Caged molecular beacons: controlling nucleic acid hybridization with light

We have constructed a novel class of light-activatable caged molecular beacons (cMBs) that are caged by locking two stems with a photo-labile biomolecular interaction or covalent bond. With the cMBs, the nucleic acid hybridization process can be easily controlled with light, which offers the possibility for a high spatiotemporal resolution study of intracellular mRNAs.     

厦门大学"化学学科拔尖学生培养试验计划"的探索与实践

全面介绍了厦门大学化学学科拔尖学生培养试验计划的探索与实施,包括:目标定位、生源遴选、导师配备、课程体系、科研训练、管理机制和实施成效等。     

Preparation and electro‐optical properties of polymer dispersed liquid crystal films with relatively low liquid crystal content

In this paper, polymer dispersed liquid crystals (PDLC) films with LC content as low as 40 wt% were prepared, and the electro‐optical properties were carefully investigated. To accomplish this, different (meth)acrylate copolymerizaiton monomers have been used. The electro‐optical properties and morphologies of the PDLC films were strongly influenced by the chemical structure of copolymerization monomers (hydroxypropyl methacrylate (HPMA), glycidyl methacrylate, hydroxypropyl acrylate) and their feed ratio. Lower driven voltage and higher contrast ratio were achieved when the PDLC films showed a morphology with suitably LC domain size. At high HPMA content, a thin polymer film was formed on the surface of PDLC samples, which is beneficial to decrease the total LC content in PDLC devices. Copyright © 2013 John Wiley & Sons, Ltd.     

A Multifunctional Nanomicelle for Real‐Time Targeted Imaging and Precise Near‐Infrared Cancer Therapy

Simultaneous targeted cancer imaging, therapy and real‐time therapeutic monitoring can prevent over‐ or undertreatment. This work describes the design of a multifunctional nanomicelle for recognition and precise near‐infrared (NIR) cancer therapy. The nanomicelle encapsulates a new pH‐activatable fluorescent probe and a robust NIR photosensitizer, R16FP, and is functionalized with a newly screened cancer‐specific aptamer for targeting viable cancer cells. The fluorescent probe can light up the lysosomes for real‐time imaging. Upon NIR irradiation, R16FP‐mediated generation of reactive oxygen species causes lysosomal destruction and subsequently trigger lysosomal cell death. Meanwhile the fluorescent probe can reflect the cellular status and in situ visualize the treatment process. This protocol can provide molecular information for precise therapy and therapeutic monitoring.     

Directional Regulation of Enzyme Pathways through the Control of Substrate Channeling on a DNA Origami Scaffold

Artificial multi‐enzyme systems with precise and dynamic control over the enzyme pathway activity are of great significance in bionanotechnology and synthetic biology. Herein, we exploit a spatially addressable DNA nanoplatform for the directional regulation of two enzyme pathways (G6pDH–MDH and G6pDH–LDH) through the control of NAD⁺ substrate channeling by specifically shifting NAD⁺ between the two enzyme pairs. We believe that this concept will be useful for the design of regulatory biological circuits for synthetic biology and biomedicine.     

Recent Progress in Aptamer‐Based Functional Probes for Bioanalysis and Biomedicine

Nucleic acid aptamers are short synthetic DNA or RNA sequences that can bind to a wide range of targets with high affinity and specificity. In recent years, aptamers have attracted increasing research interest due to their unique features of high binding affinity and specificity, small size, excellent chemical stability, easy chemical synthesis, facile modification, and minimal immunogenicity. These properties make aptamers ideal recognition ligands for bioanalysis, disease diagnosis, and cancer therapy. This review highlights the recent progress in aptamer selection and the latest applications of aptamer‐based functional probes in the fields of bioanalysis and biomedicine.     

