4D-Printed MXene-Based Artificial Nerve Guidance Conduit for Enhanced Regeneration of Peripheral Nerve Injuries.

Repairing larger defects (>5 mm) in peripheral nerve injuries (PNIs) remains a significant challenge when using traditional artificial nerve guidance conduits (NGCs). A novel approach that combines 4D printing technology with poly(L-lactide-co-trimethylene carbonate) (PLATMC) and Ti3C2Tx MXene nanosheets is proposed, thereby imparting shape memory properties to the NGCs. Upon body temperature activation, the printed sheet-like structure can quickly self-roll into a conduit-like structure, enabling optimal wrapping around nerve stumps. This design enhances nerve fixation and simplifies surgical procedures. Moreover, the integration of microchannel expertly crafted through 4D printing, along with the incorporation of MXene nanosheets, introduces electrical conductivity. This feature facilitates the guided and directional migration of nerve cells, rapidly accelerating the healing of the PNI. By leveraging these advanced technologies, the developed NGCs demonstrate remarkable potential in promoting peripheral nerve regeneration, leading to substantial improvements in muscle morphology and restored sciatic nerve function, comparable to outcomes achieved through autogenous nerve transplantation.

Sea Cucumber-Inspired Microneedle Nerve Guidance Conduit for Synergistically Inhibiting Muscle Atrophy and Promoting Nerve Regeneration.

Muscle atrophy resulting from peripheral nerve injury (PNI) poses a threat to a patient's mobility and sensitivity. However, an effective method to inhibit muscle atrophy following PNI remains elusive. Drawing inspiration from the sea cucumber, we have integrated microneedles (MNs) and microchannel technology into nerve guidance conduits (NGCs) to develop bionic microneedle NGCs (MNGCs) that emulate the structure and piezoelectric function of sea cucumbers. Morphologically, MNGCs feature an outer surface with outward-pointing needle tips capable of applying electrical stimulation to denervated muscles. Simultaneously, the interior contains microchannels designed to guide the migration of Schwann cells (SCs). Physiologically, the incorporation of conductive reduced graphene oxide and piezoelectric zinc oxide nanoparticles into the polycaprolactone scaffold enhances conductivity and piezoelectric properties, facilitating SCs' migration, myelin regeneration, axon growth, and the restoration of neuromuscular function. These combined effects ultimately lead to the inhibition of muscle atrophy and the restoration of nerve function. Consequently, the concept of the synergistic effect of inhibiting muscle atrophy and promoting nerve regeneration has the capacity to transform the traditional approach to PNI repair and find broad applications in PNI repair.

High-Area-Capacity Cathode by Ultralong Carbon Nanotubes for Secondary Binder-Assisted Dry Coating Technology.

Thick electrodes with high mass loading and increased content of active materials are critical for achieving higher energy density in contemporary lithium-ion batteries (LIBs). Nonetheless, producing thick electrodes through the commonly used slurry coating technology remains a formidable challenge. In this study, we have addressed this challenge by developing a dry electrode technology by using ultralong multiwalled carbon nanotubes (MWCNT) as a conductive additive and secondary binder. The mixing process of electrode compositions and the fibrillation process of the polytetrafluoroethylene (PTFE) binder were optimized. The resulting LiCoO2 (LCO) electrode exhibited a remarkable mass loading of 48 mg cm-2 and an active material content of 95 wt %. Notably, the thick LCO electrode demonstrated a superior mechanical strength and electrochemical performance. After 100 cycles at a current density of 1/3 C, the electrode still exhibited a capacity retention of 91% of its initial capacity. This dry electrode technology provides a practicable and scalable approach to the powder-to-film LIB electrode manufacturing process.

3D printing of Rg3-loaded hydrogel scaffolds: anti-inflammatory and scar-formation related collagen inhibitory effects for scar-free wound healing.

