Characterizing physical properties and in vivo OCT imaging study of Cu-Sn-S nanocrystals

Highly yield Cu2SnS3 nanocrystals (CTS NCs) have been attracted more attentions in these years, the CTS NCs with strong absorption in near-infrared (NIR) region which can serve as the contrast agent of Optical Coherence Tomography (OCT) imaging. These NCs can be synthesized by facile method, and exhibit a Localized Surface Plasmon Resonance (LSPR) peak in NIR region. The LSPR peak position of the CTS NCs depends on the ratio of copper to tin in the synthesis process. The highest intensity of LSPR at 1380nm when Cu:Sn ratio reach to 9:1. The TEM analysis and X-ray diffraction pattern reveals the formation of CTS NCs with an average size of 6nm and the structure is kesterite crystal phase. In order to apply the NCs in vivo and in vitro study, we used PEGylated phospholipid (DSPE-PEG) to modified NCs, and the colloidal stability and cell viability of DSPE-PEG CTS NCs are very suitable for the in vivo OCT imaging study. To quantitatively analyze the contrast effect of DSPE-PEG CTS NCs, the contrast agent was injected from the tail vein of ICR mice, then applied the SD-OCT system monitor the vein of the mouse pinna for 30 minutes. The results indicated that the DSPE-PEG CTS NCs created an obvious signal in the OCT imaging process, which provide the basis for the application of CTS NCs as the contrast agent for the bioimaging study