Effects of the interaction between hydroxyapatite nanoparticles and hepatoma cells

To gain a better understanding of the anticancer effects of hydroxyapatite(HAP) nanoparticles in vivo and in vitro, the effects of the interaction of HAP nanoparticles with hepatoma cells were explored. HAP nanoparticles were prepared by homogeneous precipitation and characterized by laser particle analysis and transmission electron microscopy(TEM). HAP nanoparticles were observed to be uniformly distributed, with rod-like shapes and diameters in the range of 42.1-87.1 nm. Overnight attached, suspended, and proliferating Bel-7402 cells were incubated with HAP nanoparticles. Inverted microscopy observation revealed that HAP nanoparticles with a cell membrane showed good adsorption. TEM demonstrated that HAP nanoparticles were present on the surface of cells, continuously taken up by cells through endocytosis, and transported in vesicles close to the nucleus. Fluorescence microscopy showed that the concentrations of intracellular Ca2+ labeled with Fluo-3 calcium fluorescent probe were significantly enhanced. In addition, inverted microscopy observation revealed that suspended cells treated with HAP nanoparticles did not adhere to the culture bottle, resulting in cell death. After the overnight attached cells were treated with HAP nanoparticles for 96 h with increasing doses of HAP nanoparticles, inverted microscopy observation revealed that cell proliferation was slowed and cell–cell adhesion was weakened. Feulgen staining and image analysis indicated that the nuclear DNA content of the cells was markedly reduced, and argyrophilic nucleolar organizer region(AgNOR) staining and image analysis indicated that the number of AgNORs was signifi cantly decreased. Therefore, hepatoma cells brought about the adsorption, uptake, transport and degradation of HAP nanoparticles. In addition, HAP nanoparticles affected hepatoma cells with regard to cell–cell adhesion, cell and extracellular matrix adhesion, and DNA and protein synthesis; thus inhibiting cell proliferation. This understanding of the effects of interaction between HAP nanoparticles and hepatoma cells is useful for further study of the anticancer mechanisms of HAP nanoparticles.     

Comparative study on lattice parameters of HAP nanoparticles with those of HAP whiskers

Hydroxyapatite whiskers are used as reinforcement for biomaterials because of their needlelike morphology and strong strength of single crystal. HAP nanoparitcles are used in drug delivery system, protein separation and anticancer drug besides their implant applications. Many new properties arise from nanoeffects while nanoeffects come from specialty of nanostructure. The Ca（NO3）2·4H2O and （NH4）2HPO4 were used as starting reagents for preparation of HAP whiskers and nanoparticles. The whiskers are 100-200 μm long while nanoparticles are 30-80 nm in size. XRD is applied to characterize the lattice parameter difference of whisker and nanoparticle. Compared with those of HAP whiskers, the a-axis and b-axis of HAP nanocrystals are shortened while the c-axis is elongated. That makes nanoparticles capable of their non-needle-like morphology, higher reaction activity and special bioeffects.     

Cytotoxinic Mechanism of Hydroxyapatite Nanoparticles on Human Hepatoma Cell Lines

1　IntroductionWiththedevelopmentofthenanometerscienceandtechnology ,theuseandstudyofthenano biomaterialsonmedicalsciencebegintoshowitsbrillianttalents .Itwasfoundthatsomeinorganicnanoparticles[1] havethenano biologicaleffectascomparedwithnon nanometer[2 ] .Whenthoseinorganicnanoparticlesaresmalltothenano level,theycaninhibittheproliferationofcancercells ,andatthesametimetheyaffectedthenormalcellslittle .Tofur therconfirmthebiologicalcharacterofthenanoparticle ,thefollowingexperimentshavebeenp…     

负载磁性氧化铁纳米粒子的脂质体的制备及评价

为了增强磁性氧化铁纳米粒子(magnetic iron oxide nanoparticles,MION)的成像效果,采用薄膜分散法制备了负载MION的脂质体(MION loaded liposome,MION -LP),并对其磁共振成像(magnetic resonance imaging,MRI)灵敏度进行了探究.制备的MION -LP的粒径为(68.82±0.16)nm, Zeta电位为(-7.81±0.82)mV; 当铁离子的质量浓度为8 μg/mL时,细胞的存活率可达到80%; 对MION -LP进行普鲁士蓝染色实验显示,在HepG2和SMMC -7721内有较多的蓝染颗粒; 体外的MRI信号随MION -LP中铁离质量浓度的增加而逐渐降低; 在荷瘤裸鼠尾静脉注射MION -LP后其肿瘤区域的T2信号强度明显下降(n=3, ^*P <0.05).综上表明,制备的可视化载体MION -LP可增加MRI成像的灵敏度,因此该研究结果可为MRI可视化载体的研究提供理论和实验依据.     