During the process of wound healing, the stimulation of inflammatory factors often leads to abnormal proliferation of blood vessels and collagen, ultimately resulting in scar formation. To address this challenge, we fabricate a novel dermal extracellular matrix (DECM) hydrogel scaffold loaded with ginsenoside Rg3 (Rg3) using 3D printing technology. Mesoporous silica nanoparticles (MSNs) are introduced into the system to encase the Rg3 to control its release rate and enhance its bioavailability. We systematically evaluate the biological, physicochemical, and wound healing properties of this scaffold. In vitro studies demonstrate that the hydrogel exhibits excellent biocompatibility and solid-like rheological properties, ensuring its successful printing. In vivo studies reveal that the composite hydrogel scaffolds effectively accelerate wound healing and achieve scar-free wound healing within three weeks. Histological and immunohistochemical (IHC) analyses show that the composite hydrogel scaffolds reduce the inflammatory response and inhibit excessive collagen accumulation. These combined effects underscore the potential of our approach in effectively inhibiting scar formation.

3D printing nacre powder/sodium alginate scaffold loaded with PRF promotes bone tissue repair and regeneration.

Bone defects are a common complication of bone diseases, which often affect the quality of life and mental health of patients. The use of biomimetic bone scaffolds loaded with bioactive substances has become a focal point in the research on bone defect repair. In this study, composite scaffolds resembling bone tissue were created using nacre powder (NP) and sodium alginate (SA) through 3D printing. These scaffolds exhibit several physiological structural and mechanical characteristics of bone tissue, such as suitable porosity, an appropriate pore size, applicable degradation performance and satisfying the mechanical requirements of cancellous bone, etc. Then, platelet-rich fibrin (PRF), containing a mass of growth factors, was loaded on the NP/SA scaffolds. This was aimed to fully maximize the synergistic effect with NP, thereby accelerating bone tissue regeneration. Overall, this study marks the first instance of preparing a bionic bone structure scaffold containing NP by 3D printing technology, which is combined with PRF to further accelerate bone regeneration. These findings offer a new treatment strategy for bone tissue regeneration in clinical applications.

Implantable Nerve Conduit Made of a Self-Powered Microneedle Patch for Sciatic Nerve Repair.

Peripheral nerve defects, particularly those of a larger size, pose a significant challenge in clinical practice due to their limited regenerative capacity. To tackle this challenge, an advanced self-powered enzyme-linked microneedle (MN) nerve conduit is designed and fabricated. This innovative conduit is composed of anodic and cathodic MN arrays, which contain glucose oxidase (GOx) and horseradish peroxidase (HRP) encapsulated in ZIF-8 nanoparticles, respectively. Through an enzymatic cascade reaction, this MN nerve conduit generates microcurrents that stimulate the regeneration of muscles, blood vessels, and nerve fibers innervated by the sciatic nerve, eventually accelerating the repair of sciatic nerve injury. It is clear that this self-powered MN nerve conduit will revolutionize traditional treatment methods for sciatic nerve injury and find widespread application in the field of nerve tissue repair.

Carbon Quantum Dots Derived from Herbal Medicine as Therapeutic Nanoagents for Rheumatoid Arthritis with Ultrahigh Lubrication and Anti-inflammation.

As a typical chronic inflammatory joint disease with swelling and pain syndromes, rheumatoid arthritis (RA) is closely related to articular lubrication deficiency and excessive proinflammatory cytokines in its progression and pathogenesis. Herein, inspired by the dual effects of joint lubrication improvement and anti-inflammation to treat RA, two novel potential therapeutic nanoagents have been developed rationally by employing herbal medicine-derived carbon quantum dots (CQDs), i.e., safflower (Carthamus tinctorius L.) CQDs and Angelica sinensis CQDs, yielding ultrahigh lubrication and anti-inflammation bioefficacy. In vitro experimental results show that the two nanoagents display excellent friction reduction due to their good water solubility and spherical structure. Using RA rat models, it is indicated that the nanoagents significantly relieved swelling symptoms and inhibited the expression of related inflammatory cytokines, including IL-1, IL-6, and TNF-α, indicating their extraordinary anti-inflammation bioefficacy. Thus, combining the lubricating and anti-inflammation bioefficacy of CQDs derived from herbal medicine is an attractive strategy to develop new nanoagents for RA treatment.

