Recent Progress in Superparamagnetic Iron Oxide Nanoparticles

Superparamagnetic iron oxide nanoparticles(SPIONs)have immeasurable potentials in many fields such as nanobiotechnology and biomedical engineering because of their superparamagnetic properties and small particle size.This review introduces the methods for SPIONs synthesis,including co-precipitation,thermal decomposition,microemulsion and hydrothermal reaction,and surface modification of SPIONs with organometallic and inorganic metals,surface modification for targeted drug delivery,and the use of SPIONs as a contrast agent.In addition,this article also provides an overview of recent progress in SPIONs for the treatment of glioma,lung cancer and breast cancer.

Preparation of Superparamagnetic Dextran-coated Iron Oxide Nanoparticles used as a Novel Gene Carrier into Human Bladder Cancer Cells'

Objective: Application of magnetic nanoparticles as gene carrier in gene therapy has developed quickly. This study was designed to investigate the preparation of superparamagnetic dextran-coated iron oxide nanoparticles (SDION) and the feasibility of SDION used as a novel gene carrier for plasmid DNA in vitro. Methods: SDION were prepared by chemical coprecipitation and separated by gel filtration on Sephacryl S-300HR, characterized by TEM, laser scattering system and Vibrating Sample Magnetometer Signal Processor. The green fluorescent protein (pGFP-C2) plasmid DNA was used as target gene. SDION-pGFP-C2 conjugate compounds were produced by means of oxidoreduction reaction. The connection ratio of SDION and pGFP-C2 DNA was analyzed and evaluated by agarose electrophoresis and the concentration of pGFP-C2 in supernatant was measured. Using liposome as control, the transfection efficiency of SDION and liposome was respectively evaluated under fluorescence microscope in vitro. Results: The diameter of SDION ranges from 3 nm to 8 nm, the effective diameter was 59.2 nm and the saturation magnetization was 0.23 emu/g. After SDION were reasonably oxidized, SDION could connect with pGFP-C2 to a high degree. The transfection efficiency of SDION as gene carrier was higher than that of liposome. Conclusion: The successes in connecting SDION with pGFP-C2 plasmid by means of oxidoreduction reaction and in transferring pGFP-C2 gene into human bladder cancer BIU-87 cells in vitro provided the experimental evidence for the feasibility of SDION used as a novel gene carrier.

Biodistribution and Toxicity Assessment of Superparamagnetic Iron Oxide Nanoparticles In Vitro and In Vivo

Biodistribution and toxicity assessment are critical for safe clinical use of newly developed medicines.Superparamagnetic iron oxide nanoparticles (SPION)are effective carriers for targeted drug delivery.This study aimed to examine the toxicity and biodistribution of SPION coated with polyethylenimine (PEI)(SPION-PEI)designed for small interfering RNA (siRNA) delivery both in vitro and in vivo.SPION-PEI/siRNA complexes were prepared at different weight ratios.Cytotoxic effects of SPION-PEI/siRNA on HSC-T6 cell viability were determined by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT).Rats were divided into three groups:a control group,a normal-saline group and a SPION-PEI/siRNA group.After a single intravenous injection,in vivo nanoparticle biodistribution and accumulation were evaluated by Prussian blue staining in the heart,liver,spleen,lung and kidney 8 h,24 h,and 7 days after the injection.Their distribution was histologically studied at the three time points by measuring ironpositive areas (μm2)in organ sections stained with Prussian blue.The same organs were analyzed by H&E staining for any possible histopathological changes.Furthermore,biochemical indexes such as alanine amino transaminase (ALT),aspartate transaminase (AST),blood urea nitrogen (BUN)and creatinine (CREA)were also assessed at all experimental time points.Electrophoresis exhibited that the SPION-PEI could retard siRNA altogether at weight ratios above 4.MTT assay showed that SPION-PEI loaded with siRNA had low cytotoxicity.In vivo study revealed that the liver and spleen were the major sites of SPION-PEI/siRNA deposition.The iron content was significantly increased in the liver and spleen,peaking 24 h after intravenous injection and then declining gradually.No evidence was found of irreversible histopathological damage to any of the organs tested.These results suggested that most SPION-PEI/siRNA complexes were distributed in the liver and spleen,which might be the target organs of SPION-PEI/siRNA complexes.SPION- PEI/siRNA may serve as in vivo carrier for biomedical medicines.

