A Handheld High-Sensitivity Micro-NMR CMOS Platform With B-Field Stabilization for Multi-Type Biological/Chemical Assays

Abstract

We report a micro-Nuclear Magnetic Resonance (NMR) system compatible with multi-type biological/chemical lab-on-a-chip assays. Unified in a handheld scale (dimension: 14 x 6 x 11 cm 3 , weight: 1.4 kg), the system is capable to detect < 100 pM of Enterococcus faecalis derived DNA from a 2.5-μL sample. The key components are a portable magnet (0.46 T, 1.25 kg) for nucleus magnetization, a system PCB for I/O interface, an FPGA for system control, a current driver for trimming the magnetic (B) field, and a silicon chip fabricated in 0.18-μm CMOS. The latter, integrated with a current-mode vertical Hall sensor and a low-noise readout circuit, facilitates closed-loop B-field stabilization (2 mT  0.15 mT), which otherwise fluctuates with temperature or sample displacement. Together with a dynamic-B-field transceiver with a planar coil for micro-NMR assay and thermal control, the system demonstrates: 1) selective biological target pinpointing; 2) protein state analysis and 3) solvent-polymer dynamics, suitable for healthcare, food and colloidal applications, respectively.Compared to a commercial NMR-assay product , this platform greatly reduces the sample consumption (120x), hardware volume (175x) and weight (96x). Index TermsBaseband, biological, biosensor, chemical, CMOS, deoxyribonucleic acid (DNA), filter, Hall sensor, immunoglobulin, lab-on-a-chip, low-noise amplifier (LNA), magnetic sensing, nuclear magnetic resonance (NMR), point-of-care, polymer, power amplifier (PA), protein, radio frequency (RF), receiver (RX), transceiver (TRX), transimpedance amplifier (TIA), transmitter (TX).J S S C -M a n u s c r i p t 2 | P a g e

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