碳纳米管/羟基磷灰石复合材料兔胫骨生物相容性研究

目的：探讨不同比例碳纳米管/羟基磷灰石纳米复合材料兔胫骨的生物相容性.方法：将碳纳米管含量为2%和3%的碳纳米管/羟基磷灰石复合材料置入兔右侧胫骨的缺损处,在1周～12周分别进行x线检查、组织学检查及分子生物学分析.结果：不同碳纳米管含量的复合材料均能诱导成骨,无排斥反应.X线片、组织学检查、分子生物学检查均无明显差别.结论：碳纳米管/羟基磷灰石材料有良好的骨相容性.     

羟基磷灰石/单壁碳纳米管复合材料的表征

背景：羟基磷灰石具有接近自然人骨的强韧度和优越的生物相容性,但其力学性能却较差。 目的：制成并研究一种新型生物活性材料(羟基磷灰石/单壁碳纳米管复合材料)的各种性质。 方法：利用原位合成法制备羟基磷灰石单壁碳纳米管复合材料,并对其红外光谱、微观结构及XDR衍射分析,力学性能进行测试,对不同SWNT含量的SWNT/HAp复合材料弯曲强度与断裂韧性比较分析。 结果与结论：成功制备出的纳米羟基磷灰石单壁碳纳米管复合材料,其抗弯强度最大增幅将近50%,达到73 MPa;而断裂韧性的最大提高幅度为3倍,达到2.6 MPa•m^1/2。随着单壁碳纳米管复合材料含量的增加,复合材料的弯曲强度与断裂韧性呈现出缓慢上升的趋势。提示,纳米羟基磷灰石单壁碳纳米管复合材料显著提高了接近自然人骨的纳米级磷灰石骨材料的抗弯强度和断裂韧性,从而克服传统支撑骨材料的力学性能缺陷。     

羟基磷灰石/环氧树脂复合材料的制备与性能

用硅烷偶联剂对羟基磷灰石(HA)粉末进行表面改性,用改性后的HA粉末制备了HA/环氧复合材料。结果表明:硅烷偶联剂使HA在环氧树脂中的分散性明显改善。HA含量为4 0 wt%的复合材料具有良好的体外生物活性和生物相容性,并且其弯曲模量与生物骨接近,但强度低于生物骨,需要通过其它方式进行增强。     

羟基磷灰石/壳聚糖生物复合材料的制备研究进展

羟基磷灰石/壳聚糖复合材料因其生物相容性和合适的力学性能逐渐成为骨替代材料研究的热点。本文综述了羟基磷灰石/壳聚糖复合材料的研究现状,探讨了其特点、制备和性能。并在此基础上提出了此类材料今后的发展方向：三相复合材料和电、磁学性能的研究。     

两亲聚氨酯弹性体一羟基磷灰石生物复合材料

以聚己二酸乙二酯和聚乙二醇合成的两亲聚氨酯弹性体与羟基磷灰石通过凝胶法制备生物复合材料     

硬组织替换用羟基磷灰石复合材料的研究进展

羟基磷灰(HA)石具有与人骨无机质相似的化学成分和晶体结构，被认为是一种很有潜力的人体硬组织替换材料，但脆性太大限制了其在承载部位骨替换中的应用。因而各种羟基磷灰石复合材料受到了极大的关注。本文按照增强体的种类对羟基磷灰石复合材料进行了分类介绍。生物活性陶瓷、生物活性玻璃及玻璃陶瓷、生物惰性陶瓷、聚合物及金属等都被用来制备羟基磷灰石复合材料，但仍没有一种材料能够很好的满足硬组织替换的需要。现有HA复合材料存在的关键问题是生物性能与力学性能之间不能很好地匹配。     

可降解聚乳酸与羟基磷灰石复合材料的研究

目的研制一种用于松质骨骨组织修复及骨折固定的可降解聚乳酸与羟基磷灰石复合材料。方法利用均匀复合技术,制备出羟基磷灰石在聚乳酸基体中呈单颗粒的复合材料;分别对羟基磷灰石、聚乳酸的组成、分子量及复合材料的形貌、结构、力学性能等进行测试表征。结果制备性能良好的PDLLA/HA复合材料。结论可降解聚乳酸与羟基磷灰石的复合材料具有组成均匀,生物力学性能可以满足临床使用要求。     

