A shear-thinning,ROS-scavenging hydrogel combined with dental pulp stem cells promotes spinal cord repair by inhibiting ferroptosis

Spinal cord injury(SCI)is a serious clinical disease.Due to the deformability and fragility of the spinal cord,overly rigid hydrogels cannot be used to treat SCI.Hence,we used TPA and Laponite to develop a hydrogel with shear-thinning ability.This hydrogel exhibits good deformation,allowing it to match the physical properties of the spinal cord;additionally,this hydrogel scavenges ROS well,allowing it to inhibit the lipid peroxidation caused by ferroptosis.According to the in vivo studies,the TPA@Laponite hydrogel could synergistically inhibit ferroptosis by improving vascular function and regulating iron metabolism.In addition,dental pulp stem cells(DPSCs)were introduced into the TPA@Laponite hydrogel to regulate the ratios of excitatory and inhibitory synapses.It was shown that this combination biomaterial effectively reduced muscle spasms and promoted recovery from SCI.

Passively-targeted mitochondrial tungsten-based nanodots for efficient acute kidney injury treatment

Acute kidney injury(AKI)can lead to loss of kidney function and a substantial increase in mortality.The burst of reactive oxygen species(ROS)plays a key role in the pathological progression of AKI.Mitochondrial-targeted antioxidant therapy is very promising because mitochondria are the main source of ROS in AKI.Antioxidant nanodrugs with actively targeted mitochondria have achieved encouraging success in many oxidative stress-induced diseases.However,most strategies to actively target mitochondria make the size of nanodrugs too large to pass through the glomerular system to reach the renal tubules,the main damage site of AKI.Here,an ultra-small Tungsten-based nanodots(TWNDs)with strong ROS scavenging can be very effective for treatment of AKI.TWNDs can reach the tubular site after crossing the glomerular barrier,and enter the mitochondria of the renal tubule without resorting to complex active targeting strategies.To our knowledge,this is the first time that ultra-small negatively charged nanodots can be used to passively target mitochondrial therapy for AKI.Through in-depth study of the therapeutic mechanism,such passive mitochondria-targeted TWNDs are highly effective in protecting mitochondria by reducing mitochondrial ROS and increasing mitophagy.In addition,TWNDs can also reduce the infiltration of inflammatory cells.This work provides a new way to passively target mitochondria for AKI,and give inspiration for the treatment of many major diseases closely related to mitochondria,such as myocardial infarction and cerebral infarction.

Polydopamine-mediated graphene oxide and nanohydroxyapatite-incorporated conductive scaffold with an immunomodulatory ability accelerates periodontal bone regeneration in diabetes

Regenerating periodontal bone tissues in the aggravated inflammatory periodontal microenvironment under diabetic conditions is a great challenge.Here,a polydopamine-mediated graphene oxide(PGO)and hydroxyapatite nanoparticle(PHA)-incorporated conductive alginate/gelatin(AG)scaffold is developed to accelerate periodontal bone regeneration by modulating the diabetic inflammatory microenvironment.PHA confers the scaffold with osteoinductivity and PGO provides a conductive pathway for the scaffold.The conductive scaffold promotes bone regeneration by transferring endogenous electrical signals to cells and activating Ca2+channels.Moreover,the scaffold with polydopamine-mediated nanomaterials has a reactive oxygen species(ROS)-scavenging ability and anti-inflammatory activity.It also exhibits an immunomodulatory ability that suppresses M1 macrophage polarization and activates M2 macrophages to secrete osteogenesis-related cytokines by mediating glycolytic and RhoA/ROCK pathways in macrophages.The scaffold induces excellent bone regeneration in periodontal bone defects of diabetic rats because of the synergistic effects of good conductive,ROS-scavenging,anti-inflammatory,and immunomodulatory abilities.This study provides fundamental insights into the synergistical effects of conductivity,osteoinductivity,and immunomodulatory abilities on bone regeneration and offers a novel strategy to design immunomodulatory biomaterials for treatment of immune-related diseases and tissue regeneration.

Sustained delivery of rhMG53 promotes diabetic wound healing and hair follicle development

MG53 is an essential component of the cell membrane repair machinery,participating in the healing of dermal wounds.Here we develop a novel delivery system using recombinant human MG53(rhMG53)protein and a reactive oxygen species(ROS)-scavenging gel to treat diabetic wounds.Mice with ablation of MG53 display defective hair follicle structure,and topical application of rhMG53 can promote hair growth in the mg53/mice.Cell lineage tracing studies reveal a physiological function of MG53 in modulating the proliferation of hair follicle stem cells(HFSCs).We find that rhMG53 protects HFSCs from oxidative stress-induced apoptosis and stimulates differentiation of HSFCs into keratinocytes.The cytoprotective function of MG53 is mediated by STATs and MAPK signaling in HFSCs.The thermosensitive ROS-scavenging gel encapsulated with rhMG53 allows for sustained release of rhMG53 and promotes healing of chronic cutaneous wounds and hair follicle development in the db/db mice.These findings support the potential therapeutic value of using rhMG53 in combination with ROS-scavenging gel to treat diabetic wounds.

ROS‑Scavenging Electroactive Polyphosphazene‑Based Core–Shell Nanofibers for Bone Regeneration

Bone defects are always accompanied by inflammation due to excessive reactive oxygen species(ROS)in injured regions,which greatly impedes the regeneration of bone tissues.Although many conductive polymers have been developed to scavenge ROS,they are typically non-degradable under physiological conditions,making them unsuitable for in vivo applications.Biodegradable polyorganophosphazenes(POPPs)may serve as potent ROS-scavenging biomaterials owing to their versatile chemical structures and ease of functionalization.Herein,a PATGP-type electroactive polyphosphazene with side groups of aniline tetramer and glycine ethyl ester was compared to conventional poly(lactic-co-glycolic acid)(PLGA)in regenerating bone tissues.To conduct in vitro and in vivo evaluations,three kinds of electrospun nanofibrous meshes were prepared:PLGA,PLGA/PATGP blend,and PLGA/PATGP core–shell nanofibers.Among them,PLGA/PATGP core–shell nanofibers outperform the blend and PLGA nanofibers in terms of scavenging ROS,promoting osteogenic differentiation,and accelerating neo-bone formation.The continuous PATGP shell on the PLGA/PATGP core–shell nanofiber surface could apparently provide more significant modulation effects on cellular behaviors than the PLGA/PATGP blend nanofibers with PATGP dispersed in the PLGA matrix.Therefore,the core–shell structured PLGA/PATGP nanofibers were envisioned as a promising candidate scaffold for bone tissue engineering.Additionally,the core–shell design paved the way for biomedical applications of functional POPPs in combination with other polymeric biomaterials,without phase separation or difficulty of increasing the molecular weights of POPPs.