Ultrathin hydroxyapatite coating on pure magnesium substrate prepared by pulsed electron ablation technique

Magnesium (Mg) as a potential material for biodegradable implants is attractive due to its mechanical similarity to the bone tissue and nontoxic corrosion products. However, the rapid corrosion rate of bare magnesium is associated with hydrogen release, which may complicate the healing process. The corrosion rate may be reduced by suitable alloying, but concurrently the biocompatibility of such alloy might be deteriorated. Another way of reduction of the corrosion rate is coating. Hydroxyapatite (HA)-based coating is considered to improve biocompatibility as well as decrease the corrosion rate by the barrier effect. In this study, ultrathin (150 nm) HA and HA containing Sr coatings are deposited via pulsed electron ablation technique on pure Mg. The microstructure of the coating was assessed by scanning electron microscopy. Electrochemical methods were used to investigate the corrosion properties of prepared coatings. The materials covered by this layer were characterized by superior corrosion behavior, with corrosion rates of coated samples up to five times lower as compared with the uncoated ones. Such coating is the thinnest coating found in the literature sources.     

Synthesis of hydroxyapatite fibers using electrospinning: A study of phase evolution based on polymer matrix

Hydroxyapatite (HA) is considered as the most promising biomaterial candidate to replace and regenerate hard tissues. A small amount of β-tricalcium phosphate (β-TCP) phase is advantageous for rapid bonding of the artificial bones to natural ones due to its high solubility compared to hydroxyapatite. Synthesizing HA nanofibers from electrospinning of sol-gel is considered as a widely researched topic. Motivation of the current work was to investigate the influence of polymeric binder in the final phase evolution after heat treatment of electrospun nanofibers. Calcium phosphate nanofibers were fabricated by electrospinning sols using gelatine and polyvinylpyrrolidone as carrier polymers and subjected to heat treatment. It was realized that carrier polymers facilitate preferential calcium phosphate phase formation by forming hydroxyapatite as major phase while PVP was used and β-TCP with HA as secondary phase while gelatine was employed. XRD and thermal analyses were performed to ascertain the reason behind this interesting behaviour.     

Nanoporous aluminum oxide affects neutrophil behaviour

This study evaluates neutrophil responses on aluminum oxide membranes. Using an in vitro cell culture system, we have found that the pore size (20 and 200 nm in diameter) of alumina membranes have a significant effect on leukocyte morphology and activation. Specifically, our results show that 20-nm pore-size membranes were more potent in triggering PMN spreading and extending of pseudopodia than 200-nm pore-size membranes. The morphological changes are also associated with cell activation. In fact, adherent neutrophils on 20-nm pore-size membranes elicit much stronger initial oxygen free radical production. Overall, our results point out that membrane pore size significantly affects the extent of cellular responses of adherent neutrophils.     

生物质能发电发展状况及炉前备料系统

介绍了国内外生物质能源产业的发展状况,分析了国内生物质能发电的必然趋势,着重阐述了各类生物质能发电炉前燃料备料系统的工艺流程,指明了生物质能发电工程技术装备的研发方向。     

Corrosion resistance of Ca-P coating induced by layer-by-layer assembled polyvinylpyrrolidone/DNA multilayer on magnesium AZ31 alloy

A hydrothermal deposition method was utilized to fabricate Ca-P composite coating induced by the layer-by-layer (LbL) assembled polyvinylpyrrolidone/deoxyribonucleic acid (PVP/DNA)₂₀ multilayer on AZ31 alloy. The surface morphology and compositions were characterized by SEM, EDS, FTIR and XRD. Besides, the corrosion resistance and degradation behavior of the coating were tested via electrochemical polarization, impedance spectroscopy and immersion measurements. Results show that the main components of Ca-P coatings are hydroxyapatite, Ca₃(PO₄)₂ and Mg₃(PO₄)₂·nH₂O. The LbL-assembled DNA and PVP promote the adsorption of Ca-P deposits on the sample surface, and structures and functional groups of the polyelectrolyte in the outermost layer are the primary influencing factor for the induction of the Ca-P coating. Carboxyl groups have the best biomineralization effect among all related functional groups. The enhanced corrosion resistance and adhesion highlight a promising use of (PVP/DNA)₂₀-induced Ca-P coatings in the field of biomedical magnesium alloys.     