纳米羟基磷灰石复合材料研究进展

综述了近年来纳米羟基磷灰石复合材料研究进展,并对各种方法进行了简单比较。     

羟基磷灰石生物涂层的体外溶解性研究

观察了等离子喷涂和电结晶-碱液处理羟基磷灰石涂层模拟体液中的溶解性,XRD和SEM分析表明：等离子喷涂及热处理羟基磷灰石涂层在浸泡时CaO和a-TCP逐渐消失,出现CaCO3,两种涂层的溶解性都较强;电结晶-碱液处理羟基磷灰石涂层在浸泡时成分基本不变,溶解性较弱。     

纳米相羟基磷灰石/胶原复合材料研究进展

综述羟基磷灰石（hydroxyapatite,HA）/胶原复合材料的研究进展,着重阐述自组装纳米相羟基磷灰石/胶原复合材料的制作方法、结构特点、体内植入后修复骨缺损的效果及降解过程.基于仿生学设计的纳米相羟基磷灰石/胶原复合材料,其HA纳米晶体约50～100nm,HA的C-轴沿胶原纤维排列,形成片状包绕胶原纤维束,HA和胶原分子之间为牢固的化学键性结合,为自组装的纳米结构,和自然骨中钙化的胶原相同.复合材料体内植入后降解和骨替代的过程与骨的改建过程相似.纳米相羟基磷灰石/胶原复合材料具有生物降解性高、表面能大、生物活性好、生物相容性好等特点,作为骨修复和重建材料具有更好的前景.     

The effect of detergents on the basement membrane complex of a biologic scaffold material

The basement membrane complex (BMC) is a critical component of the extracellular matrix (ECM) that supports and facilitates the growth of cells. This study investigates four detergents commonly used in the process of tissue decellularization and their effect upon the BMC. The BMC of porcine urinary bladder was subjected to 3% Triton-X 100, 8 mM 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS), 4% sodium deoxycholate or 1% sodium dodecyl sulfate (SDS) for 24 h. The BMC structure for each treatment group was assessed by immunolabeling, scanning electron microscopy (SEM) and second harmonic generation (SHG) imaging of the fiber network. The composition was assessed by quantification of dsDNA, glycosaminoglycans (GAG) and collagen content. The results showed that collagen fibers within samples treated with 1% SDS and 8 mM CHAPS were denatured, and the ECM contained fewer GAG compared with samples treated with 3% Triton X-100 or 4% sodium deoxycholate. Human microvascular endothelial cells (HMEC) were seeded onto each BMC and cultured for 7 days. Cell–ECM interactions were investigated by immunolabeling for integrin β-1, SEM imaging and semi-quantitative assessment of cellular infiltration, phenotype and confluence. HMEC cultured on a BMC treated with 3% Triton X-100 were more confluent and had a normal phenotype compared with HMEC cultured on a BMC treated with 4% sodium deoxycholate, 8 mM CHAPS and 1% SDS. Both 8 mM CHAPS and 1% SDS damaged the BMC to the extent that seeded HMEC were able to infiltrate the damaged sub-basement membrane tissue, showed decreased confluence and an atypical phenotype. The choice of detergents used for tissue decellularization can have a marked effect upon the integrity of the BMC of the resultant bioscaffold.     

土拨鼠α干扰素新亚型基因的克隆及生物学活性分析

目的 克隆土拨鼠α干扰素（IFN-α）新亚型基因，用于土拨鼠HBV模型探索IFN-α治疗慢性乙型肝炎策略；调查慢性土拨鼠肝炎病毒（woodchuck hepatitis virus，WHY）感染的土拨鼠外周血单个核细胞（PBMC）干扰素功能状况。方法 poly（I-C）体外刺激正常和慢性WHV感染的土拨鼠PBMC，分析其表达的干扰素生物学活性。利用分子克隆技术对土拨鼠IFN-α家族基因进行克隆，并对所克隆的系列基因进行测序、分型并进行真核表达后检测表达产物生物学活性。结果 poly（I-C）刺激体外培养的土拨鼠PBMC后，慢性感染土拨鼠PBMC分泌的干扰素的活性显著差异低于正常土拨鼠（P〈0．01）。获得36个土拨鼠IFN-α基因序列克隆，测序分析后，发现有10个克隆是新亚型基因，其中8个为功能基因亚型，2个为假基因亚型，病毒保护试验证明只有功能基因亚型具有生物学活性。结论 慢性WHV感染的土拨鼠细胞免疫功能受损。新的土拨鼠IFN-α亚型基因的克隆为在土拨鼠HBV动物模型上进行干扰素基因治疗和研究干扰素治疗策略提供了新的材料。     

