TWIP-assisted Zr alloys for medical applications:Design strategy,mechanical properties and first biocompatibility assessment

This study proposes a novel strategy for the design of a new family of metastable Zr alloys.These al-loys offer improved mechanical properties for implants,particularly in applications where conventional stainless steels and Co-Cr alloys are currently used but lack suitability.The design approach is based on the controlled twinning-induced plasticity(TWIP)effect,significantly enhancing the ductility and strain-hardenability of the Zr alloys.In order to draw a“blueprint”for the compositional design of biomedical T WIP(Bio-T WIP)Zr alloys-using only non-toxic elements,the study combines D-electron phase stability calculations(specifically bond order(Bo)and mean d-orbital energy(Md))with a systematic experimental screening of active deformation mechanisms within the Zr-Nb-Sn alloy system.This research aids in ac-curately identifying the TWIP line,which signifies the mechanism shift between TWIP and classic slip as the primary deformation mechanism.To demonstrate the efficacy of the TWIP mechanism in enhancing mechanical properties,Zr-12Nb-2Sn,Zr-13Nb-1Sn,and Zr-14Nb-3Sn alloys are selected.Results indicate that the TWIP mechanism leads to a significant improvement of strain-hardening rate and a uniform elongation of∼20%in Zr-12Nb-2Sn,which displays both{332}<113>mechanical twinning and disloca-tion slip as the primary deformation mechanisms.Conversely,Zr-14Nb-3Sn exhibits the typical mechan-ical properties found in stable body-centered cubic(BCC)alloys,characterized by the sole occurrence of dislocation slip.Cell viability tests confirm the superior biocompatibility of Zr-Nb-based alloys with deformation twins on the surface,in line with existing literature.Based on the whole set of results,a comprehensive design diagram is proposed.

Biocompatibility of vascular stents manufactured using metal injection molding in animal experiments

This study aimed to evaluate the feasibility and safety of a novel stent manufactured by metal injection molding(MIM)in clinical practice through animal experiments.Vessel stents were prepared using powder injection molding technology to considerably improve material utilization.The influence of MIM carbon impurity variation on the mechanical properties and corrosion resistance of 316L stainless steel was studied.In vitro cytotoxicity and animal transplantation tests were also carried out to evaluate the safety of MIM stents.The results showed that the performance of 316L stainless steel was very sensitive to the carbon content.Carbon fluctuations should be precisely controlled during MIM.All MIM stents were successfully implanted into the aortas of the dogs,and the MIM 316L stents had no significant cytotoxicity.The novel intravascular stent manufactured using MIM can maintain a stable form and structure with fast endothelialization of the luminal surface of the stent and ensure long-term patency in an animal model.The novel intravascular stent manufactured using MIM demonstrates favorable structural,physical,and chemical stability,as well as biocompatibility,offering promising application in clinical practice.

Biocompatibility of Compounds of Extracellular Matrix and Thermally Reversible Hydrogel

A new scaffold material composed of extracellular matrix （ECM） and thermal sensitive hydrogel （HG）, and evaluated its biocompatibility were investigated. We cultured bladder smooth muscle cells with this compound material, and then observed with phase contrast microscopy and scanning electron microscope （SEM） to assess the cell growth and morphology. The cell adhesion and proliferation were detected with MTT assay and cell count. Results show the ECM/HG compounds appeared as a net-like and red-stained construction with enough meshes and without any cellular fragments. 6 h after implantation, cells were observed adhere on the compounds and extend spurious along the fibers 12 h later. Under SEM even some ECM was observed to be secreted. MTT assay shows there was obvious statistic difference among 3 groups （P〈0.05）. ECM/HG compound materials show a good biocompatibility, which confirms that it would be an ideal tissue engineering scaffolds.

