Nanofibrous Meshes Research Articles

High performance of the rare earth (Er, Gd & Pr) doped MoO3 thin films for advanced applications towards ammonia gas sensing

In this report, an economical spray pyrolysis technique was used to develop pure and 2% of Er, Gd, Pr doped MoO3 thin films. Different characterization techniques were utilized to study the properties of the pure and 2% of Er, Gd, Pr doped MoO3 thin films. The structural XRD analysis revealed monoclinic crystal structure of the MoO3 thin films with high purity and highest crystal size of 59 nm for the Pr doped MoO3 thin film. Furthermore, the lattice constant values increase with the substitution of Er, Gd, Pr dopants in MoO3 thin films. The morphological studies revealed reticulated nano-fibrous mesh morphology for all the samples and tiny rod-shaped protrusions over the surface of Pr doped MoO3 thin film. The optical studies demonstrated lower transparency, small bandgap and important defects. The gas sensing studies established the good response of the Pr doped MoO3 thin film towards the NH3 gas of 1.34 × 104% (250 ppm) with high stability and fast response (54 s) with a recovery time of 12 s. This opens door to our synthesized Pr doped MoO3 thin film materials to be used for the construction of commercial ammonia gas sensors.

Active solution heating and cooling in electrospinning enabling spinnability from various solvents

AbstractSolution electrospinning is a facile method for the production of nanofibrous meshes. Here, we present a syringe‐jacket heat exchanger as a simple add‐on for solution electrospinning, which enables spinning from various solvents by a direct and precise solution temperature control between −20 °C and 100 °C. An effective manipulation of the solvent evaporation rate is enabled by adjusting the temperature. Exemplarily, we investigated the spinning of poly(vinylidene fluoride)‐co‐hexafluoropropylene (PVDF‐HFP) in pure dimethylacetamide (DMAc) or acetone as representatives of low and highly volatile solvents. Electrospinning of these solutions is not possible at ambient conditions, either due to a too low or too high evaporation rate. However, we find that PVDF‐HFP nanofibers can be successfully electrospun from DMAc at a solution temperature of 75 °C and from acetone at −19 °C. We show for the first time the use of an active solution cooling for electrospinning from a highly volatile solvent such as acetone. The ability to precisely adjust the solution temperature during electrospinning offers an improved process control and broadens the spectrum of spinnable solution compositions. Especially the prospect of replacing highly toxic solvents with less‐toxic solvents such as acetone opens up a wide field of application for the produced fibers.

Advancement of Nanofibrous Mats and Common Useful Drug Delivery Applications.

Electrospinning enables simple and cost-effective production of polymer nanofibers from different polymer materials. Drug delivery systems are capable of achieving maximum drug treatment benefits by significantly reducing adverse complications. Electrospun nanofibers have recently attracted considerable attention owing to their distinctive properties, including flexibility and biocompatibility. The implementation of functional constituents within nanostructure fibers blends is an effective technique for the administration of a variety of drugs in animal research, broadening the nanofiber capability and reliability. The nanofibrous mesh and its various application purposes are discussed in terms of a summary of recent research, emphasizing the ease of streaming and a large number of combinations of this approach, which could lead to a breakthrough in targeted therapy.

Liquid resorbable nanofibrous surgical mesh: a proof of a concept.

Surgical mesh is widely used not only to treat but also to prevent incisional hernia formation. Despite much effort by material engineers, the 'ideal' mesh mechanically, biologically and surgically easy to use remains elusive. Advances in tissue engineering and nanomedicine have allowed new concepts to be tested with promising results in both small and large animals. Abandoning the concept of a pre-formed mesh completely for a 'pour in liquid mesh' has never been tested before. Thirty rabbits underwent midline laparotomy with closure using an absorbable suture and small stitch small bites technique. In addition, their abdominal wall closure was reinforced by a liquid nanofibrous scaffold composed of a fibrin sealant and nanofibres of poly-ε-caprolactone with or without hyaluronic acid or the sealant alone, poured in as an 'onlay' over the closed abdominal wall. The animals were killed at 6weeks and their abdominal wall was subjected to histological and biomechanical evaluations. All the animals survived the study period with no major complication. Histological evaluation showed an eosinophilic infiltration in all groups and foreign body reaction more pronounced in the groups with nanofibres. Biomechanical testing demonstrated that groups treated with nanofibres developed a scar with higher tensile yield strength. The use of nanofibres in a liquid form applied to the closed abdominal wall is easy to use and improves the biomechanical properties of healing fascia at 6weeks after midline laparotomy in a rabbit model.

