Unleashing the Potential of Electroactive Hybrid Biomaterials and Self‑Powered Systems for Bone Therapeutics

The incidence of large bone defects caused by traumatic injury is increasing worldwide,and the tissue regeneration process requires a long recovery time due to limited self-healing capability.Endogenous bioelectrical phenomena have been well recognized as critical biophysical factors in bone remodeling and regeneration.Inspired by bioelectricity,electrical stimulation has been widely considered an external intervention to induce the osteogenic lineage of cells and enhance the synthesis of the extracellular matrix,thereby accelerating bone regeneration.With ongoing advances in biomaterials and energy-harvesting techniques,electroactive biomaterials and self-powered systems have been considered biomimetic approaches to ensure functional recovery by recapitulating the natural electrophysiological microenvironment of healthy bone tissue.In this review,we first introduce the role of bioelectricity and the endogenous electric field in bone tissue and summarize different techniques to electrically stimulate cells and tissue.Next,we highlight the latest progress in exploring electroactive hybrid biomaterials as well as self-powered systems such as triboelectric and piezoelectric-based nanogenerators and photovoltaic cell-based devices and their implementation in bone tissue engineering.Finally,we emphasize the significance of simulating the target tissue’s electrophysiological microenvironment and propose the opportunities and challenges faced by electroactive hybrid biomaterials and self-powered bioelectronics for bone repair strategies.

Stiffness-tunable biomaterials provide a good extracellular matrix environment for axon growth and regeneration

Neuronal growth, extension, branching, and formation of neural networks are markedly influenced by the extracellular matrix—a complex network composed of proteins and carbohydrates secreted by cells. In addition to providing physical support for cells, the extracellular matrix also conveys critical mechanical stiffness cues. During the development of the nervous system, extracellular matrix stiffness plays a central role in guiding neuronal growth, particularly in the context of axonal extension, which is crucial for the formation of neural networks. In neural tissue engineering, manipulation of biomaterial stiffness is a promising strategy to provide a permissive environment for the repair and regeneration of injured nervous tissue. Recent research has fine-tuned synthetic biomaterials to fabricate scaffolds that closely replicate the stiffness profiles observed in the nervous system. In this review, we highlight the molecular mechanisms by which extracellular matrix stiffness regulates axonal growth and regeneration. We highlight the progress made in the development of stiffness-tunable biomaterials to emulate in vivo extracellular matrix environments, with an emphasis on their application in neural repair and regeneration, along with a discussion of the current limitations and future prospects. The exploration and optimization of the stiffness-tunable biomaterials has the potential to markedly advance the development of neural tissue engineering.

Treatment of spinal cord injury with biomaterials and stem cell therapy in non-human primates and humans

Spinal cord injury results in the loss of sensory,motor,and autonomic functions,which almost always produces permanent physical disability.Thus,in the search for more effective treatments than those already applied for years,which are not entirely efficient,researches have been able to demonstrate the potential of biological strategies using biomaterials to tissue manufacturing through bioengineering and stem cell therapy as a neuroregenerative approach,seeking to promote neuronal recovery after spinal cord injury.Each of these strategies has been developed and meticulously evaluated in several animal models with the aim of analyzing the potential of interventions for neuronal repair and,consequently,boosting functional recovery.Although the majority of experimental research has been conducted in rodents,there is increasing recognition of the importance,and need,of evaluating the safety and efficacy of these interventions in non-human primates before moving to clinical trials involving therapies potentially promising in humans.This article is a literature review from databases(PubMed,Science Direct,Elsevier,Scielo,Redalyc,Cochrane,and NCBI)from 10 years ago to date,using keywords(spinal cord injury,cell therapy,non-human primates,humans,and bioengineering in spinal cord injury).From 110 retrieved articles,after two selection rounds based on inclusion and exclusion criteria,21 articles were analyzed.Thus,this review arises from the need to recognize the experimental therapeutic advances applied in non-human primates and even humans,aimed at deepening these strategies and identifying the advantages and influence of the results on extrapolation for clinical applicability in humans.