Biocompatibility of light responsive materials prepared for accommodative intraocular lenses manufacturing

AIM:To investigate the biocompatibility and bacterial adhesion properties of light responsive materials(LRM)and analyze the feasibility and biosafety of employing LRM in the preparation of accommodative intraocular lenses(AIOLs).METHODS:Employing fundamental experimental research techniques,LRM with human lens epithelial cells(hLECs)and human retinal pigment epithelium cells(ARPE-19 cells)were co-cultured.Commercially available intraocular lenses(IOLs)were used as controls to perform cell counting kit-8(CCK-8),cell staining under varying light intensities,cell adhesion and bacterial adhesion experiments.RESULTS:LRM exhibited a stronger inhibitory effect on the proliferation of ARPE19 cells than commercially available IOLs when co-cultured with the undiluted extract for 96h(P<0.05).Under other culturing conditions,the effects on the proliferation of hLECs and ARPE-19 cells were not significantly different between the two materials.Under the influence of light irradiation at intensities of 200 and 300 mW/cm^(2),LRM demonstrated a markedly higher inhibitory effect on the survival of hLECs compared to commercially available IOLs(P<0.0001).They also showed a stronger suppressive effect on the survival rate of ARPE-19 cells,with significant differences observed at 200 mW/cm^(2)(P<0.001)and extremely significant differences at 300 mW/cm^(2)(P<0.0001).Additionally,compared to commercially available IOLs,LRM had a higher number of cells adhering to their surface(P<0.05),as well as a significantly greater number of adherent bacterium(P<0.0001).CONCLUSION:LRM,characterized by their excellent non-contact tunable deformability and low cytotoxicity to ocular tissues,show considerable potential for use in the fabrication of AIOLs.These materials demonstrate strong cell adhesion;however,during photothermal conversion processes involving shape deformation under various light intensities,the resultant temperature rise may harm surrounding cells.These factors suggest that while the material plays a positive role in reducing the incidence of posterior capsule opacification(PCO),it also poses potential risks for retinal damage.Additionally,the strong bacterial adhesion of these materials indicates an increased risk of endophthalmitis.

Biocompatibility of MIM 316L stainless steel

To evaluate the bioeompatibility of MIM 316L stainless steel,the percentage of S-period cells were detected by flow cytometry after L929 incubated with extraction of MIM 316L stainless steel,using titanium implant materials of clinical application as the contrast.Both materials were implanted in animal and the histopathological evaluations were carried out.The statistical analyses show that there are no significant differences between two groups(P>0.05),which demonstrates that MIM 316L stainless steel has a good biocompatibility.

Biocompatibility of KLD-12 Peptide Hydrogel as a Scaffold in Tissue Engineering of Intervertebral Discs in Rabbits

KLD-12 peptide with a sequence of AcN-KLDLKLDLKLDL-CNH2 was synthesized and its biocompatibility was assessed in animals. Rabbit MSCs were cultured in the hydrogel for 2 weeks. Live cells were counted by using Calcein-AM/P1 fluorescence staining. MTT was employed to assess the viability of MSCs cultured in KLD-12 peptide solution of 0.01%, 0.03%, and 0.05%. Hemolysis test, skin irritation test and implantation test were conducted to evaluate its biocompatibility with host tissues. Our results demonstrated that the MSCs in hydrogel grew well and maintained round shape. Cell survival rate was 92.15% （mean： 92.15%±1.17%） at the 7th day and there was no difference in survival rate between day 7 and day 14. Cell proliferation test showed that the A value of the KLD-12 solutions was not significantly different from that of control groups （complete culture media） （P〉0.05） at the 24th and 48th h. The hemolysis rate of KLD-12 solution was 0.112%. Skin irritation test showed that the skin injected with KLD-12 solution remained normal and the score of skin irritation was 0. The histological examination with HE staining exhibited that the skin layers were clear and there was no infiltration with neutrophilic granulocytes and lymphocytes. It is concluded that KLD-12 peptide hydrogel bad a good biocompatibility with host rabbit and MSCs, and KLD-12 pep- tide hydrogel can provide an appropriate microenvironment for MSCs.