Light-Triggered Structural Modulation of Nanofibrous Meshes to Promote Deep Penetration of Cultured Cells.

Although nanofibrous meshes are considered promising cultivation beds for maintaining cell differentiation, 3D cultivation is not possible because their nanoporous structures impede cell infiltration. To facilitate transverse cell migration across nanofibrous meshes, electrospun nanofibers are prepared with structures that vary in response to red laser light. Polyoxalate (POX), composed of oxalate linkers and oligomeric caprolactone, is synthesized and electrospun into fibrous meshes with a photosensitizer (chlorin e6, Ce6). These meshes exhibit morphological and chemical changes upon laser irradiation, and mass erosion rates of the meshes are faster after laser irradiation. Cell cultivation on POX meshes reveals that red laser effectively facilitates traverse migration of the cells without affecting cell viability. The use of light-triggered change of meshes is envisioned to promote the migration of cells during 3D matrix cultivation.

Recent Applications of Electrospun Nanofibrous Scaffold in Tissue Engineering.

Tissue engineering is a relatively new area of research that combines medical, biological, and engineering fundamentals to create tissue-engineered constructs that regenerate, preserve, or slightly increase the functions of tissues. To create mature tissue, the extracellular matrix should be imitated by engineered structures, allow for oxygen and nutrient transmission, and release toxins during tissue repair. Numerous recent studies have been devoted to developing three-dimensional nanostructures for tissue engineering. One of the most effective of these methods is electrospinning. Numerous nanofibrous scaffolds have been constructed over the last few decades for tissue repair and restoration. The current review gives an overview of attempts to construct nanofibrous meshes as tissue-engineered scaffolds for various tissues such as bone, cartilage, cardiovascular, and skin tissues. Also, the current article addresses the recent improvements and difficulties in tissue regeneration using electrospinning.

Preliminary Characterization of a Polycaprolactone-SurgihoneyRO Electrospun Mesh for Skin Tissue Engineering.

Skin is a hierarchical and multi-cellular organ exposed to the external environment with a key protective and regulatory role. Wounds caused by disease and trauma can lead to a loss of function, which can be debilitating and even cause death. Accelerating the natural skin healing process and minimizing the risk of infection is a clinical challenge. Electrospinning is a key technology in the development of wound dressings and skin substitutes as it enables extracellular matrix-mimicking fibrous structures and delivery of bioactive materials. Honey is a promising biomaterial for use in skin tissue engineering applications and has antimicrobial properties and potential tissue regenerative properties. This preliminary study investigates a solution electrospun composite nanofibrous mesh based on polycaprolactone and a medical grade honey, SurgihoneyRO. The processing conditions were optimized and assessed by scanning electron microscopy to fabricate meshes with uniform fiber diameters and minimal presence of beads. The chemistry of the composite meshes was examined using Fourier transform infrared spectroscopy and X-ray photon spectroscopy showing incorporation of honey into the polymer matrix. Meshes incorporating honey had lower mechanical properties due to lower polymer content but were more hydrophilic, resulting in an increase in swelling and an accelerated degradation profile. The biocompatibility of the meshes was assessed using human dermal fibroblasts and adipose-derived stem cells, which showed comparable or higher cell metabolic activity and viability for SurgihoneyRO-containing meshes compared to polycaprolactone only meshes. The meshes showed no antibacterial properties in a disk diffusion test due to a lack of hydrogen peroxide production and release. The developed polycaprolactone-honey nanofibrous meshes have potential for use in skin applications.

