3D printing biomimeticmaterials and structures for biomedical applications

Over millions of years of evolution,nature has created organisms with overwhelming performances due to their unique materials and structures,providing us with valuable inspirations for the development of next-generation biomedical devices.As a promising new technology,3D printing enables the fabrication of multiscale,multi-material,and multi-functional threedimensional(3D)biomimetic materials and structures with high precision and great flexibility.The manufacturing challenges of biomedical devices with advanced biomimetic materials and structures for various applications were overcome with the flourishing development of 3D printing technologies.In this paper,the state-of-the-art additive manufacturing of biomimetic materials and structures in the field of biomedical engineering were overviewed.Various kinds of biomedical applications,including implants,lab-on-chip,medicine,microvascular network,and artificial organs and tissues,were respectively discussed.The technical challenges and limitations of biomimetic additive manufacturing in biomedical applications were further investigated,and the potential solutions and intriguing future technological developments of biomimetic 3D printing of biomedical devices were highlighted.

Research perspective and prospective of additive manufacturing of biodegradable magnesium-based materials

Biodegradable metals such as magnesium(Mg)and its alloys have attracted extensive attention in biomedical research due to their excellent mechanical properties and biodegradability.However,traditional casting,extrusion,and commercial processing have limitations in manufacturing components with a complex shape/structure,and these processes may produce defects such as cavities and gas pores which can degrade the properties and usefulness of the products.Compared to conventional techniques,additive manufacturing(AM)can be used to precisely control the geometry of workpieces made of different Mg-based materials with multiple geometric scales and produce desirable medical products for orthopedics,dentistry,and other fields.However,a detailed and thorough understanding of the raw materials,manufacturing processes,properties,and applications is required to foster the production of commercial Mg-based biomedical components by AM.This review summarizes recent advances and important issues pertaining to AM of Mg-based biomedical products and discusses future development and application trends.

Fabrication of micro-nano patterned materials mimicking the topological structure of extracellular matrix for biomedical applications

With the advent of tissue engineering and biomedicine,the creation of extracellular matrix(ECM)biomaterials for in vitro applications has become a prominent and promising strategy.These ECM materials provide physical,biochemical,and mechanical properties that guide cellular behaviors,such as proliferation,differentiation,migration,and apoptosis.Because micro-and nano-patterned materials have a unique surface topology and low energy replication process that directly affect cellular biological behaviors at the interface,the fabrication of micro-nano pattern biomaterials and the regulation of surface physical and chemical properties are of great significance in the fields of cell regulation,tissue engineering,and regenerative medicine.Herein,we provide a comprehensive review of the progress in the fabrication and application of patterned materials based on the coupling of mechanical action at the micro-and nano-meter scale,including photolithography,micro-contact printing,electron beam lithography,electrospinning,and 3D printing technology.Furthermore,a summary of the fabrication process,underlying principles,as well as the advantages and disadvantages of various technologies are reviewed.We also discuss the influence of material properties on the fabrication of micro-and nano-patterns.

Direct extrusion of thin Mg wires for biomedical applications

Biodegradable wires,able to provide load-bearing support for various biomedical applications,are the novel trends in current biomaterial research.A thin 99.92%Mg wire with a diameter of 250μm was prepared via direct extrusion with an extreme reduction ratio of 1:576.The total imposed strain in a single processing step was 6.36.Extrusion was carried out at elevated temperatures in the range from 230 to 310℃and with various ram speeds ranging from^0.2 to^0.5 mm/s.The resulting wires show very good mechanical properties which vary with extrusion parameters.Maximum true tensile stress at room temperature reaches^228 MPa and ductility reaches^13%.The proposed single-step direct extrusion can be an effective method for the production of Mg wires in sufficient quantities for bioapplications.The fractographic analysis revealed that failure of the wires may be closely connected with inclusions(e.g.,Mg O particles).The results are essential for determining the optimal processing conditions of hot extrusion for thin Mg wire.The smaller grain size,as the outcome of the lower extrusion temperature,is identified as the main parameter affecting the tensile properties of the wires.

