Fe_3O_4纳米粒子的细胞相容性

背景：无论是作为化疗药物载体还是作为肿瘤热疗介质,Fe3O4纳米粒子与肿瘤细胞微观结构的作用都有待于深入研究。目的：分析Fe3O4纳米粒子的细胞相容性,探讨其在骨肉瘤化疗中作为药物载体的应用和存在的问题。方法：参照GB/T16886.5-2003（医疗器械生物学评价第5部分：体外细胞毒性试验）的评价标准和要求,偶联十六烷基三甲基溴化铵、聚乙二醇、油酸钠Fe3O4纳米粒子胶体溶液,分别与大鼠原发骨肉瘤细胞和人成纤维细胞共培养的方式对其进行细胞毒性测试。结果及结论：偶联油酸钠Fe3O4纳米粒子细胞相容性良好,参照GB/T16886.5-2003标准属于安全范围。偶联十六烷基三甲基溴化铵Fe3O4纳米粒子细胞相容性差,不适宜作为化疗药物载体进入人体。偶联聚乙二醇Fe3O4纳米粒子有一定的细胞相容性,作为磁靶向热化疗载体还需研究。     

载顺铂超顺磁γ-Fe2O3纳米粒子的制备与表征

背景:将化疗药物联接在磁性纳米载体上,在外加磁场的引导下使所载药物定向集中于靶向治疗部位,在增强疗效同时还可降低毒性不良反应。目的:制备海藻酸钠改性的磁性纳米粒子及其负载顺铂药物,分析产物的磁学性质。方法:通过Fe2+在乙醇胺水溶液中一步合成磁性纳米粒子,用海藻酸钠作偶联剂使磁性纳米粒子与顺铂相连,制备磁性纳米粒子药物。结果与结论:X射线衍射花样证明产物为γ-Fe2O3纯相,透射电子显微镜表明磁性纳米粒子直径平均约10nm,载顺铂后药物包覆于纳米粒子周围,磁化曲线显示纳米粒子为超顺磁性,核磁共振得到纳米粒子的弛豫率为0.11602mmol/ms。表明所制备磁性纳米粒子及其载顺铂超顺磁性纳米粒子药物性质稳定,具有作为磁性纳米粒子药物的特性。     

生物相容性Fe3O4@SiO2纳米粒子的合成及性能

背景:Fe3O4纳米粒子具有良好的磁学特性,SiO2具有良好的生物相容性,Fe3O4@SiO2复合纳米粒子有望成为靶向治疗的载体。目的:采用反相微乳液法合成生物相容性的Fe3O4@SiO2纳米粒子。方法:首先,以FeCl3?6H2O、FeCl2?4H2O、油酸、氨水等为原料,采用一壶化学共沉淀法合成油酸修饰的疏水性Fe3O4纳米粒子。随后,将油酸包裹的Fe3O4纳米粒子分散于环己烷中,然后将Triton-X100、正己醇及水在搅拌条件下加入到上述溶液,形成稳定的反相微乳液;在反相微乳液中,以氨水为催化剂,使正硅酸四乙酯水解、缩合,从而获得Fe3O4@SiO2复合纳米粒子。结果与结论:①透射电镜、X射线衍射显示:采用一壶化学沉淀法合成的Fe3O4具有尖晶石结构,平均粒径约为3.5nm;微乳液法能将SiO2成功包覆于Fe3O4表面,形成平均粒径为40nm的均一Fe3O4@SiO2复合纳米粒子。②磁性能分析显示:Fe3O4纳米粒子包裹后饱和磁化强度下降,但包裹前后矫顽力趋于零,均显示超顺磁性。③MTT结果显示纳米粒子与人脐静脉细胞融合细胞(EA.hy926)共培养24h时Fe3O4@SiO2组吸光度高于对照组(P<0.05);细胞培养48,72h,两组比较差异无显著性意义(P>0.05)。结果表明经反相微乳液法合成的Fe3O4@SiO2纳米粒子是一种优良的生物材料,其具有稳定、易分散及超顺磁性等特性。     

