Fabrication and characterization of hierarchical porous Ni2+ doped hydroxyapatite microspheres and their enhanced protein adsorption capacity

Hydroxyapatite (HAP) is a common bio-adsorbent, which performance depends heavily upon its morphology and microporous structure. In this study, a novel synthesis strategy was proposed for hierarchical porous HAP microspheres by a simple “one-pot” hydrothermal reaction. In the strategy, L-glutamic acid serves as soft template to modulate the morphology and inner crystalline of HAP. To evaluate the application potential, doping Ni²⁺ on hierarchical porous HAP microspheres gives metal chelated affinity adsorbents. The prepared adsorbents show a perfect spherical shape, particles size of 96.6 μm, relatively specific surface area of 48.5 m²·g^-1 and hierarchical pores (mesopores: 4 nm and macropores: 53 nm). By the adsorption evaluation, it reveals that the Ni²⁺-HAP adsorbents have high adsorption capacities of 275.11 and 97.55 m²·g^-1 for hemoglobin and bovine serum albumin, respectively, which is comparable to other similar adsorbent. Therefore, this work provides a promising method for high-efficiency hydroxyapatite microspheres for proteins purification.     

活性磷酸钙微观形貌对SAN悬浮聚合的影响

活性磷酸钙作为悬浮聚合的分散剂,在苯乙烯-丙烯腈共聚物(SAN)聚合体系中对聚合产物形貌粒径有重要影响。对活性磷酸钙(HAP)进行扫描电镜观察,发现不同来源的HAP表面形貌有较大差异。将这几种活性磷酸钙作为分散剂用于苯乙烯-丙烯腈共聚物(SAN)的悬浮聚合。对比聚合产物的粒子形貌及粒径分布,发现当HAP微观形貌为均匀竹叶形或棒状,且堆积松散时得到的聚合物粒子外观规整,粒径分布均匀。     

Synthesis and polymerizations of novel bisphosphonate‐containing methacrylates derived from alkyl α‐hydroxymethacrylates

The synthesis and polymerizations of four novel bisphosphonate‐containing monomers are reported. The monomers were synthesized from reaction of ethyl and tert‐butyl α‐bromomethacrylates with 3,3‐bis(diethoxyphosphoryl)propanoic acid or with tetraethyl 4‐hydroxybutane‐1,1‐diyldiphosphonate. Their thermal bulk polymerizations, photopolymerizations and copolymerizations with poly(ethylene glycol) methyl ether methacrylate were investigated. The homopolymerizations resulted in polymers with values of 25 000–83 000 g mol^?1; the copolymerizations yielded soluble polymers with 22–34% incorporation of the new monomers; the photopolymerizations gave some structure–reactivity correlation; and one of the homopolymers, upon hydrolysis of its bisphosphonate groups, could interact with hydroxyapatite. © 2013 Society of Chemical Industry     

Nano-HA/PLA复合材料的制备与性能评价

采用均匀沉淀法制备纳米羟基磷灰石（nano-HA）粉末.采用溶液共混-超声分散（SUD）-溶剂挥发法,制备纳米羟基磷灰石（nano-HA）/聚乳酸（PLA）复合材料薄膜,并对其均匀性、热性能等进行研究.结果表明,材料分散均匀,纳米羟基磷灰石与聚乳酸基体之间结合良好.     

聚乙烯吡咯烷酮为模板合成球状羟基磷灰石

以Ca(NO3)2.4H2O和(NH4)3PO4.3H2O为反应物,聚乙烯吡咯烷酮(PVP)为模板,成功地合成了直径为30~50nm的球状羟基磷灰石。用X射线粉末衍射(XRD)分析、傅里叶变换红外吸收光谱(FTIR)、热重-差热分析(TG-DTA)和透射电子显微镜(TEM)等手段对所制得的样品进行了表征,结果表明PVP的浓度很大程度地影响了HA的形貌。在浓度为2.0~5.0%PVP为模板的条件下可以合成直径为30~50nm的HA。球状HA形成的机理可能与PVP在溶液中的特定立体化学构象有关。     

热处理对钛基体表面电泳沉积GO/HA生物活性涂层的影响

采用电泳沉积法在钛基体表面制备氧化石墨烯(GO)/羟基磷灰石(Ca₁₀(PO₄)₆(OH)₂, HA)复合涂层,通过XRD和SEM等测试手段对不同热处理条件下得到的GO/HA涂层进行表征。研究结果表明,热处理有助于促进涂层中HA结晶度的提高,600℃和800℃的热处理温度并没有导致HA发生热分解,但有可能破坏了涂层中GO的有序晶体结构。GO/HA涂层具有优异的生物活性,但随热处理温度的升高,涂层的润湿性和生物活性下降。热处理过程有利于涂层致密,加强涂层与基体的结合,800℃热处理后的涂层结合强度高达25.31 MPa。     

