仿生心肌微环境介导的材料生物学研究

心肌梗死是由冠状动脉阻塞所引起的心肌缺氧坏死,其发病率和病死率居高不下。近年研究发现,利用组织工程手段仿生构建心肌微环境能有效改善心肌梗死区微环境,对心肌的再生能力有着重要的调控作用,能在一定程度上促进心肌再生,有望成为将来治疗心肌梗死的新方向。然而,由于对仿生心肌微环境和机体微环境交互作用、引发的生物学效应及作用机制不清楚,直接影响心肌损伤修复的过程和质量。因此,阐明仿生心肌微环境在心肌损伤修复过程中的交互作用过程及其介导的生物学效应迫在眉睫。该文系统性综述了仿生心肌微环境的构建策略及植入体内后介导的生物学效应,包括免疫调控效应、促血管再生效应以及再生协同效应等,为新型心肌补片的仿生设计和临床应用提供理论支持。

材料生物学——骨修复材料的机遇与挑战

材料与宿主微环境之间的相互作用直接影响骨修复的过程和质量。由于对材料在体内微环境中的生物学效应、修复过程及作用机理不清楚,导致目前大部分材料的修复效果不理想,难以达到真正的"骨性融合",临床应用受限。因此,弄清材料在骨修复过程中的生物学效应及其发生规律迫在眉睫。综述了骨修复材料在植入体内后产生的免疫调控效应、与体内生长因子的协同效应、以及血管化效应等一些新的生物学效应,指出了材料在体内所处的环境并非静止的,而是动态变化的,材料参数改变体内微环境,进而影响再生过程;同时,微环境也影响了材料的转归命运。聚焦材料生物学研究,揭示材料在生命活动中的作用机制和规律,将是未来组织修复材料的发展趋势。

材料的生物学性能教学的思考

《材料的生物学性能》是培养生物医用材料方向本科生的一门专业必修课。以培养学生扎实的专业知识和技能为目标,对材料的生物学性能课程进行了课程体系、教学内容、教学方法的改革,以实验教学为主,加强了学生实践能力和创新能力的培养。

生物材料在修补复杂性腹壁缺损中的使用

感染、污染或可能污染的腹壁缺损一直是疝和腹壁外科的治疗难点，主要包括补片感染、肠瘘合并疝、腹腔内脓肿、粪便性腹膜炎病史、造口旁疝修补术、无肠坏死或穿孔的嵌顿性疝、疝修补过程中实施肠切除和复发性切口疝等，上述情况统称为复杂性腹壁缺损。采用传统的合成材料如聚丙烯、聚酯或聚四氟乙烯等来修补，面临着感染、再取出材料和复发的危险。成分分离技术、可吸收补片和自体组织移植等方法由于各种局限性和并发症的存在，应用受到一定的限制。

生物性材料硫酸钙作为复合材料的应用研究与进展

背景:将硫酸钙与其他生物材料混合可以克服硫酸钙本身的缺点。目的:探讨生物性材料硫酸钙作为复合材料在局部药物释放载体及骨生物材料应用方面的性能。方法:以"硫酸钙,骨修复材料,缓释系统,生物学材料,复合材料"为中文关键词,以"Calcium sulfate,Mixture,Bone defect,Drug release"为英文关键词,采用计算机检索万方数据库、PubMed数据库等1980年1月至2012年3月有关硫酸钙作为复合材料在局部药物释放载体及骨生物材料中应用的文章。结果与结论:硫酸钙作为骨缺损修复材料具有很多优点,但吸收快、缓释药物慢等缺点限制了其应用。因此对硫酸钙作为复合材料的研究开始增多,无论是作为药物释放载体还是作为骨替代材料,硫酸钙与其他材料混合发挥了复合材料的互补特性,很大程度上满足了生物材料应具有的综合特点。这样既保留了硫酸钙的成骨和骨诱导等优点,又克服了其不足。但关于这方面研究仍处于起步阶段,复合材料的配比、体内特性、临床应用等仍需进一步研究。

应对老龄化所致慢病的智能生物材料

人口老龄化进程的不断加速直接导致骨质疏松和心血管疾病等慢性病高发,对以组织修复材料为核心的临床治疗方法提出了巨大挑战.本综述通过回顾生物材料的发展历程,总结归纳了各阶段生物材料的优劣势,同时详细论述了老龄化病损组织修复所面临的组织功能和微环境稳态难以维持的难题,最后基于此探讨如何结合人工智能、材料生物学、影像组学等新兴技术,研发能感知生理病理微环境,适时响应和主动调控生物学效应,并全周期适配病损组织修复进程的新一代“自适应”智能生物材料.