Pluronic F127/聚乳酸纳米粒子的药物作用

背景:国内关于纳米粒子在水及磷酸盐缓冲液中稳定性的研究报道较少。目的:考察PluronicF127/聚乳酸纳米粒子在水及磷酸盐缓冲液中的稳定性及PluronicF127/聚乳酸聚合物作为药物载体的可行性。方法:采用透析法制备PluronicF127/聚乳酸纳米粒子,通过高效液相色谱研究该纳米粒子作为药物载体包埋紫杉醇及体外释放行为,同时采用MTT法考察该聚合物的细胞毒性。结果与结论:PluronicF127/聚乳酸纳米粒子在水中的稳定性优于磷酸盐缓冲液,其次,温度对于纳米粒子的稳定性影响较大,无论是磷酸盐缓冲液还是水中,37℃条件下粒径变化均较大,因此纳米粒子在低温下稳定性较好。包埋紫杉醇的PluronicF127/聚乳酸纳米粒子的释放曲线在前20h内呈现快速释放,此后表现为缓慢释放,约有20%的紫杉醇释放出来,MTT测试结果表明PluronicF127/聚乳酸嵌段共聚物具有很好的生物相容性。综合以上结果表明,PluronicF127/聚乳酸适合用作药物载体。     

磁性纳米Fe_3O_4颗粒对藤黄酸诱导的U937细胞凋亡效应的影响(英文)

本研究探讨联合应用藤黄酸(GA)和磁性纳米Fe3O4颗粒(MNP-Fe3O4)治疗白血病的潜在可能性。采用MTT法检测GA对U937的细胞毒作用及GA联合MNP-Fe3O4对U937细胞生长抑制的影响;流式细胞术检测细胞凋亡率;应用Wright及DAPI染色观察凋亡细胞的形态学变化;采用实时定量RT-PCR及Western blot法分别检测细胞的caspase-3、bcl-2、bax、NF-κB和survivin基因及相应蛋白的表达。结果表明:GA对U937细胞的生长抑制作用呈现时间及剂量依赖性;MNP-Fe3O4本身无细胞毒作用,但能使GA对U937细胞的生长抑制作用增强;联合应用GA和MNP-Fe3O4诱导的细胞凋亡率较单用GA明显增加,细胞呈现典型的凋亡形态改变,同时可见caspase-3及bax表达上调,而凋亡抑制基因如bcl-2、NF-κB和survivin表达下调。结论:MNP-Fe3O4能增强GA对U937细胞的凋亡诱导作用,两者联合应用可能是一种新型而安全有效的白血病治疗方法。     

载Fe3O4液态氟碳纳米粒增强磁共振成像的实验研究

目的 制备载Fe₃O₄液态氟碳(Fe₃O₄-PFOB)纳米粒,并探讨其增强磁共振成像效果。方法 采用薄膜-超声法制备Fe₃O₄-PFOB纳米粒,并检测其理化性质。将24只健康SD大鼠随机分为3组:Fe₃O₄-PFOB纳米粒组(静脉注射Fe₃O₄-PFOB纳米粒)、PFOB纳米粒组(静脉注射PFOB纳米粒)及生理盐水组(静脉注射生理盐水)。对各组大鼠于处理后24 h行肝脏MR扫描。扫描完成后取出大鼠肝脏组织,进行HE及普鲁士蓝染色观察。 结果 所得样品为膜壳装载Fe₃O₄、中心包裹液态氟碳的纳米粒,呈球形,粒径(272.9±19.5)nm。注射Fe₃O₄-PFOB纳米粒24 h后,大鼠肝实质信号显著降低,肝脏-肌肉信号比明显减少,与其余两组比较差异均有统计学意义。普鲁士蓝染色可见Fe₃O₄-PFOB纳米粒组大鼠肝实质内有较多蓝色颗粒分布,其余两组染色阴性。HE染色各组大鼠肝脏均未见明显的形态学改变。结论 Fe₃O₄-PFOB纳米粒能有效增强磁共振成像效果,可以用作MRI阴性对比剂。     

