Hydrogels are highly hydrated three-dimensional polymeric network that mimics native tissue microenvironment. However, the utility of hydrogels is severely hampered by its limited mechanical stiffness and toughness. Ranges of chemical and physical mechanisms are proposed to engineere mechanically stiff and tough polymeric network; for example a covalent crosslinking gelatin hydrogel have stiffness between 3-30kPa. A range of nanoparticles is incorporated within the hydrogel network to enhance to mechanical stiffness by 2-5 folds. But most of these modifications render the formation of brittle hydrogels. Here, we report covalently reinforced elastomeric hydrogels from methacrylated gelatin (GelMA) and (poly-ethylene glycol)-diacid functionalized magnetic nanoparticles (MNPs) (Fig 1a). The addition of small amount of MNPs (0.0005%) to GelMA (5%) results in more than a 10-fold increase in mechanical stiffness and a 20-fold increase in toughness. The increase in mechanical stiffness of nanocomposites indicates a strong covalent interaction between the free amine groups available on GelMA backbone with the PEG-diacid group available on MNPs (size approx. 8 nm) as determined by infrared, nuclear magnetic resonance and X-ray photoelectron spectroscopy. The mechanical stiffness of nanoengineered hydrogel can be easily tailored to 1MPa by fine-tuning the size of MNPs (4, 8 and 12 nm) and GelMA concentration (2.5, 5, 10 and 15%) (Fig 1b). Moreover the nanoengineered hydrogels are highly elastomeric and can sustain more than 90% compressive strain without any plastic deformation. These nanoengineered hydrogel can be used to engineer mechanically stiff network for biomedical applications including tissue-engineered scaffolds, drug delivery vehicles, bioactuators and sensors.

Ultrastiff nanocomposite hydrogels for biomedical applications

249th National Meeting (2015)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.