Bioinspired Conductive Silk Microfiber Integrated Bioelectronic for Diagnosis and Wound Healing in Diabetes

Molecular Design and Preparation of Protein-Based Soft Ionic Conductors with Tunable Properties

Protein-based soft ionic conductors have attracted considerable research interest in recent years with great potential in applications at the human-machine interfaces. However, a fundamental mechanistic understanding of the ionic conductivity of silk-based ionic conductors is still unclear. Here, we first developed an environmental-friendly and scalable method to fabricate silk-based soft ionic conductors using silk proteins and calcium chloride. The mechanistic understanding of the ion transport and molecular interactions between calcium ions and silk proteins at variable water contents was investigated in-depth by combining experimental and simulation approaches. The results show that calcium ions primarily interact with amide groups in proteins at a low water content. The ionic conductivity is low since the calcium ions are confined around silk proteins within 2.0-2.6 Å. As water content increases, the calcium ions are hydrated with the formation of water shells, leading to the increased distance between calcium ions and silk proteins (3.3-6.0 Å). As a result, the motion of the calcium ions increased to achieve a higher ionic conductivity. By optimizing the ratio of the silk proteins, calcium ions, and water, silk-based soft ionic conductors with good stretchability and self-healing properties can be obtained. Such protein-based soft ionic conductors can be further used to fabricate smart devices such as electrochromic devices.

Multifunctional GO Hybrid Hydrogel Scaffolds for Wound Healing

Hydrogel dressings have received extensive attention for the skin wound repair, while it is still a challenge to develop a smart hydrogel for adapting the dynamic wound healing process. Herein, we develop a novel graphene oxide (GO) hybrid hydrogel scaffold with adjustable mechanical properties, controllable drug release, and antibacterial behavior for promoting wound healing. The scaffold was prepared by injecting benzaldehyde and cyanoacetate group-functionalized dextran solution containing GO into a collection pool of histidine. As the GO possesses obvious photothermal behavior, the hybrid hydrogel scaffold exhibited an obvious stiffness decrease and effectively promoted cargo release owing to the breaking of the thermosensitive C=C double bond at a high temperature under NIR light. In addition, NIR-assisted photothermal antibacterial performance of the scaffold could be also achieved with the local temperature rising after irradiation. Therefore, it is demonstrated that the GO hybrid hydrogel scaffold with vascular endothelial growth factor (VEGF) encapsulation can achieve the adjustable mechanical properties, photothermal antibacterial, and angiogenesis during the wound healing process. These features indicated that the proposed GO hybrid hydrogel scaffold is potentially valuable for promoting wound healing and other biomedical application.

Smart Textiles for Healthcare and Sustainability

At the forefront of the smart textile community, healthcare and sustainability are the two crucial objectives targeted by researchers. The development of such powerful devices has been driven by innovative fabrications of breathable, skin-conformable technologies through the use of functional and programmable materials and device structures. This Perspective focuses on the current smart textiles available in the research field, categorized into personalized healthcare, including diagnostics and therapeutics, and sustainability, including energy harvesting and conservation─personalized thermoregulation. These categories are further broken down into their platform structural technologies and performances. Furthermore, we give a comprehensive overview and highlight a few examples of current studies. Finally, we provide an outlook on these technologies for future researchers to participate. We envision that the next generation of smart textiles will revolutionize wearable technology for healthcare and sustainability.

Supertough and Highly Stretchable Silk Protein-based Films with Controlled Biodegradability

Naturally derived protein-based biopolymers are considered potential biomaterials in biomedical applications and eco-friendly materials for replacing current petroleum-based polymers due to their good biocompatibility, low environmental impact, and tunable degradability. However, current strategies for fabricating protein-based materials with superior properties and tailored functionality in a scalable manner are still lacking. Here, we demonstrate an aqueous-based scalable approach for fabricating silk protein-based films through controlled molecular self-assembly (CMS) of silk proteins with plasticizers and salt ions. The films fabricated using this method can achieve a toughness of up to 64±5 MJ/m³ with a stretchability of up to 574±31%. We also demonstrate the tunable enzymatic degradability, low in vitro cytotoxicity, and good in vivo biocompatibility of the films. Furthermore, the films can be patterned with predesigned complex structures through laser cutting and functionalized with bioactive components. The functional silk protein-based films show great potential in various applications, including flexible electronics, bioelectronics, tissue engineering, and bioplastic packaging. STATEMENT OF SIGNIFICANCE: Inspired by the naturally optimized multi-scale self-assembly of silk proteins in natural silks, we develop an aqueous-based approach for scalable production of superior protein-based films through controlled molecular self-assembly (CMS) of silk proteins with glycerol and calcium ions. The prepared silk films present outstanding mechanical properties, controlled enzymatic biodegradability, low in vitro cytotoxicity, and good in vivo biocompatibility. Notably, the films fabricated using this method can achieve a high toughness of 64±5 MJ/m³ with a stretchability of 594±31%. The approach introduced in this work provides a facile route toward making silk-based materials with superior properties. It also paves new avenues for developing functional protein-based materials with precisely controlled structures and properties for various applications.

