Point of Care Biosensor Platform for the Quantitation of Magnetic Lateral Flow Assays

Point-of-Care (POC) diagnostic is currently the most accessible form of medical diagnosis because it is affordable, sensitive, specific, user-friendly, rapid/robust, equipment-free/minimal, and distributable to those in need. In this work, we investigate a new induction-based transducer designed around a lateral flow assay that is low cost, portable and enhances the sensitivity of the test by 100 times.
The biosensor is comprising of a pair of single wound pickup coils wrapped around an LFIA test strip. A pair of the excitation coil, wrapped around the pickup coils, is used to excite magnetic particles that are immuno-trapped at the test line. This generates a voltage signal across the pickup coil pair that is proportional to the difference in the number of magnetic particles trapped in the test line and the reference. We have developed analytical models and performed simulations to optimize the sensitivity of the chip and manufactured a working prototype for under $3 with sensitivity equal to $50,000 AGFM setup.
The femtoMag chip was driven at 10 MHz and 0.1 mA. A series of pregnancy test strips with various concentration of hCG pregnancy hormone is read. The reader generates a 4 μV signal for 0.01 ng/mL of hCG where the test line is not visible beyond 2 ng/mL.