Chitosan–Vitamin C Complex: A Nature-Inspired Adhesive for Bonding Poly(methyl methacrylate) Devices for Biomedical Applications

In our ongoing efforts to develop a biocompatible adhesive for thermoplastic bonding, we have introduced a chitosan–vitamin C (CSVC) hydrogel as a non-toxic adhesive reagent for bonding poly(methyl methacrylate) (PMMA). The bonding approach was successfully conducted using the CSVC hydrogel assisted by mild pressure for 20 min at room temperature. Hydrogen bonding and ionic cross-linking between CSVC and PMMA are suggested to be the prominent chemical interactions that accelerate the robust bonding of PMMA substrates. The hydrophilic modifications of PMMA by the CSVC hydrogel were confirmed by water contact angle analysis, Fourier-transform infrared spectroscopy, and scanning electron microscopy. Notably, the highest bond strength was achieved up to 1.48 MPa with perfect bonding performance characterized by clog-free and leak-proof microchannels. The bonded microdevices were applied to on-chip culturing of mesenchymal stem cells (MSCs), which can effectively promote the formation of MSC spheroids. Thus, the CSVC hydrogel is a promising nature-inspired adhesive that is expected to give a great impulse to the development of microdevices for advanced biomedical applications.