Double-network hydrogel enhanced by SS31-loaded mesoporous polydopamine nanoparticles:Symphonic collaboration of near-infrared photothermal antibacterial effect and mitochondrial maintenance for full-thickness wound healing in diabetes mellitus

Diabetic wound healing has become a serious healthcare challenge.The high-glucose environment leads to persistent bacterial infection and mitochondrial dysfunction,resulting in chronic inflammation,abnormal vascular function,and tissue necrosis.To solve these issues,we developed a double-network hydrogel,constructed with pluronic F127 diacrylate(F127DA)and hyaluronic acid methacrylate(HAMA),and enhanced by SS31-loaded mesoporous polydopamine nanoparticles(MPDA NPs).As components,SS31,a mitochondria-targeted peptide,maintains mitochondrial function,reduces mitochondrial reactive oxygen species(ROS)and thus regulates macrophage polarization,as well as promoting cell proliferation and migration,while MPDA NPs not only scavenge ROS and exert an anti-bacterial effect by photothermal treatment under near-infrared light irradiation,but also control release of SS31 in response to ROS.This F127DA/HAMA-MPDA@SS31(FH-M@S)hydrogel has characteristics of adhesion,superior biocompatibility and mechanical properties which can adapt to irregular wounds at different body sites and provide sustained release of MPDA@SS31(M@S)NPs.In addition,in a diabetic rat full thickness skin defect model,the FH-M@S hydrogel promoted macrophage M2 polarization,collagen deposition,neovascularization and wound healing.Therefore,the FH-M@S hydrogel exhibits promising therapeutic potential for skin regeneration.

Black tantalic oxide submicro-particles coating on PEEK fibers woven into fabrics as artificial ligaments with photothermal antibacterial effect and osteogenic activity for promoting ligament-bone healing

Design of artificial ligaments possessing both osteogenic activity and antibacterial effect that promotes ligament-bone healing and prevents bacterial infection in bone tunnels for anterior cruciate ligament(ACL)reconstruction remains a significant challenge.In this study,black tantalic oxide(BTO)submicro-particles with oxygen vacancies and structure defects were fabricated by using traditional white tan-talic oxide(WTO)through magnesium thermal reduction(MTR)method,and BTO was coated on polyetheretherketone(PEEK)fibers(PKF),which were woven into fabrics(PBT)as artificial ligaments.PBT with BTO coating exhibited excellent photothermal performance,which possessed not only antibac-terial effects in vitro but also anti-infective ability in vivo.PBT with optimized surface properties(e.g.,submicro-topography and hydrophilicity)not only significantly facilitated rat bone mesenchymal stem cells(BMSC)responses(e.g.,proliferation and osteogenic differentiation)in vitro but also stimulated new bone formation for ligament-bone healing in vivo.The presence of oxygen vacancies and structure de-fects in BTO did not change the surface properties and osteogenic activity of BPT while displaying an outstanding photothermal antibacterial effect.In summary,BPT with osteogenic activity and photother-mal antibacterial effect promoted bone regeneration and prevented bacterial infection,thereby promoting ligament-bone healing.Therefore,PBT would have tremendous potential as a novel artificial ligament for ACL reconstruction.

Porous photothermal antibacterial antioxidant dual–crosslinked cryogel based on hyaluronic acid/polydopamine for non-compressible hemostasis and infectious wound repair

Cryogel dressings with good absorption ability and photothermal antibacterial properties for preventing wound infections and treating infected wounds have attracted widespread attention.In this work,a series of cryogels with macroporous structure,antioxidant and photothermal properties were prepared based on adipic dihydrazide modified hyaluronic acid(HA-ADH),and dopamine(DA).The antioxidant properties,hemostatic properties,near infrared(NIR)assisted photothermal antibacterial ability provided by polydopamine,recyclable compression mechanical properties,and cytocompatibility were tested.The results demonstrated that the HA-ADH/DA cryogels have stable mechanical properties,great antibacterial properties against E.coli(EC)and methicillin-resistant S.aureus(MRSA).The high swelling ratio due to the high water retention of HA equipped the cryogels with the capability of absorbing exuded blood and excessive tissue fluid in the infected full-thickness skin defect model of mouse.The cryogels demonstrated good cytocompatibility and antioxidant performance through cell tests and 1,1-diphenyl-2-methylbenzohydrazino(DPPH)scavenging efficiency test.The cryogels showed enhanced blood-clotting index(BCI)and better hemostatic ability in the mouse liver trauma model and the rat deep noncompressible liver defect model compared with gauze and gelatin sponge.Furthermore,compared with commercial TegadermTMdressing in vivo,the HA-ADH/DA cryogels could greatly promote infected skin wound healing in a full-thickness infected skin defect wound model.In summary,the macroporous HAADH/DA cryogels with good antioxidant,high swelling ratio,photothermal antibacterial property,and biocompatibility are a promising hemostatic material and wound healing dressing.

Supramolecular Polymerization Powered by Escherichia coli:Fabricating a Near-Infrared Photothermal Antibacterial Agent in Situ

An Escherichia coli reduction-powered supramolecular polymerization is reported,leading to the fabrication of a near-infrared(NIR)photothermal antibacterial agent in situ.To this end,a bifunctional monomer containing two viologen moieties was designed.WhenincubatingE.coli with thebifunctional monomer and cucurbit[8]uril,viologen moieties were reduced to viologen cation radicals by E.coli,and a supramolecular polymer with supramolecular dimers of viologen cation radicals integrated into the main chain was fabricated on the surface of E.coli.

