The hard X-ray nanoprobe beamline at the SSRF

The hard X-ray nanoprobe beamline BL13U is a phase-II beamline project at the Shanghai Synchrotron Radiation Facility.The beamline aims to enable comprehensive experiments at high spatial resolutions ranging from 50 to 10 nm.The X-ray energy range of the beamline,5-25 keV,can detect most elements in the periodic table.Two operating modes were designed to accommodate the experimental requirements of high-energy resolution or high photon flux,respectively.X-ray nanofluorescence,nanodiffraction,and coherent diffraction imaging are developed as the main experimental techniques for BL13U.This paper describes the beamline optics,end station configurations,experimental methods under development,and preliminary test results.This comprehensive overview aims to provide a clear understanding of the beamline capabilities and potential applications.

Electrical characterization of an individual nanowire using flexible nanoprobes fabricated by atomic force microscopy-based manipulation

Nanowires have emerged as promising one-dimensional materials with which to construct various nanocircuits and nanosensors.However,measuring the electrical properties of individual nanowires directly remains challenging because of their small size,thereby hindering the comprehensive understanding of nanowire-based device performance.A crucial factor in achieving reliable electrical characterization is establishing well-determined contact conditions between the nanowire sample and the electrodes,which becomes particularly difficult for soft nanowires.Introduced here is a novel technique for measuring the conductivity of an individual nanowire with the aid of automated nanomanipulation using an atomic force microscope.In this method,two nanowire segments cut from the same silver nanowire are positioned onto a pair of gold electrodes,serving as flexible nanoprobes to establish controllable contact with the sample.By changing the contact points along the nanowire sample,conductivity measurements can be performed on different regions,thereby eliminating the influence of contact resistance by analyzing multiple current–voltage curves.Using this approach,the resistivity of a 100-nm-diameter silver nanowire is determined to be 3.49×10^(−8)Ωm.

Controllable Synthesis of Fluorescent Carbon Dots and Their Detection Application as Nanoprobes

Carbon dots(CDs), as a new member of carbon nanomaterial family, have aroused great interest since their discovery in 2004. Because of their outstanding water solubility, high sensitivity and selectivity to target analytes, low toxicity, favorable biocompatibility, and excellent photostability, researchers from diverse disciplines have come together to further develop the fundamental properties of CDs. Many methods for the production of CDs have been reported, therein, hydrothermal and solvothermal technology needs simple equipments, and microwave synthesis needs less reaction time, hence these methods become current common synthesis methods, in which many precursors have been applied to produce CDs. Due to their excellent fluorescence, CDs have made impressive strides in sensitivity and selectivity to a diverse array of salt ions,organic/biological molecules and target gases. The development of CDs as nanoprobes is still in its infancy, but continued progress may lead to their integration into environmental and biological applications. Hydrothermal,solvothermal, and microwave synthesis of fluorescent carbon dots and their detection applications as nanoprobes in salt ions, organic/biological molecules, and target gases will be reviewed.

Specific Recognition of Breast Cancer Cells In Vitro Using Near Infrared-Emitting Long-Persistence Luminescent Zn_3Ga_2Ge_2O_(10):Cr^(3+)Nanoprobes

In this paper, near-infrared emitting long-persistence luminescent Zn3Ga2Ge2O10:Cr3?(ZGG) nanoparticles with diameters of 30–100 nm and bright luminescence were prepared by a sol–gel synthesis method. After the surface amination, the nanoparticles were further bioconjugated with breast cancer-specific monoclonal antibody(anti-Ep CAM) to form ZGG-Ep CAM nanoprobes which can specifically target breast cancer cell lines(MCF7) in vitro. The results of in vitro images show that the luminescence signals from the cells treated with ZGG-Ep CAM nanoprobes are stronger than those from cells treated with ZGG-unconjugated antibody, indicating that the prepared ZGG-Ep CAM nanoprobes possessed excellent specific recognition capability. Furthermore, due to their long afterglow properties, the imaging could persist more than 1 h. Therefore, these nanoprobes could not only provide a high specificity detection method for cancer cells but also realize the long-time monitoring. Developed near-infrared emitting long-persistence luminescent nanoprobes will be expected to find new perspectives for cell therapy research and diagnosis applications.

