Magnetic nanoparticles (MNPs) are widely used in biomedical and clinical applications, including medical imaging, therapeutics, and biological sample processing. Rapid characterization of MNPs, notably their magnetic moments, should facilitate optimization of particle synthesis and accelerate assay development. Here, we report a compact and low-cost magnetometer for fast, on-site MNP characterization. Termed integrated microHall magnetometer (iHM), our device was fabricated using standard semiconductor processes: an array of Hall sensors, transistor switches, and amplifiers were integrated into a single chip, thus improving the detection sensitivity and facilitating chip operation. By applying the iHM, we demonstrate versatile magnetic assays. We measured the magnetic susceptibility and moments of MNPs using small sample amounts (∼10 pL), identified different MNP compositions in mixtures, and detected MNP-labeled single cells.
Bibliographical noteFunding Information:
The authors were supported in part by NIH grants R21-CA205322 (H. L.), R01-HL113156 (H. L.), R01-CA204019 (R. W.), R01-EB010011 (R. W.), R01-EB00462605A1 (R. W.), P01-CA069246 (R. W.); Liz Tilberis Award – Ovarian Cancer Research Fund (C. M. C); the Department of Defense OCRP Award W81XWH-14-1-0279 (H. L., C. M. C); Lotte Foundation (C. M.); MGH scholar fund (H. L.); the Institute for Basic Science (IBS-R026-D1; J. C., H. L.); and the Korea Healthcare Technology R&D Project, Ministry for Health & Welfare Affairs (HI08C2149; J. C.). The authors thank Dr. S. Jeong for helping in device fabrication and H. Kim for helping with MNP preparation.
© 2017 The Royal Society of Chemistry.
All Science Journal Classification (ASJC) codes
- Biomedical Engineering