Preparation of Biocompatible Near-Infrared Fluorescent Nanoparticles for Cellular Imaging.

Abstract

This study presents a novel and simple method to prepare a new biocompatible near-infrared (NIR) IR-780 nanoparticles (NPs) by modifying a bio-inspired silification approach. The solubility of as-prepared IR-780 NPs was greatly increased and the fluorescence intensity was dramatically enhanced by 5–7 fold compared to free IR-780 dye. Also, an exceptionally small size of 28 nm and the colloidal stability of the IR-780 NPs were sufficient to realize the desired permeability and retention effect (EPR). Furthermore, the in vitro cell viability assays indicated that the IR-780 NPs were highly safe even at the highest concentration of 1.0 mg/mL. The in vitro studies using MDA-231 breast cancer cells showed that the IR-780 NPs were successfully uptaken by the cancer cells and located at the cytoplasm of the cells. The results suggest that the IR-780 NPs may be a promising fluorescence imaging agent for clinical application.