Temperature and pH Dual-Responsive Supramolecular Polymer Hydrogels Hybridized with Functional Inorganic Nanoparticles

Supramolecular hydrogels composed of poly(ethylene glycol) (PEG) containing polymer and -cyclodextrins (-CDs) show great potential in drug delivery. Herein, PEGylated magnetic nanoparticles (MNPs) and gold nanoparticles (AuNPs) of approximate to 10 nm are synthesized in the presence of poly(poly(ethylene glycol) methyl ether acrylate) (PPEGMA) grafted poly(acrylic acid) copolymers (PPEGMA-co-PAA, P1) and PPEGMA grafted poly(2-(dimethylamino)ethyl methacrylate) copolymers (PPEGMA-co-PDMAEMA, P2), respectively. The produced PEGylated NPs are hybridized into supramolecular hydrogels by mixing them with -CDs through inclusion complexation between PEG branches and -CDs. As a result, supramolecular hydrogels hybridized with inorganic MNPs and AuNPs are prepared and characterized by rheological measurements, X-ray diffraction, and scanning electron microscopy. Both MNP and AuNP hybrid hydrogels show reversible sol-gel transition, which is stimulated by changes in temperature and pH. The nanoparticles hybridized in the hydrogels can be released gradually in the process of hydrogel disruption. These hydrogels may have potential applications in biomaterials and drug delivery.