载顺铂超顺磁γ-Fe2O3纳米粒子的制备与表征

背景：将化疗药物联接在磁性纳米载体上,在外加磁场的引导下使所载药物定向集中于靶向治疗部位,在增强疗效同时还可降低毒性不良反应。目的：制备海藻酸钠改性的磁性纳米粒子及其负载顺铂药物,分析产物的磁学性质。方法：通过Fe2＋在乙醇胺水溶液中一步合成磁性纳米粒子,用海藻酸钠作偶联剂使磁性纳米粒子与顺铂相连,制备磁性纳米粒子药物。结果与结论：X射线衍射花样证明产物为γ-Fe2O3纯相,透射电子显微镜表明磁性纳米粒子直径平均约10nm,载顺铂后药物包覆于纳米粒子周围,磁化曲线显示纳米粒子为超顺磁性,核磁共振得到纳米粒子的弛豫率为0.11602mmol/ms。表明所制备磁性纳米粒子及其载顺铂超顺磁性纳米粒子药物性质稳定,具有作为磁性纳米粒子药物的特性。     

Fe3O4磁性纳米微粒——一种新型多功能医学造影剂

医学造影剂的发展使兼具疾病诊断与治疗等于一体的多功能造影剂的出现成为可能。Fe3O4磁性纳米微粒造影剂及其聚合物,因其特有的超顺磁性、靶向性、生物相容性及低细胞毒性而成为目前研究热点。本文就Fe3O4磁性纳米微粒造影剂的特性、制备及医学应用等方面进行一综述。     

偏磷酸钙纳米粒子的细胞相容性

背景：偏磷酸钙具有优异的细胞相容性能和降解性能及细胞亲和性,人骨髓间充质干细胞可以在多孔偏磷酸钙孔洞内生长和增殖,但有关偏磷酸钙纳米粒子的研究较少。 目的：制备纳米级偏磷酸钙微粒,通过流式细胞术快速检测不同浓度纳米级偏磷酸钙微粒对人骨髓间充质干细胞凋亡的影响。 方法：采用湿法球磨法制备偏磷酸钙纳米粒子,通过扫描电镜和透射电镜观察纳米粒子的形貌,通过X射线衍射分析确定纳米粒子的晶体结构。将偏磷酸钙纳米粒子混入CYAGON Oricel TM 基础培养基,使得偏磷酸钙纳米粒子的质量浓度分别为10,1,0.1 mg/L,将其与人骨髓间充质干细胞共培养7 d,通过流式细胞术分析偏磷酸钙纳米粒子质量浓度与细胞凋亡的关系。 结果与结论：采用湿法球磨法成功制备了偏磷酸钙纳米粒子,直径为10-30 nm,粒径分布较均匀,分散性较好,但晶体形状不规则;X射线衍射分析晶相检测其主晶相为β-Ca（PO3）2晶体。10 mg/L质量浓度组细胞G0/G1和G2/M比例高于1,0.1 mg/L质量浓度组（P〈0.01）;10 mg/L质量浓度组细胞早期、中晚期、总细胞凋亡率高于1,0.1 mg/L质量浓度组（P〈0.01）;说明偏磷酸钙纳米粒子对人骨髓间充质干细胞的增殖有影响,当其质量浓度从1 mg/L增加至10 mg/L后,细胞凋亡率显著增加。     

壳聚糖纳米粒子在药物递送系统中的应用进展

壳聚糖纳米粒子因其便于修饰、生物相容性好、易于降解、来源广泛等特点,近年来在生物医学领域受到广泛关注.壳聚糖纳米粒子是一种新型载体,相比于传统的纳米载体,其在改善药物稳定性、实现药物控释、提高药物细胞摄取能力等方面具有显著成效.然而,临床应用壳聚糖纳米粒子前,还需预测和评估其潜在毒性与不良反应,明确壳聚糖纳米粒子在体内...     

载Fe3O4全氟溴辛烷纳米粒增强超声显像的实验研究

目的 探讨载磁性纳米材料Fe3O4颗粒的全氟溴辛烷纳米粒(Fe3O4-PFOB)增强超声显像的效果.方法 将Fe3O4-PFOB纳米粒与RAW264.7 巨噬细胞孵育30 min、1 h后,分别进行光镜及体外超声检查.12只健康SD大鼠随机分为2组,分别于注射Fe3O4-PFOB及空白PFOB纳米粒前后进行大鼠肝脏超声显像,并用DFY超声图像定量分析诊断仪评价显像效果.结果 Fe3O4-PFOB纳米粒与巨噬细胞孵育1 h后可见大量Fe3O4-PFOB纳米粒被巨噬细胞吞噬,巨噬细胞吞噬纳米粒后能够增强超声回声信号.体内显像中,与空白PFOB纳米粒相比,Fe3O4-PFOB能够更好地增强大鼠肝实质超声显像效果,而且其增强显影时间延长.结论 膜壳装载Fe3O4颗粒的Fe3O4-PFOB纳米粒能够有效增强超声显像效果,有望实现一种造影剂多种模态显像.

