检测乙酰胆碱酯酶的双光子荧光探针的设计、合成及生物学评价

目的 设计并合成用于检测乙酰胆碱酯酶（acetylcholinesterase，AChE）的双光子荧光探针，并考察探针对AChE的成像检测性能。方法 经酯化、取代等多步有机反应合成探针，并通过¹H-NMR、¹³C-NMR和ESI-MS确认结构。考察探针与AChE发生响应后的荧光信噪比、灵敏度、特异性、酶动力学和双关子吸收截面积数值等指标；研究探针可否用于AChE抑制剂的体外筛选；利用单-双光子成像试验考察探针在细胞和组织水平上对AChE活力变化的检测能力。结果 通过¹H-NMR、¹³C-NMR和ESI-MS确认了产物的结构。体外试验表明探针与AChE响应后的荧光信噪比为15倍，检测限达到0.23 U·mL^–1，并具有很强的特异性和优良的酶亲合能力，在波长820 nm有最优的双光子吸收；探针可用于AChE抑制剂的体外筛选；探针通过单-双光子成像技术可对细胞和组织水平上的AChE活力变化进行成像检测，并且组织成像检测深度可达110 μm。结论 本研究成功开发了可用于AChE检测的双光子荧光探针，有潜力成为可用于活体中检测AChE活力的双光子成像试剂。     

绿色荧光蛋白在药物发现研究中的应用进展

目的药物的设计与筛选是药物研究的重要环节,绿色荧光蛋白(green fluorescent protein,GFP)在药物发现研究中有着重要的意义和价值。方法通过综述22篇中、英文文献,在化学药物基因药物等方面介绍了绿色荧光蛋白及其在药物发现研究中的应用。结果绿色荧光蛋白最早发现于美国西北海岸的水母中,在紫外照射下可以产生明亮的绿色荧光。它具有很多理想性的特征,如对酸、碱、氧化还原剂等许多化学试剂有极强的稳定性,因此常被于活体细胞或组织的跟踪、标记中,被喻为"活的"分子探针。通过监测绿色荧光蛋白可以对体内基因表达、细胞内蛋白质原位定位,观测肿瘤发生、生长、转移等过程,提供重要生物学靶标有效信息。结论绿色荧光蛋白在药物设计和筛选等领域展示了广阔前景,它与药物设计、药物筛选的结合将为新药研究和开发注入新的活力。     

双光子荧光影像技术在药物研发中的应用前景

双光子荧光显微成像技术具有高分辨率和高灵敏度,与激光共聚焦显微镜相比,它在成像的穿透深度上有显著提高,大大降低光毒性和光漂白,这些优点有利于双光子荧光显微成像技术用于组织样品的候选药物筛选,有望成为有效缩短新药研发周期、降低新药开发成本和提高新药命中率的手段。     

量子点在高通量中药有效成分筛选中的作用

量子点系统研究是近年来的热门话题.其研究内容涉及物理、化学、材料、生物等多学科,已成为一门新兴的交叉学科.而针对中草药的作用机制不明确、活性成分不清楚、寻找有效成分及作用的靶点困难等问题,量子点有可能成为筛选药物、发现药物靶点的有力工具.本文着重阐述了量子点作为荧光探针在中药有效成分筛选方面的研究进展.     

分子影像技术在药物研发中的应用

分子影像可在活体状态下对生物和生化过程进行无创研究。该技术包括分子探针和分子成像技术,可通过特异性探针或报告基因成像。运用分子影像技术可筛选侯选化合物,评价药物对肿瘤代谢、增殖、血管发生和凋亡的影响,评价药物对组织缺氧的影响。分子影像技术是药物作用机制研究的重要手段,将大大加快药物研发进程。     

药物蛋白质组学研究进展

药物蛋白质组学是基因组和药物发现之间的桥梁,目前已广泛应用于临床和生物医学的各个领域.其研究内容在临床前包括:构建分子药理筛选模型、筛选药物作用靶点、研究药物作用机制和毒理机制等;临床研究包括:利用疾病特异性蛋白质作为疾病分类分型和诊断的标志,还用于评价疗效和预测疾病的预后和转归等.     