In vitro and in vivo analysis of the biocompatibility of two novel and injectable calcium phosphate cements

Calcium phosphate cements(CPCs)have been widely used as bone graft substitutes for many years.The aim of this study was to evaluate the biocompatibility of two novel injectable,bioactive cements:b-tricalcium phosphate(b-TCP)/CPC and chitosan microsphere/CPC in vitro and in vivo.This was accomplished by culturing mouse pre-osteoblastic cells(MC3T3-E1)on discs and pastes of CPCs.Cell growth,adhesion,proliferation and differentiation were assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and alkaline phosphatase assays as well as by scanning electron microscopy and fluorescence.The effect of CPC paste curing was also evaluated.Implantation of two materials into the muscle tissue of rabbits was also studied and evaluated by histological analysis.Cell analysis indicated good biocompatibility in vitro.The fluorescence assay suggested that the cured material discs had no obvious effect on cell growth,while the curing process did.Histological examination showed no inflammatory cell infiltration into soft tissue.These data suggest that b-TCP/CPC and chitosan microsphere/CPC composites may be promising injectable material for bone tissue engineering.

Natural and Eco-Friendly Materials for Triboelectric Energy Harvesting

Triboelectric nanogenerators(TENGs)are promising electric energy harvesting devices as they can produce renewable clean energy using mechanical excitations from the environment.Several designs of triboelectric energy harvesters relying on biocompatible and eco-friendly natural materials have been introduced in recent years.Their ability to provide customizable self-powering for a wide range of applications,including biomedical devices,pressure and chemical sensors,and battery charging appliances,has been demonstrated.This review summarizes major advances already achieved in the field of triboelectric energy harvesting using biocompatible and eco-friendly natural materials.A rigorous,comparative,and critical analysis of preparation and testing methods is also presented.Electric power up to 14 mW was already achieved for the dry leaf/polyvinylidene fluoride-based TENG devices.These findings highlight the potential of eco-friendly self-powering systems and demonstrate the unique properties of the plants to generate electric energy for multiple applications.

MXene基水凝胶在创面修复领域的应用

背景:MXene基水凝胶是一类纳米复合的多功能性水凝胶材料,在慢性创面(如糖尿病足、压疮、癌症及外伤性溃疡等)修复领域有广阔的应用前景。目的:综述MXene基水凝胶的优势及其在创面修复领域的应用和相关作用机制。方法:检索中国知网、维普、PubMed、Science Direct数据库中收录的文章,文献检索时限为2010年1月至2023年10月,中文检索关键词为“MXene,水凝胶,组织工程应用,创面修复”,英文检索关键词为“MXene,Hydrogel,Wound repair”,最终选取符合标准的70篇文献进行综述。结果与结论:MXene基水凝胶在创面组织工程应用中具有优异的力学、导电和光热性能及生物相容性和抗菌性等生物学功效,可以与其他有机物质和无机物质相结合,在水凝胶中产生更大的治疗作用。含有MXene的水凝胶可以结合创面监测、药物递送和缓释以及光热治疗等方式应用于皮肤创面。尽管MXene基水凝胶复合材料的设计和制备已经取得一些良好进展,但仍处于基础研究阶段,缺乏临床验证其功效性和安全性,具有很大发展潜力和应用空间。

Poly(<i>N</i>-isopropylacrylamide-co-<i>N</i>-<i>tert</i>-butylacrylamide)- grafted hyaluronan as an injectable and self-assembling scaffold for cartilage tissue engineering