Responsive and self-healing structural color supramolecular hydrogel patch for diabetic wound treatment

The treatment of diabetic wounds remains a great challenge for medical community. Here, we present a novel structural color supramolecular hydrogel patch for diabetic wound treatment. This hydrogel patch was created by using N-acryloyl glycinamide (NAGA) and 1-vinyl-1,2,4-triazole (VTZ) mixed supramolecular hydrogel as the inverse opal scaffold, and temperature responsive poly(N-isopropylacrylamide) (PNIPAM) hydrogel loaded with vascular endothelial cell growth factor (VEGF) as a filler. Supramolecular hydrogel renders hydrogel patch with superior mechanical properties, in which NAGA and VTZ also provide self-healing and antibacterial properties, respectively. Besides, as the existence of PNIPAM, the hydrogel patch was endowed with thermal-responsiveness property, which could release actives in response to temperature stimulus. Given these excellent performances, we have demonstrated that the supramolecular hydrogel patch could significantly enhance the wound healing process in diabetes rats by downregulating the expression of inflammatory factors, promoting collagen deposition and angiogenesis. Attractively, due to responsive optical property of inverse opal scaffold, the hydrogel patch could display color-sensing behavior that was suitable for the wound monitoring and management as well as guidance of clinical treatment. These distinctive features indicate that the presented hydrogel patches have huge potential values in biomedical fields.

A mechanically adaptive hydrogel neural interface based on silk fibroin for high-efficiency neural activity recording

A flexible non-transient electrical platform that can realize bidirectional neural communication from living tissues is of great interest in neuroscience to better understand basic neuroscience and the nondrug therapy of diseases or disorders. The development of soft, biocompatible, and conductive neural interface with mechanical coupling and efficient electrical exchange is a new trend but remains a challenge. Herein, we designed a multifunctional neural electrical communication platform in the form of a mechanically compliant, electrically conductive, and biocompatible hydrogel electrode. Silk fibroin (SF) obtained from Bombyx Mori cocoons was compounded with aldehyde-hyaluronic acid (HA-CHO) with a dynamic network to delay or interrupt the β-sheet-induced hardening of SF chains, resulting in the fabrication of a hydrogel matrix that is mechanically matched to biological tissues. Moreover, the incorporation of functionalized carbon nanotubes (CNTs) facilitated interaction and dispersion and enabled the formation of a hydrogel electrode with a high-current percolation network, thus contributing toward improving the electrical properties in terms of conductivity, impedance, and charge storage capabilities. These advances allow high-efficiency stimulation and the recording of neural signals during in vivo implantation. Overall, a wide range of animal experiments demonstrate that the platform exhibits minimal foreign body responses, thus showing it to be a promising electrophysiology interface for potential applications in neuroscience.

Infant Skin Friendly Adhesive Hydrogel Patch Activated at Body Temperature for Bioelectronics Securing and Diabetic Wound Healing

Adhesive-caused injury is a great threat for infants with premature skin or diabetic patients with fragile skin because extra-strong adhesion might incur pain, inflammation, and exacerbate trauma upon removal. Herein, we present a skin-friendly adhesive hydrogel patch based on protein-polyphenol complexation strategy, which leads to a thermoresponsive network sensitive to body temperature. The adhesion of the hydrogel is smartly activated after contacting with warm skin, whereas the painless detachment is easily realized by placing an ice bag on the surface of the hydrogel. The hydrogel exhibits an immunomodulatory performance that prevents irritation and allergic reactions during long-period contact with the skin. Thus, the hydrogel patch works as a conformable and nonirritating interface to guarantee nondestructively securing bioelectronics on infant skin for healthcare. Furthermore, the hydrogel patch provides gentle adhesion to wounded skin and provides a favorable environment to speed up the healing process for managing diabetic wounds.

Polydopamine Biomaterials for Skin Regeneration

Designing biomaterials capable of biomimicking wound healing and skin regeneration has been receiving increasing attention recently. Some biopolymers behave similarly to the extracellular matrix (ECM), supporting biointerfacial adhesion and intrinsic cellular interactions. Polydopamine (PDA) is a natural bioadhesive and bioactive polymer that endows high chemical versatility, making it an exciting candidate for a wide range of biomedical applications. Moreover, biomaterials based on PDA and its derivatives have near-infrared (NIR) absorption, excellent biocompatibility, intrinsic antioxidative activity, antibacterial activity, and cell affinity. PDA can regulate cell behavior by controlling signal transduction pathways. It governs the focal adhesion behavior of cells at the biomaterials interface. These features make melanin-like PDA a fascinating biomaterial for wound healing and skin regeneration. This paper overviews PDA-based biomaterials' synthesis, properties, and interactions with biological entities. Furthermore, the utilization of PDA nano- and microstructures as a constituent of wound-dressing formulations is highlighted.

