Mesothelin抗体修饰的纳米探针对人胰腺癌细胞BxPC3的体外靶向研究

目的 探讨间皮素（Mesothelin）抗体修饰的荧光纳米Fe3O4@SiO2探针对人胰腺癌细胞BxPC3的靶向性能.方法 经St（o）ber法制备Fe3O4@SiO2磁核,再依次交联CdTe量子点和Mesothelin抗体,获得靶向荧光Fe3O4@SiO2纳米探针.在体外将荧光纳米Fe3O4@SiO2探针与BxPC3细胞共孵育30 min,以低表达Mesothelin的HepG-2和K562细胞作为对照,通过电荷耦合器件（CCD）成像系统和磁分离技术评估探针与癌细胞的靶向吸附性能.结果 制备的荧光纳米Fe3O4@SiO2探针颗粒大小均匀,粒径主要为120 ～ 140 nm.未交联抗体的探针与BxPC3、HepG-2、K562细胞的吸附效率均低于20％,为非特异性吸附.交联Mesothelin抗体的探针与BxPC3、HepG-2、K562细胞的吸附效率分别为（53.9±1.8）％、（8.0±2.1）％、（8.9±2.3）％,其与BxPC3细胞的吸附能力显著提高.结论 Mesothelin抗体修饰的纳米探针可有效识别高表达Mesothelin的BxPC3细胞.     

骨桥蛋白靶向磁性纳米探针对动脉斑块的分子成像

目的 通过构建新型骨桥蛋白（OPN）靶向的四氧化三铁（Fe3O4）纳米颗粒，实现对动脉粥样硬化斑块中平滑肌增殖的荧光成像。方法 通过?COOH和?NH2之间的脱水缩合反应将OPN抗体偶联至DMSA修饰的Fe3O4纳米颗粒表面，进而将荧光染料NHS-Cy5.5连接获得纳米成像探针。通过噻唑蓝（MTT）和TUNEL方法检测探针对巨噬细胞的毒性。动脉粥样硬化动物模型通过高脂喂养ApoE?/?小鼠20周构建成功，继而将探针（5mg Fe/kg）经小鼠尾静脉注射，24h后用小动物活体成像仪系统进行光学三维成像，离体血管的冰冻切片做Cy5.5的激光共聚焦检测。结果 MTT结果显示，加不同浓度探针孵育：0，5，10，15，20，25，30mg/L相较于对照组来说，细胞活性并未表现出差异[A490nm：（1.10±0.03），（1.05±0.03），（1.03±0.02），（0.96±0.02），（0.96±0.03），（0.93±0.03） vs （1.11±0.05），P＞0.05]；TUNEL结果显示，加不同浓度的探针孵育：0，10，20，25，30mg/L与对照组比较来说，细胞凋亡率差异无统计学意义[（21.2±1.5）%，（21.8±1.1）%，（21.5±1.2）%，（22.3±1.2）% vs （20.5±1.0）%，P＞0.05]，证实探针在我们所运用浓度范围内对细胞几乎是无毒性的。探针经尾静脉注射到动脉粥样硬化模型小鼠体内后，24h光学成像可见颈部有明显的信号，且组织切片的激光共聚焦结果显示，探针主要集中在斑块内，HE染色结果进一步显示斑块的性质。结论 本实验所构建的探针在所使用浓度范围内基本无任何明显毒性，且对动物颈部动脉粥样硬化斑块有较好的识别效果。     

