Synthesis and Characterization of Gelatin/Poly N-Isopropylacryl Amide Nanocomposite Hydrogels by Response Surface Methodology

In this study, after producing Poly N-isopropylacryl amide (PNIPAAm) nanoparticles by a novel method including a combination of the UV photopolymerization technique and the liposomal nanoreactors approach, which resulted in homogenous, nanosized PNIPAAm nanoparticles, gelatin/PNIPAAm hydrogels were prepared. An investigation of the effect of monomer, crosslinking agent, and nanoparticle concentrations to gelatin weight percent on the morphology, size, structure, phase transition temperature, swelling, and biodegradability of the nanocomposite hydrogels were carried out. The response surface method (RSM) was used to develop models for predicting and optimizing the hydrogels. Fourier-transform infrared spectroscopy (FTIR) spectra of the monomer, polymers, and nanocomposites indicated the incorporation of the poly N-isopropylacrylamid (PNIPAAm) nanoparticles and gelatin in the structure. Based on scanning electron microscope (SEM) images and dynamic light scattering (DLS) results, the size of the nanoparticles was 250-300 nm which were dispersed well in the gelatin hydrogel. In addition, the nanocomposites showed 80-110% swelling in water, a phase transition temperature (LCST) around 32.5 degrees C and a biodegradation capability under physiological conditions.