High-Strength, Conductive, Antifouling, and Antibacterial Hydrogels for Wearable Strain Sensors

Conductive hydrogels have shown great potential in the field of flexible strain sensors. However, their application is greatly limited due to the poor antifouling and low mechanical strength. Unfortunately, it is still a challenge to improve these two distinct properties simultaneously. Herein, a hydrogel with high strength, good conductivity, and excellent antifouling and antibacterial properties was prepared through the synergistic effect of physical and chemical cross-linking. First, acrylic acid (AA), acrylamide (AM), and 2-methacryloyloxyethyl phosphorylcholine (MPC) monomers were polymerized in the presence of chitosan chains to form the hydrogel. Then, the prepared hydrogel was immersed in a ferric ion solution to further strengthen the hydrogel through ion coordination. The obtained CS-P(AM-MPC-AA_0.2)-Fe_0.1³⁺ hydrogel showed outstanding tensile strength (1.03 MPa), excellent stretchability (1075%), good toughness (7.03 MJ/m³), and fatigue resistance. The CS-P(AM-MPC-AA_0.2)-Fe_0.1³⁺ hydrogel also demonstrated good ion conductivity (0.42 S/m) and excellent antifouling and antibacterial properties. In addition, the strain sensor constructed by the CS-P(AM-MPC-AA_0.2)-Fe_0.1³⁺ hydrogel showed high sensitivity and good stability. This work presented a facile method to construct a zwitterionic hydrogel with high-strength, conductive, antifouling, and antibacterial properties, which suggested a promising gel platform for flexible wearable sensors.

Mussel-inspired collagen-hyaluronic acid composite scaffold with excellent antioxidant properties and sustained release of a growth factor for enhancing diabetic wound healing

Long-term non-healing diabetic wounds are always a serious challenge and a global healthcare burden that needs to be resolved urgently in the clinic. Prolonged inflammation and impaired angiogenesis are the main direct causes of diabetic wounds. With the development of polymer biomaterials, various wound dressings have been created, but a few of them have been applied to the clinical management of diabetic wounds. Here, we developed a mussel-inspired bioactive scaffold consisting mainly of collagen and hyaluronic acid, which are natural biopolymer materials contained in human tissues. First, we fabricated different polydopamine modified lyophilized collagen hyaluronic acid scaffolds under different concentrations of dopamine alkaline solutions, 0.5, 1, 2 ​mg/mL, so named CHS-PDA-0.5, CHS-PDA-1, CHS-PDA-2. After testing their physical and chemical properties, antioxidant effect, inflammation regulation, as well as drug loading and release capabilities, we obtained a bioactive endothelial growth factor (EGF)-loaded wound dressing, CHS-PDA-2@EGF, which can resist reactive oxygen species (ROS) and promote the regeneration of chronic wounds in diabetic rats by reducing inflammation. In addition, the scaffold showed excellent swelling ability, a certain coagulation effect and reasonable degradation. Therefore, the scaffold has great potential to be used in clinical diabetic wound treatment as a low-cost and easily available wound dressing to accelerate chronic wound healing.

Breathable, Moisturizing, Anti-Oxidation SSD-PG-PVA/KGM Fibrous Membranes for Accelerating Diabetic Wound Tissue Regeneration

Diabetic wound tissue repair and regeneration is a multi-step process that includes cell proliferation and migration, gas and moisture management, and inflammatory responses. However, current wound dressing designs lack consideration of the wound microenvironment of diabetic patients, making diabetic wound tissue repair a challenge. Here, we report a wound dressing (SSD-PG-PVA/KGM) with a porous structure and anti-oxidant properties for promoting diabetic wound tissue repair. First, the porous structure created by electrospinning technology encourages cell proliferation and migration in the wound while also providing breathability and moisture retention. Second, adding natural polyphenols (PG) and saikosaponins (SSDs) to the wound reduced reactive oxygen species levels and oxide stress. In vitro cell experiments showed that SSD-PG-PVA/KGM had good biocompatibility. Due to the biocompatibility, anti-oxidation ability, breathability, and moisturizing, SSD-PG-PVA/KGM could effectively promote the repair of diabetic wound tissue (the wound closure rate was 95.6% at 14 days).

Design of asymmetric-adhesion lignin-reinforced hydrogels based on disulfide bond crosslinking for strain sensing application

Soft and elastic polymer hydrogel materials are booming in the fields of wearable biomimetic skin, sensors, robotics, and bioelectrodes. Currently, many researchers are exploring new chemistries for the preparation of hydrogels to improve their performance. In the present study, we design and develop a strategy to prepare lignin reinforced hydrogels based on disulfide bond crosslinking mechanisms, and resultant hydrogels exhibit excellent stretchability, with tensile strain of up to 1085.4%, and high adhesion (with the highest T-peel strength of up to 432.2 N/m to pigskin). The underlying mechanism is based on the disulfide bonds that act as crosslinkers in the as-prepared hydrogel, and they can be easily cleaved and re-formed under mild conditions. Thanks to the presence of lignin, the as-obtained hydrogels also have excellent UV shielding effect. When assembled into a strain sensor, they can output stable and sensitive sensing signals, with gauge factor (GF) of 2.72 (strain: 0-72.8%). Furthermore, a simple and effective strategy to construct asymmetric adhesive hydrogels was adopted, which is based on directional soaking of the top portion of the hydrogel in a high-concentrated calcium chloride solution. The asymmetric hydrogel strain sensor transmits accurate and stable signals without the interference of various contaminants.