从被动应用向主动设计的升华—生物医学工程(生物医学材料类)本科教育专业核心知识体系的变革与重塑

生物医学工程(生物医学材料类)专业为多学科交叉融合的典型领域,其独特的医工交叉性、知识综合性和技术前沿性,使其专业教育同时肩负“新医科”和“新工科”(简称“双新”)的改革重任。本文结合世界生物医学材料发展的趋势与前沿,分析了新形势下生物医学工程(生物医学材料类)专业教育面临的机遇与挑战,从国家重大战略和产业发展对生物医学材料人才素质新要求的角度,对“双新”背景下生物医学工程(生物医学材料类)专业教育进行了深刻的反思,提出以生物医学材料与机体不同层次的相互作用及作用效应为主线重塑专业核心知识体系、设置以《材料生物学》为核心的生物医学材料学系列课程、建立“产学研用”多元融合的生物医学工程(生物医学材料类)专业高素质人才培养体系的改革模式,以期有助于解决怎样培养引领新一轮诊疗技术变革和医疗器械产业发展的创新人才与领军人才的重大命题。

硫酸钙在骨损伤修复中的研究进展

骨损伤是较为常见的骨科疾病。骨损伤的修复是目前临床研究的难点与热点,获得理想的骨修复材料成为该领域的重点研究方向。硫酸钙是一种具有广阔应用前景的替代材料,具有良好组织相容性、成骨活性、生物力学强度等特点。本文就硫酸钙的生物学特性以及在临床应用中的研究进展做一综述,以期为硫酸钙的临床应用、科学研究提供参考。

Mechanical properties and pore structure deformation behaviour of biomedical porous titanium

Porous titanium has been shown to exhibit desirable properties as biomedical materials. In view of the load-bearing situation, the mechanical properties and pore structure deformation behaviour of porous titanium were studied. Porous titanium with porosities varying from 36%-66% and average pore size of 230 μm was fabricated by powder sintering. Microstructural features were characterized using scanning electron microscopy. Uniaxial compression tests were used to probe the mechanical response in terms of elastic modulus and compressive strength. The mechanical properties of porous titanium were found to be close to the those of human bone, with stiffness values ranging from 1.86 to 14.7 GPa and compressive strength values of 85.16-461.94 MPa. The relationships between mechanical properties and relative densities were established, and the increase in relative density showed significant effects on mechanical properties and deformations of porous titanium. In a lower relative density, the microscopic deformation mechanism of porous titanium was yielding, bending and buckling of cell walls, while the deformation of yielding and bending of cell walls was observed in the porous titanium with higher relative density.

Microstructure and properties of biodegradable β-TCP reinforced Mg-Zn-Zr composites

Magnesium alloys have good biocompatibility, but their mechanical properties and corrosion resistance may not be satisfied for using as degradable materials within bone due to its high corrosion rate in the physiological environment. Nano β-TCP particles were added into Mg-Zn-Zr alloy to improve its microstructure and the properties. As-extruded Mg-3Zn-0.8Zr alloy and Mg-3Zn-0.8Zr/xβ-TCP （x=0.5%, 1.0% and 1.5%） composites were respectively fabricated. The grains of Mg-Zn-Zr/β-TCP composites were significantly refined. The results of the tensile tests indicate that the ultimate tensile strength and the elongation of composites were improved with the addition of β-TCP. The electrochemical test result in simulation body fluid shows that the corrosion resistance of the composites was strongly enhanced comparing with that of the alloy. The corrosion potential of Mg-3Zn0.8-Zr/1.0β-TCP composite is 1.547 V and its corrosion current density is 1.20×10 6 A/cm 2 .