Iron-Imprinted Single-Atomic Site Catalyst-Based Nanoprobe for Detection of Hydrogen Peroxide in Living Cells

Fe-based single-atomic site catalysts(SASCs),with the natural metalloproteases-like active site structure,have attracted widespread attention in biocatalysis and biosensing.Precisely,controlling the isolated single-atom Fe-N-C active site structure is crucial to improve the SASCs’performance.In this work,we use a facile ion-imprinting method(IIM)to synthesize isolated Fe-N-C single-atomic site catalysts(IIM-Fe-SASC).With this method,the ion-imprinting process can precisely control ion at the atomic level and form numerous well-defined single-atomic Fe-N-C sites.The IIM-Fe-SASC shows better peroxidase-like activities than that of non-imprinted references.Due to its excellent properties,IIM-Fe-SASC is an ideal nanoprobe used in the colorimetric biosensing of hydrogen peroxide(H_(2)O_(2)).Using IIM-Fe-SASC as the nanoprobe,in situ detection of H_(2)O_(2)generated from MDA-MB-231 cells has been successfully demonstrated with satisfactory sensitivity and specificity.This work opens a novel and easy route in designing advanced SASC and provides a sensitive tool for intracellular H_(2)O_(2)detection.

Human iPS Cells Loaded with MnO2-Based Nanoprobes for Photodynamic and Simultaneous Enhanced Immunotherapy Against Cancer

How to trigger strong anti-tumor immune responses has become a focus for tumor therapy.Here,we report the human-induced pluripotent stem cells(iPSs)to deliver MnO2@Ce6 nanoprobes into tumors for simultaneous photodynamic therapy(PDT)and enhanced immunotherapy.Ce6 photosensitizer was attached on manganese dioxide(MnO2)nanoparticles,and resultant MnO2@Ce6 nanoprobes were delivered into mitomycin-treated iPSs to form iPS-MnO2@Ce6 nanoprobes.The iPS-MnO2@Ce6 actively targeted in vivo tumors,the acidic microenvironment triggered interaction between MnO2 and H2O2,released large quantities of oxygen,alleviated hypoxia in tumor.Upon PDT,singlet oxygen formed,broken iPSs released tumor-shared antigens,which evoked an intensive innate and adaptive immune response against the tumor,improving dendritic cells matured,effector T cells,and natural killer cells were activated.Meanwhile,regulatory T cells were reduced,and then the immune response induced by iPS-MnO2@Ce6 was markedly stronger than the immune reaction induced by MnO2@Ce6(P<0.05).The iPS-MnO2@Ce6 markedly inhibited tumor growth and metastasis and reduced mortality in mice models with tumor.Human iPS s loaded with MnO2-based nanoprobes are a promising strategy for simultaneous PDT and enhanced immunotherapy against tumor and own clinical translational prospect.