Photoacoustic microscopy of vascular adaptation and tissue oxygen metabolism during cutaneous wound healing

Cutaneous wounds affect millions of people every year. Vascularization and blood oxygen delivery are critical bottlenecks in wound healing, and understanding the spatiotemporal dynamics of these processes may lead to more effective therapeutic strategies to accelerate wound healing. In this work, we applied multi-parametric photoacoustic microscopy (PAM) to study vascular adaptation and the associated changes in blood oxygen delivery and tissue oxygen metabolism throughout the hemostasis, inflammatory, proliferation, and early remodeling phases of wound healing in mice with skin puncture wounds. Multifaceted changes in the vascular structure, function, and tissue oxygen metabolism were observed during the 14-day monitoring of wound healing. On the entire wound area, significant elevations of the arterial blood flow and tissue oxygen metabolism were observed right after wounding and remained well above the baseline over the 14-day period. On the healing front, biphasic changes in the vascular density and blood flow were observed, both of which peaked on day 1, remained elevated in the first week, and returned to the baselines by day 14. Along with the wound closure and thickening, tissue oxygen metabolism in the healing front remained elevated even after structural and functional changes in the vasculature were stabilized. On the newly formed tissue, significantly higher blood oxygenation, flow, and tissue metabolism were observed compared to those before wounding. Blood oxygenation and flow in the new tissue appeared to be independent of when it was formed, but instead showed noticeable dependence on the phase of wound healing. This PAM study provides new insights into the structural, functional, and metabolic changes associated with vascular adaptation during wound healing and suggests that the timing and target of vascular treatments for wound healing may affect the outcomes.

Recent Development of Conductive Hydrogels for Tissue Engineering: Review and Perspective

In recent years, tissue engineering techniques have been rapidly developed and offer a new therapeutic approach to organ or tissue damage repair. However, most of tissue engineering scaffolds are nonconductive and cannot establish effective electrical coupling with tissue for the electroactive tissues. Electroconductive hydrogels (ECHs) have received increasing attention in tissue engineering owing to their electroconductivity, biocompatibility and high water content. In vitro, ECHs can not only promote the communication of electrical signals between cells, but also mediate the adhesion, proliferation, migration, and differentiation of different kinds of cells. In vivo, ECHs can transmit the electric signal to electroactive tissues and activate bioelectrical signaling pathways to promote tissue repair. As a result, implanting ECHs into damaged tissues can effectively reconstruct physiological functions related to electrical conduction. In this review, we first present an overview about the classifications and the fabrication methods of ECHs. And then, the applications of ECHs in tissue engineering, including cardiac, nerve, skin and skeletal muscle tissue, are highlighted. At last, we provide some rational guidelines for designing ECHs towards clinical applications. This article is protected by copyright. All rights reserved.

Supramolecular Thermo-Contracting Adhesive Hydrogel with Self-Removability Simultaneously Enhancing Noninvasive Wound Closure and MRSA-Infected Wound Healing

Conventional wound closure and dressing are two crucial, time-consuming but isolated principles in wound care. Even though tissue adhesive opens a new era for wound closure, the method and biomaterial that can simultaneously achieve noninvasive wound closure and promote wound healing are highly appreciated. Herein, a novel supramolecular poly(N-isopropylacrylamide) hybrid hydrogel dressing composed of quaternized chitosan-graft-β-cyclodextrin, adenine, and polypyrrole nanotubes via host-guest interaction and hydrogen bonds is developed. The hydrogel demonstrates thermal contraction of 47% remaining area after 2 h at 37 ℃ and tissue adhesion of 5.74 kPa, which are essential for noninvasive wound closure, and multiple mechanical and biological properties including suitable mechanical properties, self-healing, on-demand removal, antioxidant, hemostasis, and photothermal/intrinsic antibacterial activity (higher 99% killing ratio within 5 min after irradiation). In both full-thickness skin incision and excision wound models, the hydrogel reveals significant wound closure after 24 h post-surgery. In acute and methicillin-resistant Staphylococcus aureus-infected wound and photothermal/intrinsic antibacterial activity assays, wounds treated with the hydrogel demonstrate enhanced wound healing with rapid wound closure rate, mild inflammatory response, advanced angiogenesis, and well-arranged collagen fibers. Altogether, the results indicate the hydrogel is promising in synchronously noninvasive wound closure and enhanced wound healing.

