Preparation of Microgels with Ultra-High Payload of Various Hydrophilic and Hydrophobic Inorganic Nanoparticle Composites Up to 92 wt.

Microgels loading with inorganic nanoparticle composites fascinate interests for various biomedical applications. However, the encapsulation of NPs into microgels usually is diffusion process driven by osmotic pressure, which is highly depended on the concentration of NPs and cause low loading efficiency. In this work, we demonstrate preparation of microgels with ultra-high content of various nano-objects (up to 92%, wt%) by a gelatin "casting" strategy using porous CaCO3 particles as templates. This approach could encapsulate various nanoparticles with different charged, hydrophilic and hydrophobic surface, shape and size within microgels, without causing aggregation or change of physicochemical properties of NPs. The hybrid microgels coupled with properties of both inorganic nanoparticles and hydrogels can be taken as an effective photothermal therapy system with great stability, reusability and degradability, and show high effective photothermal activity which is highly related to the content of nanoparticles within microgels. The strategy of fabrication of microgels with nanocomposites is certified to be simple, facile and low-cost, which has potential applications in cancer therapy, drug delivery, catalysis, detecting system and sewage treatment.