| Wounds are known as skin tissue damage or disintegration and may be caused by different causes,including thermal injury,chronic ulcers caused by trauma and diabetes mellitus,sense of compression,and venous stasis.Wound dressings need to have good histocompatibility,some binding ability with human tissues,certain antibacterial and other properties.Hydrogels have attracted much attention in the field of wound dressings due to their excellent biochemical and mechanical properties.In addition,since metal ions play an important role in biological systems and the use of metal ions in metal ion based hydrogels provides not only crosslinking and stability but also many advantages for human biological functions,metal ions have wide application prospects in hydrogels to prepare various functional materials.Among them,ferric ions have attracted much attention because of their good biofunctionality,magnetic properties,broad-spectrum bacteriostatic properties and so on.Based on this,two kinds of hydrogels chelated by ferric ions were designed and studied in this work,the main research content is as follows.(1)In the present study,a biocompatible dual-network composite hydrogel(DNCGel)sensor was obtained via a simple process.The dual network hydrogel is constructed by the interpenetration of a flexible network formed of poly(vinyl alcohol)(PVA)physical cross-linked by repeated freeze-thawing and a rigid network of ironchelated xanthan gum(XG)impregnated with Fe3+ interpenetration.The pure PVA/XG hydrogels were chelated with ferric ions by immersion to improve the gel strength(compressive modulus and tensile modulus can reach up to 0.62 MPa and 0.079 MPa,respectively),conductivity(conductivity values ranging from 9 × 10-4 S/cm to 1 × 103 S/cm)and bacterial inhibition properties(up to 98.56%).Subsequently,the effects of the ratio of PVA and XG and the immersion time of Fe3+ on the hydrogels were investigated,and DNGel3 was given the most priority on a comprehensive consideration.It was demonstrated that the DNCGel exhibit good biocompatibility in vitro,effectively facilitate wound healing in vivo(up to 97.8%healing rate)under electrical stimulation,and monitors human movement in real time.This work provides a novel avenue to explore multifunctional intelligent hydrogels that hold great promise in biomedical fields such as smart wound dressings and flexible wearable sensors.(2)Herein,a multifunctional hydrogel with ROS scavenging and photothermal antibacterial activity based on xanthan gum(XG),dopamine(DA),ferric ion and Prussian blue nanoparticles(PBNPs),named M-XG gel,was developed for the treatment of infected wound.The M-XG gel with 200-500 μm open macropores,demonstrates ideal nutrient transport and gas exchange capacity.The introduction of DA occupies the chelating sites of iron ions,further increasing the pore size and endowing the hydrogel with ideal adhesion.The increase of crosslink sites in PBNPs formed a promising equilibrium M-XG gel with identical macroporous structures and toughened mechanical performances.Due to the existence of PBNPs,M-XG gel exhibits excellent photothermal properties under 808 nm near-infrared(NIR)light irradiation with a photothermal conversion efficiency of up to 48%.Benefiting from this,the M-XG gel shows good antibacterial properties with an inhibition rate of up to nearly 100%on both Staphylococcus aureus(S.aureus)and Escherichia coli(E.coli)and 99.3%inhibition rate of multidrug-resistant Staphylococcus aureus(MRSA).Moreover,they demonstrate good biocompatibility(the hemolysis ratios of them were 2.48%)and ROS scavenging capacities(the scavenging rate can reach 60%at 120 minutes)in vitro.In MRSA-infected rat model,compared with control group,the wound closure rate of M-XG gel increased from 28%to 83%within 7 days,and the angiogenesis and collagen deposition synergistically promote infected wound healing.Therefore,the multifunctional hydrogel with connective macro-porous structures demonstrates its great potential for MRSA-infected wound tissue engineering. |
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