钼掺杂铜硅钙石的制备及其抗菌性能和细胞相容性研究

含铜生物材料在高浓度铜离子释放时对细菌有优异的抑制作用, 但同时具有细胞毒性; 而在低浓度铜离子释放时虽然具有良好的细胞相容性, 但其抗菌性能低。因此, 开发一种含铜生物材料, 使其能够在高浓度铜离子释放情况下同时具有优异抗菌性能和良好细胞相容性, 具有重要意义。本研究利用钼和铜之间的拮抗作用原理, 采用溶胶-凝胶法制备了钼掺杂铜硅钙石, 并通过细菌平板实验和细胞活力实验评价了材料的抗菌性能和细胞相容性。实验结果显示, 钼掺杂铜硅钙石释放的高浓度铜离子(高于8.87 μg∙mL ^-1)对金黄色葡萄球菌有良好的抑制性能。同时, 由于铜钼离子的拮抗作用能降低高浓度铜离子对细胞的毒性, 钼掺杂铜硅钙石释放的铜离子在9.65 μg∙mL ^-1的高浓度下依然能保证人脐静脉内皮细胞存活率高达90%。因此, 钼掺杂可以作为含铜生物材料降低其细胞毒性的一种有效途径, 为开发低细胞毒性含铜抗菌生物材料提供了新的路径。     

几种聚乳酸／生物活性陶瓷复合材料细胞相容性的比较

采用溶解共混法制备含30%硅灰石的聚乳酸/硅灰石新型生物医用复合物膜.将大鼠成骨细胞ROS 17/28系种植在复合物表面使其存活,考察生长情况和复合物的生物活性,并与目前研究应用较多的聚乳酸/羟基磷灰石、聚乳酸/磷酸三钙及聚乳酸/珍珠层粉复合物进行比较.荧光染色实验及MTT测试表明,4种复合物膜表面细胞均可以正常的生长和增殖,且呈现出聚乳酸/珍珠层粉>聚乳酸/硅灰石>聚乳酸/羟基磷灰石>聚乳酸/磷酸三钙的结果,说明聚乳酸/硅灰石复合物材料具有较好的细胞相容性,适于应用在骨修复及骨组织工程领域.     

量子点特性及荧光标记应用

量子点是直径在1～100 ml的一类半导体纳米粒子.与传统的有机荧光标记物相比,具有独特的光谱特性和良好的光化学稳定性,是一种理想的荧光标记物.本文概述了量子点基本知识及特性、标记方法以及在生物材料荧光标记中的应用及发展前景.量子点在荧光分析领域将开辟一种新的方法,在分析领域的应用也将对生命科学研究产生重要的影响.     

Albumin-based biomaterial for lung tissue engineering applications

The role of albumin-based biomaterials in tissue engineering (TE) cannot be overemphasized. The authors review the role of albumin in lungs scaffold grafting, which promotes cell seeding. Albumin grafted on decellularized lungs scaffold is presented as a great support material for cell-tissue interaction as well as for ease in attachment, growth, and differentiation when seeded with different types of cells. Albumin scaffold fabrication from different sources is a promising approach that may facilitate medical treatments from bench-to-bed, although the role of this scaffold in lungs surfactant proteins regeneration and binding needs to be fully elucidated.     

多孔NiTi形状记忆合金研究进展

评述了近10年来国内外在多孔NiTi形状记忆合金研究和应用方面的最新进展,主要内容包括:(1)近年来多孔镍钛(NiTi)形状记忆合金的发展、微观结构特点、力学性能和功能性;(2)当前制备多孔NiTi形状记忆合金的主要方法以及优缺点;(3)多孔NiTi形状记忆合金的相变和超弹性行为,以及与致密合金的比较.最后,简要介绍了多孔NiTi形状记忆合金在生物医学领域作为人体硬组织植入和修复材料,以及智能结构和阻尼器件等方面的研究和应用前景,探讨了今后多孔NiTi形状记忆合金的研究重点.