Tissue adhesive,ROS scavenging and injectable PRP-based‘plasticine’for promoting cartilage repair

Platelet-rich plasma(PRP)that has various growth factors has been used clinically in cartilage repair.However,the short residence time and release time at the injury site limit its therapeutic effect.The present study fabricated a granular hydrogel that was assembled from gelatin microspheres and tannic acid through their abundant hydrogen bonding.Gelatin microspheres with the gelatin concentration of 10wt%and the diameter distribution of 1-10 lm were used to assemble by tannic acid to form the granular hydrogel,which exhibited elasticity under low shear strain,but flowability under higher shear strain.The viscosity decreased with the increase in shear rate.Meanwhile,the granular hydrogel exhibited self-healing feature during rheology test.Thus,granular hydrogel carrying PRP not only exhibited well-performed injectability but also performed like a‘plasticine’that possessed good plasticity.The granular hydrogel showed tissue adhesion ability and reactive oxygen species scavenging ability.Granular hydrogel carrying PRP transplanted to full-thickness articular cartilage defects could integrate well with native cartilage,resulting in newly formed cartilage articular fully filled in defects and well-integrated with the native cartilage and subchondral bone.The unique features of the present granular hydrogel,including injectability,plasticity,porous structure,tissue adhesion and reactive oxygen species scavenging provided an ideal PRP carrier toward cartilage tissue engineering.

An anti-bacterial porous shape memory self-adaptive stiffened polymer for alveolar bone regeneration after tooth extraction

The regeneration of alveolar bone after tooth extraction is critical for the placement of dental implants.Developing a rigid porous scaffold with defect shape adaptability is of great importance but challenging for alveolar bone regeneration.Herein,we design and synthesize a biocompatible poly(L-glutamic acid)-g-poly(ε-caprolactone)(PLGA-g-PCL)porous shape memory(SM)polymer.The PLGA-g-PCL is then copolymerized with acryloyl chloride grafted poly(ω-pentadecalactone)(PPDLDA)having a higher phase transition temperature than shape recovery temperature to maintain stiffness after shape recovery to resist chewing force.The hybrid pol-ydopamine/silver/hydroxyapatite(PDA/Ag/HA)is coated to the surface of(PLGA-g-PCL)-PPDL scaffold to afford the anti-bacterial activity.The porous SM scaffold can be deformed into a compact size and administered into the socket cavity in a minimally invasive mode,and recover its original shape with a high stiffness at body tem-perature,fitting well in the socket defect.The SM scaffold exhibits robust antibacterial activity against Staphy-lococcus aureus(S.aureus).The porous microstructure and cytocompatibility of PLGA allow for the ingrowth and proliferation of stem cells,thus facilitating osteogenic differentiation.The micro-CT and histological analyses demonstrate that the scaffold boosts efficient new bone regeneration in the socket of rabbit mandibular first premolar.This porous shape memory self-adaptive stiffened polymer opens up a new avenue for alveolar bone regeneration.

Highly tough and elastic microspheric gel for transarterial catheter embolization in treatment of liver metastasis tumor

Transarterial embolization is a widely recognized clinical treatment method for liver tumors.Given that the soft and easily damaged features of embolic particles may limit tumor embolization efficiency,the present study carries out an attempt of fabricating tough and elastic microspheric gel for promoting embolization efficiency.To promote the toughness of hydrogel,poly(ethylene glycol)-co-poly(ε-caprolactone)-co-poly(ethylene glycol)(PPP)and PPP with two terminal double bonds(PPPDA)are co-assembled into nano-micelles,which are connected with methacrylated chitosan(CSMA)to fabricate microspheric gels via microfluidic technology.Lowering double bond density of micelles promotes the freedom degree of micelles,significantly enhancing hydrogel toughness.To compensate for the strength loss caused by the decrease of double bond density of micelles,phytic acid(PA)are employed to interact with CS to form a physical network,further improving hydrogel strength and toughness.The CS-PPPDA&PPP-PA microspheric gels exhibit higher blocking effect in vitro.A rabbit VX2 liver metastasis tumor model is prepared to verify the embolization efficacy of CS-PPPDA&PPP-PA microspheric gels.Compared with clinical used microspheres,fewer CS-PPPDA&PPP-PA microspheric gels can achieve enough embolization efficiency.After embolization for 14 days,CS-PPPDA&PPP-PA microspheric gels exhibit improved tumor necrosis rate and promoted tumor cells apoptosis with reduced inflammation in surrounding tissues,confirming advanced embolic efficiency of tough microgels.