Abstract：

Objective To study the feasibility of the Fe3O4-loaded lipid perfluorooctylbromide nanoparticles (Fe3O4-PFOB) for enhanced ultrasound imaging.Methods The Fe3O4-PFOB nanoparticles,incubated with RAW264.7 macrophage cells,were monitored by microscope and ultrasound.Twelve SD rats were randomized into two groups,Fe3O4-PFOB group and PFOB group.Ultrasound imaging of rats' liver was performed before and after intravenous injection of the contrast agents.The liver echogenic intensity was quantified by DFY ultrasound quantified system analysis.Results Incubation of the Fe3O4-PFOB nanoparticles with macrophages resulted in the uptake of Fe3O4-PFOB by macrophages.Macrophages loaded with Fe3O4-PFOB exhibited enhanced echogenicity in vitro.In in vivo imaging,Fe3O4-PFOB produced better and prolonged ultrasound enhancement of rats' liver compared to PFOB nanoparticles.Conclusions Fe3O4-PFOB nanoparticles could enhance ultrasound imaging and may potentially serve as a multimodal probe for ultrasound,CT and MR imaging.     

Au/Fe3O4 core–shell nanoparticles are an efficient immunochromatography test strip performance enhancer—a comparative study with Au and Fe3O4 nanoparticles

Immunochromatography test strips that use metal particles constructed from Au, Fe₃O₄, and Au/Fe₃O₄ nanoparticles were developed for the rapid detection of avian influenza virus subtype H7 (AIV H7). The principle of this immunochromatography test strip was based on a sandwich immunoreaction in which AIV H7 antigens bind specifically to their corresponding antibodies on a nitrocellulose membrane. An antibody–metal (Au, Fe₃O₄ or Au/Fe₃O₄) nanoparticle conjugate was used as a label and coated onto a glass fiber membrane, which was used as a conjugate pad. To create a test and a control zone, an anti-H7 polyclonal antibody and an anti-IgG antibody were immobilized onto the nitrocellulose membrane, respectively. Positive samples displayed brown/red lines in the test and control zones of the nitrocellulose membrane, whereas negative samples resulted in a brown/red line only in the control zone. The limit of detection (LOD) of the Au/Fe₃O₄ nanoparticle-based immunochromatography test strips was found to be 10^3.5 EID₅₀ (EID₅₀: 50% Egg Infective Dose), which could be visually detected by the naked eye within 15 min. In addition, 200 clinical samples were tested using the Au/Fe₃O₄ nanoparticle-based immunochromatography test strip to estimate its performance, and seven were positive for AIV H7. In summary, the Au/Fe₃O₄ nanoparticle-based immunochromatography test strip offers a simple and cost-effective tool for the rapid detection of AIV H7.

Immunochromatography test strips that use metal particles constructed from Au, Fe₃O₄, and Au/Fe₃O₄ nanoparticles were developed for the rapid detection of avian influenza virus subtype H7 (AIV H7).     

Graphene tailored by Fe3O4 nanoparticles: low-adhesive and durable superhydrophobic coatings

This study reports stable superhydrophobic Fe₃O₄/graphene hybrid coatings prepared by spin coating of the Fe₃O₄/graphene/PDMS mixed solution on titanium substrates. By tailoring graphene sheets with Fe₃O₄ nanoparticles, the superhydrophobicity of graphene platelets was largely enhanced with a water contact angle of 164° and sliding angle <2°. Fe₃O₄ nanoparticles interact with FLG sheets via Fe–O–C covalent link, to form a graphene micro-sheet pinned strongly by nano-sized Fe₃O₄. The newly-formed micro/nano-structured sheets interact with each other via strong dipole–dipole attractions among Fe₃O₄ nanoparticles, confirmed by the blue shifts of G band observed in Raman spectra. The strongly interactive micro/nano-structured sheets are responsible for the improvement of both the surface hydrophobicity and the durability towards water impacting. The obtained hybrid coatings possess excellent durability in various environments, such as acidic and basic aqueous solutions, simulating ocean water. And also the coatings can retain their stable superhydrophobicity in Cassie–Baxter state even after annealing at 250 °C or refrigerating at −39 °C for 10 h. We employed an AFM to probe nanoscale adhesion forces to examine further the ability of the as-prepared coatings to resist the initial formation of water layers which reflects the ability to prevent the water spreading. The most superhydrophobic and durable hybrid coating with 1.8 g Fe₃O₄, shows the smallest adhesion force, as expected, indicating this surface possesses the weakest initial water adhesive strength. The resulting low-adhesive superhydrophobic coating shows a good self-cleaning ability. This fabrication of low-adhesive and durable superhydrophobic Fe₃O₄/FLG hybrid coatings advances a better understanding of the physics of wetting and yield a prospective candidate for various practical applications, such as self-cleaning, microfluidic devices, etc.