Effect of hydroxyapatite nanoparticles on K562 cells in vitro

Stable and single-dispersed hydroxyapatite （HAP） nanoparticles were synthesized with ultrasonic-assisted method. HAP nanoparticles were characterized by dynamic light scattering, XRD （X-ray diffraction） and TEM （Transmission Electron Microscopy）. The effect of HAP nanoparticles on the K562 human myelogenous leukemia cell line was investigated by MTT assay and cell count test, and the mechanism was studied through the changes of cell cycle and ultrastructure. The results showed that HAP nanoparticles inhibited the proliferation of K562 cells dramatically in vitro. HAP nanoparticles entered the cytoplasm of K562 cells and the cells were arrested at G/M phase, thus, the cells died directly.     

Synthesis,characterization and antibacterial property of strontium half and totally substituted hydroxyapatite nanoparticles

Nanoparticles of hydroxyapatite（HAP）, strontium half substituted hydroxyapatite （SrCaHAP） and strontium totally substituted hydroxyapatite （SrHAP） were prepared by sol-gel-supercritical fluid drying （SCFD） method. The nanoparticles were characterized by element content analysis, FT-IR, XRD and TEM, and the effects of strontium substitution on crystal structure, crystallinity, particle shape and antibacterial properties of the nanoparticles on Escherichia coli, Staphylococcus aureus, Lactobacillus were researched. Results show that strontium can half and totally substitute for calcium and enter the structure of apatite according to the initial atomic ratios of Sr/[Sr＋Ca] as 0.5, 1. The substitution decreases the IR wavenumbers of SrCaHAP and SrHAP, and changes the morphology of the nanoparticles from short rod shaped HAP to needle shaped SrCaHAP, and back to short rod shaped SrHAP. The crystallinity of HAP is higher than that of SrCaHAP, but is lower than that of SrHAP. Moreover, the antibacterial property of SrCaHAP and SrHAP are improved after the calcium is half and totally substituted by strontium.     

Morphologies of hydroxyapatite nanoparticles adjusted by organic additives in hydrothermal synthesis

Properties of hydroxyapatite (HA, Ca₁₀(PO₄)₆(OH)₂), including bioactivity, biocompatibility, solubility and adsorption could be tailored over wide ranges by the control of particle composition, particle size and morphology. In order to satisfy various applications, well-crystallized pure HA nanoparticles were synthesized at moderate temperatures by hydrothermal synthesis, and HA nanoparticles with different lengths were obtained by adding organic additives. X-ray diffractometry (XRD) and Fourier transform infrared (FTIR) spectrometry were used to characterize these nanoparticles, and the morphologies of the HA particles were observed by transmission electron microscopy (TEM). The results demonstrate that shorter rod-like HA particles can be prepared by adding cetyltrimethylammonium bromide (CTAB), as the additive of CTAB can block the HA crystal growth along with c-axis. And whisker HA particles are obtained by adding ethylenediamine tetraacetic acid (EDTA), since EDTA may have effect on the dissolution-reprecipitation process of HA.     

Preparation and Characterization of Nanosized Hydroxyapatite Particles in AOT Inverse Microemulsion

1　IntroductionSynthetichydroxyapatite (HAP) ,whichisthemajorconstitutionofnaturalboneandteeth ,iswell knownasbiocompatibleandbioactivematerialthathasbeenwidelyusedinmanyclinicalapplications[1 3] .Forexample ,po roushydroxyapatitehasbeenusedinbone ingrow…     

表面修饰铂的铜纳米颗粒的制备及催化性能

为探索表面修饰铂的铜纳米颗粒的催化性能,分别以硫酸铜、氯铂酸为前驱物、硼氢化钾为还原剂制备了溶剂稳定的铜和铂纳米颗粒;并以铜纳米颗粒为种子、将氯铂酸溶解其中,在以硼氢化钾为还原剂的基础上制备了表面修饰了铂的铜纳米颗粒。所制备的三种纳米颗粒均为球形,粒径分别为1.7 nm、2.1 nm、2.4 nm.在30℃、1.01×105Pa的条件下,所制备的表面修饰了铂的铜纳米颗粒在环己烯的催化加氢反应中具有比铂纳米颗粒和铜纳米颗粒更高的催化活性。     

