量子点在生物学中的研究进展

量子点作为一种新型的荧光标记物近年来已在生物学中获得广泛应用。本文总结了量子点的主要光学特性,其中包括荧光激发和发射光谱特性、量子产额、光漂白特性和荧光寿命等。重点综述了量子点在细胞标记、活体和组织成像、组合标记和光动力学治疗等生物学中的应用及其最新研究进展。同时讨论了量子点在应用中可能存在的细胞毒性等主要问题,最后对量子点在生物学中的应用前景作了展望。     

量子点对细菌的标记及抗菌作用

目的量子点是近年来发展起来的一种新型的荧光纳米材料,与传统的材料相比具有独特的性质,所以在生物传感器、实时追踪、多色标记及成像等方面有着广泛的应用。本文主要对量子点在细菌标记和抗菌等方面的应用进行了综述。     

用量子点标记活细胞

量子点是一种具有纳米尺寸的半导体晶体。与传统的荧光染料相比,量子点拥有许多独特的光学特性,如宽的吸收谱、窄而对称的发射谱、耐漂白、亮度高和荧光寿命长等。由于其出色的光物理特性和相对较小的尺寸,量子点可作为生物学研究的荧光探针。随着量子点合成与修饰技术的发展,其在生物和医学领域的应用已从探索阶段逐步发展到了应用阶段。将量子点应用于活细胞标记,将为揭示细胞内的复杂生命现象提供全新的视野。该文重点介绍了量子点的荧光特性、用量子点标记活细胞所要克服的障碍及基本的标记策略和方法。     

综述——基于纳米材料的生物检测与医学诊断技术：功能化量子点在肿瘤活体成像中的应用

量子点表面经生物分子或药物分子修饰而具有生物功能．功能化量子点具有独特的光学性质和生物相容性,在生物医学光学诊断和治疗领域具有广泛的应用．本文简要介绍了功能化量子点制备及修饰方法,综合评述了量子点在肿瘤活体诊断和治疗中的应用,包括活体淋巴结成像、血管动态成像、肿瘤成像和抗肿瘤药物示踪等,讨论了功能化量子点在肿瘤活体诊断和治疗中的应用前景以及面临的挑战．     

在光动力疗法中应用的量子点

概述了现存的主要量子点的构成及其特点,阐述了量子点的性质主要由量子点的成分、结构、包覆和尺寸所决定。并重点讨论量子点在光动力疗法中,量子点直接代替传统光敏剂、量子点的荧光共振能量转移、量子点作为宽禁带半导体材料TiO2的敏化剂等三种不同应用中,对量子点的要求,通过讨论指出由于其特性,量子点将在光动力疗法中得到更广泛的应用,也对在光动力疗法中应用的量子点的毒性及其他可能产生的问题提出了展望。     

靶向吲哚菁绿纳米探针介导的光声治疗

光声治疗是一种利用纳米材料的光声效应选择性破坏癌细胞的方法。本研究采用叶酸作为肿瘤靶向分子,以聚乙二醇包裹吲哚菁绿形成纳米粒子(ICG-PL-PEG-FA),利用此纳米粒子在近红外区的光吸收特性,开展光声治疗研究。实验结果表明,这种叶酸标记的纳米探针对高表达叶酸的EMT6细胞具有高靶向选择性和靶向光杀伤性。这种基于包含吲哚菁绿纳米探针的光声治疗将有潜力发展为一种安全,高效的癌症治疗技术。     

固定剂、封片剂、温度及除菌方式对量子点标记细胞的影响

为了为利用量子点标记细胞、组织,进一步研究其功能提供新的方法,本实验观察了3种发射波长的量子点（quautum dost,QDs）对所标记的小鼠腹腔巨噬细胞和正常皮肤的影响。利用发射波长610mm的红色荧光水溶液（量子点610）、发射波长为523mm的绿色荧光水溶液（量子点523）和发射波长576nm的黄色荧光脂溶性溶液（量子点576）的3种量子点（5mg／ml）以及具有吞噬能力的小鼠腹腔巨噬细胞、正常皮肤为载体,观察不同的除菌方式、温度、封片剂及固定剂对量子点标记细胞、组织的影响,为量子点在生物体内的应用及在生物制片过程中对其性能的影响等研究奠定基础。     

量子点的荧光特性在生物标记成像中的应用及展望

与传统的荧光染料相比,量子点作为一种新型的无机荧光纳米材料,具有激发光谱宽而连续、发射光谱窄而对称、光稳定性好、荧光寿命长、量子产率高和生物毒性小等优点,被广泛地应用于生命科学的许多领域,其在细胞标记(固定细胞和离体活细胞)和活体示踪成像领域具有独特的应用优势.它突破了传统的有机荧光染料在荧光性能及生物毒性等方面的不可克服的缺陷.它的应用,极大地推动了生命体系高灵敏、原位、实时、动态示踪成像研究的发展.该文综述了量子点的荧光性质及其在细胞标记(固定细胞和离体活细胞)和活体实时动态示踪成像中的应用,并对其在荧光原位杂交,流式细胞术,实时荧光定量pcr等方面的应用前景进行了展望.     

