α半水硫酸钙复合功能化多壁碳纳米管骨修复材料生物相容性

旨在评价α半水硫酸钙复合功能化多壁碳纳米管骨修复材料的生物相容性,为后期临床实验奠定基础。分别采用兔L929成纤维细胞与材料浸提液以及材料片剂与兔骨髓基质干细胞复合培养,在不同时段运用倒置显微镜观察,MTT检测,扫描电子显微镜分析等手段,观察材料对细胞的相容性;进行急性、亚急性毒性实验,肌肉植入实验,骨植入实验等,观察材料对组织的相容性。结果表明,L929成纤维细胞在材料浸提液中生长良好,MTT检测与对照组无显著差异(P>0.05);扫描电子显微镜结果显示,细胞能在材料上黏附并增殖;体内实验表明材料对机体无毒,无致敏性,组织相容性佳。α半水硫酸钙/碳纳米管复合材料表现出的良好生物相容性,有望在骨组织工程中得到广泛运用。     

许旺细胞复合改性PLA\PGA的体外生物学研究

目的：评价小鼠许旺细胞体外复合改性聚乳酸\聚羟基乙酸（PLA\PGA）的细胞活性及生物相容性。方法：转绿色荧光蛋白基 因（GFP）小鼠的许旺细胞传代培养至第2 代,然后通过MTT 检测在不同改性技术（H2O2、NaOH、NaClO4、K2CrO4及超声波）处理 的PLA\PGA 浸提液中许旺细胞的增殖情况,检测许旺细胞在PLA\PGA表面的黏附及其细胞形态。结果：于培养1 d,3 d测得在 不同改性技术处理的PLA\PGA浸提液OD值,1 天时,各浸提液组和对照组相比无显著性差异,许旺细胞的活力及增殖无影响。3 天时,经NaClO4及K2CrO4处理的PLA\PGA 与对照组相比具有统计学差异,影响许旺细胞的增殖,对许旺细胞有毒性;荧光显微 镜下观察到许旺细胞在改性PLA\PGA 表面逐渐伸展,形成伪足,最终粘附在材料表面。结论：经H2O2、NaOH 及超声波改性 PLA\PGA无细胞毒性,具有良好的生物相容性和黏附性,可以用于组织工程化神经的构筑。     

生物降解可吸收形状记忆聚合物的生物相容性研究

目的:我们利用经美国FDA批准成为临床使用材料的聚己内酯为主要原料,发明了一种可吸收的形状记忆聚合物,添加的辅料偶联剂为烃氧基硅烷;多官能团单体选自含2个到3个烯键的有机酯,如季戊四醇三烯酸酯等;填料选用含有活性钙离子的化合物,如磷酸氢钙等,均为生物相容性良好,且可吸收的材料(专利号:200610023175).通过体外细胞学实验,对该生物降解可吸收记忆聚合物的生物相容性进行评价.方法:实验采用3T3细胞进行原代及传代培养,然后将细胞接种到两组载体上—生物降解可吸收记忆聚合物组和裸皿培养组,建立不同的3T3细胞培养系统.利用绘制细胞生长曲线、MTT比色及3H-胸腺嘧啶(3H-TdR)掺入方法观察体外培养3T3细胞在生物降解可吸收记忆聚合物载体上的活力、增殖及DNA合成情况,研究生物降解可吸收记忆聚合物载体的生物相容性.结果:在生物降解可吸收记忆聚合物和裸皿中培养时,3T3细胞的活力、增殖和代谢等生物学特性无明显差别.结论:体外细胞学实验表明这种生物降解可吸收记忆聚合物具有良好的生物相容性.     

两种体外细胞毒性检测方法的比较研究

目的比较两种常用的细胞毒性检测方法在医疗器械生物学评价中的相关性。方法分别采用MTT比色法和细胞增殖度法,在37℃条件下,将五种医疗器械／生物材料的浸提液分别与小鼠成纤维细胞（L-929）接触2天和2,4,7天,比较材料对细胞的毒性影响。结果5种不同的材料浸提液分别表现出不同程度的细胞毒性反应（0～2级）。将MTT比色法与细胞增殖度法（2天）的实验数据进行相关性分析,显示两者之间具有良好的相关性（R=0．977）。结论MTT比色法由于其检测所需的细胞量相对较少,试验步骤相对简便、检测周期短,因此具有一定的优越性,是个值得推荐的细胞毒性检测方法。     