毛细管电泳技术在研究生物分子间相互作用和药物筛选中的应用

毛细管电泳技术是八十年代初发展起来的一种新型分离分析技术。由于其分析时间短，样品消耗少，分离度高，应用灵活，能够在生理条件或者接近生理条件的缓冲液中运行等优点，广泛应用于研究生物分子间的相互作用。本文就毛细管电泳研究生物分子间相互作用的基本原理，及其在生物分子间相互作用和药物筛选中的应用进行了综述。对不同的分子间相互作用体系，如蛋白质-蛋白质／多肽，蛋白质-DNA／RNA，蛋白质-糖，抗原-抗体，蛋白质-药物，脂质体-蛋白质／药物等进行了论述。同时也探讨了毛细管电泳从组合化学库中筛选先导药物及其在药物筛选中的应用。     

毛细管电泳和微流控芯片在药物筛选中的应用

药物筛选是现代药物开发流程中测试和获取特定生理活性化合物的一个步骤.毛细管电泳技术由于具有样品消耗量小、速度快、柱效高以及所用溶液体系较接近生物体液组成等特点,已经成为一种非常具有潜力的药物及先导化合物的高效筛选工具.文中就毛细管电泳技术在药物筛选中的最新应用情况进行综述,具体从测定药物解离常数pKa值、药物脂水分配系数(logP)、药物与蛋白质的结合常数的测定以及手性药物筛选等方面进行论述,同时也探讨了微流控芯片技术在高通量药物筛选方面的最新研究进展.     

用荧光参数表征牛血清白蛋白在脲中的变化过程

目的 研究牛血清白蛋白在脲中的构象变化过程,根据荧光参数的变化,建立蛋白构象与环境变化的关系,从分子水平探讨蛋白质构象变化而致不稳定的原因.方法 采用内源性荧光法、荧光淬灭法及荧光探针法研究牛血清白蛋白在脲中的构象变化过程.结果 随着脲浓度的增加,牛血清白蛋白中内源性色氨酸荧光峰位先蓝移后红移,荧光强度逐步衰减;而8 -苯胺基-1-萘磺酸与牛血清白蛋白结合物的荧光峰位则逐步红移,荧光强度逐渐衰减.结论 在变性过程中,牛血清白蛋白的色氨酸残基所处区域构象经历了一个先紧缩后舒展的三态过程;而8 -苯胺基-1-萘磺酸的探针结合位点与色氨酸残基可能位于牛血清白蛋白的不同区域,且构象变化更为灵敏.     

研究开发出对 mRNA-蛋白质相互作用的定量检测的新技术

近日，来自美国爱因斯坦医学院的研究人员在著名国际学术期刊 cell 发表了一项最新研究进展，他们利用双光子荧光涨落分析技术实现了对 mRNA-蛋白质相互作用的定量检测，这一技术对于研究 mRNA 在细胞内不同时空条件下的表达具有重要推动作用。     

Cellular screening assays using fluorescence microscopy.

The recent development of automated fluorescence imaging systems has enabled fluorescence microscopy to be used for the purposes of compound screening. This information-rich technique has found various applications, including screening for the effect of kinase inhibitors on the cytoskeleton, agonist-stimulated receptor internalization, and protein phosphorylation and acetylation. The discovery of novel fluorescent proteins and new fluorescent dyes will find many applications in multichannel fluorescence imaging assays.     

High-content assays in oncology drug discovery: opportunities and challenges

High-content screening (HCS), a process that combines fluorescence microscopic imaging and automated image analysis, has had a significant impact on drug discovery since its introduction in the mid 1990s. The application of HCS within pharmaceutical drug discovery has become widespread, notably within oncology drug discovery. The trends, challenges and considerations for HCS that affect the successful and pragmatic implementation of this process in drug discovery will be outlined.     