氧化石墨烯-DNA纳米探针用于三磷酸腺苷的检测与药物递送

癌细胞内三磷酸腺苷(ATP)浓度异常与肿瘤发生发展过程密切相关,因此,快速、准确地检测细胞内外ATP水平具有重要意义。盐酸阿霉素(DOX)是一种广泛使用的抗癌药物,能嵌入DNA碱基对,并通过抑制DNA复制和转录诱导细胞凋亡。氧化石墨烯(Graphene oxide, GO)由于具有毒性低、比表面积大和易功能化,可以有效、稳定地负载DNA纳米探针进入细胞等优点而被广泛应用。然而,复杂环境中的生物分子容易通过物理吸附竞争性结合到GO表面,导致假阳性信号。基于此,提出了一种新型的GO-DNA纳米探针,并将其应用于ATP的检测与抗癌药物DOX靶向递送。以ATP的核酸适配体与其互补链杂交形成双链DNA(dsDNA),并通过G-C碱基对负载DOX,利用互补链延伸的poly A序列吸附到GO表面构建了GO-dsDNA-DOX纳米探针,能极大程度地降低复杂环境中物理吸附引起的干扰,减少假阳性信号产生。ATP与适配体特异性结合会导致DOX释放,根据其荧光“off-on”实现ATP的定量分析,DOX荧光强度与ATP含量在0.08~8.0 mmol/L范围内呈现良好的线性关系,线性方程为IF=3.0897c+129.08,检测限(3σ/k)为0.059 mmol/L,且方法具有良好的选择性和抗干扰能力。细胞毒性及荧光成像结果表明,负载DOX的纳米探针在人乳腺癌细胞(MCF-7)内有明显的药物释放,显著诱导细胞凋亡。该研究建立了一种免修饰、简单和快速的ATP含量检测分析方法,并利用癌细胞内高浓度ATP实现靶向药物递送,降低了对正常细胞的毒副作用,为癌症的治疗提供了新思路。

血小板膜仿生纳米靶向探针的制备及体外寻靶实验研究

目的制备血小板膜仿生纳米靶向探针(PLT-RAP@NPs),探讨其在体外的免疫逃逸、靶向和黏附能力,以及联合超声靶向微泡释放技术(UTMD)后的载药释放情况。方法采用单乳化-溶剂挥发法合成纳米探针RAP@NPs,梯度离心-反复冻融法提取血小板膜囊泡,超声震荡法制备PLT-RAP@NPs,检测其粒径、表面电位及稳定性,观察其微观形态,计算其包封率和载药率,确定雷帕霉素(RAP)负载的最佳方案。DiI荧光染料分别标记聚乳酸-羟基乙酸共聚物(PLGA,DiI@PLGA组)和PLT@PLGA(PLT-DiI@PLGA组),用于模拟RAP@NPs、PLT-RAP@NPs进行体外寻靶实验的荧光强度检测;将其分别与巨噬细胞、泡沫细胞和内皮细胞共孵育2 h,观察DiI@PLGA组与PLT-DiI@PLGA组橙红色荧光强度,分析各细胞对DiI@PLGA和PLT-DiI@PLGA的吞噬、摄取和黏附能力。细胞增殖-毒性实验观察不同浓度RAP(3.00μg/ml、6.25μg/ml、12.50μg/ml、25.00μg/ml、50.00μg/ml、100.00μg/ml)的游离RAP、RAP@NPs和PLT-RAP@NPs对细胞增殖活性的影响。体外药物控释实验观察PLT-RAP@NPs联合UTMD后载药释放效果。结果本实验制备的PLT-RAP@NPs呈球形,大小均匀,表面覆盖薄膜,“核-壳”结构清晰,平均粒径(286.83±5.25)nm,平均表面电位-(15.60±5.04)mV。当100 mg PLGA负载3 mg RAP时,包封率为60.35%,载药率为2.18%。体外寻靶实验结果显示,巨噬细胞与纳米靶向探针共孵育2 h后,DiI@PLGA组橙红色荧光强度约为PLT-DiI@PLGA组3倍;泡沫细胞与靶向纳米探针共孵育2 h后,PLT-DiI@PLGA组橙红色荧光强度约为DiI@PLGA组4倍;内皮细胞与纳米靶向探针共孵育2 h后,PLT-DiI@PLGA组橙红色荧光强度较DiI@PLGA组增强。细胞增殖-毒性实验结果显示,随着RAP浓度增高,游离RAP中细胞增殖活性下降,而RAP@NPs和PLT-RAP@NPs中细胞增殖活性变化较小。体外药物控释实验结果显示,RAP@NPs和PLT-RAP@NPs中RAP均缓慢释放,72 h积累药物释放量分别为42.12%和33.74%,联合UTMD后积累药物释放量分别提升至75.57%和67.54%。结论成功制备PLT-RAP@NPs,其可抑制巨噬细胞吞噬、增强泡沫细胞摄取和提高内皮细胞黏附,从而实现免疫逃逸及靶向能力,联合UTMD可进行RAP靶向控释。

