Fabrication and characterization of biosilver nanoparticles loaded calcium pectinate nano-micro dual-porous antibacterial wound dressings

A neoteric antibacterial ceria-silver nanozyme for abiotic surfaces

Community-associated and hospital-acquired infections caused by bacteria continue to yield major global challenges to human health. Bacterial contamination on abiotic surfaces is largely spread via high-touch surfaces and contemporary standard disinfection practices show limited efficacy, resulting in unsatisfactory therapeutic outcomes. New strategies that offer non-specific and broad protection are urgently needed. Herein, we report our novel ceria-silver nanozyme engineered at a molar ratio of 5:1 and with a higher trivalent (Ce3+) surface fraction. Our results reveal potent levels of surface catalytic activity on both wet and dry surfaces, with rapid, and complete eradication of Pseudomonas aeruginosa, Staphylococcus aureus, and methicillin resistant S. aureus, in both planktonic and biofilm form. Preferential electrostatic adherence of anionic bacteria to the cationic nanozyme surface leads to a catastrophic loss in both aerobic and anaerobic respiration, DNA damage, osmodysregulation, and finally, programmed bacterial lysis. Our data reveal several unique mechanistic avenues of synergistic ceria-Ag efficacy. Ag potentially increases the presence of Ce3+ sites at the ceria-Ag interface, thereby facilitating the formation of harmful H2O2, followed by likely permeation across the cell wall. Further, a weakened Ag-induced Ce-O bond may drive electron transfer from the Ec band to O2, thereby further facilitating the selective reduction of O2 toward H2O2 formation. Ag destabilizes the surface adsorption of molecular H2O2, potentially leading to higher concentrations of free H2O2 adjacent to bacteria. To this end, our results show that H2O2 and/or NO/NO2-/NO3- are the key liberators of antibacterial activity, with a limited immediate role being offered by nanozyme-induced ROS including O2•- and OH•, and likely other light-activated radicals. A mini-pilot proof-of-concept study performed in a pediatric dental clinic setting confirms residual, and continual nanozyme antibacterial efficacy over a 28-day period. These findings open a new approach to alleviate infections caused by bacteria for use on high-touch hard surfaces.

Applications of drug delivery systems, organic, and inorganic nanomaterials in wound healing

The skin is known to be the largest organ in the human body, while also being exposed to environmental elements. This indicates that skin is highly susceptible to physical infliction, as well as damage resulting from medical conditions such as obesity and diabetes. The wound management costs in hospitals and clinics are expected to rise globally over the coming years, which provides pressure for more wound healing aids readily available in the market. Recently, nanomaterials have been gaining traction for their potential applications in various fields, including wound healing. Here, we discuss various inorganic nanoparticles such as silver, titanium dioxide, copper oxide, cerium oxide, MXenes, PLGA, PEG, and silica nanoparticles with their respective roles in improving wound healing progression. In addition, organic nanomaterials for wound healing such as collagen, chitosan, curcumin, dendrimers, graphene and its derivative graphene oxide were also further discussed. Various forms of nanoparticle drug delivery systems like nanohydrogels, nanoliposomes, nanofilms, and nanoemulsions were discussed in their function to deliver therapeutic agents to wound sites in a controlled manner.

The fabrication and evaluation of silver nanoparticle-based keratin scaffolds

The biotoxicity caused by focus releasing of Ag, which associated with the Ag loading mode, is a problematic issue that need to be solved for practical utilization of the keratin based wound dressing. In this study, keratin/AgNPs blend scaffolds (Ker/Ag) and keratin scaffolds with AgNPs attached on the scaffold's wall surface (Ag@Ker) were prepared. Structure and physical properties of the scaffolds were tested and investigated. In comparison to the Ag@Ker scaffolds, the Ker/Ag scaffolds with uniform dispersion of AgNPs have larger tensile strength and slower degradation rate. Both kind of scaffolds present excellent antibacterial property with 10 μg mL^-1 AgNPs addition, while the Ker/Ag displayed a linear Ag releasing ratio in the first 5-7 days, which is beneficial for obtaining a continuous antibacterial property and avoiding the biotoxicity caused by focus release of Ag. Correspondingly, cytotoxicity assay further reveals that the continuously slow release of Ag of the Ker/Ag scaffolds accelerated the proliferation of cell. Infectious animal models and histological studies showed that the Ker/Ag scaffolds can effectively inhibit the inflammatory response and accelerate epithelialization. Thus, it can be concluded that the Ker/Ag scaffolds with uniform dispersion of AgNPs are more attractive as wound repair materials.