Technological Advances in High-Throughput Screening

High-throughput screening (HTS) is the process of testing a large number of diverse chemical structures against disease targets to identify 'hits'. Compared to traditional drug screening methods, HTS is characterized by its simplicity, rapidness, low cost, and high efficiency, taking the ligand-target interactions as the principle, as well as leading to a higher information harvest. As a multidisciplinary field, HTS involves an automated operation-platform, highly sensitive testing system, specific screening model (in vitro), an abundant components library, and a data acquisition and processing system. Various technologies, especially the novel technologies such as fluorescence, nuclear-magnetic resonance, affinity chromatography, surface plasmon resonance, and DNA microarray, are now available, and the screening of more than 100,000 samples per day is already possible. Fluorescence-based assays include the scintillation proximity assay, time-resolved energy transfer, fluorescence anisotropy, fluorescence correlation spectroscopy, and fluorescence fluctuation spectroscopy. Fluorescence-based techniques are likely to be among the most important detection approaches used for HTS due to their high sensitivity and amenability to automation, giving the industry-wide drive to simplify, miniaturize, and speed up assays. The application of NMR technology to HTS is another recent trend in drug research. One advantage afforded by NMR technology is that it can provide direct information on the affinity of the screening compounds and the binding location of protein. The structure-activity relationship acquired from NMR analysis can sharpen the library design, which will be very important in furnishing HTS with well-defined drug candidates. Affinity chromatography used for library screening will provide the information on the fundamental processes of drug action, such as absorption, distribution, excretion, and receptor activation; also the eluting curve can give directly the possibility of candidate drug. SPR can measure the quantity of a complex formed between two molecules in real-time without the need for fluorescent or radioisotopic labels. SPR is capable of characterizing unmodified biopharmaceuticals, studying the interaction of drug candidates with macromolecular targets, and identifying binding partners during ligand fishing experiments. DNA microarrays can be used in HTS be used to further investigate the expression of biological targets associated with human disease, which then opens new and exciting opportunities for drug discovery. Without doubt, the addition of new technologies will further increase the application of HTS in drug screening and its related fields.     

High-content screening: a new primary screening tool?

Given a pharmaceutical landscape in which fewer drugs are succeeding in reaching the market, pharmaceutical and biotechnological companies are seeking alternative screening methodologies that will be compatible with the large scale of current combinatorial chemical libraries. In this context, HCS has received considerable attention. Imaging technologies are playing an increasing role in the drug discovery and development process, and this role is projected to increase further in the future. Currently, these technologies are rarely applied in primary screening campaigns but, rather, are used in the processes that precede and follow primary screening. Imaging technologies are employed for target identification and validation, secondary screening, ADMET studies, and pharmacokinetic studies. Various labeling technologies are deployed for such imaging, including fluorescence, luminescence, PET and computer tomography (CT). This feature review discusses high-content analysis (HCA), including the HCS technology and methodology involved, and the future potential of HCA in the drug discovery process.     

Quantum dots, lighting up the research and development of nanomedicine

Quantum dots (QDs) have proven themselves as powerful inorganic fluorescent probes, especially for long term, multiplexed imaging and detection. The newly developed QDs labeling techniques have facilitated the study of drug delivery on the level of living cells and small animals. Moreover, based on QDs and fluorescence imaging system, multifunctional nanocomplex integrated targeting, imaging and therapeutic functionalities have become effective materials for synchronous cancer diagnosis and treatment. In this review, we will summarize the recent advances of QDs in the research of drug delivery system from the following aspects: surface modification strategies of QDs for drug delivery, QDs as drug nanocarriers, QD-labeled drug nanocarriers, QD-based fluorescence resonance energy transfer (FRET) technique for drug release study as well as the development of multifunctional nanomedicines. Possible perspective in this field will also be discussed. FROM THE CLINICAL EDITOR: This review discusses the role and significance of quantum dots (QDs) from the following aspects: surface modification strategies of QDs for drug delivery, QDs as drug nanocarriers, QD-labeled drug nanocarriers, QD-based fluorescence resonance energy transfer (FRET) technique for drug release study as well as the development of multifunctional nanomedicines.     