Electrospun hybrid nanofibrous meshes with adjustable performance for potential use in soft tissue engineering

Electrospun nanofibrous scaffolds have gained extensive attention in the fields of soft tissue engineering and regenerative medicine. In this study, a series of biodegradable nanofibrous meshes were fabricated by electrospinning poly(ε-caprolactone) (PCL) and poly( p-dioxanone) (PPDO) blends with various mass ratios. All the as-developed PCL/PPDO nanofibrous meshes possessed smooth and highly aligned fiber morphology. The mean fiber diameter was 521.5 ± 76.6 nm for PCL meshes and 485.8 ± 88.9 nm for PPDO meshes, and the mean fiber diameter seemed to present a decreasing tendency with the increasing of the PPDO component. For pure PCL meshes, the contact angle was about 117.5 ± 1.6°, the weight loss ratio was roughly 0.2% after 10 weeks of degradation, and the tensile strength was 41.2 ± 2.3 MPa in the longitudinal direction and 4.2 ± 0.1 MPa in the transverse direction. It was found that the surface hydrophilicity and in vitro degradation properties of PCL/PPDO meshes apparently increased, but the mechanical properties of PCL/PPDO meshes obviously decreased when more PPDO component was introduced. The biological tests showed that 4:1 PCL/PPDO nanofibrous meshes and 1:1 PCL/PPDO nanofibrous meshes could obviously promote the adhesion and proliferation of human adipose derived mesenchymal stem cells more than pure PCL and PPDO meshes and 1:4 PCL/PPDO meshes. The results demonstrated that it is feasible to adjust the surface hydrophilicity, degradation profile, and mechanical properties as well as biological properties of as-obtained nanofibrous meshes by blending PCL and PPDO components. This study provides meaningful reference and guidance for the design and development of PCL/PPDO hybrid nanofibrous scaffolds for soft tissue engineering research and application.

Chondrogenic differentiation induced by extracellular vesicles bound to a nanofibrous substrate

Extracellular vesicles (EVs) are being increasingly studied owing to its regenerative potential, namely EVs derived from human bone marrow mesenchymal stem cells (hBM-MSCs). Those can be used for controlling inflammation, repairing injury, and enhancing tissue regeneration. Differently, the potential of EVs derived from human articular chondrocytes (hACs) to promote cartilage regeneration has not been thoroughly investigated. This work aims to develop an EVs immobilization system capable of selectively bind EVs present in conditioned medium obtained from cultures of hACs or hBM-MSC. For that, an anti-CD63 antibody was immobilized at the surface of an activated and functionalized electrospun nanofibrous mesh. The chondrogenic potential of bound EVs was further assessed by culturing hBM-MSCs during 28 days under basal conditions. EVs derived from hACs cultured under differentiation medium or from chondrogenically committed hBM-MSCs induced a chondrogenic phenotype characterized by marked induction of SOX9, COMP, Aggrecan and Collagen type II, and matrix glycosaminoglycans synthesis. Indeed, both EVs immobilization systems outperformed the currently used chondroinductive strategies. These data show that naturally secreted EVs can guide the chondrogenic commitment of hBM-MSCs in the absence of any other chemical or genetic chondrogenic inductors based in medium supplementation.