Biomimetic natural biomaterials for tissue engineering and regenerative medicine:new biosynthesis methods,recent advances,and emerging applications

Biomimetic materials have emerged as attractive and competitive alternatives for tissue engineering(TE)and regenerative medicine.In contrast to conventional biomaterials or synthetic materials,biomimetic scaffolds based on natural biomaterial can offer cells a broad spectrum of biochemical and biophysical cues that mimic the in vivo extracellular matrix(ECM).Additionally,such materials have mechanical adaptability,micro-structure interconnectivity,and inherent bioactivity,making them ideal for the design of living implants for specific applications in TE and regenerative medicine.This paper provides an overview for recent progress of biomimetic natural biomaterials(BNBMs),including advances in their preparation,functionality,potential applications and future challenges.We highlight recent advances in the fabrication of BNBMs and outline general strategies for functionalizing and tailoring the BNBMs with various biological and physicochemical characteristics of native ECM.Moreover,we offer an overview of recent key advances in the functionalization and applications of versatile BNBMs for TE applications.Finally,we conclude by offering our perspective on open challenges and future developments in this rapidly-evolving field.

Bio-Based Waterborne Poly(Vanillin-Butyl Acrylate)/MXene Coatings for Leather with Desired Warmth Retention and Antibacterial Properties

This study presents a solvent-free,facile synthesis of a bio-based green antibacterial agent and aromatic monomer methacrylated vanillin(MV)using vanillin.The resulting MV not only imparted antibacterial properties to coatings layered on leather,but could also be employed as a green alternative to petroleum-based carcinogen styrene(St).Herein,MV was copolymerized with butyl acrylate(BA)to obtain waterborne bio-based P(MV-BA)miniemulsion via miniemulsion polymerization.Subsequently,MXene nanosheets with excellent photothermal conversion performance and antibacterial properties,were introduced into the P(MV-BA)miniemulsion by ultrasonic dispersion.During the gradual solidification of P(MV-BA)/MXene nanocomposite miniemulsion on the leather surface,MXene gradually migrated to the surface of leather coatings due to the cavitation effect of ultrasonication and amphiphilicity of MXene,which prompted its full exposure to light and bacteria,exerting the maximum photothermal conversion efficiency and significant antibacterial efficacy.In particular,when the dosage of MXene nanosheets was 1.4 wt%,the surface temperature of P(MV-BA)/MXene nanocomposite miniemulsioncoated leather(PML)increased by about 15℃ in an outdoor environment during winter,and the antibacterial rate against Escherichia coli and Staphylococcus aureus was nearly 100%under the simulated sunlight treatment for 30 min.Moreover,the introduction of MXene nanosheets increased the air permeability,water vapor permeability,and thermal stability of these coatings.This study provides a new insight into the preparation of novel,green,and waterborne bio-based nanocomposite coatings for leather,with desired warmth retention and antibacterial properties.It can not only realize zerocarbon heating based on sunlight in winter,reducing the use of fossil fuels and greenhouse gas emissions,but also improve ability to fight off invasion by harmful bacteria,viruses,and other microorganisms.

Rational design of natural leather-based water evaporator for electricity generation and functional applications

In recent years,water evaporation-induced electricity has attracted a great deal of attention as an emerging green and renewable energy harvesting technology.Although abundant materials have been developed to fabricate hydrovoltaic devices,the limitations of high costs,inconvenient storage and transport,low environmental benefits,and unadaptable shape have restricted their wide applications.Here,an electricity generator driven by water evaporation has been engineered based on natural biomass leather with inherent properties of good moisture permeability,excellent wettability,physicochemical stability,flexibility,and biocompatibility.Including numerous nano/microchannels together with rich oxygen-bearing functional groups,the natural leather-based water evaporator,Leather_(Emblic-NPs-SA/CB),could continuously produce electricity even staying outside,achieving a maximum output voltage of∼3 V with six-series connection.Furthermore,the leather-based water evaporator has enormous potential for use as a flexible self-powered electronic floor and seawater demineralizer due to its sensitive pressure sensing ability as well as its excellent photothermal conversion efficiency(96.3%)and thus fast water evaporation rate(2.65 kg m^(−2)h^(−1)).This work offers a new and functional material for the construction of hydrovoltaic devices to harvest the sustained green energy from water evaporation in arbitrary ambient environments,which shows great promise in their widespread applications.

Magnesium-based biomaterials for coordinated tissue repair:A comprehensive overview of design strategies,advantages,and challenges

Magnesium-based biomaterials(MBMs)are one of the most promising materials for tissue engineering due to their unique mechanical properties and excellent functional properties.This review describes the development,advantages,and challenges of MBMs for biomedical applications,especially for tissue repair and regeneration.The history of the use of MBMs from the beginning of the 20th century is traced,and the transformative advances in contemporary applications of MBMs in areas such as orthopedics and cardiovascular surgery are emphasized.The review also provides insight into the signaling pathways affected by MBMs,such as the PI3K/Akt and RANKL/RANK/OPG pathways,which are critical for osteogenesis and angiogenesis.The review advocates that future research should focus on optimizing alloy compositions,surface modification and exploring innovative technologies such as 3D printing to improve the efficacy of MBMs in complex tissue repair.The potential of MBMs to tissue engineering and regenerative medicine is significant,urging further exploration and interdisciplinary collaboration to maximize their therapeutic effects.

