Superstable and Intrinsically Self-Healing Fibrous Membrane with Bionic Confined Protective Structure for Breathable Electronic Skin.

Considerable effort has been devoted to the fabrication of electronic skin that can imitate the self-healing and sensing function of biological skin. Almost all self-healing electronic skins are composed of airtight elastomers or hydrogels, which will cause skin inflammation. Fibrous membranes are ideal materials for preparing highly sensitive breathable electronic skins. However, the development of intrinsically self-healing fibrous membranes with high stability is still a challenge. Here, a novel interface protective strategy is reported to develop intrinsically self-healing fibrous membranes with a bionic confined structure for the first time, which were further assembled into an all-fiber structured electronic skin through interfacial hydrogen bonding. The electronic skin is multifunctional with self-powering, self-healing, breathability, stretchability, and thermochromism functionalities, which is highly promising for application in intelligent wearable sensing systems.

Tribo-charge enhanced and cellulose based biodegradable nanofibrous membranes with highly fluffy structure for air filtration and self-powered respiration monitoring systems.

Recently, the demand for healthcare products especially wearable smart masks is increasing. The biosafety and degradability of smart masks are crucial for human health and environmental protection. However, the development of biodegradable and biocompatible fibrous membranes with high filtration efficiency and low pressure drop is still a challenge. How to realize the collaborative improvement between air filtration efficiency and pressure drop of the nanofibrous membrane is still a challenge. Here, a tribo-charge enhanced and biodegradable nanofibrous membranes (TCB NFMs) with highly fluffy structure for air filtration and self-powered respiration monitoring systems is reported for the first time. The filtration efficiency and pressure drop of the prepared membranes for 0.3 µm NaCl particulates is 99.971% and 41.67 Pa. The TCB NFMs based smart mask possesses a series of satisfactory and excellent characteristics, such as self-powered, biodegradable, biocompatible, high filtration efficiency, and low pressure drop, which is highly promising for application in air filtration systems and intelligent wearable respiration monitoring systems.

Biomaterials based on hyaluronic acid, collagen and peptides for three-dimensional cell culture and their application in stem cell differentiation.

In recent decades, three-dimensional (3D) cell culture technologies have been developed rapidly in the field of tissue engineering and regeneration, and have shown unique advantages and great prospects in the differentiation of stem cells. Herein, the article reviews the progress and advantages of 3D cell culture technologies in the field of stem cell differentiation. Firstly, 3D cell culture technologies are divided into two main categories: scaffoldless and scaffolds. Secondly, the effects of hydrogels scaffolds and porous scaffolds on stem cell differentiation in the scaffold category were mainly reviewed. Among them, hydrogels scaffolds are divided into natural hydrogels and synthetic hydrogels. Natural materials include polysaccharides, proteins, and their derivatives, focusing on hyaluronic acid, collagen and polypeptides. Synthetic materials mainly include polyethylene glycol (PEG), polyacrylic acid (PAA), polyvinyl alcohol (PVA), etc. In addition, since the preparation techniques have a large impact on the properties of porous scaffolds, several techniques for preparing porous scaffolds based on different macromolecular materials are reviewed. Finally, the future prospects and challenges of 3D cell culture in the field of stem cell differentiation are reviewed. This review will provide a useful guideline for the selection of materials and techniques for 3D cell culture in stem cell differentiation.

A Conductive Bioengineered Cardiac Patch for Myocardial Infarction Treatment by Improving Tissue Electrical Integrity.

Conductive scaffolds are of great value for constructing functional myocardial tissues and promoting tissue reconstruction in the treatment of myocardial infarction (MI). Here, a novel scaffold composed of silk fibroin and polypyrrole (SP50) with a typical sponge-like porous structure and electrical conductivity similar to the native myocardium is developed. An electroactive engineered cardiac patch (SP50 ECP) with a certain thickness is constructed by applying electrical stimulation (ES) to the cardiomyocytes (CMs) on the scaffold. SP50 ECP can significantly express cardiac marker protein (α-actinin, Cx-43, and cTnT) and has better contractility and electrical coupling performance. Following in vivo transplantation, SP50 ECP shows a notable therapeutic effect in repairing infarcted myocardium. Not only can SP50 ECP effectively improves left ventricular remodeling and restore cardiac functions, such as ejection function (EF), but more importantly, improves the propagation of electrical pulses and promote the synchronous contraction of CMs in the scar area with normal myocardium, effectively reducing the susceptibility of MI rats to arrhythmias. In conclusion, this study demonstrates a facile approach to constructing electroactive ECPs based on porous conductive scaffolds and proves the therapeutic effects of ECPs in repairing the infarcted heart, which may represent a promising strategy for MI treatment.

