DNA-纳米多孔羟基磷灰石修饰电极用于研究DNA与亚甲基蓝的相互作用

利用溶胶-凝胶法将具有优良生物相容性和独特吸附性的羟基磷灰石(HAp)修饰在玻碳电极上形成纳米多孔薄膜. 电化学实验结果证明该纳米多孔羟基磷灰石薄膜能有效地将双链DNA吸附于其表面. 采用循环伏安法系统研究了固定在HAp薄膜上的DNA与亚甲基蓝(MB)之间的相互作用. 实验结果表明, 在20～200 mV•s^－1扫描速度范围内该电极反应过程系表面反应控制; 在pH 6.0～7.4范围内, MB在DNA修饰电极上的峰电位随pH的增加而向负方向移动; 当磷酸盐缓冲溶液中的离子强度小于59 mmol•L^－1时, MB与DNA之间为静电作用, 当离子强度大于59 mmol•L^－1时, 二者之间既有静电作用, 也有部分嵌入作用. 根据Langmuir吸附公式, 得出MB与DNA之间的结合常数为4.2×10⁴ mol^－1•L.     

羟基磷灰石/氧化锆复合涂层的水热电沉积及其性能

羟基磷灰石/氧化锆复合涂层的水热电沉积及其性能;水热电沉积;羟基磷灰石;ZrO2;结合强度;生物活性     

Electronic pressure control of gas chromatography-mass spectrometry for the confirmation of pesticide residues in cereals and related products

Summary A qualitative study using two new stationary phases (spherical aggregates of calcium phosphate hydroxy-apatite and lead phosphate hydroxyapatite) as adsorbents in high performance liquid chromatography has achieved the separation of: a standard mixture of globular proteins; colecalciferol and related compounds (produced by irradiation and heating of provitamin D₃); and a mixture of organophosphorus insecticides used in agriculture.     

Surface chemical analysis and chromatographic characterization of polyethylenimine-coated hydroxyapatite with various amount of polyethylenimine

Polyethylenimine (PEI) has been widely used as a coating material to produce stationary phase for ion-exchange chromatography of biomolecules. However, a precise study of the PEI coating fraction has been lacking, despite such quantification being very important for fundamental research as well as identifying further industrial applications.In this study, we produced four types of PEI-coated hydroxyapatite (PEI-HAp) with various fractions of PEI (0.16%, 0.5%, 1.0%, 1.5%) using a spray-drying system to evaluate correlations between coating fractions and the thermochemical or chromatographic behaviors of theses products. The thermal analyses of these matrices showed two exothermic peaks when the PEI coating fraction exceeded 1.0%. The one peak indicated a PEI decomposition peak and the other would indicate bond dissociation of PEI layers formed over the HAp surface as the PEI concentration increased. Furthermore, the chromatographic analysis for the surface chemical characteristics showed the correlation between coating fraction and the retention time of protein or nucleotide. Acidic or phosphorylated proteins were more strongly adsorbed as the PEI coating fraction increased when the initial coating fraction was low, but at fraction exceeding 0.5%, constant retention was observed. The retention time of nucleotides increased in proportion to the fraction of PEI added. The good selectivity of PEI-HAp may be attributable to multifunctional interactions of electrostatic and bare Ca sites on HAp, not just the amino sites of PEI. These precise studies of PEI coating fraction are our original novel contributions, which could be achieved by quantitative consideration using thermal analysis and chromatography.     

载银羟基磷灰石抗菌粉体和陶瓷的制备及抗菌性能

采用水热法一步合成载银羟基磷灰石抗菌粉体(Ag-HA),并将其应用于抗菌陶瓷的制备。研究结果表明水热条件下HA实际载银量与AgNO₃加入量存在较好的线性关系。XRD和TEM分析结果显示Ag-HA与HA具有相同的晶体结构,水热条件下Ag⁺取代Ca²⁺在HA晶体中的位置,生成Ag_xCa_10-x(PO₄)₆(OH)₂。Ag-HA长度随Ag⁺掺入量的增加而增大,当Ag⁺掺入量增加至1.50%时,Ag-HA由棒状生长为晶须状。选择4.50% Ag-HA作为抗菌粉体,其掺入量为9wt%时,陶瓷的抗菌率>99.9%,此时釉料中Ag₃PO₄含量为0.56%,低于目前研究中釉料中Ag₃PO₄添加量(2wt%~4wt%),不但在一定程度上解决了抗菌陶瓷产品成本较高的问题,而且满足JC/T 897-2002(抗菌陶瓷制品抗菌性能)对抗菌陶瓷抗菌性能的要求。     

Modified-Hydroxyapatite-Chitosan Hybrid Composite Interfacial Coating on 3D Polymeric Scaffolds for Bone Tissue Engineering

Three dimensional (3D) scaffolds have huge limitations due to their low porosity, mechanical strength, and lack of direct cell-bioactive drug contact. Whereas bisphosphonate drug has the ability to stimulate osteogenesis in osteoblasts and bone marrow mesenchymal stem cells (hMSC) which attracted its therapeutic use. However it is hard administration low bioavailability, and lack of site-specificity, limiting its usage. The proposed scaffold architecture allows cells to access the bioactive surface at their apex by interacting at the scaffold's interfacial layer. The interface of 3D polycaprolactone (PCL) scaffolds has been coated with alendronate-modified hydroxyapatite (MALD) enclosed in a chitosan matrix, to mimic the native environment and stupulate the through interaction of cells to bioactive layer. Where the mechanical strength will be provided by the skeleton of PCL. In the MALD composite's hydroxyapatite (HAP) component will govern alendronate (ALD) release behavior, and HAP presence will drive the increase in local calcium ion concentration increases hMSC proliferation and differentiation. In results, MALD show release of 86.28 ± 0.22. XPS and SEM investigation of the scaffold structure, shows inspiring particle deposition with chitosan over the interface. All scaffolds enhanced cell adhesion, proliferation, and osteocyte differentiation for over a week without in vitro cell toxicity with 3.03 ± 0.2 kPa mechanical strength.     