硅磷酸钙复合骨水泥对L929细胞增殖相关基因表达的影响

制备了新型的硅磷酸钙复合骨水泥,Real-time PCR法研究了该材料对L929细胞3个细胞增殖相关基因表达的影响,并与MTT法做对比,旨在探讨从分子水平评价材料生物相容性的可能性及其作用机制。MTT结果表明,所有实验组浸提液对L929细胞均没有明显的毒性作用,一定浓度的含硅酸三钙骨水泥的浸提液能刺激细胞的增殖。Real-time PCR结果显示,不含硅酸三钙骨水泥不同浓度的浸提液培养3 h后,L929细胞CyclinD1、PCNA和SDH基因mRNA水平与对照组相比变化不大;添加50%wt硅酸三钙的骨水泥上述3个基因mRNA水平均显著增高。其中CyclinD1 mRNA水平在浸提液浓度为100%、75%和50%时,分别比对照组增加了44.74%、51.79%和43.84%;在浸提液浓度分别为75%、50%和100%、75%时,PCNA和SDH基因mRNA水平分别比对照组增加了64.60%、54.76%和45.07%、54.85%。结果提示,制备的这种新型硅磷酸钙复合骨水泥具有良好的生物活性,L929细胞CyclinD1、PCNA、SDH基因表达量的变化可以作为评价材料生物相容性的一种潜在方法。     

聚乳酸基热固性聚氨酯及其形状记忆性能

通过聚乳酸二元醇和聚乳酸-聚己内酯共聚物二元醇与六亚甲基二异氰酸酯(HDI)三聚体交联反应合成了一系列生物基热固性聚氨酯(Bio-PUs)。利用傅里叶红外(FTIR)、差示扫描量热分析(DSC)、热失重分析(TGA)、万能拉伸机和细胞毒性等测试方法对获得的聚乳酸基聚氨酯进行了表征。结果表明,与聚乳酸二元醇相比,聚乳酸-聚己内酯共聚物二元醇降低了生物基热固性聚氨酯的玻璃化温度(Tg),提高了热固性聚氨酯的热稳定性;且聚乳酸-聚己内酯型聚氨酯的力学性能和形状记忆性能更为优异。其中,聚乳酸-聚己内酯共聚物二元醇分子量为3 000时得到的热固性聚氨酯(Bio-PU2-3000)的杨氏模量为277.7 MPa,伸长率为230%;聚乳酸-聚己内酯共聚物二元醇分子量为1 000得到的热固性聚氨酯(Bio-PU2-1000)在人体体温下的形变回复时间仅为93 s。另外,通过显微镜观察到细胞在含聚乳酸基热固性聚氨酯的培养液中生长状态良好,表明制备得到的生物基聚氨酯无细胞毒性。     

新型战伤急救止血剂体外细胞毒性研究

目的:研究新型战伤急救止血剂的体外细胞毒性,初步探讨其用于战伤急救止血时的生物安全性.方法:参照我国医疗器械生物学评价标准,选用小鼠L929细胞,应用MTT法、直接接触培养法、流式细胞检测细胞凋亡法、扫描电镜直接观察细胞生长状况等检测新型战伤急救止血剂的细胞毒性.结果:新型战伤急救止血剂细胞毒性为0-1级,符合我国医疗器械评价标准毒性分级标准,各浓度组与阴性对照组无差异,P＞0.05;L929细胞与沸石直接接触生长良好,流式细胞仪检测细胞凋亡率与阴性对照组无差异;扫描电镜观察在沸石表面生长良好.结论:复合新型战伤急救止血剂细胞相容性良好,符合我国医疗器械安全性评价标准,是一种安全、高效、多功能的战伤止血剂.     

皮肤细胞复合改性聚乳酸构建组织工程皮肤

目的:探讨以改性聚乳酸为细胞外基质网架构建组织工程皮肤的可行性。方法:采用盐溶法制备机械性能得到部分改进的聚乳酸多孔泡沫网架,向改进的聚乳酸网架接种真皮成纤维细胞和表皮角质形成细胞,以普通聚乳酸支架作为对照,构建组织工程皮肤。体外培养一周,对网架进行形态学观察。主要观察指标:①一般形态观察②组织学观察。结果:复层组织工程皮肤在结构上与正常皮肤相似,具有真皮、表皮双层结构。改性聚乳酸网架上有双层细胞生长,生长的细胞与网架接触,并且在其表面形成较为明显而连续的细胞层。随着培养时间的延长,发生了一系列变化:表皮部分细胞层数逐渐增多,真皮部分细胞也逐渐增多,并向表皮层深入,位于表皮与网架之间。结论:双醛淀粉作为良好的增柔剂在改善聚乳酸网架的机械性能的同时,也具有良好的细胞相容性,不影响细胞的生长增殖和代谢,可以进一步用作组织工程皮肤的支架材料。     

