Electrospun Scaffolds as Antimicrobial Herbal Extract Delivery Vehicles for Wound Healing.

Herbal extracts have been used in traditional remedies since the earliest myths. They have excellent antimicrobial, anti-inflammatory, and antioxidant activities owing to various bioactive components in their structure. However, due to their inability to reach a target and low biostability, their use with a delivery vehicle has come into prominence. For this purpose, electrospun nanofibrous scaffolds have been widely preferred for the delivery and release of antimicrobial herbal extracts due to the flexibility and operational versatility of the electrospinning technique. Herein, we briefly reviewed the electrospun nanofibrous scaffolds as delivery systems for herbal extracts with a particular focus on the preclinical studies for wound-healing applications that have been published in the last five years. We also discussed the indirect effects of herbal extracts on wound healing by altering the characteristics of electrospun mats.

Novel three-dimensional bioglass functionalized gelatin nanofibrous scaffolds for bone regeneration.

The clinical use of FDA-approved bone morphogenetic proteins (BMPs) are impeded by high costs, super-high dosage requirement, short half-life, and other undesirable side effects. Therefore, designing a biomaterial that can promote new bone formation without using exogenous BMPs is highly desirable in clinical applications. In the present work, a new kind of nanofibrous scaffold composed of gelatin and 45S5 bioglass (GF/45S5 BG) was prepared through thermally induced phase separation method together with the particle leach technique (TIPS&P). In addition to the significantly higher mechanical strength, the composite scaffolds (GF/45S5 BG) significantly increased osteogenic differentiation of human mesenchymal stem cells (hMSCs) in vitro compared with the neat scaffold (GF) without adding other biological agents, for example, BMPs or hormones. Most importantly, our in vivo studies also indicated that GF/45S5 BG scaffolds could directly promote ectopic bone regeneration in SD rats without exogenous BMP2. In summary, both in vitro and in vivo results indicated that the novel 45S5 bioglass functionalized GF nanofibrous scaffold is a promising alternative for bone tissue engineering.

Fabrication and characterization of herbal drug enriched Guar galactomannan based nanofibrous mats seeded with GMSC's for wound healing applications.

Electrospun nanofibrous Guar gum/PVA based scaffold matrix incorporated with standardized extracts of four traditional medicinal plants of wound healing repute namely - Acalypha indica (A.i), Aristolochia bracteolata (A.b), Lawsonia inermis (L.i) and Thespesia populnea (T.p) was developed. Combinatorial ratio optimization of the extracts subject to their impact on nanofibre morphology, thermal and swelling stability resulted in a 4:4:1:1 blend of A.i, A.b, T.p and L.i at 20% of the total weight of the polymer mix. Dermal toxicity studies on female wistar rats established the nontoxicity of the generated Scaffold/Dressing. Cutaneous wound healing ability of Mesenchymal Stem Cells (MSC's) is well characterized to amplify their delivery and efficacy at the wound site. Apart from ease of accessibility, increased immune modulation of Gingival MSC's is their clear merit relative to those conventionally sourced from adipose tissues and bone marrow. A population of cells were isolated from discarded sample of human gingiva, following standard procedures and characterized as per minimal criteria as described by International Society for Cellular Therapy's (ISCT). The Cytocompatibility and proliferation of GMSC's were evaluated by MTT and Calcein AM assay demonstrating the viability of the seeded GMSC's up to 6 days. In vivo efficacy of the scaffold with and without GMSC's showed complete restoration of the tissue with minimal scarring. This investigation thus generated an herb drug enriched nanofibrous mat as a dressing and also a skin like scaffold with GMSC's, integrating the biological and technological benefits of herbal medicine and stem cell therapy respectively for skin regenerative applications.

In vivo efficiency of the collagen coated nanofibrous scaffold and their effect on growth factors and pro-inflammatory cytokines in wound healing.

Exploring the importance of nanofibrous scaffold with traditionally important medicine as a wound dressing material prevents infection and aids in faster healing of wounds. In the present study, the Collagen (COL) from the marine fish skin was extracted and employed for coating the Poly(3-hydroxybutyric acid) (P)-Gelatin (G) nanofibrous scaffold with a bioactive Coccinia grandis extract (CPE) fabricated through electrospinning. Further, the fabricated collagen coated nanofibrous scaffold (PG-CPE-COL) applied to the experimental wound of rats and the wound healing was analyzed with by physiochemical and biological techniques. The increased level of hydroxyproline, hexosamine and uronic acid was observed in PG-CPE-COL treated than the other groups. The CPE and collagen in the nanofibrous scaffold accelerates the wound healing and thereby reduced the inflammation caused by the cyclooxygenase-2 (COX-2) and inducible nitric oxide synthases (iNOS) in wound healing. The nanofibrous scaffold has influenced the expression of various growth factors such as vascular endothelial growth factor (VEGF), epidermal growth factor (EGF) and transforming growth factor (TGF-ß). In addition, the PG-CPE-COL nanofibrous scaffold increases the deposition of collagen synthesis and accelerates reepithelialization. Thus, the results suggest that the collagen coated nanofibrous scaffold with bioactive traditional medicine enhanced the faster healing of wound.

Novel class of collector in electrospinning device for the fabrication of 3D nanofibrous structure for large defect load-bearing tissue engineering application.

Adequate porosity, appropriate pore size, and 3D-thick shape are crucial parameters in the design of scaffolds, as they should provide the right space for cell adhesion, spreading, migration, and growth. In this work, a novel design for fabricating a 3D nanostructured scaffold by electrospinning was taken into account. Helical spring-shaped collector was purposely designed and used for electrospinning PCL fibers. Improved morphological properties and more uniform diameter distribution of collected nanofibers on the turns of helical spring-shaped collector are confirmed by SEM analysis. SEM images elaboration showed 3D pores with average diameter of 4 and 5.5 micrometer in x-y plane and z-direction, respectively. Prepared 3D scaffold possessed 99.98% porosity which led to the increased water uptake behavior in PBS at 37°C up to 10 days, and higher degradation rate compared to 2D flat structure. Uniaxial compression test on 3D scaffolds revealed an elastic modulus of 7 MPa and a stiffness of 102 MPa, together with very low hysteresis area and residual strain. In vitro cytocompatibility test with MG-63 osteoblast-like cells using AlamarBlue™ colorimetric assay, indicated a continuous increase in cell viability for the 3D structure over the test duration. SEM observation showed enhanced cells spreading and diffusion into the underneath layers for 3D scaffold. Accelerated calcium deposition in 3D substrate was confirmed by EDX analysis. Obtained morphological, physical, and mechanical properties together with in vitro cytocompatibility results, suggest this novel technique as a proper method for the fabrication of 3D nanofibrous scaffolds for the regeneration of critical-size load bearing defects. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1535-1548, 2017.