Design Considerations for CMOS-Integrated Hall-Effect Magnetic Bead Detectors for Biosensor Applications

Area of Science:

• Micro/Nano-fabrication
• Biosensors
• Magnetic Nanoparticles

Background:

• Magnetic bead labels are widely used in biological assays.
• Existing detection methods face limitations in speed and accuracy.
• On-chip integration offers potential for miniaturization and improved performance.

Purpose of the Study:

• To develop a design methodology for on-chip magnetic bead label detectors.
• To quantify and mitigate signal errors in magnetic bead detection.
• To create a high-performance detection platform for magnetic bead-based assays.

Main Methods:

• Design of an 8192-element Hall sensor array using a commercial 0.18 μm CMOS process.
• Quantification and adjustment of signal errors related to label binding and detection area.
• Single-mask postprocessing for fabrication.

Main Results:

• Demonstration of the design methodology with a functional Hall sensor array.
• Accurate quantification of 1% surface coverage of 2.8 μm magnetic beads in 30 seconds.
• Achieved a coefficient of variation of 7.4%.

Conclusions:

• The developed methodology enables accurate and rapid detection of magnetic bead labels.
• The Hall sensor array is a suitable platform for sensitive biological assays.
• This technology advances on-chip detection capabilities for bioassays.