Novel poly(N-isopropylacrylamide-co-N-tert-butylacrylamide)-grafted hyaluronan [P(NIPAAm-co-NtBAAm)-g-HA] has been developed as a modified derivative to improve phase-transition characteristics of PNIPAAm-g-HA, which has a lower critical solution temperature (LCST) of approximately 32°C. This promising self-assembling biomaterial has potential as an injectable scaffold for in situ cartilage tissue engineering. LCST of the P(NIPAAm-co-NtBAAm)-g-HA decreased to approximately 3.6°C compared to that of the original PNIPAAm-g-HA. This modification enabled self-assembly at body temperatures lower than the temperature of the parental PNIPAAm-g-HA molecule. Cytotoxicity and acute systemic toxicity assays revealed that P(NIPAAm-co-NtBAAm)-g-HA was not hazardous. The DNA content of chondrogenic differentiated mesenchymal stem/stromal cells (MSCs) embedded in the gels was higher than that of biomaterial-free aggregates during the culture periods. Cartilage-related genes were also expressed in chondrogenic differentiated MSCs embedded in the P (NIPAAm-co-NtBAAm)-g-HA hydrogel. Specifically, an increased expression of SRY-related HMG box-containing gene 9 (Sox9) observed in the hydrogel group compared to controls. These data suggest that P(NIPAAm-co-NtBAAm)-g-HA is a promising injectable scaffold with thermoresponsive properties suitable for in situ cartilage tissue engineering.

Nanoparticles for the treatment of spinal cord injury

Spinal cord injuries lead to significant loss of motor, sensory, and autonomic functions, presenting major challenges in neural regeneration. Achieving effective therapeutic concentrations at injury sites has been a slow process, partly due to the difficulty of delivering drugs effectively. Nanoparticles, with their targeted delivery capabilities, biocompatibility, and enhanced bioavailability over conventional drugs, are garnering attention for spinal cord injury treatment. This review explores the current mechanisms and shortcomings of existing treatments, highlighting the benefits and progress of nanoparticle-based approaches. We detail nanoparticle delivery methods for spinal cord injury, including local and intravenous injections, oral delivery, and biomaterial-assisted implantation, alongside strategies such as drug loading and surface modification. The discussion extends to how nanoparticles aid in reducing oxidative stress, dampening inflammation, fostering neural regeneration, and promoting angiogenesis. We summarize the use of various types of nanoparticles for treating spinal cord injuries, including metallic, polymeric, protein-based, inorganic non-metallic, and lipid nanoparticles. We also discuss the challenges faced, such as biosafety, effectiveness in humans, precise dosage control, standardization of production and characterization, immune responses, and targeted delivery in vivo. Additionally, we explore future directions, such as improving biosafety, standardizing manufacturing and characterization processes, and advancing human trials. Nanoparticles have shown considerable progress in targeted delivery and enhancing treatment efficacy for spinal cord injuries, presenting significant potential for clinical use and drug development.

研磨处理可注射牙髓细胞外基质促进牙髓再生

背景:可注射细胞外基质材料用于牙髓组织再生时,首先需要经过胃蛋白酶消化,再与其他基质成分如水凝胶结合使用,而这也意味着天然细胞外基质材料所保留的微环境遭到破坏。目的:探讨研磨处理条件下制备的可注射牙髓细胞外基质材料用于牙髓组织再生的效果。方法:(1)将获取的猪牙来源牙髓组织经过脱细胞处理后制备成牙髓脱细胞基质材料,经过液氮冷冻、高速研磨处理后,制备成可注射牙髓细胞外基质材料,比较可注射牙髓细胞外基质材料和天然牙髓细胞外基质在细胞黏附效率和微结构方面的差异,免疫组化分析可注射牙髓细胞外基质中的细胞外基质蛋白质成分;(2)将接种有牙髓干细胞的可注射牙髓细胞外基质材料注入到牙本质基质材料构建的牙髓腔中,植入裸鼠皮下1,3,5周后取材,观察可注射牙髓细胞外基质材料的体内改建速率及其在裸鼠皮下的异位牙髓组织再生能力。结果与结论:(1)与天然牙髓细胞外基质相比,可注射牙髓细胞外基质材料显著提高了细胞黏附率,并保留了与天然牙髓细胞外基质相似的多孔胶原结构;(2)与天然牙髓细胞外基质相比,免疫组化染色显示可注射牙髓细胞外基质材料中层粘连蛋白、Ⅰ型胶原蛋白和整合素β1的表达没有显著变化,而纤连蛋白的表达显著下降;(3)体内实验显示,可注射牙髓细胞外基质材料具有优异的成血管能力,并促进了牙髓样组织的形成。结果表明,研磨处理的可注射牙髓细胞外基质材料可促进牙髓再生。

