Abstract:

Chiral supramolecular hydrogels that can mimic the chiral extracellular microenvironment are of special significance in tissue engineering， however， it still remains a great challenge for their low long lifetime stability. Herein， we introduce inorganic hydroxyapatite nanoparticles （HAP） to the well-established phenylalanine derivative chiral supramolecular hydrogel （LPF）， aiming to improve its mechanical performance as well as biofunctions. Morphological studies revealed an inversion of the chirality of LPF after HAP incorporation. Rheological experiments confirmed the long-term stability and superior mechanical property of the hybrid hydrogel over the neat hydrogel， where LPF/HAP hydrogel exhibited an improved elastic modulus of 3353 Pa， standing over three months， and LPF hydrogel collapsed soon within 24 hours with a much lower storage modulus （G'） value of 452 Pa. The abundant coordination interactions supplied by Ca²⁺ ions on the surface of HAP nanoparticles crosslinking with the carboxyl group are considered to be the crucial factors of the mechanical strengthening. Moreover， the HAP incorporation led to an enhanced stimulation of the osteogenesis of the osteoblastic cells， demonstrating by the increasement of the alkaline phosphatase （ALP） activity on LPF/HAP substrate， which ascribed not only to the osteoinductive ability of hydroxyapatite， but also to the improved stiffness and stability induced by HAP. The findings indicate that the chiral supramolecular hydrogel is promising in bone tissue engineering via inorganic nanoparticle strengthening and functionalization.

Key words: Supramolecular hydrogel, Inorganic nanoparticle, Hybrid, Mechanical stability, Osteogenesis, Chirality.