Self-powered enzyme-linked microneedle patch for scar-prevention healing of diabetic wounds.

Diabetic wounds with complex pathological features and a difficult-to-heal nature remain a formidable challenge. To address this challenge, we design and fabricate a self-powered enzyme-linked microneedle (MN) patch composed of anode and cathode MN arrays, which respectively contain glucose oxidase (GOx) and horseradish peroxidase (HRP) encapsulated in ZIF-8 nanoparticles. The enzymatic cascade reaction in the MN patch can effectively reduce local hyperglycemia in diabetic wounds while generating stable microcurrents to promote rapid healing of diabetic wounds. Therefore, the diabetic wounds treated with this MN patch exhibit rapid, complete, and scar-preventative healing, which can be attributed to the synergistic actions of hypoglycemic, antibacterial, anti-inflammatory, and bioelectrical stimulation. In brief, the self-powered MN patch is an effective method to rapidly promote diabetic wound healing and prevent scar formation.

Toward robust solid-state lithium metal batteries by stabilizing a polyethylene oxide-based solid electrolyte interface with a biomass polymer filler.

Achieving all-solid-state lithium-based batteries with high energy densities requires lightweight and ultrathin solid-state electrolytes (SSEs) with high Li+ conductivity, but this still poses significant challenges. Herein, we designed a robust and mechanically flexible SSE (denoted BC-PEO/LiTFSI) by using an environmentally friendly and low-cost approach that involves bacterial cellulose (BC) as a three-dimensional (3D) rigid backbone. In this design, BC-PEO/LiTFSI is tightly integrated and polymerized through intermolecular hydrogen bonding, and the rich oxygen-containing functional groups from the BC filler also provide the active site for Li+ hopping transport. Therefore, the all-solid-state Li-Li symmetric cell with BC-PEO/LiTFSI (containing 3% BC) showed excellent electrochemical cycling properties over 1000 h at a current density of 0.5 mA cm-2. Furthermore, the Li-LiFePO4 full cell showed steady cycling performance under 3 mg cm-2 areal loading at a current of 0.1 C, and the resultant Li-S full cell maintained over 610 mAh g-1 for upward of 300 cycles at 0.2 C and 60 °C.

Biomimetic chitosan nanoparticles with simultaneous water lubricant and anti-inflammatory.

Rheumatoid arthritis (RA) is a chronic inflammatory immune and lubrication dysfunction disease that causes great damage to the joints. Herein, inspired by the unique biochemistry structure and excellent hydration of chondroitin sulfate (CHI) existing in joint system, one kind of novel polysaccharide nanoparticle lubricant, that is chitosan nanoparticles (CS NPs) grafting CHI (CS-CHI), is synthesized by one-step surface chemistry reaction. CHI with negative charges can form hydration layers on the surface of CS NPs, thus improving the lubricity of nanoparticles. Simultaneously, CS-CHI NPs have effective loading and sustained drug release ability for anti-inflammatory drug diclofenac sodium (DS), along with good biocompatibility. Finally, based on a collagen-induced rat RA model, in vitro animals experimental results indicate that the as-synthesized CS-CHI@DS NPs has obvious inhibitory effects on inflammatory factors and can effectively prevent the damaged cartilage from further destruction.

Biomimetic chitosan-derived bifunctional lubricant with superior antibacterial and hydration lubrication performances.

The lubrication deficiency in joints is a major cause of osteoarthritis. One of the most commonly used treatment means is to inject artificial lubricants, but there is a potential risk of infection during the injection process. Therefore, developing artificial lubricants with dual functions of friction-reduction and antibacterial is urgent. In this work, a novel polysaccharide-derived lubricant with simultaneous anti-bacteria and water-lubrication properties, called CS-MPC-N, is developed by grafting 2­methacryloyloxylethyl phosphorylcholine (MPC) and nisin peptide onto backbone of chitosan (CS). Compared to the control CS, CS-MPC-N exhibits good lubrication and friction-reduction properties because of its excellent water solubility. Especially, CS-MPC-N shows low friction coefficient (0.03 âˆ¼ 0.05) at the sliding interfaces of artificial joints materials or even natural articular cartilages. Moreover, CS-MPC-N can effectively inhibit the proliferation of Staphylococcus aureu, exhibiting excellent antibacterial effect. This kind of novel polysaccharide-derived lubricant is expected to be used in treating infectious arthritis.

