Cellulose-Based pH-Responsive Janus Dressing with Unidirectional Moisture Drainage for Exudate Management and Diabetic Wounds Healing

Diabetic wounds with hyperglycemic tissue exudates and bacterial infections have become a great challenge that seriously delays the healing of diabetic wounds. Therefore, multifunctional  dressings for exudate management of diabetic wound are urgently needed. Herein, a smart dressing with rapid moisture-drained and non-adhesive, pH-responsive, and antibacterial capabilities is proposed for exudate management and wound monitoring. The Janus dressing is assembled with an antioxidant, pH-sensitive, and hydrophilic cellulose cover and an antibacterial hydrophobic polycaprolactone bottom layer that directly contacts with the wounds, which can unidirectionally and irreversibly drain the wound exudates and weaken the wet adhesion to the wound. In response to the humoral pH variations (5-9) during the healing process ofdiabetic wounds, the healing process can be in situ monitored according to the distinct pH-responsive colors of the Janus dressing at different healing stages. In vivo assays and histopathological studies suggest that the Janus dressing has a superior pro-healing rate, collagen deposition, and angiogenesis than commercial gauze. Notably, such a mulitfunctional dressing provides real-time wound monitoring simply through a smartphone integrated with Python-RGB programs, which can significantly alleviate the hyperglycemic exudate-flooded environment as an alternative strategy for diabetic wound treatment.     

Magnetic Field-Directed Deep Thermal Therapy via Double-Layered Microneedle Patch for Promoting Tissue Regeneration in Infected Diabetic Skin Wounds

Although near-infrared (NIR) light-based photothermal therapies have shown therapeutic potential for infected wounds, the attenuation of NIR light intensity in tissue has severely limited the usage in deep bacterial infections. Herein, magneto-thermal responsive bilayer microneedles (Fe-Se-HA MNs) consisting of functionalized hyaluronic acid (HA), ferro-ferric oxide (Fe₃O₄), and micelle-protected selenium nanoparticles (SeNPs@LAS) are constructed to overcome this challenge based on a self-designed disk-shaped electromagnetic field device (Disk-ZVS). The electromagnetic field generated by the Disk-ZVS shows virtually no intensity attenuation in living tissue. Finite element simulations showed that the field intensity and electromagnetic loss are concentrated on the tips of Fe-Se-HA MNs. The MNs are able to puncture hard scabs, penetrate into bacterial biofilms, and perform effective magnetic-thermal conversion for deep hyperthermia sterilization. Following, the Fe-Se-HA MNs can be gradually degraded by excessive hyaluronidase in diabetic wound to release SeNPs, which reduce reactive oxygen species (ROS) to regulate wound redox homeostasis. Meanwhile, the SeNPs are beneficial to angiogenesis, which facilitates blood vessel formation and promotes wound repair. Therefore, various functions can be achieved for the Fe-Se-HA MNs, such as magneto-thermal disinfection, deep and non-invasive tissue penetration, anti-inflammation, and pro-angiogenesis, which shows great potential as an adjunctive therapy for infected diabetic wounds.     

Silk Fibroin as an Efficient Biomaterial for Drug Delivery,Gene Therapy,and Wound Healing

Silk fibroin (SF), an organic material obtained from the cocoons of a silkworm Bombyx mori, is used in several applications and has a proven track record in biomedicine owing to its superior compatibility with the human body, superb mechanical characteristics, and its controllable propensity to decay. Due to its robust biocompatibility, less immunogenic, non-toxic, non-carcinogenic, and biodegradable properties, it has been widely used in biological and biomedical fields, including wound healing. The key strategies for building diverse SF-based drug delivery systems are discussed in this review, as well as the most recent ways for developing functionalized SF for controlled or redirected medicines, gene therapy, and wound healing. Understanding the features of SF and the various ways to manipulate its physicochemical and mechanical properties enables the development of more effective drug delivery devices. Drugs are encapsulated in SF-based drug delivery systems to extend their shelf life and control their release, allowing them to travel further across the bloodstream and thus extend their range of operation. Furthermore, due to their tunable properties, SF-based drug delivery systems open up new possibilities for drug delivery, gene therapy, and wound healing.     

MoSi2基复合材料的高温裂纹自愈合行为

采用X射线衍射、扫描电镜和三点弯曲强度测试方法研究MoSi2基复合材料Viekers压痕裂纹试样的高温裂纹自愈合行为和强度的变化.结果表明:Viekers压痕在材料表面造成明显裂纹并引起强度的急剧衰减.经过1500℃保温1h处理,在材料表面形成一层SiO2玻璃膜,材料表面的裂纹表现出良好的自愈合性能,抗弯强度恢复到345.3MPa.裂纹自愈合机理主要是高温下原子扩散作用引起的裂纹钝化和裂纹面的连接,另外材料表面SiO2玻璃层的形成也将促进表面缺陷和微裂纹的愈合.裂纹愈合是强度恢复的主要原因,而热处理对裂纹附近应力的松弛作用和表层压应力的形成也都有利于材料强度的提高.     