端粒酶与癌症靶向治疗

端粒酶是癌组织中特异表达的关键酶,与肿瘤细胞无限增殖关系密切。端粒酶在癌细胞表面表达特异性抗原,是癌细胞的标记之一。靶向治疗作为癌症新兴的治疗方法,具有特异性强、副作用小等传统方法所不具有的优点。针对端粒酶这一特异靶点的靶向治疗可以利用免疫学基本原理,通过抗原的特异性识别有效杀伤癌细胞。已有许多端粒酶肽段应用于实验室及临床研究,具有广阔的应用前景;但应用免疫疗法也有其缺陷,端粒酶抗原免疫耐受的问题也是亟待解决的问题之一,在临床上的广泛应用还有一段路要走。     

量子点在基因转染中的应用研究进展

量子点因其独特的纳米尺寸效应、光学特性和生物相容性,既能作为纳米载体与目的基因结合,又能作为纳米荧光标记物跟踪记录其在转染过程中的位置,给基因工程的发展带来了新的契机。在阐述量子点用于基因转染的优势、标记基因的方法等基础上,作者系统综述了量子点在基因转染中的应用,并对其发展趋势和应用前景进行了展望。     

Bioconjugated quantum dots for cancer research: Present status,prospects and remaining issues

Semiconductor quantum dots (QDs) are nanoparticles in which charge carriers are three dimensionally confined or quantum confined. The quantum confinement provides size-tunable absorption bands and emission color to QDs. Also, the photoluminescence (PL) of QDs is exceptionally bright and stable, making them potential candidates for biomedical imaging and therapeutic interventions. Although fluorescence imaging and photodynamic therapy (PDT) of cancer have many advantages over imaging using ionizing radiations and chemo and radiation therapies, advancement of PDT is limited due to the poor availability of photostable and NIR fluorophores and photosensitizing (PS) drugs. With the introduction of biocompatible and NIR QDs, fluorescence imaging and PDT of cancer have received new dimensions and drive. In this review, we summarize the prospects of QDs for imaging and PDT of cancer. Specifically, synthesis of visible and NIR QDs, targeting cancer cells with QDs, in vitro and in vivo cancer imaging, multimodality, preparation of QD-PS conjugates and their energy transfer, photosensitized production of reactive oxygen intermediates (ROI), and the prospects and remaining issues in the advancement of QD probes for imaging and PDT of cancer are summarized.     

基于CdSe-ZnS量子点的PDT体外灭活 HL60最佳实验参数的研究

随着光动力学疗法( photodynamic therapy,PDT)基础研究的不断深入和临床应用的广泛开展,根据患者的个体差异寻求高性能的光敏剂和精确量化光动力剂量,已成为亟待解决的难题,并日渐成为PDT研究的热点.以ZnS包裹的CdSe量子点(CdSe-ZnS)作为光敏剂,以人前髓细胞（早幼细胞）株HI6O为研究对...     

Construction of photodynamic‐effect immunofluorescence probes by a complex of quantum dots,immunoglobulin G and chlorin e6 and their application in HepG2 cell killing

In this study, tri‐functional immunofluorescent probes (Ce6–IgG–QDs) based on covalent combinations of quantum dots (QDs), immunoglobulin G (IgG) and chlorin e6 (Ce6) were developed and their photodynamic ability to induce the death of cancer cells was demonstrated. Strategically, one type of second‐generation photosensitizer, Ce6, was first coupled with anti‐IgG antibody using the EDC/NHS cross‐linking method to construct the photosensitive immunoconjugate Ce6–IgG. Then, a complex of Ce6–IgG–QDs immunofluorescent probes was obtained in succession by covalently coupling Ce6–IgG to water soluble CdTe QDs. The as‐manufactured Ce6–IgG–QDs maintained the bio‐activities of both the antigen–antibody‐based tumour targeting effects of IgG and the photodynamic‐related anticancer activities of Ce6. By way of polyclonal antibody interaction with rabbit anti‐human epidermal growth factor receptor (anti‐EGFR antibody, N‐terminus), Ce6–IgG–QDs were labelled indirectly onto the surface of human hepatocarcinoma (HepG2) cells in cell recognition and killing experiments. The results indicated that the Ce6–IgG–QDs probes have excellent tumour cell selectivity and higher photosensitivity in photodynamic therapy (PDT) compared with Ce6 alone, due to their antibody‐based specific recognition and location of HepG2 cells and the photodynamic effects of Ce6 killed cells based on efficient fluorescence resonance energy transfer between QDs and Ce6. Copyright © 2015 John Wiley & Sons, Ltd.     