VEGFR-2靶向超顺磁性氧化铁磁性纳米探针构建及肝癌细胞磁共振分子成像

目的制备血管内皮生长因子受体(VEGFR)-2靶向磁共振(MR)分子探针,探讨其对肝癌细胞的特异性靶向作用。方法采用共沉淀法制备超顺磁性氧化铁(SPIO),用壳聚糖对其表面进行修饰,耦联anti-VEGFR2抗体,制备VEGFR-2靶向MR分子探针(anti-VEGFR2-CS@SPION),以未修饰的SPIO纳米粒作为对照组。DLS法测量粒径大小、分布及Zeta电位,3.0T MR检测T2弛豫率。MTT法评价探针的安全性,通过激光共聚焦显微镜检测以及普鲁士蓝染色的方法验证探针与肝癌细胞结合的特异性。3.0T MR观察探针的体外MR成像能力。结果 SPIO和antiVEGFR2-CS@SPION的粒径分别为20.6 nm和38.4 nm;Zeta电位分别为-(20.3±1.32)m V、(3.58±1.28)m V。T2弛豫率分别为0.179×10~6M~(-1)S~(-1)、0.201×106M~(-1)S~(-1)。细胞毒性实验表明探针在高浓度下对细胞没有毒性;激光共聚焦显微镜检测显示,抗体探针与Hep G2细胞特异性结合;antiVEGFR2-CS@SPION与Hep G2细胞孵育后经普鲁士蓝染色,细胞内见较多的蓝染颗粒,而单纯SPIO组细胞内未见蓝色颗粒。体外MR成像显示,anti-VEGFR2-CS@SPION组、单纯SPIO组和空白对照组的T2值分别为(55.6±1.4)ms、(99.8±0.77)ms和(110.8±0.95)ms,差异有统计学意义(F=317.547,P<0.01)。结论壳聚糖修饰和SPIO标记的anti-VEGFR2抗体探针具有良好的生物学特性和体外肝癌细胞MR显像能力。     

葡萄糖受体介导的肿瘤靶向2-DG修饰超顺磁性氧化铁的制备及体外实验

目的 合成一种2-脱氧-D-葡萄糖(2-DG)包被γ-Fe2O3纳米探针,检测其性质特征及对前列腺癌PC3细胞葡萄糖受体的靶向性摄取.方法 运用化学共沉淀法合成γ-Fe2O3@二巯基丁二酸(DMSA),再与2-DG共轭生成γ-Fe2O3@DMSA-DG,红外光谱和透射电镜检测粒子结构特征;噻唑蓝试验(MTT)法进行细胞毒性实验,分别加入含无糖DMEM的探针培养基γ-Fe2O3@DMSA、γ-Fe2O3@DMSA-DG、γ-Fe2O3@DMSA-DG+ 2-DG(4.5 mg/mL),将探针在不同时间( 10 min、20 min、1h、2h)孵育PC3细胞,运用普鲁士兰染色法和铁三嗪法分析PC3细胞对探针的吸收情况,并以体外MRI观察T2WI信号强度变化.结果 2-DG以酰胺键连接γ-Fe2O3@DMSA,粒子平均直径10 mm;探针未见明显毒性;γ-Fe2O3@DMSA-DG可被PC3细胞靶向摄取,并可在早期被2-DG抑制.结论 本研究成功合成γ-Fe2O3@DMSA-DG探针,其对PC3细胞葡萄糖受体有较好的靶向性,使用临床型MR仪可对其进行监测.     

骨桥蛋白基因沉默对肝癌侵袭转移的抑制作用

目的 探讨应用小于扰RNA(siRNA)沉默骨桥蛋白(OPN)基因的表达对人肝癌细胞株侵袭转移的抑制作用. 方法于体外化学合成针对OPN序列特异性的舣链RNA(dsRNA),转染人肝癌细胞株(HCC LM3),用实时定量PCR和Western blot检测OPN mRNA水平和蛋白表达.通过生长曲线、克隆形成和Matrigel侵袭实验,观察肝癌细胞生物学行为的指标.统计学方法采用SPSS11.5软件进行q检验,计数资料用χ<'2>检验. 结果与空白组相比,siRNA特异性转染HCC-LM3细胞OPN mRNA水平下降84.7%,蛋白水半下降81%(P<0.5);细胞克隆形成数目下降(1.91个对比5.40个,P<0.01);穿过人工基底膜的细胞数减少(13.5个对比33.4个,P<0.05),阴性对照组的OPN mRNA与空白对照组差异无统计学意义(29.7个对比33.4个,P>0.05).结论 沉默OPN基因表达-口J在体外阻遏肝癌侵袭.     

骨桥蛋白基因沉默对肝癌侵袭转移的抑制作用

目的 探讨应用小于扰RNA(siRNA)沉默骨桥蛋白(OPN)基因的表达对人肝癌细胞株侵袭转移的抑制作用. 方法于体外化学合成针对OPN序列特异性的舣链RNA(dsRNA),转染人肝癌细胞株(HCC LM3),用实时定量PCR和Western blot检测OPN mRNA水平和蛋白表达.通过生长曲线、克隆形成和Matrigel侵袭实验,观察肝癌细胞生物学行为的指标.统计学方法采用SPSS11.5软件进行q检验,计数资料用χ<'2>检验. 结果与空白组相比,siRNA特异性转染HCC-LM3细胞OPN mRNA水平下降84.7%,蛋白水半下降81%(P<0.5);细胞克隆形成数目下降(1.91个对比5.40个,P<0.01);穿过人工基底膜的细胞数减少(13.5个对比33.4个,P<0.05),阴性对照组的OPN mRNA与空白对照组差异无统计学意义(29.7个对比33.4个,P>0.05).结论 沉默OPN基因表达-口J在体外阻遏肝癌侵袭.     