Compressed Hydrogen-Induced Synthesis of Quaternary Trimethyl Chitosan-Silver Nanoparticles with Dual Antibacterial and Antifungal Activities

Quaternary Trimethyl Chitosan (QTMC) and QTMC-Silver Nanoparticles (QTMC-AgNPs) have been synthesized, characterized, and tested as antibacterial agents against Staphylococcus aureus, Escherichia coli, and two plant fungi (Sclerotium rolfsil and Fusarium oxysporum). The as-prepared water-soluble QTMC was in situ reacted with silver nitrate in the presence of clean compressed hydrogen gas (3 bar) as a reducing agent to produce QTMC-AgNPs. UV-vis, ATR-FTIR, HR-TEM/SEM, XPS, DLS, XRD, and TGA/DTG were employed to assess the optical response, morphology/size, surface chemistry, particle size distribution, crystal nature, and thermal stability of the synthesized QTMC-AgNPs, respectively. The as-prepared QTMC-AgNPs were quasi-spherical in shape with an average particle size of 12.5 nm, as determined by ImageJ software utilizing HR-TEM images and further validated by DLS analysis. The development of crystalline nanoparticles was confirmed by the presence of distinct and consistent lattice fringes with an approximate interplanar d-spacing of 2.04 nm in QTMC-AgNPs. The QTMC-AgNPs exhibited significant antibacterial activity with a clear zone of inhibition of 30 mm and 26 mm around the disks against E. coli and S. aureus, respectively. In addition, QTMC-AgNPs showed highly efficient antifungal activity with 100% and 76.67% growth inhibition against two plant pathogens, S. rolfsii and F. oxysporum, respectively, whereas QTMC revealed no impact. Overall, QTMC-AgNPs showed a promising therapeutic potential and,thus, can be considered for drug design rationale.

A Critical Review of the Antimicrobial and Antibiofilm Activities of Green-Synthesized Plant-Based Metallic Nanoparticles

Metallic nanoparticles (MNPs) produced by green synthesis using plant extracts have attracted huge interest in the scientific community due to their excellent antibacterial, antifungal and antibiofilm activities. To evaluate these pharmacological properties, several methods or protocols have been successfully developed and implemented. Although these protocols were mostly inspired by the guidelines from national and international regulatory bodies, they suffer from a glaring absence of standardization of the experimental conditions. This situation leads to a lack of reproducibility and comparability of data from different study settings. To minimize these problems, guidelines for the antimicrobial and antibiofilm evaluation of MNPs should be developed by specialists in the field. Being aware of the immensity of the workload and the efforts required to achieve this, we set out to undertake a meticulous literature review of different experimental protocols and laboratory conditions used for the antimicrobial and antibiofilm evaluation of MNPs that could be used as a basis for future guidelines. This review also brings together all the discrepancies resulting from the different experimental designs and emphasizes their impact on the biological activities as well as their interpretation. Finally, the paper proposes a general overview that requires extensive experimental investigations to set the stage for the future development of effective antimicrobial MNPs using green synthesis.

Swelling, Protein Adsorption, and Biocompatibility In Vitro of Gel Beads Prepared from Pectin of Hogweed Heracleum sosnówskyi Manden in Comparison with Gel Beads from Apple Pectin