纳米技术在动脉粥样硬化中的应用与研究进展

动脉粥样硬化(atherosclerosis,AS)是一种常见的心血管疾病,其治疗和预防一直是医学界的研究热点。纳米技术作为一种新兴技术,具有独特的优势,可以在AS的预防、诊断和治疗中发挥重要作用。本文就纳米技术在AS疾病中应用的最新研究进行综述,系统地讨论了纳米技术在AS诊疗中的作用,全面分析了基于不同的表面修饰物的纳米药物载体,负载诊断和治疗药物,实现监控AS疾病的进展和靶向治疗AS的作用,旨在为AS的临床治疗提供新的思路。

核酸功能化纳米探针检测水体中痕量Pb^(2+)的研究

铅离子(Pb^(2+))属于三大重金属污染物之一,是一种严重危害环境和人体健康的重金属元素。基于此,本研究建立一种简便、经济的水体中Pb^(2+)的检测方法。将纳米金颗粒(AuNP)作为荧光团标记脱氧核糖核酸酶(DNAzyme)的载体和猝灭剂,两者形成AuNP DNAzyme纳米探针。利用DNAzyme对目标物Pb^(2+)进行特异性识别,Pb^(2+)催化DNAzyme底物链裂解,实现荧光信号恢复。基于荧光信号的变化,实现了Pb^(2+)在5~125 nmol/L范围内的线性检测,并且Pb^(2+)的检出限为3.41 nmol/L。此外,该传感器对Pb^(2+)有较好的抗干扰性能,对Pb^(2+)加标的河水样品进行检测,回收率为95.90%~100.83%。表明该传感器在环境监测领域具有广阔的应用前景。

基于MRI可视化有机小分子纳米探针IR-PEG-FA-Gd用于肝癌光热治疗研究

目的制备靶向肝癌的MRI纳米探针IR-PEG-FA-Gd(IPFG),评估其近红外光热转化性能,探讨其光热治疗肝癌的效果。方法用物理螯合法将Gd3+螯合至IR-PEG-FA纳米粒子中,制备靶向肝癌的MRI纳米探针IPFG;使用808nm激光器监测其体内外光热升温性能;构建原位肝癌小鼠模型,利用IVIS成像和MRI监测IPFG光热治疗肝癌的效果。结果在808nm激光照射下,IPFG溶液在4min内温度可达87.3℃;皮下瘤模型中IPFG组3min内瘤体温度达到48.0℃。即便覆盖3mm鸡胸肉组织模拟生物环境,IPFG溶液仍能在4 min内升温至47.3℃;经光热治疗后,IPFG组肿瘤信号几乎消失,显著优于IPG组及对照组,且IPFG组MRI成像分辨率更高。结论IPFG具有良好的近红外光热转换效能,其在肝癌光热治疗中展现出优异的MRI成像和光热治疗效果,为肝癌的精准治疗提供了新的策略。