Boron nitride nanosheets modified with zinc oxide nanoparticles as novel fillers of dental resin composite.

OBJECTIVE: The purpose of this study was to synthesize boron nitride nanosheets modified with zinc oxide nanoparticles (BNNSs/ZnO) and incorporate them as a novel inorganic filler to get an antibacterial dental resin composite. METHODS: The BNNSs/ZnO nanocomposites were synthesized via the hydrothermal method and characterized by Field Emission Scanning Electron Microscope (FESEM), Transmission Electron Microscopy (TEM), Energy Dispersive Spectrometer (EDS), X-ray Diffraction (XRD) and Fourier Transform-Infrared (FTIR) Spectroscopy. The BNNSs/ZnO or BNNSs were added into the experimental dental composite with different proportions, respectively. The mechanical and physical properties of the modified dental composite were evaluated. Their antibacterial activities were also assessed by quantitative analysis using Streptococcus mutans (S. mutans). RESULTS: The BNNSs/ZnO nanocomposites were successfully synthesized, and the growth of ZnO nanoparticles (ZnO NPs) on boron nitride nanosheets was confirmed. The flexural strength (FS), flexural modulus (FM) and the compressive strength (CS) of all modified resin composites showed no change compared to the control group. The curing depth, degree of conversion, water absorption and solubility of the modified composites were still within the clinical requirement. The antibacterial rates of the modified composites were significantly increased compared to the control group, which can reach 98 % when 0.5 % BNNSs/ZnO was added. SIGNIFICANCE: The modified dental resin composite with novel BNNSs or BNNSs/ZnO fillers shows significantly high antibacterial activity with suitable physicochemical and mechanical properties.

Long-Cycling All-Solid-State Batteries Achieved by 2D Interface between Prelithiated Aluminum Foil Anode and Sulfide Electrolyte.

All-solid-state batteries (ASSBs) with alloy anodes are expected to achieve high energy density and safety. However, the stability of alloy anodes is largely impeded by their large volume changes during cycling and poor interfacial stability against solid-state electrolytes. Here, a mechanically prelithiation aluminum foil (MP-Al-H) is used as an anode to construct high-performance ASSBs with sulfide electrolyte. The dense Li-Al layer of the MP-Al-H foil acts as a prelithiated anode and forms a 2D interface with sulfide electrolyte, while the unlithiated Al layer acts as a tightly bound current collector and ensures the structural integrity of the electrode. Remarkably, the MP-Al-H anode exhibits superior lithium conduction kinetics and stable interfacial compatibility with Li6 PS5 Cl (LPSCl) and Li10 GeP2 S12 electrolytes. Consequently, the symmetrical cells using LPSCl electrolyte can work at a high current density of 7.5 mA cm-2 and endure for over 1500 h at 1 mA cm-2 . Notably, ≈100% capacity is retained for the MP-Al-H||LPSCl||LiCoO2 full cell with high area loadings of 18 mg cm-2 after 300 cycles. This work offers a pathway to improve the interfacial and performance issues for the application of ASSBs.

The preparation of lactoferrin/magnesium silicate lithium injectable hydrogel and application in promoting wound healing.