The study aims to develop gel beads with improved functional properties and biocompatibility from hogweed (HS) pectin. HS4 and AP4 gel beads were prepared from the HS pectin and apple pectin (AP) using gelling with calcium ions. HS4 and AP4 gel beads swelled in PBS in dependence on pH. The swelling degree of HS4 and AP4 gel beads was 191 and 136%, respectively, in PBS at pH 7.4. The hardness of HS4 and AP4 gel beads reduced 8.2 and 60 times, respectively, compared with the initial value after 24 h incubation. Both pectin gel beads swelled less in Hanks’ solution than in PBS and swelled less in Hanks’ solution containing peritoneal macrophages than in cell-free Hanks’ solution. Serum protein adsorption by HS4 and AP4 gel beads was 118 ± 44 and 196 ± 68 μg/cm² after 24 h of incubation. Both pectin gel beads demonstrated low rates of hemolysis and complement activation. However, HS4 gel beads inhibited the LPS-stimulated secretion of TNF-α and the expression of TLR4 and NF-κB by macrophages, whereas AP4 gel beads stimulated the inflammatory response of macrophages. HS4 gel beads adsorbed 1.3 times more LPS and adhered to 1.6 times more macrophages than AP4 gel beads. Thus, HS pectin gel has advantages over AP gel concerning swelling behavior, protein adsorption, and biocompatibility.

Nanomaterials for application in wound Healing: current state-of-the-art and future perspectives

Nanoparticles are the gateway to the new era in drug delivery of biocompatible agents. Several products have emerged from nanomaterials in quest of developing practical wound healing dressings that are nonantigenic, antishear stress, and gas-exchange permeable. Numerous studies have isolated and characterised various wound healing nanomaterials and nanoproducts. The electrospinning of natural and synthetic materials produces fine products that can be mixed with other wound healing medications and herbs. Various produced nanomaterials are highly influential in wound healing experimental models and can be used commercially as well. This article reviewed the current state-of-the-art and briefly specified the future concerns regarding the different systems of nanomaterials in wound healing (i.e., inorganic nanomaterials, organic and hybrid nanomaterials, and nanofibers). This review may be a comprehensive guidance to help health care professionals identify the proper wound healing materials to avoid the usual wound complications.

Characterization and Biocompatibility Properties In Vitro of Gel Beads Based on the Pectin and κ-Carrageenan

This study aimed to investigate the influence of kappa (κ)-carrageenan on the initial stages of the foreign body response against pectin gel. Pectin-carrageenan (P-Car) gel beads were prepared from the apple pectin and κ-carrageenan using gelling with calcium ions. The inclusion of 0.5% κ-carrageenan (Car0.5) in the 1.5 (P1.5) and 2% pectin (P2) gel formulations decreased the gel strength by 2.5 times. Car0.5 was found to increase the swelling of P2 gel beads in the cell culture medium. P2 gel beads adsorbed 30–42 mg/g of bovine serum albumin (BSA) depending on pH. P2-Car0.2, P2-Car0.5, and P1.5-Car0.5 beads reduced BSA adsorption by 3.1, 5.2, and 4.0 times compared to P2 beads, respectively, at pH 7. The P1.5-Car0.5 beads activated complement and induced the haemolysis less than gel beads of pure pectin. Moreover, P1.5-Car0.5 gel beads allowed less adhesion of mouse peritoneal macrophages, TNF-α production, and NF-κB activation than the pure pectin gel beads. There were no differences in TLR4 and ICAM-1 levels in macrophages treated with P and P-Car gel beads. P2-Car0.5 hydrogel demonstrated lower adhesion to serous membrane than P2 hydrogel. Thus, the data obtained indicate that the inclusion of κ-carrageenan in the apple pectin gel improves its biocompatibility.

Development of nitric oxide releasing visible light crosslinked gelatin methacrylate hydrogel for rapid closure of diabetic wounds

Management of non-healing and slow to heal diabetic wounds is a major concern in healthcare across the world. Numerous techniques have been investigated to solve the issue of delayed wound healing, though, mostly unable to promote complete healing of diabetic wounds due to the lack of proper cell proliferation, poor cell-cell communication, and higher chances of wound infections. These challenges can be minimized by using hydrogel based wound healing patches loaded with bioactive agents. Gelatin methacrylate (GelMA) has been proven to be a highly cell friendly, cell adhesive, and inexpensive biopolymer for various tissue engineering and wound healing applications. In this study, S-Nitroso-N-acetylpenicillamine (SNAP), a nitric oxide (NO) donor, was incorporated in a highly porous GelMA hydrogel patch to improve cell proliferation, facilitate rapid cell migration, and enhance diabetic wound healing. We adopted a visible light crosslinking method to fabricate this highly porous biodegradable but relatively stable patch. Developed patches were characterized for morphology, NO release, cell proliferation and migration, and diabetic wound healing in a rat model. The obtained results indicate that SNAP loaded visible light crosslinked GelMA hydrogel patches can be highly effective in promoting diabetic wound healing.