形状记忆聚合物在组织工程中的应用

形状记忆聚合物是由固定相和可逆相构成的具有在外界刺激条件下诱导形状改变特性的一类高分子智能材料。相较于传统的形状记忆合金与陶瓷,其具有特定的生物可降解性、更高的机械性能调控空间、更强的形变恢复能力及更优良的生物相容性。凭借材料特性,近阶段针对形状记忆聚合物在组织工程领域的应用研究愈发广泛,包括血管组织、骨骼肌组织、神经组织与骨组织等方面。综述近年来形状记忆聚合物在多种组织工程领域研究中的实验创新、技术突破与应用拓展,例如将其作为新型多孔血管支架、骨骼肌修复支架、神经修复导管与骨缺损填充物等。可预见随着技术和材料的不断发展,形状记忆聚合物在组织工程领域的应用将更加成熟。     

合浦珠母贝珍珠的生物学性能初步检测

本研究报道了合浦珠母贝珍珠的生物学性能初步检测结果。珍珠作为—种天然的生物材料。在医药、化妆品工业等领域中的应用已很广泛。本研究对合浦珠母贝珍珠进行了体外细胞毒性试验、溶血试验和经静脉全身急性毒性试验的研究。实验结果表明,合浦珠母贝珍珠具有较好的细胞相容性,其浸提液对实验动物无明显毒性。在本研究中,合浦珠母贝珍珠的浸提液对兔血红细胞的溶血指数高于对照组。     

人手指柔性触觉感知的记忆特性

触觉再现技术是当前虚拟现实和远程操作机器人领域的前沿,而柔性触觉则是其重要的研究内容。触觉再现接口的设计需要充分研究人手的触觉感知特性。本文在柔性触觉装置上研究了人手指柔性触觉记忆特性。先通过回忆性实验确定人手指的柔性触觉记忆容量,在记忆容量范围内又进行了再认性实验,对人手指的柔性触觉记忆反应时间进行分析。本实验方法简单有效,得出的结论不仅可以用来改进触觉再现装置的设计,而且为触觉再现技术的研究提供了生理学依据。     

Biobased poly(propylene sebacate) as shape memory polymer with tunable switching temperature for potential biomedical applications

From the point of better biocompatibility and sustainability, biobased shape memory polymers (SMPs) are highly desired. We used 1,3-propanediol, sebacic acid, and itaconic acid, which have been industrially produced via fermentation or extraction with large quantities as the main raw materials for the synthesis of biobased poly(propylene sebacate). Diethylene glycol was used to tailor the flexibility of the polyester. The resulted polyesters were found to be promising SMPs with excellent shape recovery and fixity (near 100% and independent of thermomechanical cycles). The switching temperature and recovery speed of the SMPs are tunable by controlling the composition of the polyesters and their curing extent. The continuously changed switching temperature ranging from 12 to 54 °C was realized. Such temperature range is typical for biomedical applications in the human body. The molecular and crystalline structures were explored to correlate to the shape memory behavior. The combination of potential biocompatibility and biodegradability of the biobased SMPs makes them suitable for fabricating biomedical devices.     

Watchband‐Like Supercapacitors with Body Temperature Inducible Shape Memory Ability

Smart watches have gained worldwide popularity because they can integrate diverse functions all in one. However, their energy storage devices currently being used are placed in the watches, and this design seriously limited the energy support ability and the future boost space. Herein, for the first time, a strategy to integrate energy storage device with watchband is put forward, which is realized by the preparation of watchband‐like solid‐state supercapacitors using graphene coated on TiNi alloy flake as the negative electrode, ultrathin MnO₂/Ni film as the positive electrode, and different gel electrolytes as the separator. Statical and dynamical bending tests both verify that the as‐fabricated devices have excellent electrochemical performance reliability during bending process. The devices also exhibit the distinctive shape memory ability owing to the use of TiNi shape memory alloy. As a state of the art, such a watchband‐like supercapacitor is connected with an electronic watch to show its potential application. Interestingly, this “watchband” can not only support power to the watch, but also can maintain the shape memory property which can be automatically induced by touching it with the human wrist. In addition, it exhibits excellent biocompatibility. Thus, the smart supercapacitor is qualified for a promising candidate for the next‐generation smart watches.     