骨桥蛋白基因沉默对肝癌侵袭转移的抑制作用

目的 探讨应用小于扰RNA(siRNA)沉默骨桥蛋白(OPN)基因的表达对人肝癌细胞株侵袭转移的抑制作用. 方法于体外化学合成针对OPN序列特异性的舣链RNA(dsRNA),转染人肝癌细胞株(HCC LM3),用实时定量PCR和Western blot检测OPN mRNA水平和蛋白表达.通过生长曲线、克隆形成和Matrigel侵袭实验,观察肝癌细胞生物学行为的指标.统计学方法采用SPSS11.5软件进行q检验,计数资料用χ<'2>检验. 结果与空白组相比,siRNA特异性转染HCC-LM3细胞OPN mRNA水平下降84.7%,蛋白水半下降81%(P<0.5);细胞克隆形成数目下降(1.91个对比5.40个,P<0.01);穿过人工基底膜的细胞数减少(13.5个对比33.4个,P<0.05),阴性对照组的OPN mRNA与空白对照组差异无统计学意义(29.7个对比33.4个,P>0.05).结论 沉默OPN基因表达-口J在体外阻遏肝癌侵袭.     

骨桥蛋白基因沉默对肝癌侵袭转移的抑制作用

目的 探讨应用小于扰RNA(siRNA)沉默骨桥蛋白(OPN)基因的表达对人肝癌细胞株侵袭转移的抑制作用. 方法于体外化学合成针对OPN序列特异性的舣链RNA(dsRNA),转染人肝癌细胞株(HCC LM3),用实时定量PCR和Western blot检测OPN mRNA水平和蛋白表达.通过生长曲线、克隆形成和Matrigel侵袭实验,观察肝癌细胞生物学行为的指标.统计学方法采用SPSS11.5软件进行q检验,计数资料用χ<'2>检验. 结果与空白组相比,siRNA特异性转染HCC-LM3细胞OPN mRNA水平下降84.7%,蛋白水半下降81%(P<0.5);细胞克隆形成数目下降(1.91个对比5.40个,P<0.01);穿过人工基底膜的细胞数减少(13.5个对比33.4个,P<0.05),阴性对照组的OPN mRNA与空白对照组差异无统计学意义(29.7个对比33.4个,P>0.05).结论 沉默OPN基因表达-口J在体外阻遏肝癌侵袭.     

骨桥蛋白基因沉默对肝癌侵袭转移的抑制作用

目的 探讨应用小于扰RNA(siRNA)沉默骨桥蛋白(OPN)基因的表达对人肝癌细胞株侵袭转移的抑制作用. 方法于体外化学合成针对OPN序列特异性的舣链RNA(dsRNA),转染人肝癌细胞株(HCC LM3),用实时定量PCR和Western blot检测OPN mRNA水平和蛋白表达.通过生长曲线、克隆形成和Matrigel侵袭实验,观察肝癌细胞生物学行为的指标.统计学方法采用SPSS11.5软件进行q检验,计数资料用χ<'2>检验. 结果与空白组相比,siRNA特异性转染HCC-LM3细胞OPN mRNA水平下降84.7%,蛋白水半下降81%(P<0.5);细胞克隆形成数目下降(1.91个对比5.40个,P<0.01);穿过人工基底膜的细胞数减少(13.5个对比33.4个,P<0.05),阴性对照组的OPN mRNA与空白对照组差异无统计学意义(29.7个对比33.4个,P>0.05).结论 沉默OPN基因表达-口J在体外阻遏肝癌侵袭.     