Direct and indirect immunolabelling of HeLa cells with quantum dots

With excellent optical properties, quantum dots (QDs) have been made as attractive molecular probes for labelling cells in biological research. In this study high‐quality CdSe QDs prepared in a paraffin–oleic acid system were used as fluorescent labels in direct and indirect detection of carcinoembryonic antigen (CEA), a cancer marker expressed on the surface of HeLa cells. The primary antibody (Ab) (rabbit anti‐CEA8) and secondary Ab (goat anti‐rabbit IgG) were covalently linked to carboxyl‐functioned CdSe QDs, and both the QDs–antibody and QDs–IgG probes were successfully used to label HeLa cells. The present study demonstrates the practicability of CdSe QDs as an attractive type of fluorescent labels for biological applications such as protein probes and cell imaging. Copyright © 2008 John Wiley & Sons, Ltd.     

Potential therapeutic application of gold nanoparticles in B-chronic lymphocytic leukemia (BCLL): enhancing apoptosis

Background  

Neuroblastoma, a frequently occurring solid tumour in children, remains a therapeutic challenge as existing imaging tools are inadequate for proper and accurate diagnosis, resulting in treatment failures. Nanoparticles have recently been introduced to the field of cancer research and promise remarkable improvements in diagnostics, targeting and drug delivery. Among these nanoparticles, quantum dots (QDs) are highly appealing due to their manipulatable surfaces, yielding multifunctional QDs applicable in different biological models. The biocompatibility of these QDs, however, remains questionable.     

量子点-人表皮生长因子纳米荧光探针的制备及其对卵巢癌细胞SKOV-3的识别

在连接试剂1-乙基-3（3-二甲基胺基丙基）碳二亚胺盐酸盐（1-ethyl-3（3-dimethylamino propyl）-carbodiimide,EDC）的作用下,将水相合成的量子点（Quantumdots,QDs）与人表皮生长因子（Epidermal growth factor,EGF）进行了连接,通过毛细管电泳、吸收光谱以及荧光光谱对连接前后的QDs进行了表征,获得的QDs—EGF可识别卵巢癌细胞SKOV-3。     

功能化量子点在肿瘤诊治中的应用

量子点是一种半导体纳米晶体,它可发出激发荧光,具有亮度高、稳定时间长和发射光谱可调节等特性,是同时检测多信号的良好材料.这些独特性质使得它们在肿瘤诊治领域中的应用日益受到人们的重视.对量子点进行功能化修饰,如偶联抗体等活性物质后,可以对肿瘤细胞进行特异性识别及示踪,以实现对肿瘤的诊断和治疗.文中分别从分子靶向识别、淋巴结定位和药物传递等方面探讨了功能化量子点在肿瘤诊断和治疗中的最新进展.此外,还讨论了量子点的毒性以及用于肿瘤检测和治疗的多功能量子点的设计方法,并提出了其实际应用的潜在方向.     

Molecular profiling of single cancer cells and clinical tissue specimens with semiconductor quantum dots

Semiconductor quantum dots (QDs) are a new class of fluorescent labels with broad applications in biomedical imaging, disease diagnostics, and molecular and cell biology. In comparison with organic dyes and fluorescent proteins, quantum dots have unique optical and electronic properties such as size-tunable light emission, improved signal brightness, resistance against photobleaching, and simultaneous excitation of multiple fluorescence colors. Recent advances have led to multifunctional nanoparticle probes that are highly bright and stable under complex in vitro and in vivo conditions. New designs involve encapsulating luminescent QDs with amphiphilic block copolymers, and linking the polymer coating to tumor-targeting ligands and drug-delivery functionalities. These improved QDs have opened new possibilities for real-time imaging and tracking of molecular targets in living cells, for multiplexed analysis of biomolecular markers in clinical tissue specimens, and for ultrasensitive imaging of malignant tumors in living animal models. In this article, we briefly discuss recent developments in bioaffinity QD probes and their applications in molecular profiling of individual cancer cells and clinical tissue specimens.     

Targeting and sensing cancer cells with ZnO nanoprobes in vitro

A new class of zinc oxide quantum dots (ZnO QDs) was investigated as nanoprobes for targeting cancer cells in vitro. ZnO nanoparticles were synthesized using conventional sol–gel method and encapsulated using trimethoxy aminopropyl silane. Transferrin, the ligand targeting the cancer cells, was conjugated to the ZnO QDs. In vitro imaging studies using MDA-MB-231 showed the biocompatible ZnO nanoprobe selectively binding to the cell surface receptor and internalizing through receptor-mediated endocytosis. Time-lapsed photobleaching studies indicate the ZnO QDs to be resistant to photobleaching, making them suitable for long term imaging purpose. Investigation of the ZnO nanoprobe as a platform for sensitive bioassays indicates that it can be used as an alternative fluoroprobe for cancer cell targeting and sensing applications.