pH sensitive release of doxorubicin anticancer drug from gold nanocomposite hydrogel based on poly(acrylic acid) grafted onto salep biopolymer

In this manuscript, synthesis, characterization, swelling behavior, and drug delivery performance of a gold nanocomposite hydrogel (GNH) based on poly(acrylic acid) grafted onto salep, as a biocompatible polymer, are described. Gold nanoparticles (AuNPs) as nanometer base, ammonium persulfate as an initiator, N,N-methylenebisacrylamide as a crosslinker, and acrylic acid as pH sensitive monomer were employed for the preparation of entitled GNH in aqueous solution and their amounts were optimized to reach the highest water absorbance. The synthesized GNHs were fully characterized by using FTIR spectroscopy, thermogravimetric analysis, EDAX spectrum, SEM, TEM, and AFM images, and a mechanism for superabsorbent hydrogel nanocomposite formation was suggested. Swelling kinetics in double-distilled water and the absorbency were also investigated. Furthermore, the on–off switching behaviors of the nanocomposite at different pHs were investigated. Doxorubicin hydrochloride is a chemotherapeutic drug and a hydrophilic molecule, with nitrogen and oxygen in its chemical structure. Because nitrogen and oxygen can bind to gold surfaces with high affinity, most frequently nitrogen- and oxygen-modified ligands are used as stabilizing agents, which interact with the surface of the AuNPs by formation of Au–nitrogen and Au–oxygen bonds. This Au nanoparticle–drug conjugate can be incorporated into the bio-based hydrogel matrices to make a hydrogel nanocomposite system. The pH response of this GNH makes it suitable for acting as a controlled drug delivery system. Furthermore, the role of AuNPs in effective release of doxorubicin is discussed by comparing the release in hydrogel and nanocomposite systems.