Magnolol Hybrid Nanofibrous Mat with Antibacterial, Anti-Inflammatory, and Microvascularized Properties for Wound Treatment

Procyanidin-crosslinked gradient silk fibroin composite nanofiber scaffold with sandwich structure for rotator cuff repair

Improving the regeneration of the tendon-bone interface (TBI) helps to decrease the risk of rotator cuff retears after repair surgeries. Unfortunately, the lack of inherent healing capacity of the TBI, insufficient mechanical properties, and abnormal and persistent inflammation during repair are the key factors leading to suboptimal healing of the rotator cuff. Therefore, a high-strength rotator cuff repair material capable of regulating the unbalanced immune response and enhancing the regeneration of the TBI is urgently needed. In this study, a novel sandwiched silk fibroin composite nanofiber scaffold with a biomimetic gradient structure was prepared through layer-by-layer continuous electrospinning, and then procyanidin was utilized to further enhance the mechanical properties and biological activities of the scaffold. The physicochemical characterization revealed that the procyanidin-crosslinked sandwiched gradient scaffold (GMPC) possessed an appropriate porosity and pore size and superior mechanical properties. Cytocompatibility assessment and immunofluorescence staining indicated that GMPC allowed rapid adhesion, proliferation, and infiltration of osteoblasts. ELISA and macrophage polarization experiments further confirmed that GMPC could effectively inhibit excessive inflammation in injured tissues and regulate the polarization of macrophages to the beneficial phenotype. Therefore, the procyanidin-crosslinked sandwiched gradient nanofiber scaffold might be a promising candidate for rotator cuff repair.

Polymer-Free Electrospinning of β-Cyclodextrin-Oligolactide for Magnolol and Honokiol Pharmaceutical Formulations

Background: Magnolol (MG) and honokiol (HK) are bioactive compounds extracted from Magnolia obovata and Magnolia Officinalis trees with significant pharmacological properties, including antioxidant and antibacterial activity. However, their poor water solubility and low bioavailability limit the therapeutic potential. Methods: To address these limitations, this study aims to develop MG and HK formulations by co-electrospinning using custom-synthesized β-cyclodextrin-oligolactide (β-CDLA) derivatives. MALDI MS and NMR were employed for the structural assessment of the β-CDLA derivatives. This polymer-free electrospinning technique utilizes the high solubility of β-CDLA to incorporate MG and HK into fibrous webs. The morphology of the resulting fibers is established by SEM and further characterized using FTIR and NMR spectroscopy to confirm the successful incorporation of MG and HK. The antioxidant activity was determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, while the antimicrobial activity was evaluated against several standard microorganisms (Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans). Results: The MG and HK electrospun formulations were prepared using highly concentrated feed solutions in dimethylformamide (180% w/v). The resulting β-CDLA fibers, with diameters above 400 nm and an active compound content of 7% wt., exhibited enhanced long-term antioxidant activity and improved antimicrobial efficacy, including notable activity against Escherichia coli. Conclusions: This study demonstrates the potential of MG and HK-loaded β-CDLA fibrous formulations as delivery systems with prolonged antioxidant activity and notable antibacterial efficacy, providing a promising platform for biomedical applications.

VR23 and Bisdemethoxycurcumin Enhanced Nanofiber Niche with Durable Bidirectional Functions for Promoting Wound Repair and Inhibiting Scar Formation

Chronic wounds pose a significant clinical challenge worldwide, which is characterized by impaired tissue regeneration and excessive scar formation due to over-repair. Most studies have focused on developing wound repair materials that either facilitate the healing process or control hyperplastic scars caused by over-repair, respectively. However, there are limited reports on wound materials that can both promote wound healing and prevent scar hyperplasia at the same time. In this study, VR23-loaded dendritic mesoporous bioglass nanoparticles (dMBG) are synthesized and electrospun in poly(ester-curcumin-urethane)urea (PECUU) random composite nanofibers (PCVM) through the synergistic effects of physical adsorption, hydrogen bond, and electrospinning. The physicochemical characterization reveals that PCVM presented matched mechanical properties, suitable porosity, and wettability, and enabled sustained and temporal release of VR23 and BDC with the degradation of PCVM. In vitro experiments demonstrated that PCVM can modulate the functions and polarization of macrophages under an inflammatory environment, and possess effective anti-scarring potential and reliable cytocompatibility. Animal studies further confirmed that PCVM can efficiently promote re-epithelialization and angiogenesis and reduce excessive inflammation, thereby remarkably accelerating wound healing while preventing potential scarring. These findings suggest that the prepared PCVM holds promise as a bidirectional regulatory dressing for effectively promoting scar-free healing of chronic wounds.