纳米SiO2和纳米CaCO3增强混凝土强度的试验研究

为了研究纳米SiO2、纳米CaCO3对混凝土力学性能的影响,进行了混凝土抗压强度和抗劈裂强度试验.纳米SiO2以0.5%,1.0%,2.0%,3.0%,纳米CaCO3以1.0%,3.0%等量取代水泥,标准养护7,28,78,128 d后进行混凝土强度测试.结果表明:纳米SiO2以3%等量取代时可以加速混凝土中C-S-H凝胶在水化早期和二次水化反应中的形成,从而提高混凝土的抗压和劈裂强度,从经济的角度考虑纳米SiO2的最优掺量为2%;纳米CaCO3可以吸收Ca(OH)2,促进水化碳铝酸钙的生成而提高混凝土的强度,其最优掺量为3%.     

Effects of nanoparticles on devitrification and recrystallization of aqueous glycerol and PEG-600 solutions

Nanoparticles in solution offer unique electrical,mechanical and thermal properties due to their physical presence and interaction with the state of dispersion.This work is aimed to study the effects of hydroxyapatite(HA)nanoparticles on the behavior of devitrification and recrystallization of glycerol(60%w/w)and PEG-600(50%w/w)solutions during warming.HA nanoparticles of different sizes(20,40,60 nm)and concentrations(0.1%,0.5%,w/w)were incorporated into solutions,and were studied by calorimetric analysis coupled with cryomicroscopy.The presence of HA nanoparticles has little effect on the devitrification end temperatures,but affects the devitrification onset temperatures of glycerol and PEG-600 solutions.The investigation with the cryomicroscope observed that the ice morphologies of glycerol and PEG-600 solutions are dendritic and spheric respectively.The ice fraction of glycerol solution containing 0.1%HA with the size of 60 nm decreased to 2/5 of that of the solution without nanoparticles at 45°C.The ice fractions of PEG-600 solutions increased significantly between 64°C and54°C,and the ice fraction of PEG-600 solution without nanoparticles increased by 92%within the temperature range.The findings have significant implications for biomaterial cryopreservation,cryosurgery,and food manufacturing.The complexity of ice crystal growth kinetics in nanoparticle-containing solutions awaits further study.     

In vitro and in vivo characterization of homogeneous chitosan-based composite scaffolds

With a homogeneous distribution of hydroxyapatite (HAP) crystals in polymer matrix, composite scaffolds chitosan/ HAP and chitosan/collagen/HAP were fabricated in the study. XRD, SEM and EDX were used to characterize their components and structure, in vitro cell culture and in vivo animal tests were used to evaluate their biocompatibility. HAP crystals with rod-like shape embeded in chitosan scaffold, while HAP fine-granules bond with collagen/chitosan scaffold compactly. A homogenous distribution of Ca and P elements both in chitosan/HAP scaffold and chitosan/collagen/HAP scaffold was defined by EDX pattern. The presence of collagen brought a more homogenous distribution of HAP due to its higher ability to induce HAP precipitation. The results of in vitro cell culture showed that the composite’s biocompatibility was enhanced by the homogenous distribution of HAP. In vivo animal studies showed that the in vivo biodegradation was effectively improved by the addition of HAP and collagen, and was less influenced by the homogeneous distribution of HAP when compared with a concentrated distribution one. The composite scaffolds with a homogeneous HAP distribution would be excellent alternative scaffolds for bone tissue engineering.     

Size Depending Separation of HAP:Eu Nanoparticles in Dispersed Sol

1Introduction Hydroxyapatite(Ca10(PO4)6(OH)2)isanimportant biomaterialthatiswidelyusedassubstituteorfillingma terialforscleroustissuesduetoitsgoodbiocompatibility andosteoconductivity[1,2].Inordertoinvestigatethein teractionsbetweenHAPnanoparticleswithana…     

Apoptosis of Cancer Cells Induced by HAP Nanoparticles

To confirm apoptosis is one of the hepatoma cells death pathways after HAP nanoparticles absorption,hepatoma cells were collected for ultrathin sections preparation and examined under a transmission electron microscope（TEM）after 1 h incubation with HAP nanoparticle.Apoptosis was detected by TUNEL technique.After absorption.some vacuoles with membrane containing HAP nanoparticles were found in cytoplasma.The nuclear enrelope shrinked.and some area pullulated from nucleus.The karyotin became pycnosis and assembled at the edge.An apoptosis body was found.and the data of IOD and numbers of the positive apoptosic signals in nuclear area of slides could illustrate much more apoptosis in the HAP group than those in the control group（P〈0.001）.The experimental results indicate that the HAP nanoparticles can induce cancer cells apoptosis.     

