Fabrication and Characterization of Quantum Dots-Bound Hydrogels with Fluorescent and Temperature-Sensitive Functionalities

Abstract

In this work, dual-functional composite particles possessing fluorescence and temperature-sensitive functionalities were developed in the form of QD-bound hydrogels for biomedical applications. First, the surface of silica nanoparticles (SNPs) was functionalized with olefin silanes, followed by hydrogel encapsulation through a radical polymerization. The encapsulated hydrogels were poly(N-isopropylacrylamide-co-acrylic acid) P(NIPAM-co-AAc) copolymer, showing the sensitive volume changes corresponding to the alternating temperature changes between 25 degrees C and 45 degrees C. At an optimal pH5, the hydrogel-encapsulated SNPs (SiO2@hydrogel) were effectively anchored by amino quantum dots (amino-QDs) through electrostatic (attractive) interactions between carboxylate groups of hydrogels and amine groups of QDs. QD-bound hydrogels with co-monomer ratio of [NIPAM:AAc = 83: 17 wt%] exhibited the higher PL intensity than other samples with [NIPAM: AAc = 96: 4 wt% or 91: 9 wt%], indicating that higher fraction of carboxylate groups by AAc induced the effective bounding with QDs possessing positively charged amine groups.