Preparation and characterization of intelligent and active bi-layer film based on carrageenan/pectin for monitoring freshness of salmon

This work aimed to develop and characterize a novel bi-layer film (BIF) for monitoring the freshness of salmon. The indicator layer consists of carrageenan (Car), pectin (PEC) and purple sweet potato anthocyanin (PSPA), and the antibacterial layer consists of Car and magnolol (Mag). The results showed that the Car/Mag2 had the optimal water resistance: the static water contact angle of 80.36 ± 0.92 °, moisture content of 31.38 ± 0.86 %, swelling degree of 92.96 ± 0.46 %, and water solubility of 40.08 ± 1.17 %, and showed excellent antibacterial properties against E. coli and S. aureus with antibacterial rate of 86.13 % ± 0.10 % and 97.53 % ± 0.02 %, respectively. Then BIFs with different PSPA concentration were tested. The morphology, mechanical and water vapor properties (WVP) of the BIFs were studied, and its application in salmon preservation was evaluated. The mechanical properties and WVP test results showed that the BIF0.2 had the optimal Tensile strength (TS) and WVP values. The BIFs showed distinguishable color changes between the pH ranges of 3-10. The shelf life of salmon packaged by BIF0.2 was prolonged by 2 days. Moreover, the BIF0.2 was able to effectively monitor salmon freshness. In conclusion, the BIF has great potential for monitoring salmon meat freshness.

Graphene-silymarin-loaded chitosan/gelatin/hyaluronic acid hybrid constructs for advanced full-thickness burn wound management

Burn wounds (BWs) with extensive blood loss, along with bacterial infections and poor healing, may become detrimental and pose significant rehabilitation obstacles in medical facilities. Therefore, the freeze-drying method synthesized novel hemocompatible chitosan, gelatin, and hyaluronic acid infused with graphene oxide-silymarin (CGH-SGO) hybrid constructs for application as a BW patch. Most significantly, synthesized hybrid constructs exhibited an interconnected-porous framework with precise pore sizes (≈118.52 µm) conducive to biological functions. Furthermore, the FTIR and XRD analyses document the constructs' physiochemical interactions. Similarly, enhanced swelling ratios, adequate WVTR (736 ± 78 g m-2 hr-1), and bio-degradation rates were seen during the physiological examination of constructs. Following the in vitro investigations, SMN-GO added to constructs improved their anti-bacterial (against E.coli and S. aureus), anti-oxidant, hemocompatible, and bio-compatible characteristics in conjunction with prolonged drug release. Furthermore, in vivo, implanting constructs on wounds exhibited significant acceleration in full-thickness burn wound (FT-BW) healing on the 14th day (CGH-SGO: 95 ± 2.1 %) in contrast with the control (Gauze: 71 ± 4.2 %). Additionally, contrary to gauze, the in vivo rat tail excision model administered with constructs assured immediate blood clotting. Therefore, CGH-SGO constructs with an improved porous framework, anti-bacterial activity, hemocompatibility, and biocompatibility could represent an attractive option for healing FT-BWs.