Apoptotic Effect and Anticancer Activity of Biosynthesized Silver Nanoparticles from Marine Algae Chaetomorpha linum Extract Against Human Colon Cancer Cell HCT-116

The green approach of nanoparticle synthesis has gained more attention by researchers because of its nontoxic, eco-friendly, biocompatible, and sustainable nature. The present research investigated the anticancer effectiveness of silver nanoparticles synthesized from marine algae Chaetomorpha linum (C. linum) against colon cancer cell HCT-116 in vitro. Biosynthesized silver nanoparticles (C-AgNPs) are characterized using UV-spectrophotometry, dynamic light scattering (DLS), X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM). We demonstrated the dose-dependent cytotoxic effect of C-AgNPs in human colorectal carcinoma cells (HCT-116) using MTT assay. The apoptosis induction in HCT-116 cells caused by C-AgNPs has studied fluorescence microscope by staining with fluorogenic agents 4',6-diamidino-2-phenylindole (DAPI), rhodamine 123, and 2',7'-dichlorodihydrofluorescein diacetate (H₂DCFDA). By using a flow cytometric test, the apoptotic action of C-AgNPs was performed. The immunoblotting study of caspases, as well as pro-apoptotic and anti-apoptotic protein expression, was studied using the PCR technique to understand the underlying molecular mechanism of C-AgNPs on cancer cells. The apoptotic studies showed an increase in the expression of apoptotic caspase 3, caspase 9, BH3-interacting domain death agonist (Bid), and Bax, along with a decrease in the anti-apoptotic protein like Bcl-2 and Bcl-xl, thereby veritably confirmed by immunoblotting and qPCR technique. The biosynthesized C-AgNPs was an efficient anticancer agent that can induce apoptosis in the HCT-116 colon cells.

Benefits of Polyamide Nanofibrous Materials: Antibacterial Activity and Retention Ability for Staphylococcus Aureus

Although nanomaterials are used in many fields, little is known about the fundamental interactions between nanomaterials and microorganisms. To test antimicrobial properties and retention ability, 13 electrospun polyamide (PA) nanomaterials with different morphology and functionalization with various concentrations of AgNO₃ and chlorhexidine (CHX) were analyzed. Staphylococcus aureus CCM 4516 was used to verify the designed nanomaterials’ inhibition and permeability assays. All functionalized PAs suppressed bacterial growth, and the most effective antimicrobial nanomaterial was evaluated to be PA 12% with 4.0 wt% CHX (inhibition zones: 2.9 ± 0.2 mm; log₁₀ suppression: 8.9 ± 0.0; inhibitory rate: 100.0%). Furthermore, the long-term stability of all functionalized PAs was tested. These nanomaterials can be stored at least nine months after their preparation without losing their antibacterial effect. A filtration apparatus was constructed for testing the retention of PAs. All of the PAs effectively retained the filtered bacteria with log₁₀ removal of 3.3–6.8 and a retention rate of 96.7–100.0%. Surface density significantly influenced the retention efficiency of PAs (p ≤ 0.01), while the effect of fiber diameter was not confirmed (p ≥ 0.05). Due to their stability, retention, and antimicrobial properties, they can serve as a model for medical or filtration applications.