Ultrastable graphene isolated Au Ag nanoalloy for SERS biosensing and photothermal therapy of bacterial infection

Plasmonic metal nanomaterials with intrinsic surface–enhanced Raman scattering(SERS)and photothermal properties,especially AuAg nanoalloys with both the outstanding merits of Au and Ag nanocrystals,show huge application prospects in bacterial theranostics.However,the direct exposure of AuAg nanoalloys in external conditions probably cause undesirable reactions and poisonous metal ion leakage during SERS detection and photothermal antibacterial therapy process,which severely hinder bacterial theranostics applications.Herein,we report an ultrastable graphene–isolated AuAg nanoalloy(GAA)with AuAg core confined in few–layer graphitic shell as a versatile platform for bacterial detection and therapy.The encapsulation of graphene ensures the good stability of AuAg core,that its superior SERS and photothermal properties are therefore further guaranteed.GAA is used for SERS detection of two vital bacterial biomarkers(including corrosive cyanide and pyocyanin),exhibiting good SERS quantitative and multiplexing ability.GAA is further used for photothermal antibacterial therapy application,and ultrahigh antibacterial efficacies for both Gram–negative Escherichia coli and Gram–positive Staphylococcus aureus are achieved under 808 nm laser irradiation.This work proposes a valuable method to develop robust bacterial theranostic platform.

FeS@LAB-35@Ti_(3)C_(2)as a high-efficiency nanozyme for near infrared light induced photothermal enhanced chemodynamic antibacterial activity and wound healing

The abuse of antibiotics leads to a significant increase in bacterial resistance,which makes it difficult to treat bacterial infections.Therefore,it is urgent to develop new strategies for efficient antibacterial and wound healing.Recently,nanozymes based antibacterial agents have attracted increasing attention for their multifunction and high efficiency.In this study,we report a FeS@lauramidopropyl betaine(LAB-35)@Ti_(3)C_(2)nanozyme as a high-efficiency antibacterial agent for near infrared(NIR)light induced photothermal enhanced chemodynamic antibacteria and wound healing.The FeS@LAB-35@Ti_(3)C_(2)nanozyme possesses peroxidase-like catalysis activity,which can promote the generation of hydroxyl radicals(·OH)through catalyzing the decomposition of H_(2)O_(2).FeS@LAB-35@Ti_(3)C_(2)has photothermal conversion efficiency(η=65.1%),and it exhibits enhanced catalytic activity under NIR light irradiation.The in vitro antibacterial experiments demonstrate the excellent antibacterial activity of FeS@LAB-35@Ti_(3)C_(2)against representative Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus.The animal experiments indicate that FeS@LAB-35@Ti_(3)C_(2)nanozyme can effectively inhibit wound ulceration and promote wound healing.Overall,this study proposes FeS@LAB-35@Ti_(3)C_(2)nanozyme that integrates chemodynamic and photothermal therapy,which provides an efficient strategy for bacterial inhibition and wound healing.

Antibacterial conductive self-healing hydrogel wound dressing with dual dynamic bonds promotes infected wound healing

In clinical applications,there is a lack of wound dressings that combine efficient resistance to drug-resistant bacteria with good self-healing properties.In this study,a series of adhesive self-healing conductive antibacterial hydrogel dressings based on oxidized sodium alginate-grafted dopamine/carboxymethyl chitosan/Fe3+(OSD/CMC/Fe hydrogel)/polydopamine-encapsulated poly(thiophene-3-acetic acid)(OSD/CMC/Fe/PA hydrogel)were prepared for the repair of infected wound.The Schiff base and Fe3+coordination bonds of the hydrogel structure are dynamic bonds that can be repaired automatically after the hydrogel network is disrupted.Macroscopically,the hydrogel exhibits self-healing properties,allowing the hydrogel dressing to adapt to complex wound surfaces.The OSD/CMC/Fe/PA hydrogel showed good conductivity and photothermal antibacterial properties under near-infrared(NIR)light irradiation.In addition,the hydrogels exhibit tunable rheological properties,suitable mechanical properties,antioxidant properties,tissue adhesion properties and hemostatic properties.Furthermore,all hydrogel dressings improved wound healing in the infected full-thickness defect skin wound repair test in mice.The wound size repaired by OSD/CMC/Fe/PA3 hydrogel+NIR was much smaller(12%)than the control group treated with Tegaderm™film after 14 days.In conclusion,the hydrogels have high antibacterial efficiency,suitable conductivity,great self-healing properties,good biocompatibility,hemostasis and antioxidant properties,making them promising candidates for wound healing dressings for the treatment of infected skin wounds.

A Mg^(2+)/polydopamine composite hydrogel for the acceleration of infected wound healing

Bacterial infection is a vital factor to delay the wound healing process.The antibiotics abuse leads to drug resistance of some pathogenic bacteria.Non-antibiotic-dependent multifunctional biomaterials with accelerated wound healing performance are urgently desired.Herein,we reported a composite antibacterial hydrogel PDA-PAM/Mg^(2+)that shows excellent self-healing and tissue adhesive property,and photothermal antibacterial functions for accelerating wound healing.The gel was composed of polyacrylamide(PAM),polydopamine(PDA),and magnesium(Mg^(2+))and prepared via a two-step procedure:an alkali-induced dopamine pre-polymerization and followed radical polymerization process.The composite gel shows excellent tissue adhesiveness and Mg^(2+)-synergized photothermal antibacterial activity,inducing a survival rate of 5.29% for S.aureus and 7.06%for E.coli after near infrared light irradiation.The composite hydrogel further demonstrated efficient bacteria inhibition,enhanced wound healing and collagen deposition in a full-thickness skin defect rat model.Together,the PDA-PAM/Mg^(2+) hydrogel presents an excellent wound dressing with excellent tissue adhesion,wound healing,and antibacterial functions.