Quaternized chitin/tannic acid bilayers layer-by-layer deposited poly(lactic acid)/polyurethane nanofibrous mats decorated with photoresponsive complex and silver nanoparticles for antibacterial activity

Chronic wounding treatment based on bacterially infected diabetes suffers an essential limitation in persistent skin injuries due to the resistance of progressive antibiotics, which inhibits the process of healing with wound tissue. Therefore, biologically friendly and nontoxic bio-based mats without antibiotics are taken for granted as a versatile platform for biomedical dressing, but urgently necessitates further functional diversification. Herein, a novel tannic acid (TA)/silver (Ag)-modified poly(lactic acid) (PLA)/Polyurethane (PU) antibacterial hybrid nanofibers were successfully constructed by electrospinning technology. Layer-by-layer (LBL) self-assembly technique was utilized to produce membranes via deposited biocompatible quaternized chitin (QC) and TA. The mats are enabled with outstanding flexibility, antibacterial activity, great hemocompatibility, and good ROS-scavenger in a wounding environment. Consequently, the basis of morphology and structure of electrospun membranes was verified by SEM and FT-IR. Besides, the LBL-structured surface was proved to impart improved wettability and hydrophilic via the test of water contact angle. Additionally, antimicrobial experiments demonstrate the effective broad-spectrum antibacterial ability of as-prepared hybrids, inhibiting infection of gram-positive microbial (S. aureus) as well as gram-negative microbial. Finally, the anti-oxidation performance holds great promise in conducive to the formation favorable physiological environment for wound healing. In conclusion, this work establishes a feasible but effective pathway to construct a multifunctional antibacterial dressing for the skin infection.

Polydopamine-Induced Multilevel Engineering of Regenerated Silk Fibroin Fiber for Photothermal Conversion

Solid photothermal materials with favorable biocompatibility and modifiable mechanical properties demonstrate obvious superiority and growing demand. In this work, polydopamine (PDA) induced functionalization of regenerated silk fibroin (RSF) fibers has satisfactory photothermal conversion ability and flexibility. Based on multilevel engineering, RSF solution containing PDA nanoparticles is wet spun to PDA-incorporating RSF (PDA@RSF) fibers, and then the fibers are coated with PDA via oxidative self-polymerization of dopamine to form PDA@RSF-PDA (PRP) fibers. During the wet spinning process, PDA is to adjust the mechanical properties of RSF by affecting its hierarchical structure. Meanwhile, coated PDA gives the PRP fibers extensive absorption of near-infrared light and sunlight, which is further fabricated into PRP fibrous membranes. The temperature of PRP fibrous membranes can be adjusted and increases to about 50 °C within 360 s under 808 nm laser irradiation with a power density of 0.6 W cm^-2 , and PRP fibrous membranes exhibit effective photothermal cytotoxicity both in vitro and in vivo. Under the simulated sunlight, the temperature of PRP fiber increases to more than 200 °C from room temperature and the material can generate 4.5 V voltage when assembled with a differential thermal battery, which means that the material also has the potential for flexible wearable electronic devices.

Regulation of biomaterial implantation-induced fibrin deposition to immunological functions of dendritic cells

The performance of implanted biomaterials is largely determined by their interaction with the host immune system. As a fibrous-like 3D network, fibrin matrix formed at the interfaces of tissue and material, whose effects on dendritic cells (DCs) remain unknown. Here, a bone plates implantation model was developed to evaluate the fibrin matrix deposition and DCs recruitment in vivo. The DCs responses to fibrin matrix were further analyzed by a 2D and 3D fibrin matrix model in vitro. In vivo results indicated that large amount of fibrin matrix deposited on the interface between the tissue and bone plates, where DCs were recruited. Subsequent in vitro testing denoted that DCs underwent significant shape deformation and cytoskeleton reorganization, as well as mechanical property alteration. Furthermore, the immune function of imDCs and mDCs were negatively and positively regulated, respectively. The underlying mechano-immunology coupling mechanisms involved RhoA and CDC42 signaling pathways. These results suggested that fibrin plays a key role in regulating DCs immunological behaviors, providing a valuable immunomodulatory strategy for tissue healing, regeneration and implantation.

Mussel-inspired extracellular matrix-mimicking hydrogel scaffold with high cell affinity and immunomodulation ability for growth factor-free cartilage regeneration

Background

Injury to articular cartilage cause certain degree of disability due to poor self-repair ability of cartilage tissue. To promote cartilage regeneration, it is essential to develop a scaffold that properly mimics the native cartilage extracellular matrix (ECM) in the aspect of compositions and functions.

Methods

A mussel-inspired strategy was developed to construct an ECM-mimicking hydrogel scaffold by incorporating polydopamine-modified hyaluronic acid (PDA/HA) complex into a dual-crosslinked collagen (Col) matrix for growth factor-free cartilage regeneration. The adhesion, proliferation, and chondrogenic differentiation of cells on the scaffold were examined. A well-established full-thickness cartilage defect model of the knee in rabbits was used to evaluated the efficacy and functionality of the engineered Col/PDA/HA hydrogel scaffold.

