The injectable self-crosslinking blend hydrogel by combination of collagen I and thiolated hyaluronic acid could alleviate collagen I contraction in vitro and overcome weak cell adhesive sites of hyaluronic acid. Five groups of injectable hydrogels with different ratios were prepared to investigate their gelation time, injection force, mechanical properties, swelling capacity and disintegration performance. These results indicated that Col 7 HA-SH 3 hydrogel achieved the optimal controlled and injectable effect, the gelation time was just ten seconds with injection force at 3.5 N, and the storage modulus of hydrogel could reach 11 kPa with frequency at 10 Hz. Furthermore, the phenotype maintaining, biocompatibility and chondrocytes proliferation were administrated by CLSM, SEM, histological staining, immuohistochemical staining, MTT test and glycoaminoglycans quantification. Similarly, the Col 7 HA-SH 3 blend hydrogel encapsulated chondrocytes presented most excellent proliferation potential, phenotype maintaining, biocompatibility and convenient operational characteristics. These findings might approach the underlying clinical application of blend hydrogel in cartilage repair.
Zhipeng Sun,Yilin Ding,Zetao Wang,Huitong Luo,Qi Feng,Xiaodong Cao
Bacterial infection and the resulting inflammatory cascade are key factors hindering diabetic ulcers healing. The essential prerequisites for promoting diabetic ulcer healing are to sequentially achieve rapid sterilization, prevent reinfection, and modulate the inflammatory response. Inspired by the size-dependent sequential toxin release behavior of “Malaysian exploding ant”, we develop a ROS-responsive “exploding hydrogel” (E-gel) with size-dependent sequential release effects, which sequentially performs photothermal sterilization, persistent antibacterial activity, and immune regulation. Specially, polyhexamethylene guanidine (PHMG, P) and mesoporous polydopamine nanoparticles loaded with α-lipoic acid (α-LA@MPDA NPs, LD) were encapsulated into sulfhydryl-modified hyaluronic acid (HA-SH) through disulfide bonds to form a PLD/E-gel. The high temperatures generated by the photothermal effects of MPDA can kill over 90 % of bacteria within 10 min. During the swelling period of PLD/E-gel, PHMG diffuses out and effectively prevents the wound from re-infection. Along with the degradation of PLD/E-gel, submicron-sized α-LA@MPDA NPs are released from the cross-linked network to scavenge excessive ROS and modulate the inflammatory cascade. Animal experiments shows that PLD/E-gel accelerates the healing of infected diabetic wounds in SD rats by rapidly killing bacteria, inhibiting bacterial recolonization, relieving wound inflammation, and facilitating collagen deposition. To sum up, PLD/E-gel has a great application potential for diabetic wound healing.
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