骨桥蛋白基因沉默对肝癌侵袭转移的抑制作用

目的 探讨应用小于扰RNA(siRNA)沉默骨桥蛋白(OPN)基因的表达对人肝癌细胞株侵袭转移的抑制作用. 方法于体外化学合成针对OPN序列特异性的舣链RNA(dsRNA),转染人肝癌细胞株(HCC LM3),用实时定量PCR和Western blot检测OPN mRNA水平和蛋白表达.通过生长曲线、克隆形成和Matrigel侵袭实验,观察肝癌细胞生物学行为的指标.统计学方法采用SPSS11.5软件进行q检验,计数资料用χ<'2>检验. 结果与空白组相比,siRNA特异性转染HCC-LM3细胞OPN mRNA水平下降84.7%,蛋白水半下降81%(P<0.5);细胞克隆形成数目下降(1.91个对比5.40个,P<0.01);穿过人工基底膜的细胞数减少(13.5个对比33.4个,P<0.05),阴性对照组的OPN mRNA与空白对照组差异无统计学意义(29.7个对比33.4个,P>0.05).结论 沉默OPN基因表达-口J在体外阻遏肝癌侵袭.     

Second harmonic generating (SHG) nanoprobes for in vivo imaging

Fluorescence microscopy has profoundly changed cell and molecular biology studies by permitting tagged gene products to be followed as they function and interact. The ability of a fluorescent dye to absorb and emit light of different wavelengths allows it to generate startling contrast that, in the best cases, can permit single molecule detection and tracking. However, in many experimental settings, fluorescent probes fall short of their potential due to dye bleaching, dye signal saturation, and tissue autofluorescence. Here, we demonstrate that second harmonic generating (SHG) nanoprobes can be used for in vivo imaging, circumventing many of the limitations of classical fluorescence probes. Under intense illumination, such as at the focus of a laser-scanning microscope, these SHG nanocrystals convert two photons into one photon of half the wavelength; thus, when imaged by conventional two-photon microscopy, SHG nanoprobes appear to generate a signal with an inverse Stokes shift like a fluorescent dye, but with a narrower emission. Unlike commonly used fluorescent probes, SHG nanoprobes neither bleach nor blink, and the signal they generate does not saturate with increasing illumination intensity. The resulting contrast and detectability of SHG nanoprobes provide unique advantages for molecular imaging of living cells and tissues.     

Effects of phospholipase A2 inhibitors on Ca2+ oscillations in pancreatic acinar cells

High-affinity cholecystokinin (CCK) receptors were reported to be coupled with phospholipase A2 (PLA2)-arachidonic acid (AA) pathways to mediate Ca2+ oscillations and amylase secretion in rat pancreatic acinar cells. To investigate which types of PLA2 were involved in PLA2-AA pathways, the effects of specific inhibitors for type II and type IV PLA2 on Ca2+ oscillations and amylase secretion were studied in isolated rat pancreatic acini. An inhibitor of type IV (cytosolic) PLA2, AACOCF3 inhibited Ca2+ oscillations elicited by CCK-8 (30 pM) and JMV-180 (100 nM). AACOCF3 inhibited amylase secretion stimulated by JMV-180 and low concentrations of CCK-8 (< or =30 pM). On the other hand, an inhibitor of type II (secretory, nonpancreatic) PLA2 had no effects on Ca2+ oscillations and amylase secretion stimulated by CCK-8 and JMV-180. These results suggest that high-affinity CCK receptors are coupled to cytosolic PLA2 to mediate Ca2+ oscillations and amylase secretion in rat pancreatic acinar cells.     

Rosmarinic Acid-Loaded Polymeric Nanoparticles Prepared by Low-Energy Nano-Emulsion Templating: Formulation,Biophysical Characterization,and In Vitro Studies

Rosmarinic acid (RA), a caffeic acid derivative, has been loaded in polymeric nanoparticles made up of poly(lactic-co-glycolic acid) (PLGA) through a nano-emulsion templating process using the phase-inversion composition (PIC) method at room temperature. The obtained RA-loaded nanoparticles (NPs) were colloidally stable exhibiting average diameters in the range of 70–100 nm. RA was entrapped within the PLGA polymeric network with high encapsulation efficiencies and nanoparticles were able to release RA in a rate-controlled manner. A first-order equation model fitted our experimental data and confirmed the prevalence of diffusion mechanisms. Protein corona formation on the surface of NPs was assessed upon incubation with serum proteins. Protein adsorption induced an increase in the hydrodynamic diameter and a slight shift towards more negative surface charges of the NPs. The radical scavenging activity of RA-loaded NPs was also studied using the DPPH·assay and showed a dose–response relationship between the NPs concentration and DPPH inhibition. Finally, RA-loaded NPs did not affect the cellular proliferation of the human neuroblastoma SH-SY5Y cell line and promoted efficient cellular uptake. These results are promising for expanding the use of O/W nano-emulsions in biomedical applications.     

