Send to

Choose Destination
ACS Nano. 2015 Mar 24;9(3):3184-91. doi: 10.1021/acsnano.5b00240. Epub 2015 Mar 9.

One-step detection of pathogens and viruses: combining magnetic relaxation switching and magnetic separation.

Author information

†Beijing Engineering Research Center for BioNanotechnology and CAS Key Laboratory for Biological Effects of Nanomaterials and Nanosafety, National Center for NanoScience and Technology, Beijing, 100190, China.
§Beijing Institute for Tropical Medicine, Beijing Friendship Hospital, Capital Medical University, 95 Yongan Road, Xicheng District, Beijing, 100050, China.


We report a sensing methodology that combines magnetic separation (MS) and magnetic relaxation switching (MS-MRS) for one-step detection of bacteria and viruses with high sensitivity and reproducibility. We first employ a magnetic field of 0.01 T to separate the magnetic beads of large size (250 nm in diameter) from those of small size (30 nm in diameter) and use the transverse relaxation time (T2) of the water molecules around the 30 nm magnetic beads (MB30) as the signal readout of the immunoassay. An MS-MRS sensor integrates target enrichment, extraction, and detection into one step, and the entire immunoassay can be completed within 30 min. Compared with a traditional MRS sensor, an MS-MRS sensor shows enhanced sensitivity, better reproducibility, and convenient operation, thus providing a promising platform for point-of-care testing.


homogeneous immunosensor; magnetic bead; magnetic relaxation switch; magnetic separation; one-step detection

[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for American Chemical Society
Loading ...
Support Center