Physical Properties of Muga Silk and Its Application Potential in Biomaterials

The paper investigated the physical properties of muga silk.Surface properties,linear density,moisture regain and mechanical properties of muga silk were tested before and after degumming.The results show that muga silk has tiny fineness and high strength.The average fineness and the strength of the monofilament are 1.52 dtex and 5.62 cN/dtex,respectively.This makes up for the shortcomings of other kinds of silk,and has great potential in the application of biomaterials.

Effects of different simulated fluids on anticorrosion biometallic materials

The corrosion behaviors of SUS316L stainless steel, Co Cr alloy and Ti 6Al 4V alloy in Ringer’s, PBS(-) and Hank’s solutions have been investigated. The results indicate that the corrosion of Ringer’s solution is the strongest, then followed by PBS(-) and Hank’s solution. The presence of HPO 2- 4, H 2PO - 4, SO 2- 4 and glucose in the PBS(-)and Hank’s solution probably reduces the corrosion inhibitor and corrosion current. The decrease of the solution’s pH significantly increases the corrosion rate and susceptibility to localized corrosion of SUS316L SS and Co Cr alloy. However, Ti 6Al 4V alloy exhibits an exceptional stability and has only a slight increase of corrosion rate with decreasing pH.

Effects of cold deformation on microstructure and mechanical properties of Ti-35Nb-2Zr-0.3O alloy for biomedical applications

The Ti-35Nb-2Zr-0.3O(mass fraction,%)alloy was melted under a high-purity argon atmosphere in a high vacuumnon-consumable arc melting furnace,followed by cold deformation.The effects of cold deformation process on microstructure andmechanical properties were investigated using the OM,XRD,TEM,Vicker hardness tester and universal material testing machine.Results indicated that the alloy showed multiple plastic deformation mechanisms,including stress-inducedα'martensite(SIMα')transformation,dislocation slipping and deformation twins.With the increase of cold deformation reduction,the tensile strength andhardness increased owing to the increase of dislocation density and grain refinement,and the elastic modulus slightly increasedowing to the increase of SIMα'phase.The90%cold deformed alloy exhibited a great potential to become a new candidate forbiomedical applications since it possessed low elastic modulus(56.2GPa),high tensile strength(1260MPa)and highstrength-to-modulus ratio(22.4×10-3),which are superior than those of Ti-6Al-4V alloy.

Processing and mechanical properties of porous 316L stainless steel for biomedical applications

Highly porous 316L stainless steel parts were produced by using a powder metallurgy process, which includes the selective laser sintering(SLS) and traditional sintering. Porous 316L stainless steel suitable for medical applications was successfully fabricated in the porosity range of 40%-50% (volume fraction) by controlling the SLS parameters and sintering behaviour. The porosity of the sintered compacts was investigated as a function of the SLS parameters and the furnace cycle. Compressive stress and elastic modulus of the 316L stainless steel material were determined. The compressive strength was found to be ranging from 21 to 32 MPa and corresponding elastic modulus ranging from 26 to 43 GPa. The present parts are promising for biomedical applications since the optimal porosity of implant materials for ingrowths of new-bone tissues is in the range of 20%-59% (volume fraction) and mechanical properties are matching with human bone.

High plastic Zr–Cu–Fe–Al–Nb bulk metallic glasses for biomedical applications

Four Zr–Cu–Fe–Al-based bulk metallic glasses（BMGs） with Zr contents greater than 65at% and minor additions of Nb were designed and prepared. The glass forming abilities, thermal stabilities, mechanical properties, and corrosion resistance properties of the prepared BMGs were investigated. These BMGs exhibit moderate glass forming abilities along with superior fracture and yield strengths compared to previously reported Zr–Cu–Fe–Al BMGs. Specifically, the addition of Nb into this quaternary system remarkably increases the plastic strain to 27.5%, which is related to the high Poisson＇s ratio and low Young＇s and shear moduli. The Nb-bearing BMGs also exhibit a lower corrosion current density by about one order of magnitude and a wider passive region than 316 L steel in phosphate buffer solution（PBS, pH 7.4）. The combination of the optimized composition with high deformation ability, low Young＇s modulus, and excellent corrosion resistance properties indicates that this kind of BMG is promising for biomedical applications.