An Overview of Biopolymeric Electrospun Nanofibers Based on Polysaccharides for Wound Healing Management

Currently, despite the thoroughgoing scientific research carried out in the area of wound healing management, the treatment of skin injuries, regardless of etiology remains a big provocation for health care professionals. An optimal wound dressing should be nontoxic, non-adherent, non-allergenic, should also maintain a humid medium at the wound interfacing, and be easily removed without trauma. For the development of functional and bioactive dressings, they must meet different conditions such as: The ability to remove excess exudates, to allow gaseous interchange, to behave as a barrier to microbes and to external physical or chemical aggressions, and at the same time to have the capacity of promoting the process of healing by stimulating other intricate processes such as differentiation, cell adhesion, and proliferation. Over the past several years, various types of wound dressings including hydrogels, hydrocolloids, films, foams, sponges, and micro/nanofibers have been formulated, and among them, the electrospun nanofibrous mats received an increased interest from researchers due to the numerous advantages and their intrinsic properties. The drug-embedded nanofibers are the potential candidates for wound dressing application by virtue of: Superior surface area-to volume ratio, enormous porosity (can allow oxy-permeability) or reticular nano-porosity (can inhibit the microorganisms'adhesion), structural similitude to the skin extracellular matrix, and progressive electrospinning methodology, which promotes a prolonged drug release. The reason that we chose to review the formulation of electrospun nanofibers based on polysaccharides as dressings useful in wound healing was based on the ever-growing research in this field, research that highlighted many advantages of the nanofibrillary network, but also a marked versatility in terms of numerous active substances that can be incorporated for rapid and infection-free tissue regeneration. In this review, we have extensively discussed the recent advancements performed on electrospun nanofibers (eNFs) formulation methodology as wound dressings, and we focused as well on the entrapment of different active biomolecules that have been incorporated on polysaccharides-based nanofibers, highlighting those bioagents capable of improving the healing process. In addition, in vivo tests performed to support their increased efficacy were also listed, and the advantages of the polysaccharide nanofiber-based wound dressings compared to the traditional ones were emphasized.

Skin Toxicity Assessment of Silver Nanoparticles in a 3D Epidermal Model Compared to 2D Keratinocytes

Introduction

Increased use of silver nanoparticles (AgNPs) has raised concerns that AgNPs may induce toxic effects. In vitro studies of cell monolayers and in vivo studies have produced conflicting results. The inconsistency of these results has been mainly due to limitations of two-dimensional (2D) monolayer cell systems.

Methods

A three-dimensional (3D) epidermal model called EpiKutis^®, which exhibits good tissue viability and barrier function was developed. The cytotoxicity of AgNPs against EpiKutis was compared to that against 2D keratinocytes at equivalent AgNPs doses (0.035, 0.07, 0.14, 0.28, and 0.56 ng per cell). The amount and distribution of AgNPs in the 3D EpiKutis and 2D keratinocytes after exposure were determined. The toxic mechanisms of AgNPs, such as oxidative stress and production of pro-inflammatory cytokines, were investigated.

Results

The results demonstrated that cell viability was greater than 80% and lactate dehydrogenase (LDH) release did not increase even at the highest dose of AgNPs in EpiKutis. In contrast, treatment of 2D keratinocytes with AgNPs resulted in dose-dependent decrease in cell viability from 63% to 11%, and a dose-dependent increase in LDH release from 8% to 16%. Cytotoxicity of AgNPs in 2D keratinocytes was related to oxidative damage and inflammation, as evidenced by increased levels of reactive oxygen species (ROS), malondialdehyde (MDA), IL-1α, IL-6, and IL-8. In addition, levels of superoxide dismutase (SOD) were decreased. EpiKutis treated with AgNPs did not exhibit increased oxidative damage or inflammation, which may have been due to the barrier properties of the 3D structure, resulting in reduced penetration of AgNPs. At equivalent per cell doses, total silver penetration into EpiKutis was 0.9 ± 0.1%, and total silver penetration into 2D keratinocytes was 8.8 ± 0.6% detected by ICP-MS. The penetration and distribution of AgNPs in 2D keratinocytes were confirmed by the TEM-EDS analysis, which was not found in the 3D EpiKutis. These results showed that AgNPs penetrated EpiKutis to a lesser degree than they penetrated 2D keratinocytes, which suggested that EpiKutis exhibited significant barrier function.

Discussion

The results of this study showed that AgNP toxicity should be evaluated using 3D epidermal models, which may provide better estimates of in vivo conditions than 2D models. The EpiKutis model may be an ideal model for assessment of nanotoxicity.