Release of profens from nanofibers: Challenges and opportunities

Nanofibrous meshes refer to the structures made of ultra-fine polymeric fibers. Because of nanometer measure size with an excessive strength/weight ratio, they are actual suitable as a nanosystem for delivering drug molecules. Drug molecules which mixed in nanofibers, can be released from the surrounding environment by means of various mechanisms in different manners (burst release, sustainable release and tunable release). Nanofibers can be used by way of release rate controlling strategies as proper delivery structures for drug molecules.The objective of this review is to highpoint the capacity of nanofibers as novel releasing substances for profens (Propionic acid derivative drugs including Carprofen; Naproxen; Fenoprofen; Flurbiprofen; Ibuprofen; Ketoprofen and Tiaprofenic acid). The profens are a class of nonselective, nonsteroidal anti-inflammatory drugs (NSAIDs). These drug molecules are derivatives of 2-phenylpropanoic acid. All contain a chiral center resulting in the formation of two enantiomers (R and S) of each profen. In this review, full information will be reported about the new progresses for release behaviors of profen molecules form the novel nanofibrous delivery systems. The drug releasing kinetics of profen molecules from nanofibers will be described briefly. The authors use more than 80 articles , books and thesis published in the case of nanofibrous profens delivery and releasing systems.

Chelidoniummajus L. Incorporated Emulsion Electrospun PCL/PVA_PEC Nanofibrous Meshes for Antibacterial Wound Dressing Applications.

Presently, there are many different types of wound dressings available on the market. Nonetheless, there is still a great interest to improve the performance and efficiency of these materials. Concerning that, new dressing materials containing natural products, such as medicinal plants that protect the wound from infections but also enhance skin regeneration have been or are being developed. Herein, we used for the first time a needleless emulsion electrospinning technique for incorporating Chelidonium majus L. (C. majus), a medicinal plant widely known for its traditional therapeutic properties, in Polycaprolactone (PCL)/Polyvinyl Alcohol (PVA)_Pectin (PEC) nanofibrous meshes. Moreover, the potential use of these electrospun nanofibers as a carrier for C. majus was also explored. The results obtained revealed that the produced PCL/PVA_PEC nanofibrous meshes containing C. majus extract displayed morphological characteristics similar to the natural extracellular matrix of the skin (ECM). Furthermore, the produced meshes showed beneficial properties to support the healing process. Additionally, the C. majus-loaded PCL/PVA_PEC nanofibrous meshes inhibited Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) growth, reaching a 3.82 Log reduction, and showed to be useful for controlled release, without causing any cytotoxic effect on the normal human dermal fibroblasts (NHDF) cells. Hence, these findings suggest the promising suitability of this novel wound dressing material for prevention and treatment of bacterial wound infections.

Reconstruction of Ultra-thin Alveolar-capillary Basement Membrane Mimics.

Alveolar-capillary basement membrane (BM) is ultra-thin (<2 µm) extracellular matrix that maintains integral epithelial-endothelial cell layers. In vitro reconstructions of alveolar-capillary barrier supported on synthetic scaffolds closely resembling the fibrous and ultra-thin natural BM are essential in mimicking the lung pathophysiology. Although BM topology and dimensions are well known to significantly influence cellular behavior, conventionally used BM mimics fail to recreate this natural niche. To overcome this, electrospun ultra-thin 2 µm poly(caprolactone) (PCL) nanofibrous mesh is used to establish an alveolar-capillary barrier model of lung endothelial/epithelial cells. Transepithelial electrical resistance (TEER) and permeability studies reveal integral tight junctions and improved mass transport through the highly porous PCL meshes compared to conventional dense membranes with etched pores. The chemotaxis of neutrophils is shown across the barrier in presence of inflammatory response that is naturally impeded in confined regions. Conventional requirement of 3 µm or larger pore size can lead to barrier disruption due to epithelial/endothelial cell invasion. Despite high porosity, the interconnected BM mimic prevents barrier disruption and allows neutrophil transmigration, thereby demonstrating the physiological relevance of the thin nanofibrous meshes. It is envisioned that these bipolar cultured barriers would contribute to an organ-level in vitro model for pathological disease, environmental pollutants, and nanotoxicology.