纳米掺锶羟基磷灰石的制备及其抗菌性能研究

以硝酸钙、氯化锶、磷酸氢二氨等为原料,采用溶胶-凝胶-超临界流体干燥法,制备了纳米掺锶羟基磷灰石(SrHAP).通过元素含量分析、TEM、XRD、FT-IR等手段对其结构进行了表征,分析了锶的掺入对羟基磷灰石(HAP)的结构、晶形及结晶度的影响;研究了HAP掺入锶后对大肠杆菌、金黄色葡萄球菌、乳酸杆菌的抗菌性能.结果表明:采用溶胶-凝胶-超临界CO2干燥法,可制备结晶性较好的纳米HAP和Sr/[Sr Ca]原子比为0.5的纳米SrHAP;在给定的条件下,锶可以按化学计量比掺入到HAP的结构中;HAP掺入锶后,其主要官能团红外光谱吸收峰的振动频率降低,晶形从HAP的短棒状改变为SrHAP的针状,结晶度降低,对大肠杆菌、金黄色葡萄球菌、乳酸杆菌的抗菌性能提高.     

碳酸钙磷酸化工艺制备多孔球形羟基磷灰石

研究了通过磷酸化工艺制备多孔球形羟基磷灰石的可行性. 利用(NH4)2HPO4, Na2HPO4溶液或其混合溶液,在微波加热条件下对粒度约15 mm的球形碳酸钙进行磷酸化处理,通过ESEM, XRD和EDS等手段进行表征. 结果表明,在微波加热条件下,球形碳酸钙通过与HPO42-发生阴离子交换反应,可在15 min的较短时间内转化成羟基磷灰石主相. 不同组成的HPO42-处理液对微波加热转化反应的历程有显著影响,进而影响颗粒形貌、结构和物相组成. 在不同条件下可制备出从绒毛状到细小颗粒堆积体等不同形状的多孔球形羟基磷灰石.     

二氧化锆梯度复合羟基磷灰石生物材料的制备及其生物相容性

采用干铺2烧结法制备了一种以二氧化锆(ZrO₂ ) 为基体梯度复合羟基磷灰石( HAP) 的新型生物复合材料, 并对其力学性能、微观结构和生物相容性进行了研究。用扫描电镜(SEM) 、X 射线衍射仪(XRD) 、透射电镜( TEM) 和EDAX 能谱仪对粉体和复合材料进行分析。用复合材料的浸提液进行小鼠急性毒性试验、细胞毒性试验、体外溶血试验以及兔肌肉和骨内材料植入试验, 评价复合材料的生物相容性。研究结果表明, 复合材料的表面涂层厚度约80μm , 芯部基体组织与表面均匀过渡结合, 结合良好, 没有明显界面, 涂层结合强度为15. 1 MPa ,最大弯曲强度为1112. 24 MPa , KIC为7. 3～11. 4 MPa·m1/2 。其组织相容性好, 具有良好的骨传导作用, 促进骨组织生长, 是一种较理想的新型骨科植入材料。      

Medicated Scaffolds Prepared with Hydroxyapatite/Streptomycin Nanoparticles Encapsulated into Polylactide Microfibers

The preparation, characterization, and controlled release of hydroxyapatite (HAp) nanoparticles loaded with streptomycin (STR) was studied. These nanoparticles are highly appropriate for the treatment of bacterial infections and are also promising for the treatment of cancer cells. The analyses involved scanning electron microscopy, dynamic light scattering (DLS) and Z-potential measurements, as well as infrared spectroscopy and X-ray diffraction. Both amorphous (ACP) and crystalline (cHAp) hydroxyapatite nanoparticles were considered since they differ in their release behavior (faster and slower for amorphous and crystalline particles, respectively). The encapsulated nanoparticles were finally incorporated into biodegradable and biocompatible polylactide (PLA) scaffolds. The STR load was carried out following different pathways during the synthesis/precipitation of the nanoparticles (i.e., nucleation steps) and also by simple adsorption once the nanoparticles were formed. The loaded nanoparticles were biocompatible according to the study of the cytotoxicity of extracts using different cell lines. FTIR microspectroscopy was also employed to evaluate the cytotoxic effect on cancer cell lines of nanoparticles internalized by endocytosis. The results were promising when amorphous nanoparticles were employed. The nanoparticles loaded with STR increased their size and changed their superficial negative charge to positive. The nanoparticles’ crystallinity decreased, with the consequence that their crystal sizes reduced, when STR was incorporated into their structure. STR maintained its antibacterial activity, although it was reduced during the adsorption into the nanoparticles formed. The STR release was faster from the amorphous ACP nanoparticles and slower from the crystalline cHAp nanoparticles. However, in both cases, the STR release was slower when incorporated in calcium and phosphate during the synthesis. The biocompatibility of these nanoparticles was assayed by two approximations. When extracts from the nanoparticles were evaluated in cultures of cell lines, no cytotoxic damage was observed at concentrations of less than 10 mg/mL. This demonstrated their biocompatibility. Another experiment using FTIR microspectroscopy evaluated the cytotoxic effect of nanoparticles internalized by endocytosis in cancer cells. The results demonstrated slight damage to the biomacromolecules when the cells were treated with ACP nanoparticles. Both ACP and cHAp nanoparticles were efficiently encapsulated in PLA electrospun matrices, providing functionality and bioactive properties.