Wound dressing materials which are capable of meeting the demands of accelerating wound closure and promoting wound healing process have being highly desired. Electrospun nanofibrous materials show ...great application potentials for wound healing owing to relatively large surface area, better mimicry of native extracellular matrix, adjustable waterproofness and breathability, and programmable drug delivery process. In this review article, we begin with a discussion of wound healing process and current commercial wound dressing materials. Then, we emphasize on electrospun nanofibrous materials for wound dressing, covering the efforts for controlling fiber alignment and morphology, constructing 3D scaffolds, developing waterproof-breathable membrane, governing drug delivery performance, and regulating stem cell behavior. Finally, we finish with challenges and future prospects of electrospun nanofibrous materials for wound dressings.
Graphic Abstract
Fibrous patches capable of withstanding bursting force and recruiting endogenous stem cells are of great demand for wound treatment. A programmable strategy for development of radially gradient ...nanofibrous patches with rapid deployment property, robust bursting bearing capability, and excellent mesenchymal stem cell (MSC) recruitment capability, is demonstrated. Benefiting from the royal water lily‐like radially branched architecture, the gradient fibrous (GF) patches exhibit fast deployment in aqueous solution (2 s), high bursting strength of 4.6 N, as well as “center‐to‐periphery” gradient immobilization of stromal‐cell‐derived factor 1α (SDF1α). The SDF1α gradient patches direct MSC migration from the periphery to the center along the aligned nanofibers, resulting in a 4.2 times higher migrated cell number and 2.6 times greater maximum migration distance than random fibrous patches with homogenous SDF1α. The gelatin methacryloyl coated GF patches respond to matrix metalloproteinase‐9 for “on‐demand” release of anti‐inflammatory drug diclofenac sodium (DS). Furthermore, repair of the mouse full‐thickness skin incision validates that SDF1α/DS/GF patches are able to provide feasible microenvironment to attenuate inflammation and improve endogenous MSC recruitment, leading to accelerated wound healing. This work may open a new pathway for development of smart tough fibrous patches for stimulating endogenous repair mechanisms during tissue regeneration.
A type of bioinspired radially branched nanofibrous patch with “center‐to‐periphery” gradient release and on‐demand release is developed using a straightforward and programmable strategy. The patches exhibit rapid deployment, high bursting strength, enhanced mesenchymal stem cell migration from the periphery to the center, and promote mouse wound healing eventually, indicating great promise as wound care dressings and tissue repair patches.
Wound environment-responsive materials show great potential in skin repair. Herein, a temperature-responsive fibrous hydrogel was developed with the aid of the phase-change material of natural fatty ...acids. The extracellular matrix-like methacrylate gelatin (GelMA) nanofibrous hydrogels were fabricated via electrospinning and UV-crosslinking, followed by a depot of fatty acids/aspirin (ASP) encapsulated polydopamine (PDA). The as-prepared fibrous hydrogels showed a significantly faster ASP release at 40 °C compared with those of 25 °C and 37 °C, and an “on-off” drug release was achieved at heating and cooling cycles between 40 °C and 25 °C. The in vitro cell culture tests and in vivo wound healing study proved that GelMA-PDA-ASP nanofibrous hydrogels facilitated the cell growth and accelerated wound repair. Taken together, the thermosensitive drug-releasing nanofibrous hydrogel, showed a great potential for wound care.
•Green solvent ethanol aqueous was used to formulate GelMA nanofiber membranes by electrospinning technology.•The GelMA nanofibrous hydrogels combined the advantages of hydrogels and nanofibers.•GelMA-PDA-ASP nanofiber hydrogels presented temperature-responsive drug release.•GelMA-PDA-ASP nanofiber hydrogels promoted wound healing with a wound closure ratio of 93% on day 12.
