Optical Properties of Doxorubicin Hydrochloride Load and Release on Silica Nanoparticle Platform

Silica nanoparticles (SiO(2) NPs) synthesized by the Stober method were used as drug delivery vehicles. Doxorubicin hydrochloride (DOX·HCl) is a chemo-drug absorbed onto the SiO(2) NPs surfaces. The DOX·HCl loading onto and release from the SiO(2) NPs was monitored via UV-VIS and fluorescence spectra. Alternatively, the zeta potential was also used to monitor and evaluate the DOX·HCl loading process. The results showed that nearly 98% of DOX·HCl was effectively loaded onto the SiO(2) NPs’ surfaces by electrostatic interaction. The pH-dependence of the process wherein DOX·HCl release out of DOX·HCl-SiO(2) NPs was investigated as well. For comparison, both the free DOX·HCl molecules and DOX·HCl-SiO(2) NPs were used as the labels for cultured cancer cells. Confocal laser scanning microscopy images showed that the DOX·HCl-SiO(2) NPs were better delivered to cancer cells which are more acidic than healthy cells. We propose that engineered DOX·HCl-SiO(2) systems are good candidates for drug delivery and clinical applications.