Introduction to Unity of Physics and Biology, Inorganic Life Materials

The unity between physics and biology refers to that the inorganic systems： the Solar System, galaxies and artificial systems have the same structures and functions as the organisms. The development of science and technology is demonstrating the intense unification trends of physics and biology and a holistic science and technology era is about to start. The physics and biology unify on the basis of the four seasons＇ law, which is the most important rule of the universe. Life is defined as the four seasons＇ whole with the structure and process of four seasons. The organism is basically structured into a dual four-season body by state-varying, state-stabilizing and control organizations. Animals, the Solar System and the earth are all the dual four-season bodies. In the unity between physics and biology, the inorganic life materials and inorganic life body can be manufactured artificially.

Physico-chemical properties and microstructure of hydroxyapatite-316L stainless steel biomaterials

Sintering shrinkage, compressive strength, bending strength, metallurgical morphology, microstructure and chemical composition diffusion of hydroxyapatite-316L stainless steel(HA-316L SS) composites were investigated. The results show that the sintering shrinkage of HA-316L SS composites decreases from 27.38% to 8.87% for cylinder sample or from 27.18% to 8.62% for cuboid sample with decreasing the volume ratio of HA to 316L SS, which leads to higher sintering activity of HA compared with that of 316L SS. The compressive strength of HA-316L SS composites changes just like parabolic curve (245.3→126.3→202.8 MPa) with reducing the volume ratio of HA to 316L SS. Bending strength increases from 86.3MPa to 124. 2 MPa with increasing the content of 316L SS. Furthermore, comprehensive mechanical properties of 1.0∶3.0 (volume ratio of HA to 316L SS) composite are optimal with compressive strength and bending strength equal to 202.8 MPa and 124.2 MPa, respectively. The (microstructure) and metallurgical structure vary regularly with the volume ratio of HA to 316L SS. Some chemical reaction takes place at the interface of the composites during sintering.

Getting the right stuff: controlling neural stem cell state and fate in vivo and in vitro with biomaterials

Stem cell therapy holds great promises in medical treatment by, e.g., replacing lost cells, re-constitute healthy cell populations and also in the use of stem cells as vehicles for factor and gene delivery. Embryonic stem cells have rightfully attracted a large interest due to their proven capacity of differentiating into any cell type in the embryo in vivo. Tissue-specific stem ceils are however already in use in medical practice, and recently the first systematic medical trials involving human neural stem cell （NSC） therapy have been launched. There are yet many obstacles to overcome and procedures to improve. To ensure progress in the medical use of stem cells increased basic knowledge of the molecular mechanisms that govern stem cell characteristics is necessary. Here we provide a review of the literature on NSCs in various aspects of cell therapy, with the main focus on the potential of using biomaterials to control NSC characteristics, differentiation, and delivery. We summarize results from studies on the characteristics of endogenous and transplanted NSCs in rodent models of neurological and cancer diseases, and highlight recent advancements in polymer compatibility and applicability in regulating NSC state and fate. We suggest that the development of specially designed polymers, such as hydrogels, is a crucial issue to improve the outcome of stem cell therapy in the central nervous system.

Thermodynamic analysis of growth of ternary Ⅲ-Ⅴ semiconductor materials by molecular-beam epitaxy

Thermodynamic models for molecular-beam epitaxy（MBE） growth of ternary Ⅲ-Ⅴ semiconductor materials are proposed.These models are in agreement with our experimental materials InGaP/GaAs and InGaAs/InP,and reported GaAsP/GaAs and InAsP/InP in thermodynamic growth.The lattice strain energy △G and thermal decomposition sensitive to growth temperature are demonstrated in the models simultaneously.△G is the function of the alloy composition,which is affected by flux ratio and growth temperature directly.The calculation results reveal that flux ratio and growth temperature mainly influence the growth process.Thermodynamic model of quaternary InGaAsP/GaAs semiconductor material is discussed also.