Strongly interactive graphene micro-sheets tailored by Fe₃O₄ nanoparticles exhibit low-adhesive and durable superhydrophobicity.     

Fe3O4 纳米化颗粒标记人羊膜间充质干细胞的合适条件

目的:Fe3O4 纳米化颗粒是近来发现的活体示踪剂,由于其毒性可导致标记细胞死亡,寻找合适的浓度进行细胞标记已成为活体示踪的关键.实验以人羊膜间充质干细胞作为靶点,探讨Fe3O4 纳米化颗粒标记的合适条件.方法:实验于2007-08在郑州大学完成.①细胞来源及颗粒:人羊膜间充质干细胞由郑州大学第一临床医学院神经外科杨波教授自健康产妇胎盘羊膜中提取,产妇对实验知情同意,实验经医院医学伦理委员会批准.Fe3O4 纳米颗粒由美国Sigma公司生产,商品名:菲立磁,批号094k0788.转染剂多聚左旋赖氨酸购自大连宝生生物公司,批号033K4351.②实验方法:向人羊膜间充质干细胞加入含10%胎牛血清、20μg/L碱性成纤维生长因子的DMEM/F12培养基,置于37 ℃、体积分数为0.05的CO2饱和湿度培养箱中培养,待细胞达80%～90%融合时胰酶消化传代.取传至第3代的细胞,放入含DMEM/F12培养基的10 mL培养瓶中,密度调整为1×109 L-1.设立3组:单纯Fe3O4组分为4个亚组,即向培养基中分别加入终浓度为20,30,40,80 mg/L的Fe3O4纳米颗粒;Fe3O4 多聚左旋赖氨酸组分为4个亚组,即向培养基中分别加入上述终浓度Fe3O4纳米颗粒后,再加入1.5 mg/L多聚左旋赖氨酸;培养基对照组,仅加入DMEM/F12培养基.各组细胞标记12 h后,均更换为DMEM/F12培养基培养3周.③实验评估:分别于标记后12 h、36 h、1周和3周,普鲁士蓝染色检测Fe3O4纳米颗粒进入细胞情况,锥虫蓝染色检测细胞活性.结果:①Fe3O4 纳米颗粒标记人羊膜间充质干细胞的效果:终浓度为20 mg/L的Fe3O4纳米颗粒细胞标记率为60%,终浓度为30,40,80 mg/L的Fe3O4纳米颗粒细胞标记率均为100%.单纯Fe3O4组可见少量蓝染的Fe3O4纳米化颗粒分散于细胞浆内,Fe3O4 多聚左旋赖氨酸组蓝染颗粒明显增多,部分聚集成团.②标记后细胞活性测定:与培养基对照组比较,当Fe3O4终浓度为20,30 mg/L时,单纯Fe3O4组、Fe3O4 多聚左旋赖氨酸组细胞活性均无明显变化(P > 0.05);当Fe3O4终浓度升高至40,80 mg/L时,上述2组细胞活性均显著降低(P < 0.05).结论:①与多聚左旋赖氨酸混合,能够使进入细胞内的Fe3O4纳米颗粒增多,从而加强细胞标记效果.②30 mg/L Fe3O4纳米颗粒细胞标记率可达100%,且该浓度不影响人羊膜间充质干细胞的生物活性.③30 mg/L Fe3O4纳米颗粒联合多聚左旋赖氨酸是标记人羊膜间充质干细胞的合适条件.     

