A novel magnetic bead bioassay platform using a microchip-based sensor for infectious disease diagnosis

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Immunodiagnostics

Background:

• Current laboratory tests often lack the speed and portability required for point-of-care (POC) settings.
• Enzymatic labels in traditional immunoassays like ELISA can be complex and costly.
• There is a significant need for advanced diagnostic technologies for rapid disease detection at the POC.

Purpose of the Study:

• To develop and validate a novel biosensor for detecting micron-scale paramagnetic beads as a replacement for enzymatic labels.
• To leverage complementary metal oxide semiconductor (CMOS) technology for integrated, low-cost diagnostic systems.
• To demonstrate the efficacy of the biosensor in quantifying magnetic beads via immunological recognition for clinical applications.

Main Methods:

• Fabrication of a novel biosensor using standard CMOS manufacturing processes.
• Quantification of magnetic beads bound to the sensor surface through specific antibody-antigen interactions.
• Validation of the biosensor using purified mouse IgG and human anti-dengue virus IgG in clinical serum samples.
• Demonstration of magnetic field application for controlled removal of non-specifically bound beads.

Main Results:

• The biosensor demonstrated sensitivity comparable to ELISA for purified protein detection.
• A high correlation was observed between ELISA optical density and biosensor output in clinical assays.
• Effective removal of non-specifically bound magnetic beads was achieved using a controlled magnetic field, simplifying the washing step.
• The sensor platform shows potential for mass production at a low cost.

Conclusions:

• The developed CMOS biosensor offers a promising alternative to conventional ELISA labels using magnetic beads.
• This technology facilitates the development of inexpensive, compact, and sophisticated diagnostic systems for various diseases.
• The biosensor platform is suitable for simplified, rapid, and accurate point-of-care diagnostic tests.