Results

The PDA/HA complex incorporated-hydrogel scaffold with catechol moieties exhibited better cell affinity than bare negatively-charged HA incorporated hydrogel scaffold. In addition, the PDA/HA complex endowed the scaffold with immunomodulation ability, which suppressed the expression of inflammatory cytokines and effectively activated the polarization of macrophages toward M2 phenotypes. The in vivo results revealed that the mussel-inspired Col/PDA/HA hydrogel scaffold showed strong cartilage inducing ability to promote cartilage regeneration.

Conclusions

The PDA/HA complex-incorporated hydrogel scaffold overcame the cell repellency of negatively-charged polysaccharide-based scaffolds, which facilitated the adhesion and clustering of cells on the scaffold, and therefore enhanced cell-HA interactions for efficient chondrogenic differentiation. Moreover, the hydrogel scaffold modulated immune microenvironment, and created a regenerative microenvironment to enhance cartilage regeneration.

The translational potential of this article

This study gives insight into the mussel-inspired approach to construct the tissue-inducing hydrogel scaffold in a growth-factor-free manner, which show great advantage in the clinical treatment. The hydrogel scaffold composed of collagen and hyaluronic acid as the major component, providing cartilage ECM-mimicking environment, is promising for cartilage defect repair.

Endogenous Electric-Field-Coupled Electrospun Short Fiber via Collecting Wound Exudation

Endogenous electric fields (EF) are the basis of bioelectric signal conduction and the priority signal for damaged tissue regeneration. Tissue exudation directly affects the characteristics of endogenous EF. However, current biomaterials lead to passive repair of defect tissue due to limited management of early wound exudates and inability to actively respond to coupled endogenous EF. Herein, the 3D bionic short-fiber scaffold with the functions of early biofluid collection, response to coupled endogenous EF, is constructed by guiding the short fibers into a 3D network structure and subsequent multifunctional modification. The scaffold exhibits rapid reversible water absorption, reaching maximum after only 30 s. The stable and uniform distribution of polydopamine-reduced graphene oxide endows the scaffold with stable electrical and mechanical performances even after long-term immersion. Due to its unique - bionic structure and tissue affinity, the scaffold further acts as an "electronic skin," which transmits endogenous bioelectricity via absorbing wound exudates, promoting the treatment of diabetic wounds. Furthermore, under the endogenous EF, the cascade release of vascular endothelial growth factor accelerates the healing process. Thus, the versatile scaffold is expected to be an ideal candidate for repairing different defect tissues, especially electrosensitive tissues.

Wound Dressing: From Nanomaterials to Diagnostic Dressings and Healing Evaluations

Wound dressings based on nanomaterials play a crucial role in wound treatment and are widely used in a whole range of medical settings, from minor to life-threatening tissue injuries. This article presents an educational review on the accumulating knowledge in this multidisciplinary area to lay out the challenges and opportunities that lie ahead and ignite the further and faster development of clinically valuable technologies. The review analyzes the functional advantages of nanomaterial-based gauzes and hydrogels as well as hybrid structures thereof. On this basis, the review presents state-of-the-art advances to transfer the (semi)blind approaches to the evaluation of a wound state to smart wound dressings that enable real-time monitoring and diagnostic functions that could help in wound evaluation during healing. This review explores the translation of nanomaterial-based wound dressings and related medical aspects into real-world use. The ongoing challenges and future opportunities associated with nanomaterial-based wound dressings and related clinical decisions are presented and reviewed.

The bibenzyl derivatives of Dendrobium officinale prevent UV-B irradiation induced photoaging via SIRT3

Dendrobium officinale is a valuable medicinal herb that is widely used in traditional Chinese medicine. The chemical constituents of D. officinale have attracted much attention and a large number of compounds have been reported including many bibenzyl derivatives. 13 bibenzyl derivatives from D. officinale were sent for molecular docking, surface plasmon resonance (SPR) assay and after detection of Mn-SOD and SIRT3 activities in or not in HaCaT cells, it was concluded that bibenzyl derivatives did not directly activate Mn-SOD but promoted SIRT3 proteins. In addition, HaCaT cells were irradiated with UV-B to induce an oxidative stress model in vitro to further verify the effect of bibenzyl derivatives. The results show that bibenzyl derivatives could directly bind to SIRT3, enhance the deacetylation and then activate Mn-SOD, so as to protect UV-B induced skin photoaging.

Bio-fabricated nanocomposite hydrogel with ROS scavenging and local oxygenation accelerates diabetic wounds healing

Chronic wounds, especially diabetic wounds, have been suffering from abnormal long inflammatory periods due to their pathological microenvironment of high reactive oxygen species (ROS) level and lack of blood vessels....

