A handheld magnetic sensing platform for antigen and nucleic acid detection.
The core requirements for point-of-care (POC) diagnostics necessitate low-cost, portability, easily integrated sample preparation, and quick measurement time. Frequency-shift based magnetic sensing is a measurement technique utilizing a complementary metal-oxide-semiconductor (CMOS) integrated-circuit (IC) chip for magnetic label detection. The sensing scheme leverages the low-cost manufacturing of IC chips while demonstrating the potential for multiplexing capabilities. In this article, we present modifications to this scheme for POC viability. We introduce a handheld reusable reader and a disposable open-well cartridge for the detection of nucleic acids and antigens. The diagnostic system utilizes a novel "magnetic freezing" technique to reduce measurement time, obviates baseline measurement before or during biological assay, and reduces sensor noise. We utilize these enhancements for the room temperature, amplification-free detection of a 31 base-pair DNA oligomer and the interferon-γ (IFN-γ) protein. We have demonstrated reliable measurements down to 100 pM for the DNA assay and 1 pM for the protein.
Department of Electrical Engineering, California Institute of Technology, Pasadena, California 91125, USA. hajimiri@caltech.edu.
Alex
A
Pai
Aroutin
A
Khachaturian
Stephen
S
Chapman
Alexander
A
Hu
Hua
H
Wang
Ali
A
Hajimiri
D015374:Biosensing Techniques / Q000191:economics / Q000295:instrumentation*; D004247:DNA / Q000032:analysis*; D004867:Equipment Design; D007118:Immunoassay / Q000191:economics / Q000295:instrumentation; D007371:Interferon-gamma / Q000032:analysis*; D057230:Limit of Detection; D060328:Magnetic Phenomena; D019095:Point-of-Care Systems / Q000191:economics; D012666:Semiconductors / Q000191:economics
D007371:Interferon-gamma; D004247:DNA