荧光超分子聚合物研究进展

超分子聚合物是单体通过非共价键有序组装形成的一种新型聚合物。非共价相互作用赋予了超分子聚合物动态可逆性、刺激响应性及自适性。荧光超分子聚合物是将荧光团引入到超分子聚合物中,从而赋予超分子聚合物特殊的光学性能。因此,荧光超分子聚合物固有的发光性质及动态可逆性使得超分子聚合物被广泛应用于荧光传感器、探针、显影剂及发光二极管等领域。本文根据发光颜色不同的荧光超分子聚合物的设计及应用进行分类,并对荧光超分子聚合物的未来发展进行展望。     

分子印迹荧光传感构建及应用

构建一个高灵敏、高选择性检测痕量分析物的传感器广受科研工作者关注。分子印迹技术由于具有高选择性识别、高容量吸附、快速结合、热稳定性以及低成本等优点,已广泛应用于传感构建领域。以分子印迹聚合物为识别单元,结合荧光传感技术所构建的分子印迹荧光传感器在环境污染物痕量检测方面成为研究重点。本文主要介绍分子印迹聚合物的制备方法,总结分子印迹荧光传感器的构建机理和分子印迹荧光传感器在金属离子、有机小分子以及生物大分子检测方面的应用。重点探讨分子印迹传感器在不同数量的荧光团下检测一种或多种目标分析物的方法,包括单一荧光团检测单一目标物、比率荧光检测单一目标物以及分子印迹荧光传感的多元检测。基于以上分析和总结,提出分子印迹荧光传感器的当前挑战和发展前景。     

单分子荧光技术与聚合物单链物理性质的研究

对以荧光关联光谱、荧光光子计数直方图技术、单分子荧光成像、单分子荧光散焦成像等单分子荧光技术为主要研究手段开展的关于聚合物单分子链物理化学性质的研究工作进行了总结与介绍,重点介绍了本实验室在聚电解质单链构象转变及抗衡离子分布、表界面聚合物单链动态性质、空间受限状态下聚合物单分子链及单分子链段的平动扩散、转动运动的研究工...     

基于铕配合物的荧光分子印迹的制备及其选择性检测痕量2,4,6-三氯苯酚

设计并制备了用于检测2,4,6-三氯苯酚的荧光分子印迹。由于铕配合物对模板分子的荧光淬灭作用,可用于荧光检测工具。荧光分子印迹在模板分子浓度范围0~70 nmol·L~(-1)内具有良好的荧光线性响应,相关系数为0.996 28。荧光分子印迹展现出了良好的灵敏度,其最低检出限为3.12 nmol·L~(-1)。荧光分子印迹具有较好的热稳定性,同时选择性检测实验证明荧光分子印迹对2,4,6-三氯苯酚具有良好的特异选择性。实验结果说明荧光分子印迹可用于选择性荧光检测低浓度氯酚类物质。     

新型分子印迹荧光传感器的构建与应用

分子印迹聚合物因具有构效预定性、特异识别性和广泛实用性,将其作为传感器识别单元的研究已成为当前的研究热点.分子印迹荧光传感器结合了分子印迹的高选择性与荧光检测的高灵敏度,非常适合复杂样品中痕量目标物的分析测定,在分离检测等领域备受关注.根据荧光材料的不同,本文详细介绍了以量子点、有机荧光染料、化学发光反应物质以及其他材料为荧光信号单元的新型分子印迹荧光传感器的构建与应用,总结了不同荧光传感器的构建方法、检测机理,探讨了基于比率型荧光的分子印迹传感器的制备与发展,并对分子印迹荧光传感器的发展前景进行了展望.     

荧光染料探针分子对变异细胞的识别

介绍了变异细胞的结构特征、细胞识别与荧光标记技术以及荧光染料探针分子标记细胞的方式。简述了荧光染料探针分子用于变异细胞组织的标记与识别的研究新进展。并针对目前荧光染料探针分子的应用现状，分析了未来的发展趋势，包括增强荧光染料探针分子与人体组织的相容性、靶向性，提高其灵敏度，降低毒性等的方法和途径。简述了固相合成分离技术用于探针分子的制备与纯化的优越性。     

钐配合物有序分子膜的激光诱导荧光研究

用Langmuir-Blodgett(LB)膜方法组装了可发红色荧光的钐配合物有序分子膜。用时间分辨技术得到了其激光诱导荧光光谱,并分析了荧光光谱的精细结构,计算了有序分子膜中钐离子的能级常数,测定了配合物中心离子的荧光寿命,从分子内及分子间能量转移机理上研究了分子存在状态、膜中组分对钐配合物荧光寿命及能级常数的影响。     