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.

Rejection of Permacol~ mesh used in abdominal wall repair:A case report

Permacol mesh has shown promise when used in abdominal wall repair,especially in the presence of a contaminated surgical field.This biomaterial,derived from porcine dermis collagen,has proposed advantages over synthetic materials due to increased biocompatibility and reduced foreign body reaction within human tissues.However,we present a case report describing a patient who displayed rejection to a Permacol mesh when used in the repair of abdominal wound dehiscence following an emergency laparotomy.Review of the English language literature using PubMed and Medline, showed only two previously published cases of explantation of Permacoldue to sepsis or wound breakdown. The authors believe this is the first case of severe foreign body reaction leading to rejection of Permacol.Both animal and human studies show conflicting evidence of biocompatibility.There are several reports of successful use of Permacolto repair complex incisional herniae or abdominal walls in the presence of significant contamination.It appears from the literature that Permacolis a promising material,but as we have demonstrated,it has the potential to evoke a foreign body reaction and rejection in certain subjects.

Corrosion resistance of Ti and Ti-Pd alloy in phosphate buffered saline solutions with and without H_2O_2 addition

Corrosion resistance of pure titanium（Grade 2） and Ti-Pd alloy（Grade 7） was studied using the electrochemical techniques of potentiodynamic measurements and electrochemical impedance spectroscopy（EIS）.Measurements were performed at the temperature of 36.6 ℃ in two solutions：PBS solution with pH of 7.4 simulating conditions of healthy human body,and PBS solution with pH of 5.2 and with the addition of hydrogen peroxide（0.015 mol/L） simulating the inflammatory state.It is found that,Ti Grade 7 can be a good candidate as a material for orthopedic implant application,because its corrosion resistance in the PBS solution containing H2O2 is better（lower corrosion current densities） than that of pure titanium.

Neuroendocrine and squamous colonic composite carcinoma:Case report with molecular analysis

Composite colorectal carcinomas are rare. There are amodest number of cases in the medical literature,with even fewer cases describing composite carcinoma with neuroendocrine and squamous components. There areto our knowledge no reports of composite carcinomamolecular alterations. We present a case of composite carcinoma of the splenic flexure in a 33 year-old Cau-casian male to investigate the presence and prognos-tic significance of molecular alterations in rare coloniccarcinoma subtypes. Formalin-fixed paraffin-embedded(FFPE) tissue was hematoxylin and eosin- and mucicar-mine-stained according to protocol,and immuno-stained with cytokeratin(CK) 7,CK20,CDX2,AE1/AE3,chromo-granin-A and synaptophysin. DNA was extracted from FFPE tissues and molecular analyses were performed according to lab-developed methods,followed by capil-lary electrophoresis. Hematoxylin and eosin staining showed admixed neuroendocrine and keratinized squamous cells. Positive nuclear CDX2 expression confirme dintestinal derivation. CK7 and CK20 were negative.Neuroendocrine cells stained positively for synaptophysin and AE1/AE3 and negatively for chromogranin and mucicarmine. Hepatic metastases showed a similar immunohistochemical profile. Molecular analysis revealeda G13D KRAS mutation. BRAF mutational testing wasnegative and microsatellite instability was not detected.The patient had rapid disease progression on chemotherapy and died 60 d after presentation. Although theG13D KRAS mutation normally predicts an intermed iateoutcome,the aggressive tumor behavior suggests other modifying factors in rare types of colonic carcinomas.

Microfluidic technology for multiphase emulsions morphology adjustment and functional materials preparation

Multiphase emulsions could be used as templates in considerable fields such as coating, optical materials, stan- dard particles and biomedicine. Among various emulsion forming methods, microfluidic technology, with good monodispersity, high controllability and operation simplicity, has been widely used in the preparation of multi- phase emulsions with different systems. This review would focus on the basic principles of forming multiphase emulsions, the recent progress in controlling multiphase flow in microfluidics, and preparation of functional ma- terials with microfluidics mainly by the authors＇ research group. We believe that the review will contribute to the readers in this prospective area very well. ~ 2016 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.