制备近红外光响应性仿生纳米探针及在乳腺癌光热诊疗中的应用

背景:光热疗法是一种新兴的肿瘤治疗手段,利用光热剂将光能转化为热能来实现肿瘤的无创消融。光热疗法与纳米技术的兴起为乳腺癌的治疗开辟了新视角。目的:制备一种乳腺癌细胞膜修饰的新型近红外仿生纳米探针,探究其体外近红外荧光/超声显像效果,观察其体外对同源肿瘤细胞的靶向能力和光热治疗效果。方法:以具有A-D-A结构的有机小分子ITIC-4CI作为光热剂、聚乳酸/羟基乙酸共聚物为纳米载体、小鼠乳腺癌细胞4T1细胞膜为纳米颗粒表面修饰剂,并核心负载全氟己烷,采用双步乳化法与超声法制备新型近红外仿生纳米探针(4T1m/ITIC-4CI/PFH),对纳米探针进行基本表征,并验证其对同源肿瘤细胞的靶向性;探究纳米探针的光热性能及光热稳定性,观察激光照射下纳米探针的近红外荧光/超声成像效果;采用CCK-8法和钙黄绿素/碘化丙啶染色法评估纳米探针的光热治疗效果。结果与结论:①制备的纳米探针4T1m/ITIC-4CI/PFH尺寸均一、稳定性好,平均粒径为(92.7±2.3)nm,与乳腺癌4T1细胞膜具有相似的蛋白图谱;体外细胞摄取实验证实,该纳米探针可靶向同源乳腺癌4T1细胞;②纳米探针4T1m/ITIC-4CI/PFH具有红移吸收光谱和延伸到近红外Ⅱ区的尾部发射,在激光辐照下可发出明亮的近红外Ⅱ区荧光信号;③经激光照射,纳米探针4T1m/ITIC-4CI/PFH可相变为微气泡,增强超声显像;CCK-8和钙黄绿色/碘化丙啶染色结果显示,纳米探针4T1m/ITIC-4CI/PFH对乳腺癌4T1细胞具有明显的光热杀伤效果;④结果表明,纳米探针4T1m/ITIC-4CI/PFH具有靶向同源肿瘤的能力,并可增强近红外Ⅱ区波段荧光/超声显像和光热疗法疗效。

比率型荧光聚合物纳米探针构建与铝离子检测应用

近年来,因为铝离子(Al^(3+))与多种疾病有关,严重威胁人体健康,促使人们越来越关注环境水中的Al^(3+)浓度。因此,设计一种高效的用于检测环境水中Al^(3+)浓度的荧光探针尤为重要。本文基于金属螯合增强荧光机理(CHEF),构建了一种可用于检测水中Al^(3+)浓度的比率型聚合物荧光纳米探针(NP-1)。实验结果表明,NP-1具有较好的水分散性、选择性好、检测限低(~0.97μM)等优点。此外,NP-1被成功应用于环境水样中Al^(3+)的荧光检测。

A nitroreductase-responsive nanoprobe with homogeneous composition and high loading for preoperative non-invasive tumor imaging and intraoperative guidance

Tumor microenvironment(TME)-activatable probes have been proven to effectively increase signal-tobackground ratios(SBRs)and improve the success rate of complete tumor resection.However,many fluorescence probes have to be loaded into a nanocarrier for tumor targeted delivery,which consequently encounters poor drug loading,heterogeneous composition and non-encapsulated drug aggregates occurred during nanoformulation fabrications.Herein,a nitroreductase(NTR)-activated“OFF-ON”near-infrared fluorescence nanoprobe,named Nano Bodipy,was synthesized by the spontaneous self-assembling of NTRresponsive dye-polyethylene glycol(PEG)amphiphilic polymer in water.The NTR-responsive dye acted as the hydrophobic segment in the amphiphilic polymer,yielding a homogeneous composition and a high loading of 12.2 wt%(according to calculation)in the synthesized Nano Bodipy.The synthesized Nano Bodipy can efficiently accumulate in tumors via the enhanced permeability and retention(EPR)effect,enabling non-invasive tumor-targeted fluorescence imaging and guiding complete tumor resection.Once the synthesized Nano Bodipy entered the tumor cells,they dissociated and were activated by overexpressed NTR.With the real-time fluorescence guide of Nano Bodipy,complete tumor resection surgery was performed successfully.

Rare earth fluorescent nanoprobes with minimal side effects enable tumor microenvironment activation for chemotherapy

Chemotherapy,the use of antitumor drugs to kill cancer cells,is currently one of the most effective treatments for cancer.However,serious toxic side effects caused by long-term drug accumulation can cause significant damage to the body,which limits the clinical application of antitumor drugs.In this study,a novel RENPs@DOX-Fe nanoprobe(NP) was constructed by coating the surface of rare earth nanomaterials(NaLuF_(4):Yb,Er) with a complex formed by doxorubicin(DOX) and iron ion(Ⅲ).Due to the low toxicity of anthracycline-metal complexes,the damage to normal cells is reduced.The unique acidic microenvironment in tumor cells facilitates the decomposition and gradual release of DOX from the DOX-Fe complex.In addition,the DOX-Fe complex can convert near-infrared(NIR) light into heat energy,which promotes the decomposition of the complex,further enhancing the release of DOX in the tumor environment.The change of ratio fluorescence of rare earth nanomaterials at 660 and 1550 nm after DOX release enables visual monitoring of drug release,which can potentially improve the chemotherapeutic effect.In vitro experiments established that RENPs@DOX-Fe NPs with NIR illumination had good therapeutic efficacy in tumors.This work provides new insights into designing tumor microenvironment-responsive nanoprobes for chemotherapy with minimal side effects.

