Bio-inspired dual-adhesive particles from microfluidic electrospray for bone regeneration

Bioadhesive hydrogels have demonstrated great potential in bone regeneration. However, the relatively simple adhesion mechanism and lack of intricate structural design restrict their further applications. Herein, inspired by multiple adhesion mechanisms of pollen particles and marine mussels, we present a novel type of dual-adhesive hydrogel particles fabricated from microfluidic electrospray for bone regeneration. As the particles are rapidly solidified via liquid nitrogen-assisted cryogelation, they exhibit pollen-mimicking hierarchical porous morphology and gain structure-related adhesion. Besides, the particles are further coated by polydopamine (PDA) to achieve molecular-level adhesion especially to physiological wet surfaces of bone issues. Benefiting from such dual-adhesion mechanisms, the particles can strongly adhere to bone tissue defects, and function as porous scaffolds. Moreover, the dual-adhesive particles can serve as effective vehicles to release key growth factors more than two weeks. In vitro experiments showed that the growth factors-loaden particles have excellent biocompatibility and more significantly promote angiogenesis (∼ 2-fold) and osteogenic differentiation (∼ 3-fold) than control. In vivo experiments indicated that the dual-adhesive particles could significantly enhance bone regeneration (∼ 4-fold) than control by coupling osteogenesis and angiogenesis effects. Based on these features, the bio-inspired dual-adhesive particles have great potentials for bone repair and wound healing applications.