Tb掺杂的纳米羟基磷灰石生物荧光探针的合成与表征

本文在室温下用Tb(Ⅲ)对纳米羟基磷灰石(HAP)进行表面修饰制成了新型无机生物荧光探针。在十六烷基三甲基溴化铵(CTAB)参与调控下,控制适当的反应条件,可生成20 nm左右的HAP颗粒。经表面修饰后所得的Tb-HAP颗粒的尺寸范围仍在20±5 nm之间,但具有发光特性,其最大发射峰值在544 nm,且能在可见光波段(488 nm)下进行激发。生物TEM结果表明,这种20 nm左右大小的Tb-HAP可以很容易地进入兔脊髓间充质干细胞。因此,这一具有荧光特性的Tb-HAP有望成为具有良好生物兼容性的并可在细胞内稳定存在的生物无机纳米探针。     

Preparation and characterization of polyoxymethylene‐copolymer/hydroxyapatite nanocomposites for long‐term bone implants

In this work, new polyoxymethylene (POM)/hydroxyapatite (HAp) nanocomposites for long‐term bone implants have been obtained via extrusion and injection molding processes and characterized by differential scanning calorimetry (DSC), temperature‐modulated DSC (TMDSC), scanning electron microscopy (SEM), transmission electron microscopy (TEM), wide‐angle X‐ray diffraction (WAXD), Fourier transform infrared spectroscopy (FTIR), thermogravimetry (TG), and tensile mechanical and in vitro stability tests. Based on the DSC results, it was found that the degree of crystallinity increases for POM/0.5% HAp sample and decreases for POM/1.0% HAp and POM/2.5% HAp. SEM and TEM observations for POM/HAp nanocomposites indicated that the dispersion of HAp in the polymer matrix was uniform and the diameter of the HAp particles was less than 100 nm for most of them. Young's modulus increases with increasing HAp concentration, whereby elongation at break decreases. On the contrary, HAp concentration does not have a significant influence on the tensile strength. TG results show that for POM/0.5% HAp, POM/1.0% HAp, and POM/2.5% HAp, thermal stability slightly increases in comparison to pure POM, whereas for POM/5.0 HAp and POM/10.0% HAp, lower thermal stability was observed. In vitro data reveal that with an increase of HAp content, bioactivity of nanocomposites increases; a good in vitro chemical stability of POM and POM nanocomposites was confirmed. Copyright © 2011 John Wiley & Sons, Ltd.     

聚富马酸丙二醇酯/羟基磷灰石复合多孔水凝胶的制备及其矿化性能研究

采用二步法合成了可降解的聚富马酸丙二醇酯(poly(propylene fumarate),PPF),并和N-乙烯基吡咯烷酮(N-vinyl pyrrolidone,NVP)共聚,以1,4-二氧六环为溶剂,通过改变溶剂的量制备了溶胀性能不同的PPF水凝胶.采用万能力学测试仪和扫描电子显微镜分别表征了水凝胶的压缩模量和形貌结构.选择20％ PPF和10％ NVP的聚合体系,预掺3％的纳米羟基磷灰石(hydroxyapatite,HA),以氯化钠粒子为致孔剂,制备了孔径在280～450 μm的纳米复合多孔水凝胶,使其压缩模量提高了61％.模拟体液矿化10天的结果显示,磷灰石成核位点的存在和良好的与外界液体环境物质交换的能力,促进了多孔水凝胶表面磷灰石的沉积,说明HA的复合可以有效提高PPF多孔水凝胶的成骨活性.     

Photoelectron spectroscopic studies of the formation of hydroxyapatite films on 316L stainless steel pretreated with etidronic acid

The valence band and core‐level X‐ray photoelectron spectroscopy was used to probe hydroxyapatite films formed on the surface of stainless steel. These films formed on steel may find application in medical implants. The key to the successful adhesion of the hydroxyapatite films is shown to be the initial formation of a thin, oxide‐free etidronate film on the metal. It was not found possible to prepare the hydroxyapatite films directly on the metal surfaces. Since hydroxyapatite is a key component of bone and teeth, it is likely that the coated metals will have desirable biocompatible properties. The hydroxyapatite film was exposed to air, water, and 1M sodium chloride solution as representative components of the environment of the film in the human body, and these exposures led to no detectable decomposition of the film. The thin hydroxyapatite and etidronate film on the metal show differential charging effects that caused a doubling of the peaks in some core level spectra. The valence band spectra proved especially valuable in the identification of the surface chemistry of the films, and these spectra were interpreted by comparing the experimental spectra with spectra calculated using band structure calculations which showed good agreement with experiment. The calculated spectrum of etidronic acid was found to be significantly different to that of etidronate. Copyright © 2012 John Wiley & Sons, Ltd.