Biomi metic coating of calciumphosphate on biometallic materials

The biomimetic coating process in comparison with other processes is reviewed. This processing shows advantages in the surface bio-modification, such as low cost and flexible processing, wide range of apatite composition and thickness, non-line-of-sight characteristic and possibility to coat polymers and porous implants. The (bio-)(mimetic) apatite coating is made up of larger number of globules with size of 15μm. Each globule is a group of (numerous) flakes with a size range of 100200nm to 30μm in length and 0.11μm in thickness. In-vitro and (in-vivo) studies show that the biomimetic apatite coating can promote an early and strong bonding to bone or promote the bone in-growth into the porous structure, which will be beneficial to the cementless stable fixation of orthopaedic implants. Recently developed co-precipitation of a kind of protein molecules into the HA coating shows much (promising.)

Tailored biomedical materials for wound healing

Wound healing is a long-term,multi-stage biological process that mainly includes haemostatic,inflammatory,proliferative and tissue remodelling phases.Controlling infection and inflammation and promoting tissue regeneration can contribute well to wound healing.Smart biomaterials offer significant advantages in wound healing because of their ability to control wound healing in time and space.Understanding how biomaterials are designed for different stages of wound healing will facilitate future personalized material tailoring for different wounds,making them beneficial for wound therapy.This review summarizes the design approaches of biomaterials in the field of anti-inflammatory,antimicrobial and tissue regeneration,highlights the advanced precise control achieved by biomaterials in different stages of wound healing and outlines the clinical and practical applications of biomaterials in wound healing.

产学合作背景下生物医用材料人才协同育人机制研究

产学合作背景下生物医用材料协同育人机制对实现新时代高校育人目标,促进学生终身发展,培养新时代生物医用材料行业发展需要的应用型人才至关重要。当前,产学合作背景下高校协同育人机制实践面临合作运行机制欠完善,人才培养目标有差异,人才培养方式不合理,师资力量较为薄弱的困境。该文从中国式教育现代化背景下新时代生物医用材料卓越人才培养理念,聚焦职业素养培育体系,突出能力本位教育,增强学生的创新精神、创业意识和创业能力,开展“素养引领、项目驱动、五维融合”的产学合作协同育人机制研究。

聚酰胺在医用卫生材料中的应用及研究进展

综述了聚酰胺(PA)类材料在多种医用卫生材料中的应用,包括PA缝合线、医用PA导管及球囊、PA牙托材料、抗菌PA材料、3D打印PA医卫材料、医用PA骨生长支架、药物输送类PA医用材料、创伤修复PA医用材料等,并评价了其效果及性能。

生物医用聚氨酯材料用于组织再生修复替代的应用进展

聚氨酯材料由于分子结构可设计、性能可调控,且具有优异的机械性能及生物相容性,在组织再生及替代领域展现出巨大的应用潜力。回顾了近年来聚氨酯材料在生物医学领域的发展现状,归纳了聚氨酯的结构设计、合成制备、改性方法及聚氨酯在皮肤、神经系统、心血管系统、骨骼肌系统等组织的再生修复及替代领域的最新研究进展。总结并展望了生物医用聚氨酯材料面临的问题及未来发展方向,为设计性能更加广泛可调的聚氨酯材料,以实现多重组织再生修复及替代提供参考。

天然动物皮的本体应用进展

随着社会的进步、经济繁荣和科学技术的不断发展,天然生物质材料及其衍生物的应用领域得以不断拓展。作为典型生物质材料,天然动物皮具有资源丰富、廉价易得、可再生等特点,同时兼具良好的生物相容性、可降解性、低抗原性、可加工性以及物理机械性能等应用特性。按照化学的观点,动物皮的利用方式可以分为本体利用和水解产物利用两类。本文首先简要介绍了动物皮的结构、组成及应用分类。接着,综述了动物皮在功能皮革材料、生物医用材料、柔性电子传感材料领域的本体应用研究进展。最后,结合目前研究现状,对天然动物皮的本体应用前景和发展趋势进行了展望。