Preparation and evaluation in vitro of salicylic acid-pachyman nanoparticles

Pachyman based nanoparticles loading salicylic acid as model drug (SA-PNPs) were prepared by an inverse microemulsion crosslinking approach using epichlorohydrin (ECH) as crosslinker. The effects of crosslinking reaction time, initial volume ratio of oil to aqueous phase and dosage of crosslinker on the particle size of SA-PNPs were optimized by orthogonal experimental design. SA-PNPs prepared under the optimal conditions had the average size of 230 nm and high encapsulation efficiency of 90%. The in vitro drug release was also investigated and the release data were analyzed using zero order, first order and Higuchi’s kinetics model. According to the determined coefficients, release data fitted to Higuchi’s model, which suggested that the release of SA from SA-PNPs in phosphate buffer (pH 7.4) was diffusion controlled release. The experimental results indicated that pachyman possesses a promising potential to be applied as nanocarriers for controlled drug release.     

ZrO2纳米粒子的水热合成

以锆酸四丁酯（Zr（OBu）4为原料,利用溶胶-水热法制备了ZrO2纳米粒子,分别用XRD,SEM,TEM对合成的样品进行了表征。结果表明,用水热法合成的ZrO2纳米粒子的粒径较小且均一,并且含有单斜相（Monoclinic）和四方相（Tetragonal）2种结构。     

纳米Fe基磁流体制备

文中采用直流电弧等离子体法制备了铁的纳米粒子,平均粒度小于60nm。文中选择适当的表面活性剂、载液和纳米粒子,制备了磁流体密封材料,并进行了抗酸、碱性和煤油的研究。     

碳纳米管的合成与制备

金属纳米颗粒和碳纳米管是两种重要的纳米材料,要实现碳纳米管的大批量制备,必须首先解决催化剂连续投放问题和催化剂与产物及时导出的问题.通过特殊的反应装置和工艺可以实现碳纳米管的连续制备,从而达到低成本大批量制备碳纳米管的目的.本文采用一个简单的方法合成了铁钴（Fe/Co）纳米颗粒,并采用化学气相沉积法实现了碳纳米管的批量合成,纳米颗粒的尺寸分布均匀,碳纳米管管径均匀、高纯度、结构完美.合成的碳纳米管机械强度高,同时还有独特的金属或半导体导电性.     

UV法测定聚甲基丙烯酸酯纳米粒中胰岛素的包封率

建立一种简便易行的测定聚甲基丙烯酸酯胰岛素纳米粒中游离胰岛素含量方法.用Nanosep OD100C33超滤膜分离纳米粒和游离药物,在276 nm处测定药物的吸光度,建立胰岛素含量测定方法,并对线性、回收率、精密度等指标进行考察,最后测定各种胰岛素和载体比例混合的纳米粒的包封率.结果发现,该超滤膜能较好地分离纳米粒和游离的药物,在0.11～1.10 u/mL范围内,药物在276 nm的吸光度和浓度存在良好的线性关系(r=0.999 8),线性方程为A=0.868 8C-0.001 6,高、中、低3种浓度的回收率和精密度良好.该方法操作简单、结果可靠,可用于胰岛素纳米粒中药物包封率的测定.     

微乳液法制备ZnS纳米颗粒

采用了微乳液法制备ZnS纳米颗粒.该微乳液是以Span80-Tween60为复合表面活性剂,正丁醇为助表面活性剂,120#汽油为分散介质,乙酸锌水溶液为水相的反相微乳液体系.发现该微乳液的优化配比为22g汽油,4g复合表面活性剂（Span80-Tween60配比为1.11）,正丁醇1.5mL,乙酸锌水溶液（1.2mol/L）的最大增溶量为6.3mL,在此微乳液中,逐滴加入适量Na2S水溶液并搅拌,于室温下反应30min后,对反应体系进行破乳、洗涤、分离,最后将产物浸泡在无水乙醇中,并对该产物的乙醇溶胶进行超临界干燥,得到白色疏松的纳米粉.用X射线衍射仪（XRD）和透射电子显微镜（TEM）对产物的组成、大小、形貌进行了表征,结果表明产物主要为立方晶体结构的ZnS,粒子大小均匀,粒径为10～20nm,且分散性良好.