Synthesis of Antibacterial Silver–Poly(ɛ-caprolactone)-Methacrylic Acid Graft Copolymer Nanofibers and Their Evaluation as Potential Wound Dressing

Reinforcement of Polycaprolactone/Chitosan with Nanoclay and Controlled Release of Curcumin for Wound Dressing

A novel clay-reinforced polycaprolactone/chitosan/curcumin (PCl/CS/Clay/Cur) composite film was fabricated in this study. The prepared Cur-loading composite films were characterized with attenuated total reflection Fourier transformed infrared spectroscopy, scanning electron microscopy, atomic force microscopy, water contact angle, differential scanning calorimetry, thermogravimetric analysis, and X-ray diffraction, and the results showed good dispersion of clay in the composite films. The addition of nanoclay was found to significantly increase the tensile strength. Also, the clay-enhanced drug-loading films exhibited better controlled-release profiles of Cur than those membranes without clay. Skin disinfection test demonstrated that the curcumin-loaded film could protect wound from bacterial infection. Cytotoxicity analysis proved the good biocompatibility of the composite films. The clay-enhanced Cur-loading films might be promising candidates for wound care.

Polydopamine-Based Surface Modification of ZnO Nanoparticles on Sericin/Polyvinyl Alcohol Composite Film for Antibacterial Application

Silk sericin (SS) is a type of natural macromolecular protein with excellent hydrophilicity, biocompatibility and biodegradability, but also has very poor mechanical properties. To develop sericin-based wound dressings, we utilized polyvinyl alcohol (PVA) to reinforce the mechanical property of sericin by blending PVA and sericin, then modified zinc oxide nanoparticles (ZnO NPs) on SS/PVA film with the assistance of polydopamine (PDA) to endow SS/PVA film with antibacterial activity. Scanning electron microscopy, energy dispersive spectroscopy and X-ray powder diffraction demonstrated ZnO NPs were well grafted on PDA-SS/PVA film. Fourier transform infrared spectra suggested PDA coating and ZnONPs modification did not alter the structure of sericin and PVA. Water contact angle and swelling tests indicated the excellent hydrophilicity and swellability of ZnO NPs-PDA-SS/PVA composite film. Mass loss analysis showed ZnO NPs-PDA-SS/PVA film had excellent stability. The mechanical performance test suggested the improved tensile strength and elongation at break could meet the requirement of ZnO NPs-PDA-SS/PVA film in biomaterial applications. The antibacterial assay suggested the prepared ZnO NPs-PDA-SS/PVA composite film had a degree of antimicrobial activity against Escherichia coli and Staphylococcus aureus. The excellent hydrophilicity, swellability, stability, mechanical property and antibacterial activity greatly promote the possibility of ZnO NPs-PDA-SS/PVA composite film in antibacterial biomaterials application.

Methacrylic acid/butyl acrylate onto feruloylated bagasse xylan: Graft copolymerization and biological activity

In this paper, feruloylated bagasse xylan (FBX) was synthesized with a method based on homogeneous catalytic esterification of bagasse xylan (BX) with ferulic acid (FA) in the presence of triethylamine as a catalyst, and it was further grafted with methacrylic acid (MAA) and butyl acrylate (BA) to synthesize FBX-g-MAA/BA grafted copolymer by using ammonium persulfate as initiator and N,N-methylene acrylamide as cross-linker. The effects of reaction variables including reaction time, temperature and reactant concentration on the esterification and graft reactions were investigated carefully by conducting orthogonal tests. A maximum degree of substitution (DS) of 1.76 for the esterification and a maximum graft ratio (GR) of 31% can be achieved by performing the reaction at optimized reaction parameters. The molecular docking was further performed to study the binding mode of the final product into the active site of human Caprin-2 C1q domain (4OUM, cause gastric cancer protein), liver cancer protein (1UV0) and lung cancer protein (3B9S). The software generated results were in satisfactory agreement with the evaluated biological activity. The anticancer performances of BX, FBX and FBX-g-MAA/BA copolymer were investigated by using a 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazoliumbromide (MTT) method. The results indicated that the inhibition ratio of FBX-g-MAA/BA copolymer on BEL-7407 (liver cancer cells) can reach 25.28% ± 4.01%, which is two times higher than that of BX.

Antioxidative study of Cerium Oxide nanoparticle functionalised PCL-Gelatin electrospun fibers for wound healing application

Skin wound healing involves a coordinated cellular response to achieve complete reepithelialisation. Elevated levels of reactive oxygen species (ROS) in the wound environment often pose a hindrance in wound healing resulting in impaired wound healing process. Cerium oxide nanoparticles (CeNPs) have the ability to protect the cells from oxidative damage by actively scavenging the ROS. Furthermore, matrices like nanofibers have also been explored for enhancing wound healing. In the current study CeNP functionalised polycaprolactone (PCL)-gelatin nanofiber (PGNPNF) mesh was fabricated by electrospinning and evaluated for its antioxidative potential. Wide angle XRD analysis of randomly oriented nanofibers revealed ∼2.6 times reduced crystallinity than pristine PCL which aided in rapid degradation of nanofibers and release of CeNP. However, bioactive composite made between nanoparticles and PCL-gelatin maintained the fibrous morphology of PGNPNF upto 14 days. The PGNPNF mesh exhibited a superoxide dismutase (SOD) mimetic activity due to the incorporated CeNPs. The PGNPNF mesh enhanced proliferation of 3T3-L1 cells by ∼48% as confirmed by alamar blue assay and SEM micrographs of cells grown on the nanofibrous mesh. Furthermore, the PGNPNF mesh scavenged ROS, which was measured by relative DCF intensity and fluorescence microscopy; and subsequently increased the viability and proliferation of cells by three folds as it alleviated the oxidative stress. Overall, the results of this study suggest the potential of CeNP functionalised PCL-gelatin nanofibrous mesh for wound healing applications.

