NIR-Cleavable and pH-Responsive Polymeric Yolk–Shell Nanoparticles for Controlled Drug Release

Abstract

Responsive drug release and low toxicity of drug carriers are important for designing controlled release systems. Here, a double functional diffractive o-nitrobenzyl, containing multiple electron-donating groups as a crosslinker and methacrylic acid (MAA) as a monomer, was used to decorate upconversion nanoparticles (UCNPs) to produce robust poly o-nitrobenzyl@UCNP nanocapsules using the distillation-precipitation polymerization and templating method. Poly o-nitrobenzyl@UCNP nanocapsules with a robust yolk–shell structure exhibited near-infrared (NIR) light-/pH-responsive properties. When the nanocapsules were exposed to 980 nm NIR irradiation, the loaded drug was efficiently released by altering the shell of the nanocapsules. The photodegradation kinetics of the poly o-nitrobenzyl@UCNP nanocapsules were studied. The anticancer drug, doxorubicin hydrochloride (DOX), was loaded at pH 8.0 with a loading efficiency of 13.2 wt %. The Baker–Lonsdale model was used to determine the diffusion coefficients under different release conditions to facilitate the design of dual-responsive drug release devices or systems. Additionally, cytotoxicity studies showed that the drug release of DOX could be efficiently triggered by NIR to kill cancer cells in a controlled manner.

A Facile Synthetic Approach to UV-Degradable Hydrogels

“…Numerous studies have shown that the degradation of hydrogels is mainly dependent on the light cleavage groups on the gel polymer chain segments. One of the most common light-cleavable groups is o -nitrobenzyl ester [ 19 , 20 , 21 , 22 , 23 , 24 ], which can absorb UV light energy and use it for the internal chemical reaction to break the chemical bond. The incorporation of light cleavable groups brings a variety of changes to the properties of hydrogels, yet it also imparts certain complexities to their synthesis.…”