Reduced Graphene Oxide Incorporated GelMA Hydrogel Promotes Angiogenesis For Wound Healing Applications

PURPOSE

Non-healing or slow healing chronic wounds are among serious complications of diabetes that eventually result in amputation of limbs and increased morbidities and mortalities. Chronic diabetic wounds show reduced blood vessel formation (lack of angiogenesis), inadequate cell proliferation and poor cell migration near wounds. In this paper, we report the development of a hydrogel-based novel wound dressing material loaded with reduced graphene oxide (rGO) to promote cell proliferation, cell migration and angiogenesis for wound healing applications.

METHODS

Gelatin-methacryloyl (GelMA) based hydrogels loaded with different concentrations of rGO were fabricated by UV crosslinking. Morphological and physical characterizations (porosity, degradation, and swelling) of rGO incorporated GelMA hydrogel was performed. In vitro cell proliferation, cell viability and cell migration potential of the hydrogels were analyzed by MTT assay, live/dead staining, and wound healing scratch assay respectively. Finally, in vivo chicken embryo angiogenesis (CEO) testing was performed to evaluate the angiogenic potential of the prepared hydrogel.

RESULTS

The experimental results showed that the developed hydrogel possessed enough porosity and exudate-absorbing capacity. The biocompatibility of prepared hydrogel on three different cell lines (3T3 fibroblasts, EA.hy926 endothelial cells, and HaCaT keratinocytes) was confirmed by in vitro cell culture studies (live/dead assay). The GelMA hydrogel containing 0.002% w/w rGO considerably increased the proliferation and migration of cells as evident from MTT assay and wound healing scratch assay. Furthermore, rGO impregnated GelMA hydrogel significantly enhanced the angiogenesis in the chick embryo model.

CONCLUSION

The positive effect of 0.002% w/w rGO impregnated GelMA hydrogels on angiogenesis, cell migration and cell proliferation suggests that these formulations could be used as a functional wound healing material for the healing of chronic wounds.

Surface functionalization of central venous catheter with mycofabricated silver nanoparticles and its antibiofilm activity on multidrug resistant Acinetobacter baumannii

The mycofabrication of silver nanoparticles (AgNPs) through green chemistry protocol is an advanced methodological progress in medical nanotechnology. Mycofabricated AgNPs are less toxic due to an aura of biomolecules around the nanoparticles. Hence the mycofabricated AgNPs can be used for clinical applications. The present study explores the antibiofilm activity of mycogenerated AgNPs, which were synthesized by the enzymatic reduction of silver nitrate using the marine algicolous endophytic fungus Penicillium polonicum ARA10. The mycogenerated AgNPs showed very specific and potent bactericidal activity against Acinetobacter baumannii. Anti-A.baumannii activities of mycogenerated AgNPs on planktonic as well as biofilm embedded cells were explored. The physical impact of synthesized AgNPs on A.baumannii was investigated by scanning electron microscopy and fluorescence microscopy. A bionanocomposite coating for the central venous catheter (CVC) was formulated using the mycogenerated AgNPs and polydopamine. The bionanocomposite surface was characterized by field emission scanning electron microscopy, water contact angle measurement, and Raman spectroscopy. The results showed that the mycogenerated AgNPs have potent antibiofilm activity on biofilms of A.baumannii. The scanning electron microscopy (SEM) and fluorescence microscopy images showed noticeable aberrations on the ultrastructure of A.baumannii. The SEM and FE-SEM images of biofilms on the surface of CVC samples proved that the AgNPs at minimum bactericidal concentration could destroy the structure of biofilms and lyses the bacterial cell. Thus, the present study establishes a new way to the development of 'antibacterial surfaces' based on mycogenerated AgNPs.