Electrospun poly(ε-caprolactone) matrices containing silver sulfadiazine complexed with β-cyclodextrin as a new pharmaceutical dosage form to wound healing: preliminary physicochemical and biological evaluation

Cooperation between researchers in the areas of medical, pharmaceutical and materials science has facilitated the development of pharmaceutical dosage forms that elicit therapeutic effects and protective action with a single product. In addition to optimizing pharmacologic action, such dosage forms provide greater patient comfort and increase success and treatment compliance. In the present work, we prepared semipermeable bioactive electrospun fibers for use as wound dressings containing silver sulfadiazine complexed with β-cyclodextrin in a poly(Ɛ-caprolactone) nanofiber matrix aiming to reduce the direct contact between silver and skin and to modulate the drug release. Wound dressings were prepared by electrospinning, and were subjected to ATR-FT-IR and TG/DTG assays to evaluate drug stability. The hydrophilicity of the fibrous nanostructure in water and PBS buffer was studied by goniometry. Electrospun fibers permeability and swelling capacity were assessed, and a dissolution test was performed. In vitro biological tests were realized to investigate the biological compatibility and antimicrobial activity. We obtained flexible matrices that were each approximately 1.0 g in weight. The electrospun fibers were shown to be semipermeable, with water vapor transmission and swelling indexes compatible with the proposed objective. The hydrophilicity was moderate. Matrices containing pure drug modulated drug release adequately during 24 h but presented a high hemolytic index. Complexation promoted a decrease in the hemolytic index and in the drug release but did not negatively impact antimicrobial activity. The drug was released predominantly by diffusion. These results indicate that electrospun PCL matrices containing β-cyclodextrin/silver sulfadiazine inclusion complexes are a promising pharmaceutical dosage form for wound healing.

Hydroxypropyltrimethyl Ammonium Chloride Chitosan Functionalized-PLGA Electrospun Fibrous Membranes as Antibacterial Wound Dressing: In Vitro and In Vivo Evaluation

A novel poly(lactic-co-glycolic acid) (PLGA)-hydroxypropyltrimethyl ammonium chloride chitosan (HACC) composite nanofiber wound dressing was prepared through electrospinning and the entrapment-graft technique as an antibacterial dressing for cutaneous wound healing. HACC with 30% degrees of substitution (DS) was immobilized onto the surface of PLGA membranes via the reaction between carboxyl groups in PLGA after alkali treatment and the reactive groups (⁻NH₂) in HACC molecules. The naked PLGA and chitosan graft PLGA (PLGA-CS) membranes served as controls. The surface immobilization was characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared (FTIR), thermogravimetric analysis (TGA) and energy dispersive X-ray spectrometry (EDX). The morphology studies showed that the membranes remain uniform after the immobilization process. The effects of the surface modification by HACC and CS on the biological properties of the membranes were also investigated. Compared with PLGA and PLGA-CS, PLGA-HACC exhibited more effective antibacterial activity towards both Gram-positive (S. aureus) and Gram-negative (P. aeruginosa) bacteria. The newly developed fibrous membranes were evaluated in vitro for their cytotoxicity using human dermal fibroblasts (HDFs) and human keratinocytes (HaCaTs) and in vivo using a wound healing mice model. It was revealed that PLGA-HACC fibrous membranes exhibited favorable cytocompatibility and significantly stimulated adhesion, spreading and proliferation of HDFs and HaCaTs. PLGA-HACC exhibited excellent wound healing efficacy, which was confirmed using a full thickness excision wound model in S. aureus-infected mice. The experimental results in this work suggest that PLGA-HACC is a strong candidate for use as a therapeutic biomaterial in the treatment of infected wounds.

Fabrication of Nerve Growth Factor Encapsulated Aligned Poly(ε-Caprolactone) Nanofibers and Their Assessment as a Potential Neural Tissue Engineering Scaffold

Peripheral nerve injury is a serious clinical problem to be solved. There has been no breakthrough so far and neural tissue engineering offers a promising approach to promote the regeneration of peripheral neural injuries. In this study, emulsion electrospinning technique was introduced as a flexible and promising technique for the fabrication of random (R) and aligned (A) Poly(ε-caprolactone) (PCL)-Nerve Growth Factor (NGF)&Bovine Serum Albumin (BSA) nanofibrous scaffolds [(R/A)-PCL-NGF&BSA], where NGF and BSA were encapsulated in the core while PCL form the shell. Random and aligned pure PCL, PCL-BSA, and PCL-NGF nanofibers were also produced for comparison. The scaffolds were characterized by Field Emission Scanning Electron Microscopy (FESEM) and water contact angle test. Release study showed that, with the addition of stabilizer BSA, a sustained release of NGF from emulsion electrospun PCL nanofibers was observed over 28 days. [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt; MTS] assay revealed that (R/A)-PCL-NGF and (R/A)-PCL-NGF&BSA scaffolds favored cell growth and showed no cytotoxicity to PC12 cells. Laser scanning confocal microscope images exhibited that the A-PCL-NGF&BSA scaffold increased the length of neurites and directed neurites extension along the fiber axis, indicating that the A-PCL-NGF&BSA scaffold has a potential for guiding nerve tissue growth and promoting nerve regeneration.