Modulating immune responses for enhanced cell therapies:The dual role of multi-scale biomaterials

The efficacy of cell therapy is compromised by the suboptimal survival and function of transplanted cells,which can be partly attributed to uncontrolled immunomodulation.To address this issue,the dual role of biomaterials in assisting immune activation and evasion can be used to fine-tune immune responses and improve the efficacy and safety of cell therapy.Herein,we summarize different methods used to engineer therapeutic cells with biomaterials across multiple spatial scales and review how biomaterials assist in immune activation or evasion in cell therapy based on a discussion of the effects of biomaterials on endogenous immune cells.We also discuss the appealing features of biomaterials that polarize immune responses toward type 1 or type 2 immunity.In future studies,the biophysical and biochemical properties of biomaterials could be better leveraged for immunomodulatory purposes to fuel prominent improvements in cell therapy,and the relevant regulatory mechanisms should be investigated in a more systematic and in-depth manner.

Covalent and Ionic Bonding between Tannin and Collagen in Leather Making and Shrinking:A MALDI-ToF Study

Collagen powder hydrolysates were reacted with a solution of commercial mimosa bark tannin extract.The mixture was prepared at ambient temperature and prepared at 80°C to determine what reactions,if any,did occur between the collagen protein through its amino acids and the polyphenolic condensed tannin.The reaction products obtained were analyzed by matrix assisted laser desorption ionization time-of-flight(MALDI ToF)mass spectrometry.Reactions between the two materials did appear to occur,with the formation of a relatively small proportion of covalent and ionic linkages at ambient temperature but a considerable proportion of covalent linkages tannin-protein amino acids and the disappearance of ionic bonds.The linkages between the two materials appeared to be by amination of the phenolic–OHs of the tannin by the amino groups of the non-skeletal side chains of arginine,and by esterification by the–COOH groups of glutamic and aspartic acid of the aliphatic alcohol-OH on the C3 site of the flavonoid units heterocycle of the tannin.The proportion of covalent linkages increases markedly and predominate with increasing temperatures.This tightening of the tannin-protein covalent network formed may be an additional contributing factor both to leather wear resistance and performance as well to leather shrinking when this is subjected to excessive temperatures.

A Review on Silk Fibroin as a Biomaterial in Tissue Engineering

Regenerative medicine progress is based on the development of cell and tissue bioengineering. One of the aims of tissue engineering is the development of scaffolds, which should substitute the functions of the replaced organ after their implantation into the body. The tissue engineering material must meet a range of requirements, including biocompatibility, mechanical strength, and elasticity. Furthermore, the materials have to be attractive for cell growth: stimulate cell adhesion, migration, proliferation and differentiation. One of the natural biomaterials is silk and its component (silk fibroin). An increasing number of scientists in the world are studying silk and silk fibroin. The purpose of this review article is to provide information about the properties of natural silk (silk fibroin), as well as its manufacture and clinical application of each configuration of silk fibroin in medicine. Materials and research methods. Actual publications of foreign authors on resources PubMed, Medline, E-library have been analyzed. The selection criteria were materials containing information about the structure and components of silk, methods of its production in nature. This article placed strong emphasis on silk fibroin, the ways of artificial modification of it for use in various sphere of medicine.

Topology optimization of microstructure and selective laser meltingfabrication for metallic biomaterial scaffolds

The precise design and fabrication of biomaterial scaffolds is necessary to provide a systematic study for bone tissue engineering. Biomaterial scaffolds should have sufficient stiffness and large porosity. These two goals generally contradict since larger porosity results in lower mechanical properties. To seek the microstructure of maximum stiffness with the constraint of volume fraction by topology optimization method, algorithms and programs were built to obtain 2D and 3D optimized microstructure and then they were transferred to CAD models of STL format. Ti scaffolds with 30% volume fraction were fabricated using a selective laser melting （SLM） technology. The architecture and pore shape in the metallic biomaterial scaffolds were relatively precise reproduced and the minimum mean pore size was 231μm. The accurate fabrication of intricate microstructure has verified that the SLM process is suitable for fabrication of metallic biomaterial scaffolds.