Novel three-dimensional nerve tissue engineering scaffolds and its biocompatibility with Schwann cells

Objective： To develop a novel scaffolding method for the copolymers poly lactide-co-glycolide acid （PLGA） to construct a three-dimensional （3-D） scaffold and explore its biocompatibility through culturing Schwann cells （SCs） on it. Methods： The 3-D scaffolds were made by means of melt spinning, extension and weaving. The queueing discipline of the micro-channels were observed under a scanning electronic microscope （SEM）.The sizes of the micropores and the factors of porosity were also measured. Sciatic nerves were harvested from 3-day-old Sprague Dawley （SD） rats for culture of SCs. SCs were separated, purified, and then implanted on PLGA scaffolds, gelatin sponge and poly-L-lysine （PLL）-coated tissue culture poly-styrene （TCPS） were used as biomaterial and cell-supportive controls, respectively. The effect of PLGA on the adherence, proliferation and apoptosis of SCs were examined in vitro in comparison with gelatin sponge and TCPS. Results： The micro-channels arrayed in parallel manners, and the pore sizes of the channels were uniform. No significant difference was found in the activity of Schwann cells cultured on PLGA and those on TCPS （P〉0.05）, and the DNA of PLGA scaffolds was not damaged. Conclusion： The 3-D scaffolds developed in this study have excellent structure and biocompatibility, which may be taken as a novel scaffold candidate for nerve-tissue engineering.

Biocompatibility and degradation comparisons of four biodegradable copolymeric osteosynthesis systems used in maxillofacial surgery: A goat model with four years follow-up

pplying biodegradable osteosyntheses avoids the disadvantages of titanium osteosyntheses. However, foreign-body reactions remain a major concern and evidence of complete resorption is lacking. This study compared the physico-chemical properties, histological response and radiographs of four copolymeric biodegradable osteo-synthesis systems in a goat model with 48-months follow-up. The systems were implanted subperiosteally in both tibia and radius of 12 Dutch White goats. The BioSorb FX [poly(70LLA-co-30DLLA)], Inion CPS [poly([70–78.5] LLA-co-[16–24]DLLA-co-4TMC)], SonicWeld Rx [poly(DLLA)], LactoSorb [poly(82LLA-co-18GA)] systems and a negative control were randomly implanted in each extremity. Samples were assessed at 6-, 12-, 18-, 24-, 36-, and 48-month follow-up. Surface topography was performed using scanning electron microscopy (SEM). Differential scanning calorimetry and gel permeation chromatography were performed on initial and explanted samples. Histological sections were systematically assessed by two blinded researchers using (polarized) light microscopy, SEM and energy-dispersive X-ray analysis. The SonicWeld Rx system was amorphous while the others were semi-crystalline. Foreign-body reactions were not observed during the complete follow-up. The SonicWeld Rx and LactoSorb systems reached bone percentages of negative controls after 18 months while the BioSorb Fx and Inion CPS systems reached these levels after 36 months. The SonicWeld Rx system showed the most predictable degradation profile. All the biodegradable systems were safe to use and well-tolerated (i.e., complete implant replacement by bone, no clinical or histological foreign body reactions, no [sterile] abscess formation, no re-interventions needed), but nanoscale residual polymeric fragments were observed at every system’s assessment.

