In Vitro Biocompatibility Analysis of Temperature-Responsive Hydrogel Nanocomposites

Hydrogels are hydrophilic crosslinked polymer networks that are able to absorb up to a thousand times their dry weight in water while still maintaining their form. Depending on the type of monomer and/or crosslinker present in a hydrogel system, it may be responsive to external stimuli such as pH, temperature, or osmotic potential. A newly explored area of polymers is that of hydrogel nanocomposites which are hydrogels that incorporate nanoparticulate materials into their matrix. This can give hydrogels improved properties such as increased strength due to the addition of nanoparticulate material or the ability to be heated remotely via an alternating current magnetic field when magnetic nanoparticles are present in the hydrogel. This project incorporates iron oxide magnetic particles into a poly(N-isopropylacrylamide) (PNIPAAm)-based crosslinked hydrogel nanocomposite.

One important area of research that is necessary to determine the practical uses of hydrogels is biocompatibility. Biocompatibility is often difficult to define given that a number of mechanisms have been proposed to explain the compatibility of differing materials. Biocompatibility depends on the function of the biomaterial and is defined to be specific to a given application. One potential application for the temperature-responsive systems studied includes the implantation of a hydrogel nanocomposite that can be heated externally to provide both hyperthermia and drug release capabilities. This could then be used in drug delivery and/or cancer therapy applications within the body in which the biocompatibility of the composite would be of the utmost importance.

This study focused on determining the biocompatibility of magnetic hydrogel nanocomposites at various crosslinking densities with and without magnetic nanoparticles through cytocompatibility studies. Specifically, it has been discovered that murine fibroblast respond favorably to PNIPAAm/iron oxide-based hydrogel nanocomposites.