Development of titanium dioxide nanowire incorporated poly(vinylidene fluoride-trifluoroethylene) scaffolds for bone tissue engineering applications

Critical size bone defects that do not heal spontaneously are among the major reasons for the disability in majority of people with locomotor disabilities. Tissue engineering has become a promising approach for repairing such large tissue injuries including critical size bone defects. Three-dimension (3D) porous scaffolds based on piezoelectric polymers like poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) have received a lot of attention in bone tissue engineering due to their favorable osteogenic properties. Owing to the favourable redox properties, titanium dioxide (TiO2) nanostructures have gained a great deal of attention in bone tissue engineering. In this paper, tissue engineering scaffolds based on P(VDF-TrFE) loaded with TiO2 nanowires (TNW) were developed and evaluated for bone tissue engineering. Wet-chemical method was used for the synthesis of TNW. Obtained TNW were thoroughly characterized for the physicochemical and morphological properties using techniques such as X-Ray diffraction (XRD) analysis and transmission electron microscopy (TEM). Electrospinning was used to produce TNW incorporated P(VDF-TrFE) scaffolds. Developed scaffolds were characterized by state of art techniques such as Scanning Electron Microscopy (SEM), XRD and Differential scanning calorimetry (DSC) analyses. TEM analysis revealed that the obtained TiO2 nanostructures possess nanofibrous morphology with an average diameter of 26 ± 4 nm. Results of characterization of nanocomposite scaffolds confirmed the effective loading of TNW in P(VDF-TrFE) matrix. Fabricated P(VDF-TrFE)/TNW scaffolds possessed good mechanical strength and cytocompatibility. Osteoblast like cells showed higher adhesion and proliferation on the nanocomposite scaffolds. This investigation revealed that the developed P(VDF-TrFE) scaffolds containing TNW can be used as potential scaffolds for bone tissue engineering applications.

Cerium Oxide Nanoparticle Incorporated Electrospun Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Membranes for Diabetic Wound Healing Applications

Insufficient cell proliferation, cell migration, and angiogenesis are among the major causes for nonhealing of chronic diabetic wounds. Incorporation of cerium oxide nanoparticles (nCeO₂) in wound dressings can be a promising approach to promote angiogenesis and healing of diabetic wounds. In this paper, we report the development of a novel nCeO₂ containing electrospun poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) membrane for diabetic wound healing applications. In vitro cell adhesion studies, chicken embryo angiogenesis assay, and in vivo diabetic wound healing studies were performed to assess the cell proliferation, angiogenesis, and wound healing potential of the developed membranes. The experimental results showed that nCeO₂ containing PHBV membranes can promote cell proliferation and cell adhesion when used as wound dressings. For less than 1% w/w of nCeO₂ content, human mammary epithelial cells (HMEC) were adhered parallel to the individual fibers of PHBV. For higher than 1% w/w of nCeO₂ content, cells started to flatten and spread over the fibers. In ovo angiogenic assay showed the ability of nCeO₂ incorporated PHBV membranes to enhance blood vessel formation. In vivo wound healing study in diabetic rats confirmed the wound healing potential of nCeO₂ incorporated PHBV membranes. The study suggests that nCeO₂ incorporated PHBV membranes have strong potential to be used as wound dressings to enhance cell proliferation and vascularization and promote the healing of diabetic wounds.

Titanium Nanorods Loaded PCL Meshes with Enhanced Blood Vessel Formation and Cell Migration for Wound Dressing Applications

Proper management of nonhealing wounds is an imperative clinical challenge. For the effective healing of chronic wounds, suitable wound coverage materials with the capability to accelerate cell migration, cell proliferation, angiogenesis, and wound healing are required to protect the healing wound bed. Biodegradable polymeric meshes are utilized as effective wound coverage materials to protect the wounds from the external environment and prevent infections. Among them, electrospun biopolymeric meshes have got much attention due to their extracellular matrix mimicking morphology, ability to support cell adhesion, and cell proliferation. Herein, electrospun nanocomposite meshes based on polycaprolactone (PCL) and titanium dioxide nanorods (TNR) are developed. TNR incorporated PCL meshes are fabricated by electrospinning technique and characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy (FTIR) analysis, and X-Ray diffraction (XRD) analysis. In vitro cell culture studies, in ovo angiogenesis assay, in vivo implantation study, and in vivo wound healing study are performed. Interestingly, obtained in vitro and in vivo results demonstrated that the presence of TNR in the PCL meshes greatly improved the cell migration, proliferation, angiogenesis, and wound healing. Owing to the above superior properties, they can be used as excellent biomaterials in wound healing and tissue regeneration applications.

