Fully Integrated Pneumatic-Free and Magnet-Free CMOS Ferrofluidic Platform for Comprehensive Biomolecular Processing

Area of Science:

• Microfluidics and Nanotechnology
• Integrated Circuits (IC) Design
• Biomedical Engineering

Background:

• Traditional microfluidic platforms often rely on bulky external equipment like pneumatic pumps.
• There is a need for integrated, miniaturized solutions for complex biomolecular assays.
• Ferrofluidic manipulation offers precise droplet control without external pumps.

Purpose of the Study:

• To develop a fully integrated CMOS ferrofluidic platform with on-chip electrochemical sensing and temperature regulation.
• To demonstrate the manipulation of ferrofluidic droplets using on-chip magnetic fields generated by spiral inductors.
• To validate the platform's capability for biomolecular processing, such as real-time recombinase polymerase amplification (RT-RPA).

Main Methods:

• Implementation of a 45-nm CMOS Silicon-On-Insulator (SOI) process for the ferrofluidic platform.
• Integration of 25 ferrofluidic pixels, each with spiral inductors, electrochemical cells, temperature sensors, and Joule heaters.
• Utilizing on-chip spiral inductors for both ferrofluidic droplet manipulation and heat dissipation.
• Characterization of the on-chip electrochemical potentiostat and magnetic sensors through theoretical analysis and experimental measurements.

Main Results:

• Successful demonstration of ferrofluidic droplet manipulation using on-chip magnetic fields.
• Accurate characterization of the integrated electrochemical sensor with varying methylene blue concentrations.
• Proof-of-concept biological measurements using on-chip real-time recombinase polymerase amplification (RT-RPA).
• Validation of the platform's ability to perform integrated sensing, manipulation, and temperature regulation.

Conclusions:

• The developed CMOS ferrofluidic platform provides a fully integrated solution for biomolecular processing, eliminating the need for external equipment.
• The platform's multi-functional array design offers versatility for processing various molecular analytes, supporting advanced molecular diagnostics and bioanalytical research.
• This miniaturized, integrated approach has significant potential for point-of-care diagnostics and lab-on-a-chip applications.