Shape memory of human red blood cells

The human red cell can be deformed by external forces but returns to the biconcave resting shape after removal of the forces. If after such shape excursions the rim is always formed by the same part of the membrane, the cell is said to have a memory of its biconcave shape. If the rim can form anywhere on the membrane, the cell would have no shape memory. The shape memory was probed by an experiment called go-and-stop. Locations on the membrane were marked by spontaneously adhering latex spheres. Shape excursions were induced by shear flow. In virtually all red cells, a shape memory was found. After stop of flow and during the return of the latex spheres to the original location, the red cell shape was biconcave. The return occurred by a tank-tread motion of the membrane. The memory could not be eliminated by deforming the red cells in shear flow up to 4 h at room temperature as well as at 37 degrees C. It is suggested that 1). the characteristic time of stress relaxation is >80 min and 2). red cells in vivo also have a shape memory.     

Biophoton emission of human body

For the first time systematic measurements of the "ultraweak" photon emission of the human body (biophotons) have been performed by means of a photon detector device set up in darkness. About 200 persons have been investigated. In a particular case one person has been examined daily over several months. It turned out that this biophoton emission reflects, (i) the left-right symmetry of the human body; (ii) biological rhythms such as 14 days, 1 month, 3 months and 9 months; (iii) disease in terms of broken symmetry between left and right side; and (iv) light channels in the body, which regulate energy and information transfer between different parts. The results show that besides a deeper understanding of health, disease and body field, this method provides a new powerful tool of non-invasive medical diagnosis in terms of basic regulatory functions of the body.     

Regulatory initiatives for natural latex allergy: US perspectives

The US Food and Drug Administration (FDA) has regulatory authority over foods, human drugs, cosmetics, medical devices, radiological products, biologics, and veterinary products. Among these products, FDA believes that the use of medical devices, including medical gloves, condoms, catheters, and breathing bags, represents the greatest source of natural latex proteins to exposed individuals. A medical device is defined in the Federal Food Drug and Cosmetic Act (FFDCA) as an instrument, apparatus, implement, machine, etc., that is intended for use in the diagnosis or treatment of disease or is intended to affect the structure or any function of the body of a human or other animal, and that does not achieve any of its principal intended purposes through chemical action in the body. This article provides some brief, general background about FDA's medical device regulatory process and then addresses the issue of natural latex allergy. Finally we discuss the steps the Agency has taken to evaluate the magnitude and nature of the problem, and FDA's efforts to assist manufacturers, health professionals, and others in minimizing exposure and sensitization to natural latex proteins in medical devices.     

Precision medicine in human heart modeling

Precision medicine is a new frontier in healthcare that uses scientific methods to customize medical treatment to the individual genes, anatomy, physiology, and lifestyle of each person. In cardiovascular health, precision medicine has emerged as a promising paradigm to enable cost-effective solutions that improve quality of life and reduce mortality rates. However, the exact role in precision medicine for human heart modeling has not yet been fully explored. Here, we discuss the challenges and opportunities for personalized human heart simulations, from diagnosis to device design, treatment planning, and prognosis. With a view toward personalization, we map out the history of anatomic, physical, and constitutive human heart models throughout the past three decades. We illustrate recent human heart modeling in electrophysiology, cardiac mechanics, and fluid dynamics and highlight clinically relevant applications of these models for drug development, pacing lead failure, heart failure, ventricular assist devices, edge-to-edge repair, and annuloplasty. With a view toward translational medicine, we provide a clinical perspective on virtual imaging trials and a regulatory perspective on medical device innovation. We show that precision medicine in human heart modeling does not necessarily require a fully personalized, high-resolution whole heart model with an entire personalized medical history. Instead, we advocate for creating personalized models out of population-based libraries with geometric, biological, physical, and clinical information by morphing between clinical data and medical histories from cohorts of patients using machine learning. We anticipate that this perspective will shape the path toward introducing human heart simulations into precision medicine with the ultimate goals to facilitate clinical decision making, guide treatment planning, and accelerate device design.

     

Estimation of aneurysm wall stresses created by treatment with a shape memory polymer foam device

In this study, compliant latex thin-walled aneurysm models are fabricated to investigate the effects of expansion of shape memory polymer foam. A simplified cylindrical model is selected for the in-vitro aneurysm, which is a simplification of a real, saccular aneurysm. The studies are performed by crimping shape memory polymer foams, originally 6 and 8 mm in diameter, and monitoring the resulting deformation when deployed into 4-mm-diameter thin-walled latex tubes. The deformations of the latex tubes are used as inputs to physical, analytical, and computational models to estimate the circumferential stresses. Using the results of the stress analysis in the latex aneurysm model, a computational model of the human aneurysm is developed by changing the geometry and material properties. The model is then used to predict the stresses that would develop in a human aneurysm. The experimental, simulation, and analytical results suggest that shape memory polymer foams have potential of being a safe treatment for intracranial saccular aneurysms. In particular, this work suggests oversized shape memory foams may be used to better fill the entire aneurysm cavity while generating stresses below the aneurysm wall breaking stresses.