Bioengineered Fluorescent Nanoprobe Conjugates for Tracking Human Bone Cells: In Vitro Biocompatibility Analysis

Herein, we validated novel functionalized hybrid semiconductor bioconjugates made of fluorescent quantum dots (QD) with the surface capped by chitosan (polysaccharide) and chemically modified with O-phospho-L-serine (OPS) that are biocompatible with different human cell sources. The conjugation with a directing signaling molecule (OPS) allows preferential accumulation in human bone mesenchymal stromal cells (HBMSC). The chitosan (Chi) shell with the fluorescent CdS core was characterized by spectroscopical (UV spectrophotometry and photoluminescence), by morphological techniques (Transmission Electron Microscopy (TEM)) and showed small size (ø 2.3 nm) and a stable photoluminescence emission band. The in vitro biocompatibility results were not dependent on the polysaccharide chain length (Chi with higher and lower molecular weight) but were remarkably affected by the surface modification (Chi or Chi-OPS). In addition, the efficiency of nanoparticles uptake by the cells was dependent on cells nature (human primary cells or cell lines) and tissue source (bone or skin) in the presence or absence of the OPS modification. The complex cellular uptake pathways involved in the cell labeling with the nanoparticles do not interfere on the normal cellular biology (adhesion and proliferation), osteogenic differentiation, and gene expression. The bone cells particles uptake evaluation showed a possible pathway by Caveolin-1 that regulates cell transduction in the membrane’s Caveolae. Caveolae mediates non-specific endocytosis, and it is upregulated in HBMSC. The OPS-modified nanoparticles promoted an intense intracellular trafficking by the HBMSCs that showed late-osteoblast phenotype with an increase of extracellular matrix (ECM) mineralization (Alizarin red and Von Kossa staining for calcium phosphate crystals). In this work, the OPS modified bioconjugated QD proved to be a reliable and stable fluorescent bioprobe for cell imaging and targeting research that could also help in clarifying some cellular mechanisms of particles intracellular traffic through the cytoplasmic membrane and osteogenic differentiation induction. The in vitro HBMSC’s biocompatibility responses indicated that the OPS-modified chitosan QDs have a prospective future in laboratory and pre-clinical applications such as bioimaging analysis and for ex-vivo cellular evaluation of biomedical implants.     

Effectiveness of Se/ZnO NPs in Enhancing the Antibacterial Activity of Resin-Based Dental Composites

Biofilm formation in the resin-composite interface is a major challenge for resin-based dental composites. Using doped z nanoparticles (NPs) to enhance the antibacterial properties of resin composites can be an effective approach to prevent this. The present study focused on the effectiveness of Selenium-doped ZnO (Se/ZnO) NPs as an antibacterial nanofiller in resin composites and their impact on their mechanical properties. Pristine and Se/ZnO NPs were synthesized by the mechanochemical method and confirmed through UV-Vis Spectroscopy, FTIR (Fourier Transform Infrared) analysis, X-ray Diffraction (XRD) crystallography, Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), and Zeta analysis. The resin composites were then modified by varying concentrations of pristine and Se/ZnO NPs. A single species (S. mutans and E. faecalis) and a saliva microcosm model were utilized for antibacterial analysis. Hemolytic assay and compressive strength tests were also performed to test the modified composite resin’s cytotoxicity and mechanical strength. When incorporated into composite resin, 1% Se/ZnO NPs showed higher antibacterial activity, biocompatibility, and higher mechanical strength when compared to composites with 1% ZnO NPs. The Se/ZnO NPs has been explored for the first time as an efficient antibacterial nanofiller for resin composites and showed effectiveness at lower concentrations, and hence can be an effective candidate in preventing secondary caries by limiting biofilm formation.     

