A novel antibacterial acellular porcine dermal matrix cross-linked with oxidized chitosan oligosaccharide and modified by in situ synthesis of silver nanoparticles for wound healing applications.

Not only are the physicochemical properties and biocompatibility of biomaterials important considerations, but also their antibacterial properties. In this study, a novel chemically-cross-linked antibacterial porcine acellular dermal matrix (pADM) scaffold was fabricated according to a two-step method. A naturally-derived oxidized chitosan oligosaccharide (OCOS) was used to cross-linked pADM (termed OCOS-pADM) to improve its physicochemical properties. Residual aldehyde groups within the OCOS-pADM were used in a redox reaction with Ag ions to produce Ag nanoparticles (AgNPs) in situ. As the AgNPs were tightly adhered onto the scaffold fibrils (termed OCOS-AgNPs-pADM), this effectively functionalized scaffold with antibacterial properties. The generated AgNPs were characterized by UV-Vis diffuse reflectance spectroscopy, XPS and SEM. The results of DSC, TG and enzymatic degradation demonstrated that OCOS-AgNPs-pADM possessed improved thermal stability and resistance to enzymatic degradation compared with pADM scaffolds. The kinetic experiment of the release of silver showed that silver was released in a controllable way. After introducing AgNPs into scaffolds, the OCOS-AgNPs-pADM possessed wide-spectrum antibacterial activity against Escherichia coli and Staphylococcus aureus. Furthermore, MTT assay and CLSM showed that the scaffolds had good biocompatibility. Pieces of OCOS-AgNPs-pADM were implanted into Sprague-Dawley rats to characterize their ability to repair full-thickness skin wounds. And results showed that the OCOS-AgNPs-pADM could accelerate the wound healing process. Overall, this work contributes new insight into the chemical cross-linking and functionalization of pADM scaffolds. In addition, as novel antibacterial scaffolds, OCOS-AgNPs-pADMs have the potential for development as wound dressing materials.

Chen Y ，Dan N ，Dan W ，Liu X ，Cong L ... -  《-》

Highly stable collagen scaffolds crosslinked with an epoxidized natural polysaccharide for wound healing.

As a biocompatible and bioactive natural tissue engineering collagen scaffold, porcine acellular dermal matrix (pADM) has limitations for the application in tissue regeneration due to its low strength and rapid biodegradation. Herein, to get a good wound dressing, the epoxy group was added to N-(2-hydroxypropyl)-3-trimethylammonium chitosan chloride (HTCC) to synthesize the epoxidized N-(2-hydroxypropyl)-3-trimethylammonium chitosan chloride (EHTCC), and the porcine acellular dermal matrix was modified with EHTCC at different dosage of 0, 4, 8, 12, 16 and 20%. The properties of the EHTCC-pADM were evaluated. The results indicated that the thermal stability and mechanical properties of EHTCC-pADM were remarkably improved, and the natural conformation of the matrix was maintained, which was beneficial to natural and excellent biological properties of the pADM. According to the test results of water contact angle, the hydrophilicity of the material was improved, which is conducive to cell adhesion, proliferation and growth. Cytotoxicity experiments showed that the introduction of EHTCC would not adversely affect the biocompatibility of the materials. In vivo experiments showed that EHTCC-pADM could promote wound healing. In conclusion, EHTCC-pADM is a potential collagen-based dressing for wound healing.

Zheng X ，Chen Y ，Dan N ，Dan W ，Li Z ... -  《-》

Silver nanoparticle impregnated chitosan-PEG hydrogel enhances wound healing in diabetes induced rabbits.