Imaging-guided precision oncotherapy mediated by nanoprobes: From seeing to curing

Malignant tumors are the main diseases threatening human life. Using precise theranostics to diagnose and cure tumors has emerged as a new method to improve patient survival. Based on the current development of precise tumor imaging, image-guided tumor therapy has received widespread attention because it is beneficial for developing precise treatment of tumors, has the potential to improve the efficacy of tumor therapy and reduce the incidence of adverse side effects. Nanoprobes, which are nanomaterial functionalized with specific biomolecules, have intrigued intense interest due to their great potential in monitoring biorecognition and biodetection evens. Benefiting from the unique advantages of nanomaterials, including the easy surface functionalization, the unique imaging performances, and the high drug loading capacity, nanoprobes have become a powerful tool to simultaneously realize tumor precise imaging, diagnosis, and therapy. This review introduces the non-invasive tumor precise imaging and highlights the recent advances of image-guided oncotherapy mediated by nanoprobes in anti-tumor drug delivery, tumor precise surgical navigation, chemodynamic therapy, and phototherapy. Finally, a perspective on the challenge and future direction of nanoprobes in imaging-guided tumor theranostics is also discussed.

新型一氧化氮比率型纳米探针的构建及性能研究

该文首先通过两步化学反应合成NO识别分子3,4-二氨基苯硫醇(DABT),然后制备具有强表面拉曼增强散射(SERS)效应的银包金纳米星(AuNSs@Ag)材料,并通过Ag—S键对其进行DABT修饰,制备了比率型SERS纳米探针AuNSs@Ag-DABT。利用透射电子显微镜、水合粒径、Zeta电位以及紫外吸收光谱对纳米探针进行表征,并开展了NO的定量检测。结果表明:构建的AuNSs@Ag-DABT纳米探针表面有尖锐突出的星状结构,尺寸约为80 nm。NO存在时,DABT与NO发生反应并在541 cm^(-1)附近出现一个新的拉曼峰(三唑环),而在1078 cm^(-1)处的拉曼峰(C—S离面弯曲峰)强度保持不变,因此可以根据I_(541)/I_(1078)的比值定量检测NO。在最优条件下,I541/I1078的比值与NO浓度在10~60 nmol/L范围内表现出良好的线性响应,检出限为3.89 nmol/L。选择性实验表明该比率型SERS纳米探针对NO响应具有良好的专一性和抗干扰性。