Toxicity of superparamagnetic iron oxide nanoparticles: Research strategies and implications for nanomedicine

Superparamagnetic iron oxide nanoparticles （SPIONs） are one of the most versatile and safe nanoparticles in a wide variety of biomedical applications. In the past decades, considerable efforts have been made to investigate the potential adverse biological effects and safety issues associated with SPIONs, which is essential for the development of next-generation SPIONs and for continued progress in translational research. In this mini review, we summarize recent developments in toxicity studies on SPIONs, focusing on the relationship between the physicochemical properties of SPIONs and their induced toxic biological responses for a better toxicological understanding of SPIONs.

Magnetic labeling of primary murine monocytes using very small superparamagnetic iron oxide nanoparticles

Due to their very small size,nanoparticles can interact with all cells in the central nervous system.One of the most promising nanoparticle subgroups are very small superparamagnetic iron oxide nanoparticles(VSOP)that are citrate coated for electrostatic stabilization.To determine their influence on murine blood-derived monocytes,which easily enter the injured central nervous system,we applied VSOP and carboxydextran-coated superparamagnetic iron oxide nanoparticles(Resovist).We assessed their impact on the viability,cytokine,and chemokine secretion,as well as iron uptake of murine blood-derived monocytes.We found that(1)the monocytes accumulated VSOP and Resovist,(2)this uptake seemed to be nanoparticle-and time-dependent,(3)the decrease of monocytes viability was treatment-related,(4)VSOP and Resovist incubation did not alter cytokine homeostasis,and(5)overall a 6-hour treatment with 0.75 mM VSOP-R1 was probably sufficient to effectively label monocytes for future experiments.Since homeostasis is not altered,it is safe to label blood-derived monocles with VSOP.VSOP labeled monocytes can be used to study injured central nervous system sites further,for example with drug-carrying VSOP.

Superparamagnetic iron oxide nanoparticles: promote neuronal regenerative capacity?

Currently,we know that neuronal outgrowth during development and regeneration requires a complex interaction of intra-and extracellular molecules such as growth factors,neurotransmitters and extracellular matrix proteins（O’Donnell et al.,2009）.Furthermore,the discovery of a broad spectrum of growth-promoting cues has led to novel concepts for thera-peutic strategies.

Fluorescence detection of Europiumdoped very small superparamagnetic iron oxide nanoparticles in murine hippocampal slice cultures

In the late 1980s,superparamagnetic iron oxide nanoparticles（SPIO）moved into focus as contrast agents in magnetic resonance imaging（MRI）,due to their strong relaxivity and resulting higher resolution of images.At the time,no one anticipated their high potential in basic research or for medical diagnostic andtreatment. Since then, SPIO have been evaluated notonly as spe- cific markers for MRI, but also for cell labeling and tracking （Li et al., 2013）.

Synthesis and application of superparamagnetic iron oxide nanoparticles in targeted therapy and imaging of cancer

Superparamagnetic iron oxide(SPIO)nanoparticles have become a popular strategy of cancer treatment and molecular imaging because of their versatile properties and biocompatibility.A variety of studies have shown the exciting potential of functionalized SPIO nanoparticles,such as surface-coated,targeted ligandconjugated,and/or drug-loaded SPIO nanoparticles,as powerful tools for targeted imaging and therapy.Moreover,the applications of SPIO nanoparticles that integrate diagnosis and therapy in SPIO nanoparticles facilitate the monitoring of therapeutic efficacy during treatment.In the present review,we primarily concentrate on the recent advancements in the field of SPIO nanoparticles in terms of synthesis,targeted therapy,and cancer imaging.