Angiogenic potential of airbrushed fucoidan/polycaprolactone nanofibrous meshes

Implantation of biomaterials and hybrid constructs in tissue engineering approaches presents major limitations such as inflammatory reaction and the lack of vasculature integration. Therefore, new strategies are needed to enhance implant function, immune protection, and revascularization. In this work, we developed fibrous meshes composed of fucoidan (Fu), a sulfated polysaccharide extracted from brown algae, and polycaprolactone (PCL), a synthetic biodegradable polymer, using the airbrush technique. The chemical characterization by FTIR, EDS, and XPS confirmed the presence of the two polymers in the structure of airbrushed nanofibrous meshes (ANFM). Moreover, these nanofibrous exhibited good wettability and mechanical properties envisaging their application as templates for biomaterials and cell culture. The developed ANFM were directly cultured with human pulmonary microvascular endothelial (HPMEC-ST1.6R) cells for up to 7 days. Biological results demonstrated that ANFM comprising Fu promoted cellular attachment, spreading, and proliferation of human endothelial cells. The angiogenic potential of ANFM was further evaluated by onplantation of PCL and PCL/Fu ANFM in chick chorioallantoic membrane (CAM). In ovo and ex ovo results showed that the incorporation of Fu increased the pro-angiogenic potential of ANFM. Altogether, the results suggest that airbrush biocomposite meshes could be used as a biomaterial substrate to promote vascularization.

The Effect of the Controlled Release of Platelet Lysate from PVA Nanomats on Keratinocytes, Endothelial Cells and Fibroblasts.

Platelet lysate (PL) provides a natural source of growth factors and other bioactive molecules, and the local controlled release of these bioactive PL components is capable of improving the healing of chronic wounds. Therefore, we prepared composite nanofibrous meshes via the needleless electrospinning technique using poly(vinyl alcohol) (PVA) with a high molecular weight and with a high degree of hydrolysis with the incorporated PL (10% w/w). The morphology, wettability and protein release from the nanofibers was then assessed from the resulting composite PVA–PL nanomats. The bioactivity of the PVA–PL nanomats was proved in vitro using HaCaT keratinocytes, human saphenous endothelial cells (HSVECs) and 3T3 fibroblasts. The PVA–PL supported cell adhesion, proliferation, and viability. The improved phenotypic maturation of the HaCaT cells due to the PVA–PL was manifested via the formation of intermediate filaments positive for cytokeratin 10. The PVA–PL enhanced both the synthesis of the von Willebrand factor via HSVECs and HSVECs chemotaxis through membranes with 8 µm-sized pores. These results indicated the favorable effects of the PVA–PL nanomats on the three cell types involved in the wound healing process, and established PVA–PL nanomats as a promising candidate for further evaluation with respect to in vivo experiments.

The Effect of a Polyester Nanofibrous Membrane with a Fibrin-Platelet Lysate Coating on Keratinocytes and Endothelial Cells in a Co-Culture System.

Chronic wounds affect millions of patients worldwide, and it is estimated that this number will increase steadily in the future due to population ageing. The research of new therapeutic approaches to wound healing includes the development of nanofibrous meshes and the use of platelet lysate (PL) to stimulate skin regeneration. This study considers a combination of a degradable electrospun nanofibrous blend of poly(L-lactide-co-ε-caprolactone) and poly(ε-caprolactone) (PLCL/PCL) membranes (NF) and fibrin loaded with various concentrations of PL aimed at the development of bioactive skin wound healing dressings. The cytocompatibility of the NF membranes, as well as the effect of PL, was evaluated in both monocultures and co-cultures of human keratinocytes and human endothelial cells. We determined that the keratinocytes were able to adhere on all the membranes, and their increased proliferation and differentiation was observed on the membranes that contained fibrin with at least 50% of PL (Fbg + PL) after 14 days. With respect to the co-culture experiments, the membranes with fibrin with 20% of PL were observed to enhance the metabolic activity of endothelial cells and their migration, and the proliferation and differentiation of keratinocytes. The results suggest that the newly developed NF combined with fibrin and PL, described in the study, provides a promising dressing for chronic wound healing purposes.