UV-curable hyperbranched polyester sealant with tunable mechanical properties.

Different types of wounds have different requirements of a wound sealant. One of the requirements of concern is the adaptability of the mechanical properties of biomaterials to native tissues. However, the mechanical properties of current sealant are untunable or adjustable in a small range normally. Therefore, the scope of application of these sealant is limited. In this study, we developed hyperbranched polyester (HBP)-based UV-curable sealant with tunable mechanical properties. This sealant was cured under UV-light for 2 minutes and exhibited strong adhesion with tissues. The shear adhesive strength of it to the porcine skin ranged between 20-30 kPa, which was higher than the fibrin glue (∼10 kPa). Moreover, the elastic modulus of the sealant in a tensile test ranged between 27-54 MPa, depending on the degree of acrylation of the HBPs. Additionally, we assessed the biocompatibility of the sealant by co-culturing it with mouse mesenchymal stem cells (mMSCs) for 7 days and discovered that the cell viability was unaffected. This sealant with a tunable elastic modulus might be a promising candidate for treating wounds with different elastic moduli.

Highly Wearable, Breathable, and Washable Sensing Textile for Human Motion and Pulse Monitoring.

At present, pressure sensor textiles are of great significance in the area of wearable electronics, especially for making smart or intelligent textiles. However, the design of these textile-based devices with sensitive ability, simple fabrication, and low cost is still challenging. In this study, we developed a triboelectric sensing textile constructed with core-shell yarns. Nylon filament and polytetrafluoroethylene filament were selected as the positive and negative layers, respectively, in the woven structure while the built-in helical stainless steel yarn was serving as the inner electrode layer. The sensitivity of the sensing textile can reach up to 1.33 V·kPa-1 and 0.32 V·kPa-1 in the pressure range of 1.95-3.13 kPa and 3.20-4.61 kPa, respectively. This sensing textile presented good mechanical stability and sensing capability even after 4200 cycles of continuous operation or after 4 h continuous water washing. Benefiting from the favorable merits of being highly flexible, breathable, lightweight, and even dyeable, the fabricated device was capable of being placed on any desired body parts for quantifying the dynamic human motions. It can be effectively used to measure and monitor various human movements associated with different joints, such as the hand, elbow, knee, and underarm. Moreover, the sensing textile was able to capture real-time pulse signals and reflect the current health status for human beings. This study affords an innovative and promising track for multifunctional pressure sensor textiles with wide applications in smart textiles and personalized healthcare.

Recent developments in regenerative ophthalmology.

Regenerative medicine (RM) is one of the most promising disciplines for advancements in modern medicine, and regenerative ophthalmology (RO) is one of the most active fields of regenerative medicine. This review aims to provide an overview of regenerative ophthalmology, including the range of tools and materials being used, and to describe its application in ophthalmologic subspecialties, with the exception of surgical implantation of artificial tissues or organs (e.g., contact lens, artificial cornea, intraocular lens, artificial retina, and bionic eyes) due to space limitations. In addition, current challenges and limitations of regenerative ophthalmology are discussed and future directions are highlighted.

Green electrospun and crosslinked poly(vinyl alcohol)/poly(acrylic acid) composite membranes for antibacterial effective air filtration.

Air pollution has become a major environmental concern given the ever increasing levels of particulate matter (PM) and the increased in treatment-resistant bacterial and viral strains. Major efforts are therefore required into the development of air filtration and purification technology as well as novel, alternative antiviral and antibacterial treatment modalities. Here, we report an environmentally friendly method for the generation of multifunctional poly(vinyl alcohol)/poly(acrylic acid) (PVA-PAA) composite membranes via green electrospinning and thermal crosslinking. Superhydrophobic silica nanoparticles were then incorporated into the fibers resulting in a rough surface, after which AgNO3 was introduced, resulting in the formation of Ag nanoparticles through UV reduction. The PVA-PAA-SiO2-Ag NPs membranes were found to possess high air filtration performance (with >98% filtration efficiency for PM2.5) as well as potent antibacterial and antiviral activities. The green synthesis approach avoids the use of hazardous organic solvents, thereby bypassing any potential toxicity concerns caused by organic solvent residues. These newly designed PVA-PAA-SiO2 NPs-Ag NPs nanofibrous membranes with many superior features (e.g. high filtration efficiency, high tensile strength, biological compatibility, and antibacterial properties) can be applied in eco-friendly air filtration materials, in particular for personal air filtration devices.