MOLECULAR ENGINEERING STUDIES ON NONTHROMBOGENIC BIOMATERIALS——A NOVEL CLASS OF NONTHROMBOGENIC BIOMATERIALS WITH ZWITTERIONIC STRUCTURE OF CARBOXYBETAINES

N,N-dimethyl-N-methacryloyloxyethyl-N-carboxyethyl ammonium(DMMCA)was graft-copolymerized onto thesurface of segmented poly(ether urethane)(SPEU)and PE film.The carboxybetaine structure on SPEU and PE filmsurfaces was confirmed by ATR-FTIR,XPS and water contact angle measurements.Through the experiments with plateletadhesion and protein adhesion assay in vitro,the two materials studied,including poly-DMMCA gel,all show excellentnonthrombogenicity.This confirms once again that the zwitterionic molecular structure on the surfaces of materials isessential for improving their nonthrombogenicity and biocompatibility.

Imperial Leather Original皂用香精的仿制

介绍了Imperial Leather Original皂用香精的特点及其香韵组成,详细叙述了如何运用不同香韵的单体原料仿配该香精的过程。讨论了香精的稳定性试验和三角试验。

SYNTHETI C STUDIES ON BLOOD COMPATIBLE BIOMATERIALS Ⅳ. SYNTHESIS, CHARACTERIZATION AND ANTITHROMBOGENICITY OF POLY-[N, N'( p,p-OXYDIPHENYLENE)] PYROMELLI-TIMIDE-POLYDIMETHYLDIPHENYLSILOXANE SEGMENTED COPOLYMER

A novel class of aromatic polyimide-silicone segmented copolymer was synthesized with α, ω-bis (γ-aminopropyl) polydimethyldiphenylsiloxane (APMPS) as a silicone segment precursor, from which the segmented polyamic acid-b-silicone intermediate could be prepared simply with DMF as solvent. The segmented copolymer displays microphase separation and exhibits improved antithrombogenicity, which depends mainly upon both the content level and the DP of the silicone segment. Thermal stability and mechanical property of the copolymer are between that of the aromatic polyimide and the silicone, and also relate to both the content level and the DP of the silicone segment.

Light-Dependent Properties of Finishing and Leather Defects

The uniformity of the colour in leathers for the furnishing and automotive sectors is a particularly important feature, especially for white or light-coloured articles, intended to the high-end market;on these articles any colour alteration can be very visible and unpleasant, with possible technical and economic consequences for the producers. In a previous study, we analysed the possible causes behind the formation of some peculiar pink/salmon stains on different kinds of white/beige/light-coloured leather furnishing items, where we focalized our attention on TiO2 properties and its possible interaction with some organic-based antioxidants. In recent years, due to many other similar cases of defects that occurred to tanners and to upholstery traders, we decided to enhance the investigations concerning this topic. More in detail we analysed, defective leathers, powder pigments and chemicals, in order to identify the possible role of some substances in this issue, with particular reference to some antioxidants and aluminosilicates, where several diagnostic techniques have been utilised, as ATR-IR (Attenuated Total Reflectance IR Spectroscopy), SEM-EDX (Scanning Electron Microscopy-Energy Dispersive X-ray Analysis), XRF (X-ray Fluorescence spectrometry), GC-MS (Gas Chromatography-Mass Spectrometry), and DSC/TGA (Differential scanning calorimetry/Thermogravimetry) equipment.

Toward Enhancing Wearability and Fashion of Wearable Supercapacitor with Modified Polyurethane Artificial Leather Electrolyte

Inspired by the sophisticated artificial leather garment industry and toward enhancing wearability of energy storage devices, we demonstrate a polyurethane artificial leather supercapacitor with large sheet electrodes embedded in theleather layer simultaneously working as a polyelectrolyte. This design totally reserves textiles underneath and thus addresses the well-known challenge of wearing comfortability. It provides a revolutionary configuration of wearable supercapacitors: the artificial leather on garment is also a supercapacitor.Unlike the polyvinyl alcohol-based acidic electrolytes, which are widely used, sodium chloride is used to modify the intrinsically fluorescent polyurethane leather for ionic transportation, which has no harm to human. The fluorescent leather supercapacitor is easily transferrable from any arbitrary substrates to form various patterns, enabling multifunctionalities of practical wearability, fashion, and energy storage.