Fe3O4纳米化颗粒标记人羊膜间充质干细胞的合适条件

目的：Fe3O4纳米化颗粒是近来发现的活体示踪剂，由于其毒性可导致标记细胞死亡，寻找合适的浓度进行细胞标记已成为活体示踪的关键。实验以人羊膜间充质干细胞作为靶点，探讨Fe3O4纳米化颗粒标记的合适条件。方法；实验于2007—08在郑州大学完成。①细胞来源及颗粒：人羊膜间充质干细胞由郑州大学第一临床医学院神经外科杨波教授自健康产妇胎盘羊膜中提取，产妇对实验知情同意，实验经医院医学伦理委员会批准。Fe3O4纳米颗粒由美国Sigma公司生产，商品名：菲立磁，批号094k0788。转染剂多聚左旋赖氨酸购自大连宝生生物公司，批号033K4351。②实验方法：向人羊膜间充质干细胞加入含10％胎牛血清、20μg／L碱性成纤维生长因子的DMEM／F12培养基，置于37℃、体积分数为0．05的CO2饱和湿度培养箱中培养，待细胞达80％～90％融合时胰酶消化传代。取传至第3代的细胞，放入含DMEM/F12培养基的10mL培养瓶中，密度调整为1×10^9L^-1。设立3组：单纯Fe3O4组分为4个亚组，即向培养基中分别加入终浓度为20，30，40，80mg／L的Fe3O4纳米颗粒；Fe3O4＋多聚左旋赖氨酸组分为4个亚组，即向培养基中分别加入上述终浓度Fe3O4纳米颗粒后，再加入1．5mg／L多聚左旋赖氨酸；培养基对照组，仅加入DMEM／F12培养基。各组细胞标记12h后，均更换为DMEM／F12培养基培养3周。③实验评估：分别于标记后12h、36h、1周和3周，普鲁士蓝染色检测Fe3O4纳米颗粒进入细胞情况，锥虫蓝染色检测细胞活性。结果：①Fe3O4纳米颗粒标记人羊膜间充质干细胞的效果：终浓度为20mg／L的Fe3O4纳米颗粒细胞标记率为60％，终浓度为30，40，80mg／L的Fe3O4纳米颗粒细胞标记率均为100％。单纯Fe3O4组可见少量蓝染的Fe3O4纳米化颗粒分散于细胞浆内，Fe3O4＋多聚左旋赖氨酸组蓝染颗粒明显增多，部分聚     

Cycling stability of Fe2O3 nanosheets as supercapacitor sheet electrodes enhanced by MgFe2O4 nanoparticles

The Fe₂O₃ material is a common active material for supercapacitor electrodes and has received much attention due to its cheap and easy availability and high initial specific capacitance. In the present study, we prepared adhesive-free Fe₂O₃ sheet electrodes for supercapacitors by growing Fe₂O₃ material on nickel foam by hydrothermal method. The sheet electrode exhibited a high initial specific capacitance of 863 F g⁻¹, but we found that the sheet lost its specific capacitance too quickly through cyclic stability tests. To solve this problem, Fe₂O₃/MgFe₂O₄ composites were grown on nickel foam (NF). It was found through testing that the cycling stability of the sheet electrode gradually increased as the content of MgFe₂O₄ material increased. When the molar ratio of Fe₂O₃ to MgFe₂O₄ material was 1 : 1, the initial specific capacitance of the sheet electrode was 815 F g⁻¹ and the capacitance remained at 81.25% of the initial specific capacitance after 1000 cycles. The better cycling stability results from the more stable structure of the composite, the synergistic effect leading to better reversibility of the reaction.

Compounding of Fe₂O₃ with MgFe₂O₄, leading to morphological changes and synergistic effects, resulting in significantly improved cycling stability of supercapacitor sheet electrode.     