Silk fibroin-based dressings with antibacterial and anti-inflammatory properties

Silk fibroin is a fibrillar protein obtained from arthropods such as mulberry and non-mulberry silkworms. Silk fibroin has been used as a dressing in wound treatment for its physical, chemical, mechanical, and biological properties. This systematic review analyzed studies from PubMed, Web of Science, and Scopus databases to identify the molecules preferred for functionalizing silk fibroin-based dressings and to describe their mechanisms of exhibiting anti-inflammatory and antibacterial properties. The analysis of the selected articles allowed us to classify the dressings into different conformations, such as membranes, films, hydrogels, sponges, and bioadhesives. The incorporation of various molecules, including antibiotics, natural products, peptides, nanocomposites, nanoparticles, secondary metabolites, growth factors, and cytokines, has allowed the development of dressings that promote wound healing with antibacterial and immunomodulatory properties. In addition, silk fibroin-based dressings have been established to have the potential to regenerate wounds such as venous ulcers, arterial ulcers, diabetic foot, third-degree burns, and neoplastic ulcers. Evaluation of the efficacy of silk fibroin-based dressings in tissue engineering is an area of great activity that has shown significant advances in recent years.

Bacteria-targeted magnolol-loaded multifunctional nanocomplexes for antibacterial and anti-inflammatory treatment

Natural plant-derived small molecules have shown great potential for their antimicrobial and anti-inflammatory properties. In this study, we successfully developed a nanocomplex consisting of magnolol (Mag), a surfactant with an 18 carbon hydrocarbon chain and multi-amine head groups (C18N3), and a peptide (cyclic 9-amino acid peptide (CARG)) with targeting capabilities forStaphylococcus aureus(S. aureus). The obtained Mag/C18N3/CARG nanocomplexes exhibited strong antibacterial activity againstS. aureus. Furthermore, they demonstrated anti-inflammatory effects by reducing the secretion of pro-inflammatory cytokines such as TNF-α, IL-6, and IL-1βfrom macrophage inflammatory cells. This was achieved through downregulating the activation of NF-κB, KEAP1, and NRF2 signaling pathways. In a murine skin infection model, the Mag/C18N3/CARG nanocomplexes effectively suppressed the growth ofS. aureusin the infected area and promoted wound healing. Additionally, in a mouse model of acute kidney injury (AKI), the nanocomplexes significantly reduced the levels of blood urea nitrogen and creatinine, leading to a decrease in mortality rate. These findings demonstrate the potential of combining natural plant-derived small molecules with C18N3/CARG assemblies as a novel approach for the development of effective and safe antibacterial agents.

Silk fibroin-derived electrospun materials for biomedical applications: A review

Electrospinning is a versatile technique for fabricating polymeric fibers with diameters ranging from micro- to nanoscale, exhibiting multiple morphologies and arrangements. By combining silk fibroin (SF) with synthetic and/or natural polymers, electrospun materials with outstanding biological, chemical, electrical, physical, mechanical, and optical properties can be achieved, fulfilling the evolving biomedical demands. This review highlights the remarkable versatility of SF-derived electrospun materials, specifically focusing on their application in tissue regeneration (including cartilage, cornea, nerves, blood vessels, bones, and skin), disease treatment (such as cancer and diabetes), and the development of controlled drug delivery systems. Additionally, we explore the potential future trends in utilizing these nanofibrous materials for creating intelligent biomaterials, incorporating biosensors and wearable sensors for monitoring human health, and also discuss the bottlenecks for its widespread use. This comprehensive overview illuminates the significant impact and exciting prospects of SF-derived electrospun materials in advancing biomedical research and applications.

An antibacterial and healing-promoting collagen fibril constructed by the simultaneous strategy of fibril reconstitution and ε-polylysine anchoring for infected wound repair

The development of antibacterial dressings has attracted much attention to address the disordered wound healing caused by bacterial infection. Constructing dressings that have desirable antibacterial activity and could promote wound healing is important for infected wound repair. Inspired by the role of the key regulator collagen fibrils with D-periodic functional domains in the physiological wound healing process, we developed an antibacterial and wound healing-promoting collagen fibril with a structure highly similar to natural collagen in ECM and inherent antibacterial activity by the simultaneous strategy of fibril reconstitution and the antibacterial agent ε-polylysine (ε-PL) anchoring. Accompanied by the fibrillogenesis of collagen molecules, the anchorage of ε-PL into collagen fibrils was actualized through the formation of the covalent bond catalyzed by transglutaminase (TGase) between ε-PL and collagen. The collagen fibril possessed natural D-periodicity and achieved 20% ε-PL graft yield by co-assembling collagen/ε-PL mediated by 25 U g-1 TGase, which showed a satisfactory proliferation of L929 fibroblasts and sustained inhibition rates above 90% against E. coli and S. aureus. The rat S. aureus-infected dermal wound model further demonstrated that the reconstituted antibacterial collagen fibril visibly promoted re-epithelialization, new collagen deposition, and angiogenesis by down-regulating the inflammatory-relative gene IL-6 and up-regulating the relative activity factor expression of CD31, achieving accelerated infected wound healing with 61.89% ± 3.96% wound closure on postoperative day 7 and full closure on day 14.