Electrospun polyvinyl alcohol membranes incorporated with green synthesized silver nanoparticles for wound dressing applications

Electrospun membranes have the potential to act as an effective barrier for wounds from the external environment to prevent pathogens. In addition, materials with good antibacterial properties can effectively fight off the invading pathogens. In this paper, we report the development of a novel electrospun polyvinyl alcohol (PVA) membrane containing biosynthesized silver nanoparticle (bAg) for wound dressing applications. Plant extract from a medicinal plant Mimosa pudica was utilized for the synthesis of bAg. Synthesized bAg were characterized by Ultraviolet-Visible (UV) Spectroscopy and Fourier Transform Infrared Spectroscopy (FTIR). The morphology of bAg was obtained from Transmission Electron Microscopy (TEM) and found that they were spherical in morphology with average particle size 7.63 ± 1.2 nm. bAg nanoparticles incorporated PVA membranes were characterized using several physicochemical techniques such as Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS) and X-Ray Diffraction (XRD) analysis. Experimental results confirmed the successful incorporation of bAg in PVA fibers. PVA nanofiber membranes incorporated with bAg showed good mechanical strength, excellent exudate uptake capacity, antibacterial activity, blood compatibility and cytocompatibility.

Natural product-based nanomedicines for wound healing purposes: therapeutic targets and drug delivery systems

Wound healing process is an intricate sequence of well-orchestrated biochemical and cellular phenomena to restore the integrity of the skin and subcutaneous tissue. Several plant extracts and their phytoconstituents are known as a promising alternative for wound healing agents due to the presence of diverse active components, ease of access, and their limited side effects. The development of nanotechnological methods can help to improve the efficacy of different therapeutics as well as herbal-based products. Here, we present a review of the efficacy of the plant based-nanomaterials in the management of wounds and discuss the involved therapeutic targets. For this purpose, a profound search has been conducted on in vitro, in vivo, and/or clinical evidences evaluating the efficacy and pharmacological mechanisms of natural product-based nanostructures on different types of wounds. Different pharmacological targets are involved in the wound healing effects of herbal-based nanostructures, including suppressing the production of inflammatory cytokines and inflammatory transduction cascades, reducing oxidative factors and enhancing antioxidative enzymes, and promoting neovascularization and angiogenic pathways through increasing the expression of vascular endothelial growth factor, fibroblast growth factor, and platelet-derived growth factor. Moreover, nanostructure of plant extracts and their phytochemicals can enhance their bioavailability, control their release in the form of sustained delivery systems to the wound site, and enhance the permeability of these therapeutics to the underlying skin layers, which are all necessary for the healing process. Overall, various plant extracts and their natural compounds, used in nanoformulations, have demonstrated high activity in the management of wounds and thus can be assumed as future pharmaceutical drugs.

Skin bioprinting: a novel approach for creating artificial skin from synthetic and natural building blocks

Significant progress has been made over the past few decades in the development of in vitro-engineered substitutes that mimic human skin, either as grafts for the replacement of lost skin, or for the establishment of in vitro human skin models. Tissue engineering has been developing as a novel strategy by employing the recent advances in various fields such as polymer engineering, bioengineering, stem cell research and nanomedicine. Recently, an advancement of 3D printing technology referred as bioprinting was exploited to make cell loaded scaffolds to produce constructs which are more matching with the native tissue. Bioprinting facilitates the simultaneous and highly specific deposition of multiple types of skin cells and biomaterials, a process that is lacking in conventional skin tissue-engineering approaches. Bioprinted skin substitutes or equivalents containing dermal and epidermal components offer a promising approach in skin bioengineering. Various materials including synthetic and natural biopolymers and cells with or without signalling molecules like growth factors are being utilized to produce functional skin constructs. This technology emerging as a novel strategy to overcome the current bottle-necks in skin tissue engineering such as poor vascularization, absence of hair follicles and sweat glands in the construct.