MRI tracking of human Wharton’s jelly stem cells seeded onto acellular dermal matrix labeled with superparamagnetic iron oxide nanoparticles in burn wounds

Background:In vivo cell tracking after transplantation in regenerative medicine remains an unmet challenge and limits current understanding of the wound healing mechanism through cell-based therapies.This study investigated tracking of human Wharton’s jelly stem cells(hWJSCs)seeded onto an acellular dermal matrix(ADM)and labeled with superparamagnetic iron oxide nanoparti-cles(SPIONs)by magnetic resonance imaging(MRI)in burn injury.Method:The hWJSCs were characterized and assessed for growth kinetics.A total of 30 rats were enrolled in three equal groups.Group 1 underwent scald burn injury left without treatment,the group 2 was treated by an ADM that was prepared from cosmetic surgery skin samples and the group 3 received hWJSCs labeled with SPIONs seeded onto an ADM.Tensile strength was evaluated before and after interventions,real time PCR assessed apoptosis,and Prussian blue staining,scanning electron microscopy(SEM)and MRI were used for the tracking of labeled cells.Results:The hWJSCs exhibited mesenchymal stem cell properties.Population doubling time was 40.1 hours.SPIONs did not show any toxic effect.The hWJSCs seeded onto an ADM decreased Bax and increased Bcl-2 gene expression.Internalization of SPIONs within hWJSCs was confirmed by Prussian blue staining,SEM and MRI until day 21.There was a significant difference between the Young’s moduli of normal skin and the group receiving hWJSCs seeded onto an ADM.Histological observations and SEM imaging confirmed that MRI is an accurate method to track SPION-labeled hWJSCs in vivo.Conclusions:This study showed that SPION labeling coupled with MRI can be used to further understand the fate of stem cells after transplantation in a burn model.

Superparamagnetic iron oxide nanoparticle targeting of adipose tissue-derived stem cells in diabetes-associated erectile dysfunction

Erectile dysfunction （ED） is a major complication of diabetes, and many diabetic men with ED are refractory to common ED therapies. Adipose tissue-derived stem cells （ADSCs） have been shown to improve erectile function in diabetic animal models. However, inadequate cell homing to damaged sites has limited their efficacy. Therefore, we explored the effect of ADSCs labeled with superparamagnetic iron oxide nanoparticles （SPIONs） on improving the erectile function of streptozotocin-induced diabetic rats with an external magnetic field. We found that SPIONs effectively incorporated into ADSCs and did not exert any negative effects on stem cell properties. Magnetic targeting of ADSCs contributed to long-term cell retention in the corpus cavernosum and improved the erectile function of diabetic rats compared with ADSC injection alone. In addition, the paracrine effect of ADSCs appeared to play the major role in functional and structural recovery. Accordingly, magnetic field-guided ADSC therapy is an effective approach for diabetes-associated ED therapy.

Magnetic nanoparticles conjugated with “RPE cell-MCP-1 antibody-VEGF antibody” compounds for the targeted therapy of age-related macular degeneration: a hypothesis

Age-related macular degeneration（AMD） is the leading cause of vision loss in the elderly throughout the world. Treatment of AMD utilizing retinal pigment epithelium（RPE） transplantation represents a promising therapy. However, simplex RPE transplantation can only replace the diseased RPE cells, but has no abilities to stop the development of AMD. It has been indicated that oxidization triggers the development of AMD by inducing the dysfunction and degeneration of RPE cells, which results in the upregulation of local monocyte chemotactic protein-1（MCP-1） expression. MCP-1 induces macrophage recruiment which triggers local inflammation. As a result, the expression of vascular endothelial growth factor（VEGF） is upregulated by MCP-1mediated inflammation and results in the formation of choroidal neovascularization（CNV）. We accordingly propose a targeted therapy of AMD by subretinal transplanting the compound of RPE cell, MCP-1 antibody, and VEGF antibody and using a magnetic system to guide RPE cell compounds conjugated with superparamagnetic iron oxide nanoparticles（SPIONs）. Furthermore, SPION-labelled RPE cells can be tracked and detected in vivo by non-invasive magnetic resonance imaging（MRI）. This novel RPE cell transplantation methodology seems very promising to provide a new therapeutic approach for the treatment of AMD.

A biotechnological perspective on the application of iron oxide nanoparticles

In recent decades, magnetic iron nanoparticles （NPs） have attracted much attention due to properties such as superparamagnetism, high surface area, large surface-to-volume ratio, and easy separation under external magnetic fields. Therefore, magnetic iron oxides have potential for use in numerous applications, including magnetic resonance imaging contrast enhancement, tissue repair, immunoassay, detoxification of biological fluids, drug delivery, hyperthermia, and cell separation. This review provides an updated and integrated focus on the fabrication and characterization of suitable magnetic iron NPs for biotechnological applications. The possible perspective and some challenges in the further development of these NPs are also discussed.