基于大环分子的主客体超分子荧光探针

针对环境污染源的早期检测和疾病的预防与治疗已经研究开发出许多检测技术手段,其中,荧光探针作为一种方便、灵敏、可视化的检测技术得到了广泛关注与认可。大环分子荧光探针作为一类重要的荧光探针逐渐引起了研究者的关注。大环分子具有特定尺寸、可特异性配合某些基团的空腔。因此,在设计这类荧光探针时可以充分利用大环分子的空腔优势。此外,大环分子容易通过化学修饰制备多种功能化衍生物,这也为设计大环荧光探针提供了更多选择。本文回顾了大环分子荧光探针的设计策略,主要从探针的化学组成以及相互作用机理来阐述,为大环分子荧光探针的设计提供了系统的理论指导。     

分子印迹荧光传感器研究进展

分子印迹技术是结合高分子化学、分析化学、材料科学等发展起来的一门边缘学科,是模拟受体-抗体相互作用的一种新技术。分子印迹荧光传感器结合了分子印迹聚合物的预定识别性和高选择性以及荧光检测的高灵敏性,成为传感领域的研究热点。本文主要介绍了分子印迹荧光传感器的研究进展,重点概述了分子印迹荧光传感器的制备原理、检测方式及其在有机小分子和离子检测中的应用,并对其发展前景进行了展望。     

活细胞内单个分子荧光检测

简要介绍了单个分子荧光检测在活细胞体系研究中的优势,介绍并讨论了单个分子荧光检测的主要技术和标记、检测方法,并回顾了目前单个分子荧光检测技术在生命科学研究中所取得的进展。     

Unambiguous detection of target DNAs by excimer-monomer switching molecular beacons

A new class of molecular beacons were developed in which pyrene fluorophores were connected both at 3' and 5' ends of a single-stranded oligonucleotide. The two pyrene-based fluorophores were synthesized from the same starting material, so that the preparation of the beacons was simplified. The detection strategy of the beacons for target DNAs is based on "excimer-monomer emission switching" of the pyrene fluorophores: excimer emission of the pyrene moieties changed to monomer one when the beacons hybridized with the targets. This type of two-state mode of fluorescence allows unambiguous detection of the target DNAs because strict 1:1 correlation between the nonhybridized and the hybridized beacons can be monitored by the presence of isoemissive points of the fluorescence changes. The beacons can detect target 19-mer DNAs and can discriminate the targets from their single-nucleotide mismatches at 1 nM concentration. Advantages of the excimer-monomer switching molecular beacons were discussed in comparison with conventional ones.     

Surface-enhanced Raman nanoparticle beacons based on bioconjugated gold nanocrystals and long range plasmonic coupling

We have developed a new class of surface-enhanced Raman scattering beacons (SERS beacons) that can be turned on and off by long-range plasmonic coupling, induced by biomolecular recognition and binding events. The beacons are based on colloidal gold nanocrystals in two sizes (40 and 60 nm) and are prepared by spectral encoding with a Raman reporter molecule, functionalized with thiolated DNA probes, and stabilized and protected by low molecular weight poly(ethylene glycol)s (PEGs). The results show the SERS signal intensities increase by 40-200-fold when the nanoparticle beacons are activated by plasmonic coupling, much higher than the bright-to-dark intensity ratios reported for traditional molecular beacons. Multivalent gold nanoparticles also have exquisite specificity and are able to recognize single-base mismatches or mutations. This class of SERS nanoparticle beacons has novel mechanisms for molecular detection and signal amplification, and its long-range coupling nature raises new opportunities in developing plasmonic probes to detect proteins, cells, and intact viruses.     

TaqMan-分子灯标：一种新型的荧光基因检测探针

在TaqMan及分子灯标的基础上开发了一类新型的均相荧光检测探针—— TaqMan-分子灯标(TaqMan-MB)，该探针集合了分子灯标的发夹结构及TaqMan探针降 解作用的工作原理，使检测效果更好．与实时PCR仪联用，可用于靶基因的定量检 测．     

Specific and Direct Amplified Detection of MicroRNA with MicroRNA:Argonaute‐2 Cleavage (miRACle) Beacons

MicroRNA detection is a valuable method for determining cell identity. Molecular beacons are elegant sensors that can transform intracellular microRNA concentration into a fluorescence intensity. While target binding enhances beacon fluorescence, the degree of enhancement is insufficient for demanding applications. The addition of specialty nucleases can enable target recycling and signal amplification, but this process complicates the assay. We have developed and characterized a class of beacons that are susceptible to the endogenous nuclease Argonaute‐2 (Ago2). After purification of the complex by co‐immunoprecipitation, microRNA:Ago2 cleavage (miRACle) beacons undergo site‐ and sequence‐specific cleavage, and show a 13‐fold fluorescence enhancement over traditional beacons. The system can be adapted to any microRNA sequence, and can cleave nuclease‐resistant, non‐RNA bases, potentially allowing miRACle beacons to be designed for cells without interference from non‐specific nucleases.     

