Mechanically strong interpenetrating network hydrogels for differential cellular adhesion

Hydrogels as "soft-and-wet" materials have been widely used as tissue engineering scaffolds due to their similarity to natural extracellular matrix. However, it remains extremely challenging to develop mechanically strong hydrogels that can stimulate desirable mammalian cell adhesion but reduce the probable fouling from microbes and other unwanted cells. To achieve this purpose, we fabricated interpenetrating network (IPN) hydrogels consisting of cell-adhesive gelatin and non-fouling carboxybetaine (CBMA) via a "one-pot" synthesis process. Far stronger than their parent gels of gelatin and pCBMA, the IPN gels presented compressive and stretch fracture stresses over 6.5 and 2.4 MPa, and failure strains over 95% and 700%, respectively. The obtained IPN gels only allowed the adhesion and confluence of parenchymal mammalian cells (e.g. human umbilical vein endothelial cells, HUVEC; smooth muscle cells, SMC) but resisted well the attachment of platelets and microbes. In this regard, the CBMA/gelatin IPN gels can be potentially used in the construction of artificial soft tissues such as blood vessels because of their specific mechanical and differential adhesive properties.