Lysozyme-encapsulated gold nanoclusters for ultrasensitive detection of folic acid and in vivo imaging.

ABSTRACT

Herein, lysozyme-encapsulated gold nanoclusters (AuNCs@Lzm, AuL) were favorably obtained by a simple and economical synthesis. The resulting AuL exhibits low toxicity, exceptional stability and intense red fluorescence at 650 nm, which can enter living cells and is mainly located in lysosomes. The AuL selectively and sensitively drove to detect folic acid (FA) with a detection limit as low as 0.19 nM based on the combination of the static quenching and the internal filtering effect. Interestingly, the fascinating results discovered that the AuL with ignorable toxicity was adsorbed from the intestine into the liver, and essentially was cleared from the body in 6 days without significant bioaccumulation in zebrafish. Furthermore, the hyaluronic acid (HA) coating AuLH exhibits remarkably targeted tumors towards MCF-7>HeLa > HepG2¼NIH/3T3≈DC, which attributed to the number of receptors expressed by the cells. All these advantages highlight that the AuL is a versatile nanoplatform for sensing, in vivo fluorescence imaging and tumor targeting.