Hybridization of DNA and PNA molecular beacons to single-stranded and double-stranded DNA targets

Molecular beacons are sensitive fluorescent probes hybridizing selectively to designated DNA and RNA targets. They have recently become practical tools for quantitative real-time monitoring of single-stranded nucleic acids. Here, we comparatively study the performance of a variety of such probes, stemless and stem-containing DNA and PNA (peptide nucleic acid) beacons, in Tris-buffer solutions containing various concentrations of NaCl and MgCl(2). We demonstrate that different molecular beacons respond differently to the change of salt concentration, which could be attributed to the differences in their backbones and constructions. We have found that the stemless PNA beacon hybridizes rapidly to the complementary oligodeoxynucleotide and is less sensitive than the DNA beacons to the change of salt thus allowing effective detection of nucleic acid targets under various conditions. Though we found stemless DNA beacons improper for diagnostic purposes due to high background fluorescence, we believe that use of these DNA and similar RNA constructs in molecular-biophysical studies may be helpful for analysis of conformational flexibility of single-stranded nucleic acids. With the aid of PNA "openers", molecular beacons were employed for the detection of a chosen target sequence directly in double-stranded DNA (dsDNA). Conditions are found where the stemless PNA beacon strongly discriminates the complementary versus mismatched dsDNA targets. Together with the insensitivity of PNA beacons to the presence of salt and DNA-binding/processing proteins, the latter results demonstrate the potential of these probes as robust tools for recognition of specific sequences within dsDNA without denaturation and deproteinization of duplex DNA.     

A modified molecular beacon combining the properties of TaqMan probe

A modified molecular beacon that possesses a stem-hairpin structure as seen in conventional molecular beacons and can be cleaved during PCR in designed, and it can specifically recognize the presence of the target and was obviously more sensitive than conventional molecular beacons.     

Molecular beacons: a novel DNA probe for nucleic acid and protein studies

A new concept has been introduced for molecular beacon DNA molecules. Molecular beacons are a new class of oligonucleotides that can report the presence of specific nucleic acids in both homogeneous solutions and at the liquid-solid interface. They emit an intense fluorescent signal only when hybridized to their target DNA or RNA molecules. Biotinylated molecular beacons have been designed and used for the development of ultrasensitive DNA sensors and for DNA molecular interaction studies at a solid-liquid interface. Molecular beacons have also been used to study protein-DNA interactions. They have provided a variety of exciting opportunities in DNA/RNA/protein studies.     

Chimeric peptide beacons: a direct polypeptide analog of DNA molecular beacons

We have developed a new biosensor architecture, which is comprised of a polypeptide-peptide nucleic acid tri-block copolymer and which we have termed chimeric peptide beacons (CPB), that generates an optical output via a mechanism analogous to that employed in DNA-based molecular beacons.     

Advanced Photosensitizer Activation Strategies for Smarter Photodynamic Therapy Beacons

Photodynamic therapy (PDT) is a clinical treatment in which a light‐absorbing drug called a photosensitizer (PS) is combined with light and molecular oxygen to generate cytotoxic singlet oxygen. PDT provides additional tissue selectivity compared to conventional chemotherapy as singlet oxygen is generated only in areas in which PS accumulates and that are simultaneously illuminated by a light source with sufficient irradiance and dose. Early PDT beacons built on this concept by adding an analyte‐responsive element that simultaneously turns on PDT and fluorescence, providing both an additional layer of selectivity and real‐time feedback of the PS′s activation state. More recent PDT beacons have expanded this idea, with new methods now available for sensing analytes, generating singlet oxygen, and reporting treatment status. In this Minireview, we consider developments in advanced activation strategies implemented in therapeutic and theranostic beacons.     

Monitoring mRNA in living cells in a 3D in vitro model using TAT-peptide linked molecular beacons

There is a growing need for the development of in vitro 3D cell culture models for assessing newer therapeutics for clinical applications and mechanisms of human pathology. Molecular beacons have been successfully delivered in two-dimensional (2D) systems to monitor, detect, and localize specific mRNA expression in living cells at the single cell level. However, to date the use of molecular beacons in three-dimensional (3D) systems has not been reported. To translate this technology into specific clinical targeted applications, it is critical to develop and demonstrate efficacy in a 3D system. For the first time the use of TAT-peptide conjugated molecular beacons to monitor mRNA in a 3D in vitro system has been reported.