Despite the progression in wound treatment, the development of wound dressings with considerable skin regeneration capability and improved patient comfort still faces huge challenges. In this study, ...a type of asymmetric wettable gradient nanofibrous membrane, which is composed of a hydrophobic polyvinyl butyral (PVB)–polydimethylsiloxane (PDMS) upper layer, a PVB–PDMS/gelatin middle layer, and a hydrophilic gelatin lower layer, has been fabricated. The PVB–PDMS upper layer gave dramatically elevated water contact angles from 71.27° to 125.45° as compared with the gelatin membrane, indicating an asymmetric wettability. The composite membrane exhibited outstanding waterproof capability with a hydrostatic pressure of 58.21 kPa, excellent breathability with a water vapor transmission rate of 8.80 kg m–2 d–1, improved stretchability and tear resistance, and dramatic improvement in mesenchymal stem cell recruitment with the immobilization of stromal-cell-derived factor-1α for accelerating skin regeneration. The development of asymmetric wettable nanofibrous membranes offers insight into wound-dressing design.
Despite recent progress in hydrogel wound dressings, joint wound treatment remains an ongoing challenge due to their poor adhesive and stretchable properties. Herein, inspired by protein ...secretion-curing process of natural marine mussels, an adhesive nanofibrous hydrogel is developed via a sequential crosslinking strategy. Firstly, to avoid uncontrolled self-polymerization of dopamine (DA), DA grafted gelatin (GT) nanofibers are fabricated via electrospinning under pH value around 4. Further, the fibrous hydrogels are in-situ crosslinked under pH value of about 8 to strengthen the intermolecular interaction within fibers. The DA crosslinked GT fibrous hydrogels via Michael addition and Schiff base reaction exhibit superior adhesive and tensile properties which are 1.5 times and 3.1 times higher than those of GT fibrous hydrogels, respectively. The in vitro cytocompatibility tests and in vivo wound healing study further prove that GT grafted DA nanofibrous hydrogels are able to accelerate wound healing. Taken together, we demonstrate a simple and versatile strategy for generating adhesive and stretchable nanofibrous hydrogel, showing a great potential for joint wound care.
•Inspired by protein secretion-curing process of marine mussels, dopamine (DA) sequentially crosslinked gelatin (GT) (GT/EDC–NHS–DA) nanofibrous hydrogels was first developed.•GT/EDC–NHS–DA nanofibrous hydrogels possessed exceptional bio-adhesiveness ensuring close and stable wound contact.•GT/EDC–NHS–DA nanofibrous hydrogels possessed great tensile mechanical property allowing for 150° frequent facile bending.•GT/EDC–NHS–DA nanofibrous hydrogels promoted wound healing significantly with a wound healing ratio of 96% on postoperative day 15.
A multicluster packet collision resolution （PCR） scheme is a kind of recently proposed virtualMIMO techniques. In existing multicluster PCR schemes, a large-scale wireless Ad Hoc network is divided ...into clusters and the single cluster PCR scheme is applied independently to resolve collisions in each cluster. However, there are still some flaws in existing multicluster PCR schemes. In this paper, by presenting a concise theoretical analysis model and a new CNS algorithm, a novel multicluster PCR scheme is proposed. Analysis and simulation results show that the proposed scheme can obtain high performance gain with low complexity. The proposed scheme is more robust and applicable than existing schemes.
试验研究了稻茬套播油菜种植密度与产量和分枝习性的关系。结果表明：(1)在较低密度条件下(1～3万株／667m. )，油菜籽产量随着密度的增加呈递增趋势，其适宜的密度为3万株／667m. 左右；超过3万株／667m. ，油菜籽产量随着密度的增加呈递减趋势。(2)主攻油菜籽140kg/667m. 的产量水平，适宜每株有效分枝数为3～4个，群体有效分枝数为10～12万个／667m. ...，分枝结角果数占总角果数的75％左右。
Effects of different planting densities on the yield and primary branch characteristics of rape undermwed in rice field were studied．The results were as follows．(1)The rapeseed yield increased with the planting density increasing when the density Was between 1×10 ~3×10 plants／667m. ．when the density was greater than 3×1 0 plants／667m. ，the yield decreased with the density increasing．and the appropriate density Was 3×10 plants／667m. ；(2)To obtain the yield of 140 kg／667m. ，the appropriate number of efficient primary branches per plant is 3～4 and that of the efficient colony branches iS 10× 10 ～ 12×10 branches／667m. ，and the ratio of pods of primary branches to total pods is about 75％ ．
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