磁响应水凝胶在骨组织工程中的作用与优势

背景:磁响应水凝胶在骨组织工程中具有极大的优势,有利于微创、高效地促进成骨。目的:阐述磁响应水凝胶在骨组织工程领域的应用进展。方法:检索PubMed、Web of Science、万方和中国知网数据库检索相关文献,英文检索词为“Magnetic Hydrogels,Magnetic Nanoparticles,Superparamagnetic Nanoparticles,Fe3O4,SPIONs,Magnetic Fields,Bone Regeneration,Bone Repair,Bone Tissue Engineering”;中文检索词为“磁性水凝胶、磁性纳米粒子、超顺磁性氧化铁纳米粒、磁场、氧化铁纳米粒、骨再生、骨重建、骨修复、骨组织工程”,根据纳入与排除标准对所有文章进行初筛后,最终纳入60篇文章进行综述。结果与结论:①近年来由于磁性纳米粒子的出现,大量的磁响应支架材料被开发出来,其中,含有氧化铁纳米粒子和超顺磁性氧化铁纳米粒子的磁响应水凝胶力学性能突出、生物相容性良好,能够快速响应外部磁场,为种子细胞提供成骨所需的磁机械信号。②磁响应水凝胶可以作为载体精准调控生长因子的释放时机。③基于磁响应水凝胶的三维微环境培养平台下,磁响应水凝胶与细胞之间的界面磁力能够激活细胞表面敏感受体、增强细胞活性、促进新生骨质与宿主骨的整合。④可注射磁响应水凝胶能够应用于骨肿瘤的磁热疗以及生物成像领域。⑤目前,磁响应水凝胶有望模拟出天然骨组织中观察到的各向异性分层结构,然而关于磁响应水凝胶的研究大多集中于体外研究,与体内的局部微环境作用机制仍然不充分。⑥因此,目前基于磁性纳米粒子已经成功地应用于磁共振成像的示踪,未来有望在磁性纳米粒子的性能上优化,构建具有合适降解性能、机械性能和血管功能化的能够实时监测体内变化的磁响应水凝胶。

超顺磁性氧化铁纳米颗粒标记靶向癌胚抗原的CAR-T细胞及体外磁共振成像研究

目的采用超顺磁性氧化铁纳米颗粒(superparamagnetic iron oxide nanoparticles,SPIONs)标记靶向癌胚抗原(carcinoembryonic antigen,CEA)的嵌合抗原受体T细胞(chimeric antigen receptor T cells,CAR-T细胞),并进行体外磁共振成像研究,为监测CEA CAR-T细胞的体内回输治疗提供依据。方法将ferumoxytol、肝素钠和硫酸鱼精蛋白分别以高(ferumoxytol 100μg/mL,肝素钠4 IU/mL,硫酸鱼精蛋白120μg/mL)、中(ferumoxytol 50μg/mL,肝素钠2 IU/mL,硫酸鱼精蛋白60μg/mL)、低(ferumoxytol 25μg/mL,肝素钠1 IU/mL,硫酸鱼精蛋白30μg/mL)剂量混合形成SPIONs复合物FHP(ferumoxytol/heparin/protamine),然后与CEA CAR-T细胞共孵育进行细胞标记。CCK-8、EdU和流式细胞术检测FHP对细胞的生物相容性,普鲁士蓝染色检测细胞对FHP的摄入情况,电感耦合等离子体-质谱法(inductively coupled plasma-mass spectrometry,ICP-MS)定量检测细胞中Fe含量,流式细胞术检测FHP标记的CEA CAR-T细胞对肿瘤细胞的杀伤作用,磁共振成像(magnetic resonance imaging,MRI)扫描FHP标记的CEA CAR-T细胞。结果高、中、低剂量的FHP对CEA CAR-T细胞的活力没有明显影响,CCK-8实验显示细胞活性均在100%以上;EdU实验显示各组细胞DNA复制活性均在94.3%以上。普鲁士蓝染色显示CEA CAR-T细胞可摄取FHP,且随FHP浓度的增加,摄取量增大。ICP-MS进一步检测显示胞内Fe含量为(440.23±189.36)ng/mL。肿瘤细胞杀伤实验表明FHP标记的CEA CAR-T细胞的杀伤肿瘤细胞能力良好。MRI扫描显示随着FHP浓度的增高,FHP标记的CEA CAR-T细胞T2WI信号呈明显降低趋势(P<0.01)。结论SPIONs复合物FHP具有良好的生物相容性并能够有效标记CEA CAR-T细胞,可作为CEA CAR-T细胞的磁标记物,为临床提供一种可行的MRI示踪方法。

