Real-time, multiplexed electrochemical DNA detection using an active complementary metal-oxide-semiconductor...

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Analytical Chemistry

Background:

• Optical biosensing using fluorescence is standard for DNA microarrays but requires bulky equipment.
• Electrochemical detection offers a path to portable, point-of-care devices.
• Multiplexed electrochemical detection needs active substrates and integrated electronics for efficiency and signal integrity.

Purpose of the Study:

• To develop an active electrochemical biosensor array using CMOS technology for on-chip DNA hybridization detection.
• To enable quantitative analysis of DNA targets labeled with ferrocene redox labels.
• To demonstrate a portable alternative to traditional fluorescence-based microarrays.

Main Methods:

• Fabrication of a 4x4 array of gold working electrodes on a custom CMOS chip (5 mm x 3 mm).
• Integration of potentiostat electronics, including control amplifiers and analog-to-digital converters.
• Utilizing cyclic voltammetry to drive redox reactions, sense DNA binding, and transmit digital data.

Main Results:

• Demonstrated multiplexed and specific detection of DNA targets.
• Achieved real-time monitoring of DNA hybridization events.
• Successfully transmitted digital data off-chip for analysis, showcasing on-chip quantification.

Conclusions:

• The developed CMOS-based electrochemical biosensor array enables on-chip, quantitative DNA hybridization detection.
• This technology facilitates the design of portable biosensing devices for point-of-care applications.
• Offers advantages over fluorescence methods, including real-time monitoring and reduced system complexity.