Germanium Nanoparticles Prepared by Laser Ablation in Low Pressure Helium and Nitrogen Atmosphere for Biophotonic Applications

Due to particular physico-chemical characteristics and prominent optical properties, nanostructured germanium (Ge) appears as a promising material for biomedical applications, but its use in biological systems has been limited so far due to the difficulty of preparation of Ge nanostructures in a pure, uncontaminated state. Here, we explored the fabrication of Ge nanoparticles (NPs) using methods of pulsed laser ablation in ambient gas (He or He-N₂ mixtures) maintained at low residual pressures (1–5 Torr). We show that the ablated material can be deposited on a substrate (silicon wafer in our case) to form a nanostructured thin film, which can then be ground in ethanol by ultrasound to form a stable suspension of Ge NPs. It was found that these formed NPs have a wide size dispersion, with sizes between a few nm and hundreds of nm, while a subsequent centrifugation step renders possible the selection of one or another NP size fraction. Structural characterization of NPs showed that they are composed of aggregations of Ge crystals, covered by an oxide shell. Solutions of the prepared NPs exhibited largely dominating photoluminescence (PL) around 450 nm, attributed to defects in the germanium oxide shell, while a separated fraction of relatively small (5–10 nm) NPs exhibited a red-shifted PL band around 725 nm under 633 nm excitation, which could be attributed to quantum confinement effects. It was also found that the formed NPs exhibit high absorption in the visible and near-IR spectral ranges and can be strongly heated under photoexcitation in the region of relative tissue transparency, which opens access to phototherapy functionality. Combining imaging and therapy functionalities in the biological transparency window, laser-synthesized Ge NPs present a novel promising object for cancer theranostics.     

OPN在喉癌组织中的表达变化及LV-shOPN对喉癌Hep-2细胞侵袭转移的影响

目的观察人喉鳞状细胞癌（LSCC）组织中骨桥蛋白（OPN）的表达变化及慢病毒shOPN对喉癌Hep-2细胞侵袭转移的影响。方法采用免疫组化SP法,检测44例LSCC及癌旁正常组织中的OPN。干扰OPN慢病毒载体（LV-shOPN）转染Hep-2细胞,Western blot检测该细胞其中的OPN,MTT法检测Hep-2细胞增殖活性,Transwell小室实验检测Hep-2细胞的侵袭力。结果 LSCC组织和癌旁正常组织中OPN阳性表达率分别为75.0%（33/44）、13.6%（6/44）,两者相比,P〈0.01;OPN的表达与LSCC颈部淋巴结转移、临床分期、病理组织学分级有关（P均〈0.01）。LV-shOPN转染后Hep-2细胞中OPN蛋白表达下降、细胞增殖活性及侵袭力降低（P均〈0.05）。结论 OPN在喉癌组织中的表达高于癌旁正常组织,可能参与了喉癌的发生、发展和转移;LV-shOPN能够有效抑制Hep-2细胞的生长和侵袭转移。     

Preparation of SiO2-Protecting Metallic Fe Nanoparticle/SiO2 Composite Spheres for Biomedical Application

Functionalized Fe nanoparticles (NPs) have played an important role in biomedical applications. In this study, metallic Fe NPs were deposited on SiO₂ spheres to form a Fe/SiO₂ composite. To protect the Fe from oxidation, a thin SiO₂ layer was coated on the Fe/SiO₂ spheres thereafter. The size and morphology of the SiO₂@Fe/SiO₂ composite spheres were examined by transmission electron microscopy (TEM). The iron form and its content and magnetic properties were examined by X-ray diffraction (XRD), inductively-coupled plasma mass spectrometry (ICP-MS) and a superconducting quantum interference device (SQUID). The biocompatibility of the SiO₂@Fe/SiO₂ composite spheres was examined by Cell Counting Kit-8 (CCK-8) and lactate dehydrogenase (LDH) tests. The intracellular distribution of the SiO₂@Fe/SiO₂ composite spheres was observed using TEM. XRD analysis revealed the formation of metallic iron on the surface of the SiO₂ spheres. According to the ICP-MS and SQUID results, using 0.375 M FeCl₃·6H₂O for Fe NPs synthesis resulted in the highest iron content and magnetization of the SiO₂@Fe/SiO₂ spheres. Using a dye loading experiment, a slow release of a fluorescence dye from SiO₂@Fe/SiO₂ composite spheres was confirmed. The SiO₂@Fe/SiO₂ composite spheres co-cultured with L929 cells exhibit biocompatibility at concentrations <16.25 µg/mL. The TEM images show that the SiO₂@Fe/SiO₂ composite spheres were uptaken into the cytoplasm and retained in the endosome. The above results demonstrate that the SiO₂@Fe/SiO₂ composite spheres could be used as a multi-functional agent, such as a magnetic resonance imaging (MRI) contrast agent or drug carriers in biomedical applications.