^(131)I标记贝伐单抗偶联载紫杉醇超顺磁性氧化铁纳米粒的制作及生物分布实验

为了研究^(131)I标记贝伐单抗偶联载紫杉醇超顺磁性氧化铁纳米粒(^(131)I-Bevacizumab-Paclitaxel-Superparamagnetic Iron Oxide Nanoparticles,^(131)I-BEV-PTX-SPIONs)的制备和生物学分布。将30只成瘤裸鼠分为单靶向组及双靶向组,再按时间点2 h、6 h、12 h、24 h及48 h分为5个亚组,每亚组各3只,尾静脉注射^(131)IBEV-PTX-SPIONs后,进行生物学分布及单光子发射计算机断层成像术(Single-Photon Emission Computed Tomography,SPECT)显像。^(131)I-BEV-PTX-SPIONs的粒径约220 nm,分散性尚可;^(131)I标记率为81.4%;放射性化学纯度(Radiochemical Purity,RCP)>99%;在PB缓冲液中稳定性良好;在体外PTX(Paclitaxel)缓释性能良好;与A549细胞有较好的亲和力。体内生物学分布结果:随着时间的延长,肿瘤组织的放射性计数相对增高,12 h达高峰;T/NT(Target to Nontarget)比值逐渐升高,48 h达7.80±0.50。6 h、12 h、24 h、48 h时,双靶向组的肿瘤组织放射性计数及T/NT比值均高于单靶向组,差异均具有统计学意义(P<0.05),且差异性随着时间延长越来越显著。SPECT显像结果:2 h肿瘤部位即有放射性聚集,且随着时间的延长,放射性聚集增加并持续稳定,T/NT比值持续上升。初步研究结果显示,^(131)I-BEV-PTX-SPIONs具有用于肺癌诊疗的潜质,值得进一步研究。

基于频率筛选的磁粒子成像量化分析研究

为实现磁粒子成像(magnetic particle imaging,MPI)中示踪剂铁量化,本研究基于仿真程序,采集二维扫描图像,筛选信号频率并重建图像,以聚类结果作为先验信息,约束水平集函数的演化,对示踪剂图像进行分割,并借助Dice系数、IoU等参数定量评估分割效果。通过计算分割区域的信号强度总和,建立MPI信号与已知示踪剂铁含量的校正曲线。结果显示,频率筛选后显著缩短了信号重建时间;基于先验的水平集方法Dice系数和IoU均大于0.90,实现了肿瘤区域较精准的分割;通过本研究建立的MPI信号强度与铁含量的校正曲线,实现了示踪剂铁量化,平均误差为3.11%,最小误差0.03%。结果表明,基于先验的水平集方法可实现较精确的图像分割和铁量化,为MPI临床前定量研究提供参考。

超顺磁性氧化铁纳米粒子在肿瘤诊断及治疗方面的应用

超顺磁性氧化铁纳米粒子(superparamagnetic iron oxide nanoparticle, SPION)由于其独特的性质,如低毒、生物相容性、强大的磁性,以及在多功能模式中的优越作用,在肿瘤诊断、构建多模态肿瘤分子影像探针及治疗方面展现出巨大的潜力,今后可以在临床上提高肿瘤诊断的特异性、敏感性,实现诊疗一体化,本文从SPION的成像机制、合成方法出发,阐述近年来SPION在肿瘤的各种靶向成像、多模态成像和治疗方面的研究进展,展望未来SPION在肿瘤诊断及治疗中的发展前景,旨在为更好地构建基于SPION的新型诊疗一体化肿瘤探针提供参考。

