1000/类细胞膜仿生药物缓释涂层冠脉支架材料的研究

由单体2-(甲基丙烯酰氧基)乙基-2-(三甲基氨基)乙基磷酸酯(MPC)、甲基丙烯酸十八酯(SMA)、甲基丙烯酸羟丙酯(HPMA)和甲基丙烯酸(三甲氧)硅基丙酯(TSMA)合成了一种新型类细胞膜涂层材料.接触角显示聚合物/水界面向更加亲水方向转化.这种类细胞膜能防止血小板黏附,显著延长复钙化时间.将雷帕霉素作为模型药物植被药物涂层支架,动物实验表明,这种涂层支架能有效预防再狭窄的发生.     

Metabolism evaluation of biomimetic prodrugs by in vitro models and mass spectrometry

Glycerolipidic prodrug is an interesting concept to enhance lymphatic absorption of polar drugs intended to oral delivery such as didanosine (ddI). In order to improve ddI bioavailability, two didanosine glycerolipidic prodrugs, the phosphorylated (ProddIP) and the non-phosphorylated derivatives (ProddINP) were synthesized to follow triglyceride metabolism. The biomimetism approach of these prodrugs has been studied in vitro at two steps. First, liposomal formulation of each prodrug was incubated with a lipolysis model based on pancreatin and analysed using liquid chromatography combined with tandem mass spectrometry (LC–MS/MS). These experiments evidenced that both didanosine prodrugs were recognized by the lipases; as expected, they were cleaved at both positions sn-1 and sn-3 of glycerol. ProddIP was metabolised twice more rapidly than ProddINP suggesting an implication of some phospholipases in ProddIP degradation. Secondly, the detection of dideoxyadenosine triphosphate (ddA-TP) into HIV-1 infected cells after their incubation with ProddINP loaded liposomes evidenced their ability to release ddI that could penetrate into the cells and be metabolised by intracellular kinases. These results confirmed that the synthesized glycerolipidic prodrugs of didanosine could be investigated for a biomimetic approach with final aiming of increasing the drug oral bioavailability by enhancing intestinal absorption.     

Naturally derived myocardial matrix as an injectable scaffold for cardiac tissue engineering

Myocardial tissue lacks the ability to significantly regenerate itself following a myocardial infarction, thus tissue engineering strategies are required for repair. Several injectable materials have been examined for cardiac tissue engineering; however, none have been designed specifically to mimic the myocardium. The goal of this study was to investigate the in vitro properties and in vivo potential of an injectable myocardial matrix designed to mimic the natural myocardial extracellular environment. Porcine myocardial tissue was decellularized and processed to form a myocardial matrix with the ability to gel in vitro at 37 °C and in vivo upon injection into rat myocardium. The resulting myocardial matrix maintained a complex composition, including glycosaminoglycan content, and was able to self-assemble to form a nanofibrous structure. Endothelial cells and smooth muscle cells were shown to migrate towards the myocardial matrix both in vitro and in vivo, with a significant increase in arteriole formation at 11 days post-injection. The matrix was also successfully pushed through a clinically used catheter, demonstrating its potential for minimally invasive therapy. Thus, we have demonstrated the initial feasibility and potential of a naturally derived myocardial matrix as an injectable scaffold for cardiac tissue engineering.     

绣线菊二萜生物碱的研究

根据绣线菊二萜生物碱生源上来源于丝氨酸的特点，论述该类生物碱应归于真生物碱，同时提出用单萜环烯醚苷仿生合成其类似物的可能性。     

高浓度模拟体液仿生合成快速制备羟基磷灰石涂层

采用三种不同的预处理工艺对NiTi合金基体进行活化处理,利用柠檬酸作为缓冲剂配制高浓度模拟体液(Simulated body fluid,SBF)5×SBF1和5×SBF2,通过仿生合成在预处理后的NiTi合金基体上快速形成了钙磷涂层。对钙磷涂层的显微结构、组成和形貌进行了研究,结果表明:涂层呈多孔网状,由直径小于3μm的球形颗粒堆积而成,X射线衍射(XRD)测试显示其主要成分为羟基磷灰石;而缺少晶体生长抑制剂Mg2 和HCO3-的5×SBF高浓度模拟体液则明显地加快了羟基磷灰石涂层的形成。     