Fabrication of gelatin-based and Zn2+-incorporated composite hydrogel for accelerated infected wound healing

Gelatin-based hydrogels have a broad range of biomedical fields due to their biocompatibility, convenience for chemical modifications, and degradability. However, gelatin-based hydrogels present poor antibacterial ability that hinders their applications in treating infected wound healing. Herein, a series of multifunctional hydrogels (Gel@Zn) were fabricated through free-radical polymerization interaction based on gelatin methacrylate (GelMA) and dopamine methacrylate (DMA), and then immersed them into zinc nitrate solutions based on the metal coordination and ionic bonding interaction. These designed hydrogels wound dressings show strong antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) by increasing intracellular reactive oxygen species (ROS) level and changing bacterial membrane permeability. Meanwhile, the hydrogels exhibit good cytocompatibility, enhance the adhesion, proliferation, and migration of NIH-3T3 cells. Furthermore, Gel@Zn-0.08 (0.08 ​M Zn2+ immersed with Gel sample) presents a good balance between antibacterial effect, cell viability, and hemolytic property. Compared with 3 ​M commercial dressings, Gel@Zn-0.04, and Gel@Zn-0.16, the Gel@Zn-0.08 could significantly improve the healing process of S. aureus-infected full-thickness wounds via restrained the inflammatory responses, enhanced epidermis and granulation tissue information, and stimulated angiogenesis. Our study indicates that the Zn-incorporated hydrogels are promising bioactive materials as wound dressings for infected full-thickness wound healing and skin regeneration.

Electronic Textiles for Wearable Point-of-Care Systems

Traditional public health systems are suffering from limited, delayed, and inefficient medical services, especially when confronted with the pandemic and the aging population. Fusing traditional textiles with diagnostic, therapeutic, and protective medical devices can unlock electronic textiles (e-textiles) as point-of-care platform technologies on the human body, continuously monitoring vital signs and implementing round-the-clock treatment protocols in close proximity to the patient. This review comprehensively summarizes the research advances on e-textiles for wearable point-of-care systems. We start with a brief introduction to emphasize the significance of e-textiles in the current healthcare system. Then, we describe textile sensors for diagnosis, textile therapeutic devices for medical treatment, and textile protective devices for prevention, by highlighting their working mechanisms, representative materials, and clinical application scenarios. Afterward, we detail e-textiles' connection technologies as the gateway for real-time data transmission and processing in the context of 5G technologies and Internet of Things. Finally, we provide new insights into the remaining challenges and future directions in the field of e-textiles. Fueled by advances in chemistry and materials science, textile-based diagnostic devices, therapeutic devices, protective medical devices, and communication units are expected to interact synergistically to construct intelligent, wearable point-of-care textile platforms, ultimately illuminating the future of healthcare system in the Internet of Things era.

Conductive Biomaterials as Bioactive Wound Dressing for Wound Healing and Skin Tissue Engineering

Conductive biomaterials based on conductive polymers, carbon nanomaterials, or conductive inorganic nanomaterials demonstrate great potential in wound healing and skin tissue engineering, owing to the similar conductivity to human skin, good antioxidant and antibacterial activities, electrically controlled drug delivery, and photothermal effect. However, a review highlights the design and application of conductive biomaterials for wound healing and skin tissue engineering is lacking. In this review, the design and fabrication methods of conductive biomaterials with various structural forms including film, nanofiber, membrane, hydrogel, sponge, foam, and acellular dermal matrix for applications in wound healing and skin tissue engineering and the corresponding mechanism in promoting the healing process were summarized. The approaches that conductive biomaterials realize their great value in healing wounds via three main strategies (electrotherapy, wound dressing, and wound assessment) were reviewed. The application of conductive biomaterials as wound dressing when facing different wounds including acute wound and chronic wound (infected wound and diabetic wound) and for wound monitoring is discussed in detail. The challenges and perspectives in designing and developing multifunctional conductive biomaterials are proposed as well.

Antioxidative and Conductive Nanoparticles-Embedded Cell Niche for Neural Differentiation and Spinal Cord Injury Repair

Following spinal cord injury (SCI), the transmission of electrical signals is interrupted, and an oxidative microenvironment is generated, hindering nerve regeneration and functional recovery. The strategies of regulating oxidative pathological microenvironment while restoring endogenous electrical signal transmission hold promise for SCI treatment. However, challenges are still faced in simply fabricating bioactive scaffolds with both antioxidation and conductivity. Herein, aiming to construct an antioxidative and conductive microenvironment for nerve regeneration, the difunctional polypyrrole (PPy) nanoparticles were developed and incorporated into bioactive collagen/hyaluronan hydrogel. Owing to the embedded PPy in hydrogel, the encapsulated bone marrow mesenchymal stem cells (BMSCs) can be protected from oxidative damage, and their neuronal differentiation was promoted by the synergy between conductivity and electrical stimulation, which is proved to be related to PI3K/Akt and the mitogen-activated protein kinase (MAPK) pathway. In SCI rats, the BMSC-laden difunctional hydrogel restored the transmission of bioelectric signals and inhibited secondary damage, thereby facilitating neurogenesis, resulting in prominent nerve regeneration and functional recovery. Overall, taking advantage of a difunctional nanomaterial to meet two essential requirements in SCI repair, this work provides intriguing insights into the design of biomaterials for nerve regeneration and tissue engineering.