Recovery Technology of DMF from Wet Type Polyurethane Synthetic Leather Waste Gas

A new recovery technology is developed to recycle N,N-dimethyl formamide （DMF） in waste gas from wet type polyurethane synthetic leather industry. Given that the concentration of DMF in waste gas was as low as 325.6- 688.3 mg·m^-3, it was necessary to make sure two phases contact adequately and strengthen the mass transfer by increasing contact area and enhancing the turbulence. Therefore, two-stage countercurrent absorption and two-stage fog removing system were introduced into the technology. The top section of the absorption column was filled with structured wire-ripple stainless steel packing BX500, while the lower section with sting-ripple packing CB250Y. Total height of packing material was 6 m. In addition, there were both two-stage fog removing layer and high efficiency liquid distributor at the column top. All the operating parameters, including temperature, pressure, flow rate and liquid position, could be controlled by computers without manual operation, making sure the outlet gas achieved the national emission standard that the DMF concentration should be below 40 mg·m^-3. The whole equipment could recover 237.6 t of DMF each year, with the profit up to CNY 521×10^3.

Review of magnesium-based biomaterials and their applications

In biomedical applications,the conventionally used metallic materials,including stainless steel,Co-based alloys and Ti alloys,often times exhibit unsatisfactory results such as stress shielding and metal ion releases.Secondary surgical operation(s)usually become inevitable to prevent long term exposure of body with the toxic implant contents.The metallic biomaterials are being revolutionized with the development of biodegradable materials including several metals,alloys,and metallic glasses.As such,the nature of metallic biomaterials are transformed from the bioinert to bioactive and multi-biofunctional(anti-bacterial,anti-proliferation,anti-cancer,etc.).Magnesium-based biomaterials are candidates to be used as new generation biodegradable metals.Magnesium(Mg)can dissolve in body fluid that means the implanted Mg can degrade during healing process,and if the degradation is controlled it would leave no debris after the completion of healing.Hence,the need for secondary surgical operation(s)for the implant removal could be eliminated.Besides its biocompatibility,the inherent mechanical properties of Mg are very similar to those of human bone.Researchers have been working on synthesis and characterization of Mg-based biomaterials with a variety of composition in order to control the degradation rate of Mg since uncontrolled degradation could result in loss of mechanical integrity,metal contamination in the body and intolerable hydrogen evolution by tissue.It was observed that the applied methods of synthesis and the choice of components affect the characteristics and performance of the Mg-based biomaterials.Researchers have synthesized many Mg-based materials through several synthesis routes and investigated their mechanical properties,biocompatibility and degradation behavior through in vitro,in vivo and in silico studies.This paper is a comprehensive review that compiles,analyses and critically discusses the recent literature on the important aspects of Mg-based biomaterials.

Biodegradation of Leather Waste by Enzymatic Treatment

The treatment of shavings,trimmings and splits of leather waste from tanneries has a potential to generate value-added products. In this study enzymatic treatment of leather waste was performed. This method utilizes alkaline protease produced by Bacillus subtilis in our laboratory by submerged fermentation. Optimum conditions of pH,time duration,temperature and concentration of enzyme were determined for maximum degradation of leather waste. The amount of degradation was measured by the release of amino acid hydroxyproline. Amino acid composition in the hydrolysate obtained by the enzyme hydrolysis was determined. This relative simple biotreatment of leather waste may provide a practical and economical solution.

SYNTHETIC STUDIES ON BLOOD COMPATIBLE BIOMATERIALSⅡ. SYNTHESIS OF POLY(ETHYLENEGLYCOL MONOMETHYLLTHER ) METHACRYLATE AND ANTITHROMBOGENICITY OF ITS COPOLYMERS

Poly （ethyleneglycol monomethylether） methacrylate （PEGMM）was synthesized by means of the reaction of methacrylyl chloride with sodium monomethylpolyethyleneglycoxide and was characterized by FTIR,;H-NMR,and ultraviolet spectrometries. A series of poly （vinyl alcohol）-graft-PEGMM （PVA-g-PEGMM ）and methyl methacrylate-PEGMM copolymer （PMMA-PEGMM） were prepared and tested for antithrombogenicity in vitro. The results indicate that the antithrombogenicity of the copolymers basically increases with the increasing of the DP of polyoxyethylene （POE） chain and tends to a plateau after the DP around 114,i.e. the long chain structure of POE is favourable to the antithrombogenicityof its copolymers ;moreover, the extent of the improvement ofantithrombogenicity also relates to the PEGMM content of the copolymers and the kind of the matrix that the POE chains are located on. These results are consistent with the anticipation of the hypothesis of maintaining proteins normal conformations for blood compatible bioraaterials.