Shape-controlled synthesis of magnetic Fe3O4 nanoparticles with different iron precursors and capping agents

This paper describes a modified method to prepare monodisperse Fe₃O₄ magnetic nanoparticles with different shapes (cube, octahedron, and sphere). The shape of the magnetic nanoparticles could be conveniently controlled by changing the types of precursor/capping agent and concentration of capping agent. The prepared samples were characterized using scanning electron microscopy, X-ray diffraction and vibrating sample magnetometry. Cubes and octahedra were formed using ferrous sulfate heptahydrate as an iron source, ethylene glycol as a solvent and potassium hydroxide (KOH) as a capping agent while spheres were formed by using ferric chloride hexahydrate as an iron source, ethylene glycol as a solvent and ammonium acetate as a capping agent. By varying KOH concentration (0.5 M, 1 M, 1.5 M, and 5 M), the shape was transformed from cubes to octahedra because octahedra are developed dominantly at higher concentration of KOH within the reaction mixture. The magnetic studies show superparamagnetic behavior for all samples at room temperature. The Fe₃O₄ nanoparticles show the magnetic saturation values of 87 emu g⁻¹, 85 emu g⁻¹, and 82 emu g⁻¹ for spheres, cubes, and octahedrons, respectively.

This paper describes a modified method to prepare monodisperse Fe₃O₄ magnetic nanoparticles with different shapes (cube, octahedron, and sphere).     

Removal of arsenic(v) from aqueous solutions using sulfur-doped Fe3O4 nanoparticles

In this study, magnetic sulfur-doped Fe₃O₄ nanoparticles (Fe₃O₄:S NPs) were applied as adsorbents for the removal of As(v). Fe₃O₄:S NPs were fabricated by a two-step route, which included low-temperature mixing and high-temperature sintering. The as-prepared Fe₃O₄:S NPs could effectively remove As(v) under a wide pH range of 2–10 and presented a high As(v) adsorption capacity of 58.38 mg g⁻¹, which was much better than undoped Fe₃O₄ nanoparticles (20.24 mg g⁻¹). Adsorption experiments exhibited a pseudo-second-order model of adsorption kinetics and a Langmuir isotherm model of adsorption isotherms. Additionally, the coexisting ions such as NO₃⁻, SO₄²⁻, and CO₃²⁻ had no significant effect on As(v) adsorption and the adsorbent worked well in actual smelting wastewater. XPS and FTIR spectra of Fe₃O₄:S NPs before and after As(v) adsorption showed that Fe–OH groups played a significant role in the adsorption mechanisms. Moreover, the magnetic Fe₃O₄:S NPs adsorbents after adsorption could be rapidly separated from wastewater with an external magnetic field. Therefore, Fe₃O₄:S NPs could be an ideal candidate for the removal of As(v) from water.

Magnetic Fe₃O₄:S NPs presented a much better As(v) adsorption performance than undoped Fe₃O₄ NPs due to sulfur doping.     

Magnetically retrievable Ce-doped Fe3O4 nanoparticles as scaffolds for the removal of azo dyes

Considering the significant impact of magnetically retrievable nanostructures, herein, Fe₃O₄ and Ce-doped Fe₃O₄ nanoparticles were employed as scaffolds for the removal of the Reactive Black 5 (RB5) azo dye. We synthesized the Ce-doped Fe₃O₄ nanoparticles via hydrothermal treatment at 120 °C for 10 h with varying cerium concentrations (1.5–3.5%) and characterized them using basic techniques such as FTIR and UV-visible spectroscopy, and XRD analysis. The retention of their magnetic behaviors even after cerium amalgamation was demonstrated and confirmed by the VSM results. FESEM and EDX were used for the morphological and purity analysis of the synthesized nanoabsorbents. XPS was carried out to determine the electronic configuration of the synthesized samples. The porosity of the magnetic nanoparticles was investigated by BET analysis, and subsequently, the most porous sample was further used in the adsorption studies for the cleanup of RB5 from wastewater. The dye adsorption studies were probed via UV-visible spectroscopy, which indicated the removal efficiency of 87%. The prepared Ce-doped Fe₃O₄ nanoabsorbent showed the high adsorption capacity of 84.58 mg g⁻¹ towards RB5 in 40 min. This is attributed to the electrostatic interactions between the nanoabsorbent and the dye molecules and high porosity of the prepared sample. The adsorption mechanism was also analyzed. The kinetic data well-fitted the pseudo-first-order model, and the adsorption capability at different equilibrium concentrations of the dye solution indicated monolayer formation and chemisorption phenomena. Furthermore, the magnetic absorbent could be rapidly separated from the wastewater using an external magnetic field after adsorption.

Considering the significant impact of magnetically retrievable nanostructures, herein, Ce-doped Fe₃O₄ nanoparticles were employed as scaffolds for the removal of the Reactive Black 5 (RB5), an azo dye.