Tough, Durable and Strongly Bonded Self-Healing Cartilage-mimicking Noncovalent Assembly Hydrogel Nanostructures: The Interplay of Experiment and Theory

High-strength, strongly bonded and self-healing materials would be of great interest for several applications, however, the experimental and in-silico design of all such properties in a single material is challenging. In the present work, encouraged by cartilage tissue, polyacrylamide (PAM)-based tough and durable dimers (PAM-Ag and PAM-BNOH) and trimer (PAM-Ag-BNOH) nanocomposites were synthesized by encapsulating silver (Ag) and hydroxylated hexagonal boron nitride (BNOH). The strong interfacial interaction was achieved by introducing (computational modelling and DFT approaches) noncovalent bonds involved in the dimer and trimer nanohybrids. The fabricated PAM-Ag-BN nanocomposite showed higher mechanical strength (0.31 MPa compressive strength and 0.29 MPa Young’s modulus) than that of dimer hydrogel composites. The long-term durability of the hydrogel samples was tested by electrochemical testing of hydrogels in simulated body fluid and the higher corrosion resistance (icorr 2.65 × 10-5 A/cm2) was obtained for trimer hydrogel. Moreover, the supramolecular cross-linked assembly of PAM-Ag-BN perfectly showed the bioactivity including bone formation ability, self-healing performance, restricted cytotoxicity, and anti-microbial activity. The synergistic effect of nano and micron-sized particles in PAM-Ag-BN ensued in the strong interfacial interlocking through the formation of hydrogen bonding between Ag, BNOH and PAM. Therefore, the fabricated tough hydrogel composite can be a leading biomaterial for soft tissue (articular cartilage) regeneration. The present research opens new directions in developing smart self-healing nanocomposites vastly used in cartilage tissue engineering.