Next‐generation Antimicrobial Peptides (AMPs) incorporated nanofibre wound dressings

AbstractAntimicrobial peptides (AMPs) containing polymer‐based nanodelivery systems offer to overcome many challenges in wound care. While preventing the contact of the external agents on the wound, it also addresses a rising concern on the drug resistance. AMPs as the host defence peptides have been increasingly recognized for therapeutic potential owning to their critical role in innate immunity. Here we investigated a nanofibre mesh approach using AMPs incorporated polyethylene oxide (PEO) for wound healing applications. PEO was prepared to carry GH12‐COOH‐M2 (type 1 AMP) and AMP2 (type 2 AMP), and their antibacterial activity was assessed againstStaphylococcus epidermidis (S. epidermidis). PEO‐AMP nanofibre meshes were successfully formed by using pressurized gyration (PG), which allows rapid mass production. Bacterial viability of the nanofibre meshes was investigated using the AlamarBlue assay. Fibre morphology, size distribution and AMP incorporation in the nanofibres were characterized by scanning electron microscopy (SEM), fluorescence microscopy (polarization contrast images) and Fourier transform infrared spectroscopy (FTIR). While both PEO‐AMP1 and PEO‐AMP2 nanofibres indicate promising bacterial inhibition at 105 µg/ml, PEO‐AMP2 fibres showed the highestS. epidermidisreduction. The results demonstrated that increase in the AMP content reduced the bacterial growth. Another important implementation of the PEO‐AMP nanofibres is that they can be tuned to rapidly releasing the peptides. Antimicrobial peptide‐loaded nanofibres represent a viable biologically active solution to next‐generation wound dressings.

Co-electrospun nano-/microfibrous composite scaffolds with structural and chemical gradients for bone tissue engineering

Recent trends in scaffold design for tissue engineering have focused on providing structural, mechanical and chemical cues for guiding cell behaviors. In this study, we presented a structural/compositional gradient nano-/microfibrous mesh by co-electrospinning, using silk fibroin-poly(ε-caprolactone) (SF-PCL) nanofibers and PCL microfibers. The pore size, porosity, and physical property of the gradient meshes were qualified. Cell proliferation of mouse osteoblast-like MC3T3-E1 cells was carried out to estimate the effect of structural and compositional gradients on biocompatibility. Furthermore, the 2-D mesh was rolled up and the compressive property of 3-D cylinder was investigated. The results suggested that the rolled-up gradient cylinder scaffold exhibited higher osteogenic differentiation compared to the pristine nanofibrous cylinder sample. By incorporating Chinese medicine ginsenoside Rg1, sustained release was achieved in composite meshes. Rg1-containing nanofibrous meshes and Rg1 gradient cylinders enhanced the cell proliferation of human umbilical vein endothelial cells (HUVECs). The developed fibrous scaffold may provide structural, compositional, and chemical gradients for bone regeneration. BriefsStructural and chemical gradient fibrous scaffold fabricated by co-electrospinning.

Development of Thermo-Responsive Polycaprolactone-Polydimethylsiloxane Shrinkable Nanofibre Mesh.

A thermally activated shape memory polymer based on the mixture of polycaprolactone (PCL) and polydimethylsiloxane (PDMS) was fabricated into the nanofibre mesh using the electrospinning process. The added percentages of the PDMS segment in the PCL-based polymer influenced the mechanical properties. Polycaprolactone serves as a switching segment to adjust the melting temperature of the shape memory electro-spun PCL–PDMS scaffolds to our body temperature at around 37 °C. Three electro-spun PCL–PDMS copolymer nanofibre samples, including PCL6–PDMS4, PCL7–PDMS3 and PCL8–PDMS2, were characterised to study the thermal and mechanical properties along with the shape memory responses. The results from the experiment showed that the PCL switching segment ratio determines the crystallinity of the copolymer nanofibres, where a higher PCL ratio results in a higher degree of crystallinity. In contrast, the results showed that the mechanical properties of the copolymer samples decreased with the PCL composition ratio. After five thermomechanical cycles, the fabricated copolymer nanofibres exhibited excellent shape memory properties with 98% shape fixity and above 100% recovery ratio. Moreover, biological experiments were applied to evaluate the biocompatibility of the fabricated PCL–PDMS nanofibre mesh. Owing to the thermally activated shape memory performance, the electro-spun PCL–PDMS fibrous mesh has a high potential for biomedical applications such as medical shrinkable tubing and wire.