Effectiveness of Semi-Supervised Active Learning in Automated Wound Image Segmentation

Appropriate wound management shortens the healing times and reduces the management costs, benefiting the patient in physical terms and potentially reducing the healthcare system’s economic burden. Among the instrumental measurement methods, the image analysis of a wound area is becoming one of the cornerstones of chronic ulcer management. Our study aim is to develop a solid AI method based on a convolutional neural network to segment the wounds efficiently to make the work of the physician more efficient, and subsequently, to lay the foundations for the further development of more in-depth analyses of ulcer characteristics. In this work, we introduce a fully automated model for identifying and segmenting wound areas which can completely automatize the clinical wound severity assessment starting from images acquired from smartphones. This method is based on an active semi-supervised learning training of a convolutional neural network model. In our work, we tested the robustness of our method against a wide range of natural images acquired in different light conditions and image expositions. We collected the images using an ad hoc developed app and saved them in a database which we then used for AI training. We then tested different CNN architectures to develop a balanced model, which we finally validated with a public dataset. We used a dataset of images acquired during clinical practice and built an annotated wound image dataset consisting of 1564 ulcer images from 474 patients. Only a small part of this large amount of data was manually annotated by experts (ground truth). A multi-step, active, semi-supervised training procedure was applied to improve the segmentation performances of the model. The developed training strategy mimics a continuous learning approach and provides a viable alternative for further medical applications. We tested the efficiency of our model against other public datasets, proving its robustness. The efficiency of the transfer learning showed that after less than 50 epochs, the model achieved a stable DSC that was greater than 0.95. The proposed active semi-supervised learning strategy could allow us to obtain an efficient segmentation method, thereby facilitating the work of the clinician by reducing their working times to achieve the measurements. Finally, the robustness of our pipeline confirms its possible usage in clinical practice as a reliable decision support system for clinicians.     

Impact of Freeze-Drying on Cord Blood (CB), Serum (S), and Platelet-Rich Plasma (CB-PRP) Preparations on Growth Factor Content and In Vitro Cell Wound Healing

Blood-based preparations are used in clinical practice for the treatment of several eye disorders. The aim of this study is to analyze the effect of freeze-drying blood-based preparations on the levels of growth factors and wound healing behaviors in an in vitro model. Platelet-rich plasma (PRP) and serum (S) preparations from the same Cord Blood (CB) sample, prepared in both fresh frozen (FF) and freeze-dried (FD) forms (and then reconstituted), were analyzed for EGF and BDNF content (ELISA Quantikine kit). The human MIO-M1 glial cell line (Moorfield/Institute of Ophthalmology, London, UK) was incubated with FF and FD products and evaluated for cell migration with scratch-induced wounding (IncuCyte S3 Essen BioScience), proliferation with cyclin A2 and D1 gene expression, and activation with vimentin and GFAP gene expression. The FF and FD forms showed similar concentrations of EGF and BDNF in both the S and PRP preparations. The wound healing assay showed no significant difference between the FF and FD forms for both S and PRP. Additionally, cell migration, proliferation, and activation did not appear to change in the FD forms compared to the FF ones. Our study showed that reconstituted FD products maintained the growth factor concentrations and biological properties of FF products and could be used as a functional treatment option.     

Cold Atmospheric Plasma Jet Treatment Improves Human Keratinocyte Migration and Wound Closure Capacity without Causing Cellular Oxidative Stress

Cold Atmospheric Plasma (CAP) is an emerging technology with great potential for biomedical applications such as sterilizing equipment and antitumor strategies. CAP has also been shown to improve skin wound healing in vivo, but the biological mechanisms involved are not well known. Our study assessed a possible effect of a direct helium jet CAP treatment on keratinocytes, in both the immortalized N/TERT-1 human cell line and primary keratinocytes obtained from human skin samples. The cells were covered with 200 µL of phosphate buffered saline and exposed to the helium plasma jet for 10–120 s. In our experimental conditions, micromolar concentrations of hydrogen peroxide, nitrite and nitrate were produced. We showed that long-time CAP treatments (≥60 s) were cytotoxic, reduced keratinocyte migration, upregulated the expression of heat shock protein 27 (HSP27) and induced oxidative cell stress. In contrast, short-term CAP treatments (<60 s) were not cytotoxic, did not affect keratinocyte proliferation and differentiation, and did not induce any changes in mitochondria, but they did accelerate wound closure in vitro by improving keratinocyte migration. In conclusion, these results suggest that helium-based CAP treatments improve wound healing by stimulating keratinocyte migration. The study confirms that CAP could be a novel therapeutic method to treat recalcitrant wounds.     

广域相量测量技术在智能电网中的应用

近年来,我国特高压输电技术进入了一个快速发展的新阶段,特高压试验示范工程已投入运行,三华特高压同步电网将于2012年初步建成。同时,作为下一代电网技术代表的智能电网概念正在广泛讨论中。但到目前为止,还存在大量关键技术需要深入研究。国内从2003年开始大力发展广域相量测量技术,该技术在特高压大电网的动态特性监视和动态安全稳定评估等方面具有优势和发展前景,是未来智能电网的重要基础技术之一。文章回顾了国内广域相量测量技术的发展过程和现状,最后提出了发展思路和需要深入研究的领域。     

动态二硫键自修复聚氨酯改性沥青的制备和性能

为提高沥青路面的长期抗开裂性,开发了一种基于动态二硫键自修复聚氨酯改性沥青.以胱胺二盐酸盐为原料合成了含二硫键的聚氨酯扩链剂（CY-OA）,再通过分步共聚合成了二硫键交联聚氨酯弹性体（PU-SS）,并与沥青混合得到自修复聚氨酯改性沥青（PSA）,研究了PU-SS和PSA的物理化学性能、微观形态和自修复性能.结果表明,PU-SS的掺入提高了沥青的低温抗变形能力,其动态二硫键的自修复机制促进了沥青固有的自修复能力,实现了协同修复.