中央研究院 原子與分子科學研究所

The negatively charged nitrogen-vacancy (NV^–) center in fluorescent nanodiamond (FND) is a point defect with unique magneto-optical properties.  It emits far-red fluorescence at ~700 nm and its intensity can be magnetically modulated with a depth of more than 10% at a field strength of 30 mT.  We have closely examined this property and illustrated its practical use in biomedicine by applying a periodic, time-varying magnetic field to FNDs deposited on surface or dispersed in solution with a lock-in detection method.  We achieved selective and sensitive detection of 100-nm FNDs on nitrocellulose membrane at a particle density of 0.04 ng/mm² (or ~2 × 10⁴ particles/mm²) and in aqueous solution with a particle concentration of 1 ng/mL (or ~1 fM) in 10 s as the detection limits.  The utility and versatility of the technique were demonstrated with an application to background-free detection of FNDs as reporters for FND-based lateral flow immunoassays as well as selective quantification of FNDs in tissue digests for in vivo studies.

link: 相關連結