Stretchable and sensitive sensor based on carbon nanotubes/polymer composite with serpentine shapes via molding technique

Abstract

With the rapid development of wearable devices in recent years, stretchable strain sensors based on electrically conductive composites have attracted a great deal of attention owing to their good stretchability and piezoresistivity. However, due to the intrinsic restriction of these types of composites, the conventional stretchable strain sensors cannot do well in all aspect of sensing performance. A stretchable strain sensor based on carbon nanotubes/poly(dimethylsiloxane) composite with the serpentine shape was devised and fabricated. The sensor was readily manufactured through a molding technique. Not only can this sensor distinguish tension strain from transverse or longitudinal direction, but also exhibits good linearity of response to tensile strain. In terms of sensitivity, hysteresis and response time, the stretchable strain sensor showed significant performance. The sensing performance of this proposed stretchable sensor has been demonstrated to be good in this work and it also shows a good prospect for utilization in multifunctional wearable devices.     

The management of first-line biologic therapy failures in rheumatoid arthritis: Current practice and future perspectives

The introduction of biologic disease–modifying anti-rheumatic drugs (bDMARDs) has dramatically changed the management of rheumatoid arthritis (RA). However, in a real-life setting about 30–40% of bDMARD treated patients experience drug discontinuation because of either inefficacy or adverse events. According to international recommendations, to date the best strategy for managing first-line bDMARD failures has not been defined yet and available data (especially on TNF inhibitors [TNFis]) seem to drive toward a personalized approach for the individual patient. Some TNFi partial responders may benefit from optimization of concomitant methotrexate therapy or from switching to a different concomitant sDMARD such as leflunomide. Conversely, apart from infliximab, TNFi dose escalation seems to be poor efficacious and poor cost-effective compared with alternative strategies. Albeit counterintuitive, the use of a second TNFi after the failure of the first-one (cycling strategy) is supported by clear evidences and has become widespread in the 2000s as the result of the limited alternative options till the introduction of bDMARDs with a mechanism of action other than TNF blockade. Nowadays, the use of abatacept, rituximab, tocilizumab, or JAK inhibitors as second-line agent (swapping strategy) is strongly supported by RCTs and real-life experiences. In the absence of head-to-head trials directly comparing these two strategies, meta-analyses of separated RCTs failed to find significant differences in favor of one or another choice. However, results from most observational studies, including well designed prospective pragmatic randomised analyses, demonstrated the superiority of swapping over cycling approach, whereas only few studies reported a comparable effectiveness. In this review, we aimed to critically analyze all the potential therapeutic options for the treatment of first-line bDMARD failures in order to provide a comprehensive overview of available strategies to be applied in clinical practice.     

Replication protein A: a reliable biologic marker of prognostic and therapeutic value in human astrocytic tumors

Replication protein A is a single-stranded DNA–binding protein that is required for the stabilization of single-stranded DNA and identified in replication foci where members of cyclin-dependent kinases–cyclin complexes are also present. In this study, we investigated the expression of replication protein A1 and replication protein A2 subunits of replication protein A protein in correlation with cyclins D2 and D3 and nuclear factor κB expression and assessed their prognostic significance in 66 patients with astrocytomas. Statistically significant positive associations emerged between (a) replication protein A1 and replication protein A2 protein expression (P < .0001); (b) cyclins D2 and D3 expression (P < .0001); (c) replication protein A1, replication protein A2, and cyclins D2 and D3 expression and histologic grade (P = .0001 in all correlations); (d) replication protein A1 and cyclin D2 or D3 expression (P < .0001 in both relationships); and (e) replication protein A2 and cyclin D2 or D3 expression (P < .0001 in both relationships). Nuclear factor κB1/p50 expression was positively correlated with replication protein A1, replication protein A2, and cyclins D2 and D3 expression, although these relationships failed to retain statistical significance when they were adjusted for histologic grade. Replication protein A2 expression seemed to independently affect survival in grade IV (P = .005) as well as in the entire cohort (P = .006). None of the molecules under study seemed to influence survival in lower grades (II/III), either by univariate or by multivariate analysis. In conclusion, replication protein A1, replication protein A2, and cyclins D2 and D3 seem to have a parallel role in the promotion of cell cycle in astrocytic tumors being implicated in the malignant progression of these neoplasms. Moreover, replication protein A2 protein seems to be a useful prognostic indicator in patients with astrocytomas.     