Bone Remodeling, Biomaterials And Technological Applications: Revisiting Basic Concepts

Presently, several different graft materials are employed in regenerative or corrective bone surgery. However current misconceptions about these biomaterials, their use and risks may compromise their correct application and development. To unveil these misconceptions, this work briefly reviewed concepts about bone remodeling, grafts classification and manufacturing processes, with a special focus on calcium phosphate materials as an example of a current employed biomaterial. Thus a search on the last decade was performed in Medline, LILACS, Scielo and other scientific electronic libraries using as keywords biomaterials, bone remodeling, regeneration, biocompatible materials, hydroxyapatite and therapeutic risks. Our search showed not only an accelerated biotechnological development that brought significant advances to biomaterials use on bone remodeling treatments but also several therapeutic risks that should not be ignored. The biomaterials specificity and limitations to clinical application point to the current need for developing safer products with better interactions with the biological microenvironments.

Antimicrobial bio-inspired active packaging materials for shelf life and safety development:A review

Foodstuffs are highly vulnerable to contamination caused by microbial pathogens,thereby causing food-borne diseases.Earlier,plastic packaging materials have been in frequent use in order to protect from pathogen infection and increase the shelf life of foodstuffs.However,there remains a controversy about the use of plastic due to its non-degradable nature and eco-toxicity.Bio-polymer based materials recently gained attention in the food industry as an alternative because of their potent antimicrobial and non-toxic nature.This review provides an overview of the application of bio-based active materials for designing an ideal antimicrobial packaging film to inhibit the growth of food-borne pathogens.Specifically,it highlights the various materials that go into making bio-based packaging material,desirable properties for an ideal packaging material,its possible interaction mechanism with the pathogens,and concludes with a case study on muscle foods.Bio-polymers reinforced with active materials such as essential oils,peptides,proteins,nanoparticles make for excellent bio-based active packaging materials.These show a broad range of antibacterial activity against Escherichia coli,Listeria monocytogenes,Salmonella sp.,and Staphylococcus aureus.Multiple mechanisms are involved during the interaction of packaging films with these pathogens viz.generation of reactive oxygen species,disturbing the cell membrane permeability,inhibiting the enzyme activity.The bio-based polymer packaging film can be a better substitute for plastic-based food packaging material in terms of degradability and cost-effectiveness.The current research scenario suggests a future commercial level dominance of bio-based food packaging materials in the active packaging material industry.

Archival Examination of the Change in Packaging Materials of Chemical Injections

Based on the deepening awareness of the risk of changing packaging materials of injections,the national regulatory authorities and the China National Pharmaceutical Packaging Association have issued the relevant guidelines and group standards for changing packaging materials in recent years,greatly improving the research and development and technical requirements of packaging materials of injections.In 2021,Guangdong Province carried out the archival examination of the change of listed drugs,among which the proportion of the acceptance of changed injection packaging materials has increased year by year.On the basis of sorting out the archival examination work and combining with the cases of changing packaging materials of chemical injections accepted by Guangdong Province during 2021-2022,the requirements and problems of archival examination were analyzed and discussed to provide a reference and idea for applicants when studying the change in packaging materials.

油气田注入井况中管材氧腐蚀的研究进展

油气田注入井况中管材腐蚀问题突出,造成油气行业严重的资源浪费及安全隐患,而氧腐蚀已成为导致管材穿孔失效的主要原因之一。综述了近年来油气田注入环境中管材氧腐蚀的研究进展,重点关注了注入井况、注入参数(如工艺条件、温度、含氧量、流速等)对金属材料氧腐蚀的影响,探讨了氧腐蚀的机理及防护方法,并分析了目前研究中存在的不足。结合油气田工程需求,对未来该领域的研究工作提出了建议。

生物水凝胶激光加工工艺及体外生物相容性研究

针对生物水凝胶增材制造无法实现精细结构打印的问题,采用激光加工对SA水凝胶和GelMA水凝胶进行实验,通过激光切割、激光雕刻等探究了激光加工生物水凝胶的机制及各参数对激光加工效果的影响,通过细胞增殖实验分析HUVECs细胞在激光加工的水凝胶上的生长情况。实验表明,激光功率、进给速度等参数对于激光加工水凝胶的深度和表面质量有较大影响,细胞能够在激光加工的水凝胶上正常增殖,这可为生物医学相关应用提供有益的指导。