The development of novel wound dressings with highly effective antibacterial and accelerating wound healing properties has become the focus of current research. In this study, a novel and injectable lactoferrin (LF)/lithium magnesium silicate hydrogel (LMSH) was first synthesized through a simple electrostatic interaction method. The physical and biological properties are systematically characterized. The results show that the synthesized LF/LMSH has good antibacterial properties and biocompatibility. More importantly, it can effectively promote wound healing in the rat full-thickness skin wound model after 14 days post-operation, and the healing rate can reach 99.1 %, which is much higher than that of other groups. Meanwhile, histochemical and immunofluorescent staining confirm that the prepared injectable LF/LMSH has good pro-collagen deposition, pro-angiogenic and anti-inflammatory properties. The healed wounds present a consistently thickened epidermis with more follicular and glandular structures, indicating the great potential of the prepared material for wound management.

Theoretical and Experimental Understanding of Metal Single-Atom Electrocatalysts for Accelerating the Electrochemical Reaction of Lithium-Sulfur Batteries.

Metal single-atom materials have attracted tremendous attention in the research field of lithium-sulfur (Li-S) batteries because they can effectively improve the reaction kinetics of sulfur cathodes. However, it is still difficult to determine the best metal single-atom catalyst for Li-S batteries, due to the lack of a unified measurement and evaluation method. Herein, a series of metal single-atom- and nitrogen-doped graphene materials (M-NG, M = Fe, Co, Ni, Ir, Ru) have been prepared as the catalysts for promoting the reaction kinetics of the sulfur reduction reaction process. Using rotating disk electrode measurements and density functional theory-based theoretical calculations, Ni-NG was screened out to be the best catalyst. It is found that Ni-NG materials can provide a kinetically favorable pathway for the reversible conversion of polysulfide conversion, thus increasing the utilization of sulfur. By coating the Ni-NG materials on the separator as a multifunctional interlayer, a commercially available sulfur cathode presents a stable specific capacity of 701.8 mAh g-1 at a current rate of 0.5C over 400 cycles. Even with a high sulfur loading of 3.8 mg cm-2, a high areal capacity of 4.58 mAh cm-2 can be achieved. This work will provide a fundamental understanding of efficient single-atom catalyst materials for Li-S batteries.

Structural characteristics and rheological properties of hydroxypropyl trimethyl ammonium chloride chitosan.

Hydroxypropyl trimethyl ammonium chloride chitosan (HACC) was synthesized by reacting chitosan with glycidyl trimethylammonium chloride. Atomic force microscopy showed that HACC exhibited disorderly coils in dilute solution and formed a three-dimensional network. Flow, thixotropy, and dynamic viscoelasticity tests were conducted using an MCR301 rheometer. The HACC solution was a non-Newtonian pseudoplastic fluid, and the shear behavior of different concentrations (2-6 %, w/v) was evaluated by the Williamson model fitting. Furthermore, the thixotropy was highly dependent on concentration changes: the high-concentration solution structure was difficult to recover in a short time. The dynamic viscoelasticity test indicated that the viscoelasticity of the HACC solution not only exhibited a viscous behavior similar to that of a fluid, but also exhibited elastic properties of weak gel. HACC exhibited high-strength solid-like gel characteristics at high temperature.

3D Printed Piezoelectric Wound Dressing with Dual Piezoelectric Response Models for Scar-Prevention Wound Healing.

During the long process of wound defect repair, the bioelectric stimulation around the wound gradually decreases, which can cause gradual down-regulation of the wound healing cascade response, disordered deposition of collagen fibers, and abnormal remodeling of the extracellular matrix (ECM). All these combined will eventually result in delayed wound healing and scar tissue formation. To resolve these issues, a novel ZnO nanoparticles modified PVDF/sodium alginate (SA) piezoelectric hydrogel scaffold (ZPFSA) is prepared by 3D printing technology. The prepared ZPFSA scaffold has dual piezoelectric response models, mainly consisting of vertical swelling and horizontal friction, which can be used to simulate and amplify endogenous bioelectricity to promote wound healing and prevent scar formation. Compared with other composite scaffolds, ZPFSA 0.5 (contain 0.5% ZnO nanoparticles) exhibits good biocompatibility, excellent antimicrobial properties, and stable piezoelectric response, so that it can significantly accelerate the wound healing and effectively prevent the scar tissue formation within 2 weeks thanks to the cascade regulation in wound healing, including cell migration, vascularization, collagen remodeling, and the expression of related growth factors. The proposed dual piezoelectric response models will provide a new solution to accelerate wound healing process, prevent scar formation, and extend new application range of piezoelectric materials in wound dressing.