A novel method of fabricating carbon nanotubes-polydimethylsiloxane composite electrodes for electrocardiography

Polymer-based flexible electrodes are receiving much attention in medical applications due to their good wearing comfort. The current fabrication methods of such electrodes are not widely applied. In this study, polydimethylsiloxane (PDMS) and conductive additives of carbon nanotubes (CNTs) were employed to fabricate composite electrodes for electrocardiography (ECG). A three-step dispersion process consisting of ultrasonication, stirring, and in situ polymerization was developed to yield homogenous CNTs–PDMS mixtures. The CNTs–PDMS mixtures were used to fabricate CNTs–PDMS composite electrodes by replica technology. The influence of ultrasonication time and CNT concentration on polymer electrode performance was evaluated by impedance and ECG measurements. The signal amplitude of the electrodes prepared using an ultrasonication time of 12 h and CNT content of 5 wt% was comparable to that of commercial Ag/AgCl electrodes. The polymer electrodes were easily fabricated by conventional manufacturing techniques, indicating a potential advantage of reduced cost for mass production.     

聚醚醚酮／羟基磷灰石／碳纤维复合材料的组织相容性初步研究

目的对新型复合材料聚醚醚酮/羟基磷灰石/碳纤维的组织相容性进行综合性评价。方法依据GB/T 16886系列标准,应用大鼠对聚醚醚酮/羟基磷灰石/碳纤维复合材料进行急性全身毒性实验、热原实验、溶血实验及皮内反应实验。结果急性全身毒性实验,各实验组大鼠一般状况良好,各时相体质量变化差异无统计学意义（P﹥0.05）,无急性全身毒性反应,肝肾标本与对照组比较无阳性病理改变;热原实验,各组大鼠在各时间段内测得的体温变化均符合热原实验评价标准;溶血实验,复合材料浸提液的溶血百分率均低于标准规定的5%;皮内反应实验,皮下组织在各时相点水肿极轻微,无红斑形成。结论新型复合材料聚醚醚酮/羟基磷灰石/碳纤维初步研究证明具有良好的组织相容性和安全性。     

炭材料在生物医学领域的应用和进展

近年来,炭材料由于它的独特的结构、优异的性能特点在生物医学领域显示了广泛的应用前景,研究表明炭材料作为生物医学材料具有良好的生物和力学相容性,因此炭材料在生物医学领域的应用有它独特的优势。炭材料作为人工生物材料已经被广泛地研究。本文阐述了炭／炭复合材料、石墨、碳纤维、纳米碳管在生物医学领域的应用和发展前景。     

PEEK/HA复合材料热稳定性及细胞毒性试验

目的制备PEEK/HA生物复合材料,研究该材料的热性能和生物相容性。方法在缩聚合成聚醚醚酮的基础上,与10%、20%、30%的纳米羟基磷灰石混合,制成聚醚醚酮/羟基磷灰石﹙PEEK/HA﹚生物复合材料。用热重分析法研究复合材料热稳定性。采用差示扫描量热仪﹙DSC﹚研究纳米羟基磷灰石对PEEK结晶动力学的影响。GFP、RFP荧光蛋白转化的大肠杆菌,与材料一起培养,观察材料对荧光蛋白表达影响。WST-1试剂盒检测该材料对Hela细胞毒性。结果 PEEK/HA复合材料热分解起始温度在500℃以上,热稳定性好。在加入20%纳米羟基磷灰石时,聚醚醚酮复合材料的结晶活化能﹙E﹚低,易于形成结晶。PEEK/HA复合材料对原核细胞和Hela细胞无明显毒性。结论 PEEK/HA生物复合材料的热性能和生物相容性良好。