on microelectrodes for improved sensitivity.
Main Results:
- Successfully reduced microelectrode dimensions to 1.2 μm × 2.05 μm, significantly smaller than previously reported.
- Optically verified uniformity of 1024 × 1024 electrodes with a pitch of 3.6 μm × 4.45 μm.
- Demonstrated higher sensitivity using trench structures compared to conventional microelectrodes.
- Successfully performed direct counting of bacteria-sized microbeads and HeLa cells using cyclic voltammetry (CV) measurements.
Conclusions:
- The developed electroless plated microelectrode arrays are suitable for high-sensitivity, direct bacteria and cell counting.
- The novel fabrication technique and circuit design overcome key limitations in current biosensing technologies.
- This technology holds promise for advanced pathogen detection and cell analysis applications.