超顺磁性葡聚糖氧化铁纳米颗粒的制备及其作为基因载体的可行性研究

背景与目的:磁性纳米颗粒作为基因载体在肿瘤基因治疗中的应用得到了迅速发展。为了能获得驱动目的基因高效稳定表达、安全无害、靶向性高、简便的新型非病毒型基因导入和治疗系统,本研究探讨超顺磁性葡聚糖氧化铁纳米颗粒(superparamagneticdextranironoxidenanoparticles,SDION)的制备及其作为体外基因载体的可行性。方法:采用化学共沉淀法制作SDION,通过丙烯葡聚糖凝胶S-300HR色谱和离心法分离SDION,用透射电镜、粒度分析仪和磁力计对SDION进行分析。以绿色荧光蛋白(GFP-C2)质粒为靶基因,通过氧化还原法构建SDION-GFP-C2复合物,用紫外分光光度计和琼脂糖凝胶电泳检测两者的结合率。以脂质体转染作为对照,荧光显微镜分别观察SDION和脂质体体外转染GFP-C2入膀胱癌细胞BIU-87的转染效率。结果:SDION直径在3～8nm之间,有效粒径为59.2nm,比饱和磁化强度为0.23emu/g。分别经10mmol/L的高碘酸钠氧化、0.5mol/L的硼氢化钠还原作用后的SDION和GFP的结合比例最大,SDION对GFPDNA的转染效率为45%左右,明显高于脂质体的转染效率(30%左右)。结论:SDION可通过氧化还原反应与GFP质粒相连,在体外可将GFP基因成功转染入人膀胱癌BIU-87细胞。

超顺磁性葡聚糖氧化铁纳米颗粒的研制及表征

目的制备葡聚糖包被的超顺磁氧化铁(SPIO)纳米粒子,并对其主要物理性质和磁学性质进行研究,探讨它作为磁共振造影剂的可能性。方法通过共沉淀法获得SPIO纳米粒子,分别采用透射电镜和光子相关光谱仪测定其粒径大小,利用邻苯二氮菲比色法测定铁的浓度,同时用核磁共振仪测定弛豫率等参数。结果X-射线衍射分析确定所制备的葡聚糖磁性粒子主要为Fe3O4晶体,粒子体均粒径为85.9 nm,氧化铁核心大小为15 nm左右,具有超顺磁性,其弛豫率和质量磁饱和度分别达到0.1567 mmol/ms和80 emu/g Fe。结论所制备的SPIO粒子稳定,其物理性质表明其具有作为磁共振造影剂的特性。

超顺磁性氧化铁(SPIO)与多聚赖氨酸(PLL)纳米粒的制备、结构验证及其空间结构表征

目的 探讨葡聚糖修饰的超顺磁性氧化铁（super-paramagnetic iron oxide,SPIO）与多聚赖氨酸（polylysine,PLL）纳米粒的制备及其结构验证和空间结构表征。方法 在共沉淀法制备葡聚糖修饰的SPIO基础上,加入PLL制备出一种新的SPIO-PLL纳米粒,利用粒度电位分析仪、透射电镜（transmission electron microscopy,TEM）对SPIO-PLL的粒径、电位、形貌学进行检测;高效液相凝胶色谱法（gel permeation chromatography,GPC）、红外光谱（fourier transform infrared spectroscopy,FTIR）及核磁共振氢谱法（1HNMR）对SPIOPLL连接成功与否进行验证;高精度的原子力显微镜（atomic force microscope,AFM）对SPIO-PLL的结构、形态及连接状态进行空间结构表征。结果 粒度电位分析和TEM结果显示SPIO-PLL的平均粒径为7.37 nm,平均电位为13.6 mV;GPC、FTIR及1HNMR结果显示SPIO及PLL之间已经成功连接;高精度AFM清楚显示出SPIO与PLL之间以亚胺键形式稳定相连。 结论 成功制备出一种性质稳定、粒径较小的新型SPIO-PLL纳米粒,这将对随后的肿瘤特异性探针制备奠定一定的基础。