BioMGE——一个用于采集和分析生物医用材料和多组学数据的数据库

随着机器学习技术的发展,生物医用材料的科学研究也逐渐走向数据驱动,利用生物测序技术来测试生物医用材料的生物功能,需要对生物医用材料进行进一步优化.因此,一个开放、共享的基础设施来存储来自不同研究领域的异构科学数据是多学科交叉联合分析的基石.本文介绍了BioMGE,一个基于灵活的自定义平台NMDMS(国家材料数据管理与服务平台)实现的数据库建设案例,用于收集生物医用材料和多组学测序数据.NMDMS的动态容器框架允许用户定义个性化的数据提交模式,存储来自生物医用材料和多组学研究领域的数据.自2019年以来,BioMGE已收集了1547100个生物医用材料和多组学数据集.BioMGE提供了数据导出接口,方便用户直接导出数据以进行数据分析.以组学数据可视化为例,提供BioMGE-viewer模块以实现对生物染色质结构数据从一维到三维的数据可视化.该数据库可为其他跨领域研究的数据共享提供了新的思路和平台.

骨科止血材料临床应用的优势、不适与面临的挑战

背景:骨蜡是可用于骨止血的填塞剂,国内外虽一直在修正骨蜡配方,但无法改变其难以被吸收的核心瓶颈,因此开发具有止血、成骨和抗菌等功能化的骨科止血材料替代骨蜡具有迫切的临床需求。目的:回顾包括骨蜡和其替代材料在内的骨科止血材料的发展历程。方法:检索Pub Med、Web of Science、万方数据库、中国知网及维普数据库中与骨蜡、止血材料、骨科止血材料研究进展相关的文献,并通过阅读文章中的摘要部分初筛,选择了136篇文献纳入综述。结果与结论:为替代传统骨蜡,研究人员从止血、成骨等实际场景的需求出发,开发出各式骨科止血材料,但相关研究多集中于基础的理化和性能测试,缺乏系统的评价体系,同时欠缺足够的大动物实验和临床试验报道。因此,目前骨蜡依旧是公认的骨科止血材料,其根本原因是已有材料的设计无法适时满足术中止血、术后成骨及临床上的新需求。未来还需要对现有止血和成骨材料的结构、组分和功能进行整合和再设计,以满足不断提高的止血与成骨需求。

可降解Zn-Li合金吻合钉的自然时效与降解机制研究

作为力学性能良好,降解速率适中的可降解金属,Zn基合金的应用前景十分广阔。研究了自然时效对Zn-Li合金性能的影响以及Zn-Li合金吻合钉的体外降解机制。通过拉伸试验和电化学试验分析时效时间对Zn-Li合金丝力学性能和耐蚀性的影响。采用浸泡实验,根据吻合钉质量变化分析不同模拟液对Zn-Li吻合钉降解速率的影响,采用扫描电子显微镜分析Zn-Li吻合钉不同部位的降解模式。结果表明,时效2.0 a的Zn-Li合金丝比时效1.0 a的拉伸强度低43.86 MPa,伸长率下降24.17%,腐蚀电势由-1.07 V下降至-1.12 V,腐蚀电流密度增加13%。Zn-Li吻合钉在模拟体液中降解速率最大,钉脚的微电偶腐蚀为最严重的腐蚀形式。

生物医学工程跨学科综合实验教学实践

结合生物医学工程专业多学科交叉特点,探讨了通过综合实验教学设计进行融会贯通教学。在实验组织上采用“项目式”实验,在实验内容上实现多元化综合设计。以“导电水凝胶材料在柔性电子及人体中的应用”为主题,设计了导电水凝胶制备、材料性能表征、柔性电极体表电信号检测及基于Python生理信号分析系列综合实验,构建了“医用材料+”实践教学。实验安排跳出章节内容实验设定的局限性,体现了生物医学工程学科的融合交叉,有效拓展了专业教学的深度和广度。

超支化聚合物在生物医学材料中应用研究进展

超支化聚合物(HBPs)具有高活性功能端基,便于修饰改性,能够设计合成结构明确且具有特定功能的高分子材料,在生物医学领域具有潜在应用价值。可控/活性自由基聚合(CLRP)技术在聚合物合成领域受到广泛关注,并将其运用到医疗产品、纳米材料、航天器件等众多领域中。近年来,在合成具有生物可降解和生物相容性的HBPs的发展方面已取得了诸多进展,对HBPs在生物医学领域的最新研究进展进行了总结,重点介绍了HBPs在药物传递、基因转染、组织工程、抗菌/防污材料、生物医学成像等方面的应用,并对HBPs的发展前景进行了展望。