&lt;p&gt;Electrospun Scaffold with Sustained Antibacterial and Tissue-Matched Mechanical Properties for Potential Application as Functional Mesh&lt;/p&gt;

IntroductionVarious materials and approaches have been used to reduce the mesh-induced inflammatory response and modify the mesh with tissue-matched mechanical properties, aiming to improve the repair of abdominal wall defects.Materials and MethodsIn this study, we fabricated a polycaprolactone (PCL)/silk fibroin (SF) mesh integrated with amoxicillin (AMX)-incorporating multiwalled carbon nanotubes (MWCNTs) via electrospinning, grafting and crosslinking, developing a sustainable antibiotic and flexible mesh. AMX was loaded into the hollow tubular MWCNTs by physical adsorption, and a nanofibrous structure was constructed by electrospinning PCL and SF (40:60 w/w). The AMX@MWCNTs were then chemically grafted onto the surfaces of the PCL/SF nanofibers by treating with 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide/N-hydroxysuccinimide (EDC/NHS) solution for simultaneous crosslinking and coating. The incorporation of AMX into the MWCNTs (AMX@MWCNTs) and the integration of the AMX@MWCNTs with the PCL/SF nanofibers were characterized. Then, the functional mesh was fabricated and fully evaluated in terms of antibacterial activity, mechanical properties and host response.ResultsOur results demonstrated that the PCL/SF nanofibrous structure was fabricated successfully by electrospinning. After integrating with AMX@MWCNT by grafting and crosslinking, the functional mesh showed undeformed structure, modified surface hydrophilicity and biocompatible interfaces, abdominal wall-matched mechanical properties, and a sustained-release antibiotic profile in E. coli growth inhibition compared to those of PCL/SF mesh in vitro. In a rat model with subcutaneous implantation, the functional mesh incited less mesh-induced inflammatory and foreign body responses than PCL/SF mesh within 14 days. The histological analysis revealed less infiltration of granulocytes and macrophages during this period, resulting in the loosely packed collagen deposition on the functional mesh and prominent collagen incorporation.DiscussionTherefore, this designed PCL/SF–AMX@MWCNT nanofibrous mesh, functionalized with antibacterial and tissue-matched mechanical properties, provides a promising alternative for the repair of abdominal wall defects.

Biocompatible indocyanine green loaded PLA nanofibers for in situ antimicrobial photodynamic therapy.

Chronic wounds and their associated bacterial infections are major issues in modern health care systems. Therefore, antimicrobial resistance (AMR), treatment costs, and number of disability-adjusted life-years have gained more interest. Recently, photodynamic therapy emerged as an effective approach against resistant and naïve bacterial strains with a low probability of creating AMR. In this study, needleless electrospinning was used to produce an indocyanine green (ICG) loaded poly(d,l-lactide) nanofibrous mesh as a photoresponsive wound dressing. The non-woven mesh had a homogeneous nanofibrous structure and showed long-term hydrolytic stability at different pH values. The antimicrobial activity was tested against several bacterial strains, namely Staphylococcus saprophyticus subsp. bovis, Escherichia coli DH5 alpha, and Staphylococcus aureus subsp. aureus. Upon irradiation with a laser of a specific wavelength (λ=810nm), the bacterial viability was significantly reduced by 99.978% (3.66 log10), 99.699% (2.52 log10), and 99.977% (3.64 log10), respectively. The nanofibrous mesh showed good biocompatibility, which was confirmed by the proliferation of mouse fibroblasts (L929) on the surface and into deeper parts of the mesh. Furthermore, a favorable proangiogenic effect was observed in ovo using the chorioallantoic membrane assay. In general, it can be concluded that ICG loaded nanofibers as an innovative wound dressing represent a promising strategy against chronic wounds associated with skin infections.