靶向Rho激酶1纳米探针联合MRI可视化动脉粥样硬化斑块的实验研究

目的评估Rho激酶(Rho-kinase,ROCK)1在动脉粥样硬化(atherosclerosis,AS)斑块中的表达,合成ROCK1靶向探针,并探索其可视化AS斑块的可行性。材料与方法ROCK1抗体与超小超顺磁性氧化铁纳米颗粒偶联制备靶向探针(Fe3O4@PEG-ROCK1)并表征。高脂喂养载脂蛋白E基因敲除(Apolipoprotein-Edeficient,ApoE^(-/-))小鼠,在10、16、22、28、34周随机取小鼠(n=5)测量体质量。主动脉免疫染色切片及蛋白印迹实验观察ROCK1的表达及活性。将34周ApoE^(-/-)小鼠分成两组,一组尾静脉注射Fe3O4@PEG(n=10),一组尾静脉注射Fe3O4@PEG-ROCK1(n=10),注射探针前及注射后8、16 h进行MRI。Image J软件计算斑块信号。病理分析腹主动脉标本。结果Fe3O4@PEG和Fe3O4@PEG-ROCK1在水溶液中均匀分散,水合粒径分别为(27.06±1.52)nm及(30.52±2.95)nm,Zeta电位分别为(−35.18±0.31)mV及(−16.60±3.26)mV。Fe3O4@PEG-ROCK1可降低巨噬细胞的吞噬清除,在一定浓度范围内无毒,且保持免疫活性。Fe3O4@PEG-ROCK1饱和磁化强度为0.0868 T及T2弛豫率为162.3 mM^(-1 )s^(-1)说明探针磁敏感性较好。随着AS进展,ApoE^(-/-)鼠体质量明显增加,ROCK1在斑块中的表达逐渐增多(r=0.959,P<0.001)。ApoE^(-/-)鼠腹主动脉ROCK1活性高于健康C57BL/6鼠(0.30±0.02 vs.0.24±0.02,P<0.001)。平扫时Fe3O4@PEG和Fe3O4@PEG-ROCK1组斑块信号分别为8.25±1.39和7.81±3.22,差异无统计学意义;注射探针后两组斑块信号均减低,与Fe3O4@PEG组相比,Fe3O4@PEG-ROCK1组的斑块信号减低更明显(8 h,5.37±1.79 vs.3.91±2.26,P=0.001;16 h,6.68±2.39 vs.4.61±2.80,P=0.001)。普鲁士蓝染色显示的铁纳米沉积区域与免疫组化的ROCK1阳性区域对应。结论ROCK1在AS斑块中表达高和活性高。ROCK1靶向探针(Fe3O4@PEG-ROCK1)是有效磁共振对比剂,有助于实现风险斑块的无创监测。

荧光纳米探针的合成及其应用研究进展

近年来涌现的荧光纳米探针独特的尺寸及结构赋予其优异的光稳定性、较高的荧光量子产率、可调的激发发射波长等众多优势,引起科研工作者的广泛关注。荧光纳米探针作为一类重要的光响应性纳米材料在小分子及生物大分子检测、细胞成像、活体诊断等领域具有广阔的应用前景,有望成为传统有机荧光染料的理想替代物。该文针对目前研究较多的量子点、金属纳米簇及金属-有机框架及其他纳米荧光探针,介绍了其结构组成、物理化学性质等基本性质,并着重阐述其主要合成方法以及在化学传感、生物医学等领域的应用及研究进展,最后对目前该领域的发展前景做出总结及展望。

一种双金属基磁共振成像纳米探针的构建及其成像性能

目的通过钒离子嵌入的策略制备一种新型钆钒基纳米颗粒(GdVN),探索其作为T1磁共振成像纳米探针的应用前景。此外,通过调控前驱体的投料比,优化GdVN纳米探针的造影性能,并进一步评估其生物安全性。方法首先,借助透射电子显微镜(TEM)与动态光散射仪(DLS)分别测定GdVN纳米探针的形貌与粒径;随后,通过X射线衍射仪(XRD)、傅里叶变换红外光谱仪(FT-IR)以及X射线光电子能谱(XPS)明确GdVN的晶体结构与组成。其次,利用0.5 T磁共振扫描仪测定纳米探针的T1弛豫率值,筛选出高弛豫率的GdVN。最后,通过MTT细胞实验评估纳米探针的细胞生物相容性。结果成功制备出GdVN纳米探针,并通过调控前驱体的投料比,优化了其造影性能。结果显示,当乙酰丙酮钆与乙酰丙酮氧钒的投料比为1∶4时,所制备的GdVN-2展现出规则的梭形形貌与良好的分散性,粒径大约为90 nm。此外,GdVN-2展示出高T1弛豫率(r1=17.76 mM^(-1) s^(-1)),且细胞实验结果证明GdVN-2具有良好的生物安全性,有利于其作为T1磁共振成像纳米探针在体内的应用。结论本研究所研发的GdVN-2磁共振成像纳米探针展示出优异的T1磁共振造影性能和生物安全性,为实现肿瘤的早期精准诊断提供技术支持。