Tissue responses to thermally-responsive hydrogel nanoparticles.

Thermally-responsive hydrogel nanoparticles of poly(N-isopropylacrylamide) (PNIPAM) and hydroxypropyl cellulose (HPC) have been synthesized. The particle size has been correlated to surfactant concentration and polymer concentration using dynamic laser light scattering techniques. The tissue compatibility of these hydrogel nanoparticles has been evaluated by comparing with poly-L-lactic acid and polystyrene nanoparticles using a mouse implantation model. Our results suggested that both PNIPAM and HPC nanoparticles triggered lesser inflammatory and fibrotic responses among all nanoparticles tested. It is likely that these hydrogel nanoparticles may be suitable for tissue augmentation or drug-delivery devices.