Fabrication of a Covalent Triazine Framework Functional Interlayer for High-Performance Lithium-Sulfur Batteries.

The shuttling effect of polysulfides is one of the major problems of lithium-sulfur (Li-S) batteries, which causes rapid capacity fading during cycling. Modification of the commercial separator with a functional interlayer is an effective strategy to address this issue. Herein, we modified the commercial Celgard separator of Li-S batteries with one-dimensional (1D) covalent triazine framework (CTF) and a carbon nanotube (CNT) composite as a functional interlayer. The intertwined CTF/CNT can provide a fast lithium ionic/electronic transport pathway and strong adsorption capability towards polysulfides. The Li-S batteries with the CTF/CNT/Celgard separator delivered a high initial capacity of 1314 mAh g-1 at 0.1 C and remained at 684 mAh g-1 after 400 cycles-1 at 1 C. Theoretical calculation and static-adsorption experiments indicated that the triazine ring in the CTF skeleton possessed strong adsorption capability towards polysulfides. The work described here demonstrates the potential for CTF-based permselective membranes as separators in Li-S batteries.

Sprayable methacrylic anhydride-modified gelatin hydrogel combined with bionic neutrophils nanoparticles for scar-free wound healing of diabetes mellitus.

Hard-to-healing or nonhealing diabetic wounds caused by hyperglycemia, bacterial infection and chronic inflammation are becoming a challenge globally. In this study, a novel hydrogel for diabetic wound healing composed of methacrylic anhydride-modified gelatin (GelMA) hydrogel and mimicking neutrophil nanoparticles was originally created. The prepared GelMA hydrogel has good sprayability and film-formation ability under blue light illumination (wavelength = 435-480 nm). Nanoparticles mimicking neutrophils belong to a double enzyme system that are encapsulated in ZIF-8 nanoparticles, which can consume glucose to produce HClO, ensuring a decrease in the glucose concentration of the wound and growth inhibition in bacteria. The hydrogel also has excellent biocompatibility, which can promote the growth and proliferation of fibroblasts. More importantly, the hydrogel can accelerate wound healing in type I diabetic rats owing to the downregulation of proinflammatory cytokines, and the wound with an area of 1 cm2 can be almost fully healed with no formation of the scar on the 21st day, as verified by histochemistry and immunohistochemistry. All these combinations indicate its potential in diabetic wound treatment.

An excellent antibacterial and high self-adhesive hydrogel can promote wound fully healing driven by its shrinkage under NIR.

The lacks of antibacterial properties, low adhesion and delayed wound healing of the hydrogel wound dressings limit their applications in wound treatment. To resolve these, a novel hydrogel composed of polydopamine (PDA), Ag and graphene oxide (GO) is fabricated for wound dressing via the chemical crosslinking of N-isopropylacrylamide (NIPAM) and N,N'-methylene bisacrylamide (BIS). The prepared hydrogel containing PDA@Ag5GO1 (Ag5GO1 denotes the mass ratio between Ag and GO is 5:1) exhibits effective antibacterial properties and high inhibition rate against E. coli and S. aureus. It shows high adhesion ability to various substrate materials, implying a simpler method to the wound obtained by self-fixing rather than suturing. More important, it can produce strong contractility under the irradiation of near-infrared light (NIR), exerting a centripetal force that helps accelerate wound healing. Thus, the hydrogel containing a high concentration PDA@Ag5GO1 irradiated by NIR can completely repair the wound defect (1.0 × 1.0 cm2) within 15 days, the wound healing rate can reach 100%, which was far higher than other groups. Taken together, the new hydrogel with excellent antibacterial, high adhesion and strong contractility will subvert the traditional treatment methods on wound defect, extending its new application range in wound dressing.