1,2-二硫方酸的气相酸性和芳香性

在ＲＨＦ／６－３１１Ｇ、ＲＨＦ／６－３１１＋Ｇ　和Ｂ３ＬＹＰ／６－３１１＋Ｇ　水平,优化得到１,２－二硫方酸（３,４．二羟基－３－环丁烯－１,２－二硫酮）三种平面构象异构体的平衡几何构型．进一步用ＭＰＺ（ｆｕｌｌ）／６－３１１＋Ｇ　、／／ＲＨＦ／６－３１１＋Ｇ　方法计算三种异构体的单点能量,发现ＺＺ型异构体是能量最低构象,且ＺＺ和ＺＥ型能量非常接近．用优化的最稳定构象ＺＺ型异构体,在ＲＨＦ／６－３１１Ｇ　／／ＲＨＦ／６－３１１Ｇ　、ＲＨＦ／６．３１１＋Ｇ　／／ＲＨＦ／６－３１１＋Ｇ　、ＭＰＺ（ｆｕｌｌ）／６．３１１＋Ｇ　／／ＲＨＦ／６－３１１＋Ｇ　和Ｂ３ＬＹＰ／６－３１１＋Ｇ　斤Ｂ３ＬＹＰ／６－３１１＋Ｇ　水平,计算其气相酸性（△Ｇ＿２９８）,并用同键反应方法在同样水平计算其芳香性稳定化能．用基团加和法（ｇｒｏｕｐｉｎｃｒｅｍｅｎｔａｐｐｒｏａｃｈ）在ＲＨＦ／６．３１１＋Ｇ　／／ＲＨＦ／６－３１１＋Ｇ　和Ｂ３ＬＹＰ／６－３１１＋Ｇ　／／Ｂ３ＬＴｈ／６－３１１＋Ｇ　水平计算其磁化率增量（　）．计算结果指出,标题化合物的键长发生了平均化,芳香性稳定化能和磁化率增量均为负值,表明它具有芳香性,实现了标题化合物芳香     

Theoretical determination of lowest structures of all‐metal aromatic clusters M4L2 (M = Al,Ga, In,Tl; L = Li,Na, K,Rb, Cs)

The researches of all‐metal aromatic clusters have been a thermic theme in inorganic aromaticity domain both experimentally and theoretically since the Al₄L^? (L = Li, Na, Cu) clusters were created by laser vaporization. In systemic determination of the lowest structures of 20 gaseous all‐metal aromatic clusters M₄L₂ (M = Al, Ga, In, Tl; L = Li, Na, K, Rb, Cs), the isomer energy differences of four low‐lying structures of each cluster were evaluated at high‐quality quantum chemistry levels. Single point calculations at the coupled cluster level were performed at geometries optimized at the MP2, B3LYP, and B3PW91 levels, and harmonic frequency calculations and zero point energy corrections were implemented following optimizations at the B3LYP and B3PW91 levels. In addition to Li‐ and Na‐containing species, theoretical investigations came down to those new clusters including K, Rb, and Cs. For many clusters, the most convincing theoretical evidences indicate that the lowest structures are a square bipyramidal isomer rather than an edge‐caped square pyramidal species. A few discrepancies were addressed at the MP2, B3LYP, and B3PW91 levels in comparison with the coupled cluster results. These findings are significant because some clusters were generated by laser vaporization and served as theoretical prototypes to test the new means for assessing aromaticity. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010     

Molecular beacons for bioanalytical applications

Molecular beacons (MBs) are hairpin-shaped oligonucleotides that contain both fluorophore and quencher moieties. They act like switches and are normally in a closed state, when the fluorophore and the quencher are brought together to turn "off" the fluorescence. When prompted to undergo conformational changes that open the hairpin structure, the fluorophore and the quencher are separated, and fluorescence is turned "on." This Education will outline the principles of MBs and discuss recent bioanalytical applications of these probes for in vitro RNA and DNA monitoring, biosensors and biochips, real-time monitoring of genes and gene expression in living systems, as well as the next generation of MBs for studies on proteins, the MB aptamers. These important applications have shown that MBs hold great potential in genomics and proteomics where real-time molecular recognition with high sensitivity and excellent specificity is critical.     

Highly sensitive and quantitative detection of rare pathogens through agarose droplet microfluidic emulsion PCR at the single-cell level

Genetic alternations can serve as highly specific biomarkers to distinguish fatal bacteria or cancer cells from their normal counterparts. However, these mutations normally exist in very rare amount in the presence of a large excess of non-mutated analogs. Taking the notorious pathogen E. coli O157:H7 as the target analyte, we have developed an agarose droplet-based microfluidic ePCR method for highly sensitive, specific and quantitative detection of rare pathogens in the high background of normal bacteria. Massively parallel singleplex and multiplex PCR at the single-cell level in agarose droplets have been successfully established. Moreover, we challenged the system with rare pathogen detection and realized the sensitive and quantitative analysis of a single E. coli O157:H7 cell in the high background of 100?000 excess normal K12 cells. For the first time, we demonstrated rare pathogen detection through agarose droplet microfluidic ePCR. Such a multiplex single-cell agarose droplet amplification method enables ultra-high throughput and multi-parameter genetic analysis of large population of cells at the single-cell level to uncover the stochastic variations in biological systems.