Targeted imaging: an important biomarker for understanding disease progression in the era of personalized medicine

The key to applying targeted imaging to personalized medicine is the choice of the right radiolabeled probe for the right target for the right disease following the lead of pharmaceutical development. The imaging approach differs depending on whether the target is a single disease control point (e.g. a specific receptor or transport protein linked to the mechanistic activity of a drug) or a general disease control point applicable to a number of treatment paradigms (e.g. proliferation, angiogenesis, inflammation). But in either case, the number of control points must be small given the time constraints on molecular imaging procedures in the clinic. Regardless of the choice, the radiotracer must be validated as binding to the target with the appropriate pharmacokinetics and pharmacodynamics for effective external imaging. Such an imaging agent developed in concert with drug development has a built in synergy that will accelerate the drug development process, targeted imaging and personalized medicine as well.     

Characterization of hydrophobized pullulan with various hydrophobicities

In this study, we prepared self-assembling nanospheres of hydrophobized pullulan. Pullulan acetate (PA), as hydrophobized pullulan, was synthesized by the acetylation of pullulan. PA derivatives were synthesized by changing the degree of acetylation. PA was characterized by Fourier transform infrared (FT-IR), X-ray diffractometry (XRD), and differential scanning calorimetry (DSC). The particle size distribution of the PA was determined using photon correlation spectroscopy (PCS) and the number-average particle size was found to depend upon the degree of acetylation of PA. Morphology by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) showed the PA nanospheres were spherical in shape. The fluorescence probe technique was used to study the self-association behavior of hydrophobized pullulans in water using pyrene as a hydrophobic probe. The critical association concentration (CAC) values were determined from the fluorescence excitation spectra, CAC values were dependent upon the degree of acetylation. Drug release studies using clonazepam (CNZ) as a hydrophobic model drug showed that the increased drug contents and increased degree of acetylation resulted in a slower release rate of drug from the nanospheres.     

Thermosensitive porphyrin-incorporated hydrogel with four-arm PEG-PCL copolymer (II): doxorubicin loaded hydrogel as a dual fluorescent drug delivery system for simultaneous imaging tracking in vivo

Visualization of a drug delivery system could reveal the pharmacokinetic properties, which is essential for the design of a novel drug delivery system. In vivo optical imaging offers an advanced tool to monitor the drug release process and the therapeutic effect by the combination of fluorescence imaging and bioluminescence imaging. Multispectral fluorescence imaging can separate the drug and the carrier without interference. Herein, a dual fluorescent anti-tumor drug delivery system was monitored with the doxorubicin-loaded hydrogel to further explore the application of the porphyrin-incorporated hydrogel with four-arm PEG-PCL copolymer as a drug carrier, based on the beneficial fluorescence and good biocompatibility of the porphyrin incorporated hydrogel. Using nude mice bearing luciferase expressed hepatic tumor as models, the whole process from the drug delivery to the tumor therapeutic effects were real time visualized simultaneously after administration at interval from 0 to 18 d. The imaging results suggest that the fluorescence signals of the drug and the carrier can be separated and unmixed from the drug-loaded hydrogel successfully, avoiding the interference of the fluorescence signals. The tumor growth or inhibition can be real time tracked and analyzed quantitatively by bioluminescence imaging. Noninvasive continuous tracking the in vivo drug delivery process simultaneously is a potential trend for the precise drug delivery and treatment.     

Fluorescence lifetime assays: current advances and applications in drug discovery

Introduction: Fluorescence lifetime assays complement the portfolio of established assay formats available in drug discovery, particularly with the recent advances in microplate readers and the commercial availability of novel fluorescent labels. Fluorescence lifetime assists in lowering complexity of compound screening assays, affording a modular, toolbox-like approach to assay development and yielding robust homogeneous assays. Areas covered: To date, materials and procedures have been reported for biochemical assays on proteases, as well as on protein kinases and phosphatases. This article gives an overview of two assay families, distinguished by the origin of the fluorescence signal modulation. Expert opinion: The pharmaceutical industry demands techniques with a robust, integrated compound profiling process and short turnaround times. Fluorescence lifetime assays have already helped the drug discovery field, in this sense, by enhancing productivity during the hit-to-lead and lead optimization phases. Future work will focus on covering other biochemical molecular modifications by investigating the detailed photo-physical mechanisms underlying the fluorescence signal.