Self-adhesive hydrogels for tissue engineering

Hydrogels consisting of a three-dimensional hydrophilic network of biocompatible polymers have been widely used in tissue engineering. Owing to their tunable mechanical properties, hydrogels have been applied in both hard and soft tissues. However, most hydrogels lack self-adhesive properties that enable integration with surrounding tissues, which may result in suture or low repair efficacy. Self-adhesive hydrogels (SAHs), an emerging class of hydrogels based on a combination of three-dimensional hydrophilic networks and self-adhesive properties, continue to garner increased attention in recent years. SAHs exhibit reliable and suitable adherence to tissues, and easily integrate into tissues to promote repair efficiency. SAHs are designed either by mimicking the adhesion mechanism of natural organisms, such as mussels and sandcastle worms, or by using supramolecular strategies. This review summarizes the design and processing strategies of SAHs, clarifies underlying adhesive mechanisms, and discusses their applications in tissue engineering, as well as future challenges.

Carbon Nanotube-Hydrogel Composites Facilitate Neuronal Differentiation While Maintaining Homeostasis of Network Activity

It is often assumed that carbon nanotubes (CNTs) stimulate neuronal differentiation by transferring electrical signals and enhancing neuronal excitability. Given this, CNT-hydrogel composites are regarded as potential materials able to combine high electrical conductivity with biocompatibility, and therefore promote nerve regeneration. However, whether CNT-hydrogel composites actually influence neuronal differentiation and maturation, and how they do so remain elusive. In this study, CNT-hydrogel composites are prepared by in situ polymerization of poly(ethylene glycol) around a preformed CNT meshwork. It is demonstrated that the composites facilitate long-term survival and differentiation of pheochromocytoma 12 cells. Adult neural stem cells cultured on the composites show an increased neuron-to-astrocyte ratio and higher synaptic connectivity. Moreover, primary hippocampal neurons cultured on composites maintain morphological synaptic features as well as their neuronal network activity evaluated by spontaneous calcium oscillations, which are comparable to neurons cultured under control conditions. These results indicate that the composites are promising materials that could indeed facilitate neuronal differentiation while maintaining neuronal homeostasis.

Triboelectric Nanogenerators for Self-Powered Wound Healing

Wound healing, one of the most complex processes in the human body, involves the spatial and temporal synchronization of a variety of cell types with distinct roles. Slow or nonhealing skin wounds have potentially life-threatening consequences, ranging from infection to scar, clot, and hemorrhage. Recently, the advent of triboelectric nanogenerators (TENGs) has brought about a plethora of self-powered wound healing opportunities, owing to their pertinent features, including wide range choices of constitutive biocompatible materials, simple fabrication, portable size, high output power, and low cost. Herein, a comprehensive review of TENGs as an emerging biotechnology for wound healing applications is presented and covered from three unique aspects: electrical stimulation, antibacterial activity, and drug delivery. To provide a broader context of TENGs applicable to wound healing applications, state-of-the-art designs are presented and discussed in each section. Although some challenges remain, TENGs are proving to be a promising platform for human-centric therapeutics in the era of Internet of Things. Consequently, TENGs for wound healing are expected to provide a new solution in wound management and play an essential role in the future of point-of-care interventions.

Performance of Polydopamine Complex and Mechanisms in Wound Healing

Polydopamine (PDA) has been gradually applied in wound healing of various types in the last three years. Due to its rich phenol groups and unique structure, it can be combined with a variety of materials to form wound dressings that can be used for chronic infection, tissue repair in vivo and serious wound healing. PDA complex has excellent mechanical properties and self-healing properties, and it is a stable material that can be used for a long period of time. Unlike other dressings, PDA complexes can achieve both photothermal therapy and electro activity. In this paper, wound healing is divided into four stages: antibacterial, anti-inflammatory, cell adhesion and proliferation, and re-epithelialization. Photothermal therapy can improve the bacteriostatic rate and remove reactive oxygen species to inhibit inflammation. Electrical signals can stimulate cell proliferation and directional migration. With low reactive oxygen species (ROS) levels, inflammatory factors are down-regulated and growth factors are up-regulated, forming regular collagen fibers and accelerating wound healing. Finally, five potential development directions are proposed, including increasing drug loading capacity, optimization of drug delivery platforms, improvement of photothermal conversion efficiency, intelligent electroactive materials and combined 3D printing.

Recent Advances in Fiber-Shaped Electronic Devices for Wearable Applications

Fiber electronics is a key research area for realizing wearable microelectronic devices. Significant progress has been made in recent years in developing the geometry and composition of electronic fibers. In this review, we present that recent progress in the architecture and electrical properties of electronic fibers, including their fabrication methods. We intensively investigate the structural designs of fiber-shaped devices: coaxial, twisted, three-dimensional layer-by-layer, and woven structures. In addition, we introduce remarkable applications of fiber-shaped devices for energy harvesting/storage, sensing, and light-emitting devices. Electronic fibers offer high potential for use in next-generation electronics, such as electronic textiles and smart integrated textile systems, which require excellent deformability and high operational reliability.