Hydrophilic cross-linked, 3-dimensional polymer matrices that can be swollen with water to form hydrogels, are highly attractive materials for biocompatible and non-fouling coatings, with a vast range of potential applications in biosensing and biomedical devices.
In the context of microbial resistance and biocontamination of surfaces, novel antimicrobial surface coatings have been prepared by incorporating zinc oxide nanoparticles into hydrogel layers of a poly(N-isopropylacrylamide) (PNIPAAm) terpolymer. The antimicrobial activity was successfully probed against E. coli in vitro. The composite films were shown to be non-cytotoxic towards NIH/3T3 cells at bactericidal loadings of ZnO, which qualifies them as promising candidates for biomedical device coatings. [1]
Functional hydrogel composite films based on natural polymers have been developed as support for endothelial and osteoblast cell co-culture. The polymer network of the parent hydrogel was formed by a carboxylated dextran derivative (BP-CMD) with benzophenone (BP) moieties as photocrosslinkable unit. The composite contained BP-functionalized silica nanoparticles as well as gelatin particles, which induce mechanical reinforcement and facilitated cell growth. The BMP-2 growth factor was covalently coupled to the polymer backbone to enhance osteoblast- and endothelial cell growth in co-culture, demonstrating the potential for bone tissue regeneration with vascularization. [2]
The thin hydrogel films were also integrated into optical sensor systems based on surface plasmon resonance (SPR) and optical waveguide mode spectroscopy (OWS) for medical diagnostics. Here, the hydrogel matrix serves as an optical waveguide, which has a high binding capacity, while acting as an anti-fouling coating to prevent unspecific deposition of components from the sampling environment. At the same time it is possibile to introduce recognition elements, such as antibodies, peptides, and proteins for specific recognition of target analytes (e.g. small hormones such as progesterone and estradiol or interleukin IL-6 related to inflammatory processes). Of particular interest are hydrogels composed of responsive polymers, which can change their physical state (e.g. the degree of swelling) upon variation of the environmental parameters (like temperature). [3]
[1] V. Schwartz et al., Adv. Funct, Mater. 2012, 22 (11), 2376-2386, DOI:10.1002/adfm.201102980.
[2] A. Brunsen et al., J. Mater. Chem. 2012, 22 (37), 19590-19604, DOI: 10.1039/c2jm34006b.
[3] A. Mateescu, et al., Membranes 2012, 2 (1), 40-69, DOI:10.3390/membranes2010040.