Non-healing wounds are among the serious complications of type-2-diabetes around the globe, associated with high incidence of bacterial infection, chronic nerve and blood vessel damage, and eventually repeated amputation of limbs and organs. Silver nanoparticles offer strong wound healing potential due to their well-known antibacterial activities. The present study reports the development of silver nanoparticle impregnated chitosan-poly ethylene glycol (PEG) hydrogel to accelerate wound healing in diabetic patients. The aim of the study was to formulate a sustained and slow release of silver nanoparticle using chitosan-PEG-Silver Nitrate based hydrogel for the treatment of chronic diabetic wounds. The silver nanoparticle containing chitosan-PEG pre-polymer solution was synthesized by reducing silver nitrate with PEG and chitosan solution, thereby, transforming the silver ions into silver nanoparticles. The resulted pre-polymer solution was then crosslinked using glutaraldehyde to form the desired hydrogel. The developed silver nanoparticle impregnated chitosan hydrogel was characterized using ultra-violet (UV) visible spectrophotometry, Fourier Transform-infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM) followed by the determination of porosity, and swelling properties. The release of AgNPs from hydrogel was determined by UV-vis spectroscopy followed by antimicrobial and antioxidant assays. The wound healing efficacy of the synthesized hydrogel was evaluated in diabetic rabbits. The results demonstrated a higher porosity, higher degree of swelling and higher water vapor transition rate (WVTR) for silver nanoparticle impregnated hydrogel compared to bare chitosan-PEG hydrogel as well as improved antimicrobial and antioxidant properties in-vitro and enhanced wound healing capability in-vivo in diabetic rabbits. The hydrogel showed a slow and sustained release of AgNPs over a period of at least seven days manifesting the slow biodegradation of developed hydrogels. The improved antimicrobial, antioxidant and wound healing results indicate that the silver nanoparticle impregnated chitosan-PEG hydrogel can be a promising material for wound healing dressing for chronic diabetic wounds.

Masood N ，Ahmed R ，Tariq M ，Ahmed Z ，Masoud MS ，Ali I ，Asghar R ，Andleeb A ，Hasan A ... -  《-》

Biomedical potential of chitosan-silver nanoparticles with special reference to antioxidant, antibacterial, hemolytic and in vivo cutaneous wound healing effects.

The aim of the present study was to prepare chitosan-PVA-silver nanoparticles (CS-AgNPs) through green method. Chitosan and PVA polymers acted as stabilizing agents. DLS and TEM analyses showed that CS-AgNPs were homogeneously dispersed in matrix with an average size of 190-200 nm. The CS-AgNPs were tested for their antioxidant and antibacterial properties and the results revealed that they exhibited higher antioxidant activity than CS powder. Moreover, CS-AgNPs were characterized by a low cytotoxicity effect at 5-200 μg/ml against Chinese Hamster Ovary (CHO-K1) cells. In addition, the prepared CS-Ag NPs were found to promote significantly the wound healing, as determined by the wound contraction ratio and histological examination. A significant improvement in wound healing progression and in oxidative stress damage were observed for CS, CS-PVA and CS-AgNPs-treated wound tissues, when compared to control and CICAFLORA®-treated groups. The wound healing effect could be attributed to the antibacterial and antioxidant synergy of AgNPs and CS. Results strongly support the possibility of using CS-AgNPs for wound care applications.

Hajji S ，Khedir SB ，Hamza-Mnif I ，Hamdi M ，Jedidi I ，Kallel R ，Boufi S ，Nasri M ... -  《-》

In situ reduction of silver nanoparticles by gelatin to obtain porous silver nanoparticle/chitosan composites with enhanced antimicrobial and wound-healing activity.

The identification of materials with beneficial properties for wound healing is a major research goal. In this study, gelatin was used as a reducing agent and stabilizer to restore silver nanoparticles (AgNPs) in situ, which were mixed with chitosan (CS), crosslinked with tannic acid, and then freeze-dried to obtain a new composite Gelatin/CS/Ag. Gelatin/CS/Ag has a dense pore structure with a pore size of about 100-250 μm. The pores were interconnected. The existence of AgNPs was proven by UV visible spectrophotometry, XRD, and electron microscopy. Gelatin/CS/Ag exhibited good mechanical properties, water absorption, and moisture retention. The material was evaluated in antibacterial experiments, and a good inhibitory effect of Gelatin/CS/Ag was observed. Gelatin/CS/Ag co-cultured with L929 cells did not show cytotoxicity. Finally, Gelatin/CS/Ag promoted wound healing and showed good biocompatibility. In summary, Gelatin/CS/Ag has promising antibacterial and wound healing properties.

Ye H ，Cheng J ，Yu K 《-》