Fabrication of Hollow poly acrylic acid Nano gels via Emulsion polymerization as a Model for loading of Drugs

Nanogels are nano-sized hydrogel networks formed by chemically or physically crosslinkedpolymer particles. Their colloidal stability affords them as good candidates for drug delivery systems.Like nanoparticles, nanogels are injectable and responsive to environmental factors, such pH, andtemperature. This work presents a facile and large-scale fabrication of poly(acrylic acid) (PAA) hollownanogels via in situ Pickering miniemulsion polymerization method. Cross-linked polyacrylonitrile (PAN)nanoparticles with hollow structure were prepared by using hydrophobic solvent as liquid core. Thecomplete hydrolysis reaction process of PAN shell leads to the successful formation of hollow PAAnanogels. The properties of PAA nanogel were characterized by FT-IR, Scanning electron microscopeand Dynamic light scattering. It is found that the nanogels have a hollow core-porous shell structure.Protein, bovine serum albumin (BSA) was used as model drugs to investigate their loading abilitiesas versatile drug-delivery vehicles. The nanogel exhibits high loading ability to protein. The maximumBSA loading capacity of PAA nanogel can reach at pH=5. This high loading capacity may be related tothe hollow core-porous shell structure of PAA nanogels. Considering the high stability of the materials,simple and mild preparation procedure, high loading capacity, and ability to protect biological agentsfrom denaturation, PAA nanogels should be promising drug-delivery carriers for drug-delivery systems.