Autogenous healing mechanism of cement-based materials

Autogenous self-healing is the innate and fundamental repair capability of cement-based materials for healing cracks.Many researchers have investigated factors that influence autogenous healing.However,systematic research on the autogenous healing mechanism of cement-based materials is lacking.The healing process mainly involves a chemical process,including further hydration of unhydrated cement and carbonation of calcium oxide and calcium hydroxide.Hence,the autogenous healing process is influenced by the material constituents of the cement composite and the ambient environment.In this study,different factors influencing the healing process of cement-based materials were investigated.Scanning electron microscopy and optical microscopy were used to examine the autogenous healing mechanism,and the maximum healing capacity was assessed.Furthermore,detailed theoretical analysis and quantitative detection of autogenous healing were conducted.This study provides a valuable reference for developing an improved healing technique for cement-based composites.

Antimicrobial-free knitted fabric as wound dressing and the mechanism of promoting infected wound healing

Fibrous biomaterials are widely used in the design and fabrication of antibacterial wound dressings.Two strategies are used to make anti-infective dressings:antibacterial and probiotic therapies,which have potential biotoxicity and other side-effects.Herein,we report a new strategy for fabricating wound dressings to combat infection.Poly(4-methyl-1-pentene)(PMP) fabric can remove bacteria from infectious wounds through dressing changes based on its efficient bacterial adhesion.The maximum adhered count of S.aureus and E.coli on the PMP fabric was 1.63 × 106CFU/cm~2 and 4.77 × 105CFU/cm~2,respectively.In addition,the PMP fabric could inhibit the twitching motility of bacteria,which is beneficial for inhibiting infection.The ability of the PMP fabric to accelerate wound healing was demonstrated in vivo in a rat wound model.After treatment with the PMP fabric dressing,pathogenic bacteria in the wound were removed through dressing change;therefore,the wound exhibited better healing speed than when the commercial dressing was used.The low bacterial concentration effectively stimulated the expression of growth factors and suppressed wound inflammation,thereby accelerating wound healing.PMP fabric has three advantages:(1) it has been approved for use in clinical treatment by the Food and Drug Administration;(2) no antibacterial agent or probiotics were used;(3) the fabric could be manufactured through an industrial production process.These results indicate that the new strategy can be used in the design of new-generation wound dressings for antibacterial applications.

Self-healable gels in electrochemical energy storage devices

In the green energy and carbon-neutral technology,electrochemical energy storage devices have received continuously increasing attention recently.However,due to the unavoidable volume expansion/shrinkage of key materials or irreversible mechanical damages during application,the stability of energy storage and delivery as well as the lifetime of these devices are severely shortened,leading to serious performance degradation or even safety issues.Therefore,the utilization of self-healable gels into electrochemical energy storage devices,such as electrodes,binders,and electrolytes,is proven as an effective method to realize long-term stable operation of these devices via the self-repairing of mechanical and electrochemical characteristics.Herein,this review first summarizes the feature and fabrication of different gels,paying special attention to hydrogels,organohydrogels,and ionogels.Then,basic concepts and figure of merit of self-healable gels are analyzed with a detailed discussion at the healing mechanisms,from reversible dynamic bonds to physical molecular diffusion,and to external healing trigger.Then we introduce all the important parts of electrochemical energy storage devices,which could be replaced by healable gels to enhance the durability,including electrodes,binders,and electrolytes.Finally,the critical challenges and future perspectives regarding the future development of healable gels based high-performance electrochemical energy storage devices or electronics are provided.

Platelet-rich plasma： combinational treatment modalities for musculoskeletal conditions

Current research on common musculoskeletal problems, including osteoart]cular cona]t]ons, tendinopathies, and muscle injuries, focuses on regenerative translational medicine. Platelet-rich plasma therapies have emerged as a potential approach to enhance tissue repair and regeneration. Platelet-rich plasma application aims to provide supraphysiological concentrations of platelets and optionally leukocytes at injured/pathological tissues mimicking the initial stages of healing. However, the efficacy of platelet-rich plasma is controversial in chronic diseases because patients＇ outcomes show partial improvements. Platelet-rich plasma can be customized to specific conditions by selecting the most appropriate formulation and timing for application or by combining platelet-rich plasma with synergistic or complementary treatments. To achieve this goal, researchers should identify and enhance the main mechanisms of healing. In this review, the interactions between platelet-rich plasma and healing mechanisms were addressed and research opportunities for customized treatment modalities were outlined. The development of combinational platelet-rieh plasma treatments that can be used safely and effectively to manipulate healing mechanisms would be valuable and would provide insights into the processes involved in physiological healing and pathological failure.

基于吡啶-铜配位的快速自修复高性能金属超分子弹性体

在机械力破坏下,弹性体容易出现裂纹,而裂纹若没有及时被修复,容易引发灾难性事故.因此,对弹性体来说,具有快速修复裂纹的能力非常重要.然而,开发同时具有快速修复能力和高机械性能的弹性体极具挑战性.本论文中,我们将吡啶-铜配位键引入丙烯酸乙酯和乙烯基吡啶的共聚物中来制备金属配位弹性体.由于吡啶-铜配位键具有强烈的光热效应,在近红外光照射30 s后,样品表面温度可以从24℃升高至60℃,在60℃时,sticky-reptation运动被激活,为金属超分子弹性体网络重组和快速自修复提供驱动力.材料拉伸强度可达到10 MPa,并且划痕破坏试样和完全断裂破坏的试样可分别在2 min和3 h内愈合.此外,在破坏和修复过程中,激光共焦显微拉曼光谱可以追踪配位键的断裂和重组,这为监测金属超分子聚合物的键级修复动力学提供了一种微观方法.