Mesoporous chitosan nanofibers loaded with norfloxacin and coated with phenylboronic acid perform as bioabsorbable active dressings to accelerate the healing of burn wounds

The paper reports new chitosan-based nanofibers, designed to address the healing of burn wounds. To this aim, mesoporous chitosan fiber mats were prepared by electrospinning using poly(ethylene oxide) as sacrificial additive, followed by loading with norfloxacin and coating with an antifungal agent via dynamic imine bonds. Dynamic vapor sorption experiment proved intra-fiber mesopores around 2.7 nm, and UV-vis, FTIR, and NMR spectroscopy confirmed the norfloxacin embedding and the imination reaction. SEM, AFM and POM techniques displayed semicrystalline nanofibers with average diameter around 170 nm entangled into a non-woven mat. Their mesoporous nature favored a rapid adsorption of fluids up to 17 g/g, and a biodegradation rate fitting the wound healing rate, i.e. up to 30 % mass loss in media of pH characteristic to wound exudate and total degradation in that characteristic to normal dermis. The composite fibers released the NFX and 2FPBA in a controlled manner, and showed antimicrobial activity against gram positive, gram negative and fungal strains. They had no cytotoxic effect on normal human dermal fibroblasts, and showed biocompatibility on experimental rats. The investigation of wound healing ability on second/third-degree burn model in rats revealed wound closure and total restoration of the fully functional dermis and epidermis.

Design of 3D polycaprolactone/ε-polylysine-modified chitosan fibrous scaffolds with incorporation of bioactive factors for accelerating wound healing

Electrospun nanofibrous scaffolds show great application potentials for wound healing owing to their effective simulation of extracellular matrix (ECM). Three-dimensional (3D) nanofibrous dressings exhibit relatively high specific surface areas, better mimicry of native ECM, adjustable hydrophilicity and breathability, good histocompatibility, enhanced wound healing, and reduced inflammation. In the present work, we designed the 3D polycaprolactone/ε-polylysine modified chitosan (PCL/PCS) nanofibrous scaffolds by an electrospinning and gas foaming process. Then, gelatin and heparin (Gel/Hep) were assembled onto the surface of PCL/PCS nanofibers by electrostatic adsorption, and vascular endothelial growth factors (VEGFs) were also synchronously incorporated into Gel/Hep layer to form a multifunctional 3D nanofibrous scaffold (PCL/PCS@Gel/Hep+VEGF) for accelerating wound healing. The as-fabricated 3D PCL/PCS@GEL/Hep+VEGF nanofibrous scaffold showed excellent antibacterial ability, hemocompatibility and biocompatibility in vitro and wound healing ability in vivo. Immunological analysis showed that the as-fabricated nanofibrous scaffold inhibited inflammation at the wound sites while promoting angiogenesis during the wound healing process. STATEMENT OF SIGNIFICANCE: The electrospun 3D fibrous scaffolds using polycaprolactone/ε-polylysine modified chitosan (PCL/PCS) have been fabricated as backbone for mimicking the extracellular matrix (ECM). Gelatin and heparin (Gel/Hep) were wrapped onto the surface of PCL/PCS fibers by electrostatic adsorption and vascular endothelial growth factors (VEGFs) were also synchronously incorporated into surface Gel/Hep layer to form multifunctional 3D fibrous scaffolds. The as-fabricated multifunctional 3D fibrous scaffolds with good antibacterial ability and biocompatibility have been used as dressings for accelerating wound healing by inhibiting inflammation at the wound sites while promoting angiogenesis during the wound healing process.