聚L-乳酸纤维的水解与其表面仿生化低结晶型磷灰石涂层的形成

研究了生物降解性聚L-乳酸(PLLA)纤维的水解与其表面仿生化低结晶型磷灰石涂层的形成。用扫描电镜及其附带的X光能谱、X光衍射、X光电子能谱、红外光谱等方法对磷灰石涂层的形貌、化学与结晶结构进行了表征。结果表明，用仿生法得到的磷灰石涂层，与天然骨无机成份的结构接近，为低结晶型磷灰石。PLLA的水解对磷灰石涂层的形成有一定促进作用，但对磷灰石涂层的化学与结晶结构没有影响。这种用仿生法形成的低结晶型磷灰石涂层，希望可以增加PLLA纤维作为骨修复材料时的生物活性。     

仿生溶液法制备磷灰石涂层研究新进展

仿生溶液法沉积磷灰石涂层是基于自然界硬组织生物矿化的机理,此法为制备生物材料开辟了新的途径。本文综述了采用仿生溶液法制备不同的材料涂层的工艺过程。     

矿化蚕丝基骨材料修复兔桡骨节段性骨缺损

[目的]探讨仿生制备矿化蚕丝基骨材料在修复兔节段性骨缺损中的作用.[方法]骨缺损模型的设计为：在兔双侧桡骨上各做一个大约1.5 cm的骨缺损,在一侧植入矿化蚕丝基骨材料,另一侧作为对照,未植入任何材料.观察时间阶段为术后4、8、12周.[结果]在术后4、8、12周,分别行大体观察、放射线,组织学切片观察骨缺损的愈合情况.术后12周植入矿化蚕丝基骨材料的一侧兔桡骨缺损完全愈合.对照组缺损处未见骨愈合.[结论]矿化蚕丝基骨材料是比较理想的骨缺损的替代材料.     

Stability of orosomucoid-coated polyisobutylcyanoacrylate nanoparticles in the presence of serum

Orosomucoid-coated polyisobutylcyanoacrylate nanoparticles are proposed as a biomimetic drug carrier. The stability of the orosomucoid layer adsorbed on the nanoparticle surface was evaluated in vitro in the presence of serum. Orosomucoid was determined by micellar electrokinetic capillary chromatography. Results showed that, in the presence of a concentrated fetal calf serum solution, the orosomucoid layer started to desorb after 5 min and that, after 30 min, only 25% of the initial adsorbed orosomucoid layer remained onto the nanoparticle surface. Using turbidimetry and photon correlation spectrometry, it was demonstrated that nanoparticle degradation was mainly responsible for the desorption of orosomucoid. With diluted human serum, orosomucoid desorption was reduced, which allowed the study of the effect of the orosomucoid layer on serum protein adsorption. By comparing the electropherograms of the proteins desorbed from orosomucoid-coated and uncoated nanoparticles, it was observed that orosomucoid could dramatically reduce the adsorption of serum protein onto the nanoparticles. An attempt to identify the main serum proteins adsorbed was also performed: haptoglobin and opsonins (immunoglobulin and C3 protein of complement) adsorbed onto uncoated nanoparticles, whereas only opsonins adsorbed to a lower extent onto orosomucoid-coated nanoparticles. Other unidentified proteins were also adsorbed.     

Get a grip: integrins in cell-biomaterial interactions

Integrin adhesion receptors have emerged as central regulators of cell–biomaterial interactions. This opinion paper discusses how integrins control cellular and host responses to biomaterials and new strategies to manipulate these adhesive interactions in order to elicit specific cellular responses.