Evaluation of Biological Toxicity of CdTe Quantum Dots with Different Coating Reagents according to Protein Expression of Engineering Escherichia coli

The results obtained from toxicity assessment of quantum dots (QDs) can be used to establish guidelines for the application of QDs in bioimaging. This paper focused on the design of a novel method to evaluate the toxicity of CdTe QDs using engineering Escherichia coli as a model. The toxicity of mercaptoacetic acid (MPA), glutathione (GSH), and L-cysteine (Cys) capped CdTe QDs was analyzed according to the heterologous protein expression in BL21/DE3, engineering Escherichia coli extensively used for protein expression. The results showed that the MPA-CdTe QDs had more serious toxicity than the other two kinds of CdTe QDs. The microscopic images and SEM micrographs further proved that both the proliferation and the protein expression of engineering Escherichia coli were inhibited after treatment with MPA-CdTe QDs. The proposed method is important to evaluate biological toxicity of both QDs and other nanoparticles

A cyclic enzymatic amplification method for sensitive and selective detection of nucleic acids

Based on Exonuclease III (Exo III) and displacing probes, we have developed a Cyclic Enzymatic Amplification Method (CEAM) for sensitive and selective detection of nucleic acids. In this design, the displacing probe is non-fluorescent on its own and cannot be digested by Exo III until displacement hybridization by a target sequence, leading to release of free non-quenched fluorophore. Because a single target sequence can lead to the release and digestion of numerous fluorophore strands from the displacing probe, a remarkable signal amplification is achieved. With this method, DNA can be detected in the picomolar range with a high selectivity and within less than 20 min.NSFC [20805038]; MOE [200803841013]; National Basic Research Program of China [2007CB935603, 2010CB732402

Agarose droplet microfluidics for highly parallel and efficient single molecule emulsion PCR

An agarose droplet method was developed for highly parallel and efficient single molecule emulsion PCR. The method capitalizes on the unique thermoresponsive sol-gel switching property of agarose for highly efficient DNA amplification and amplicon trapping. Uniform agarose solution droplets generated via a microfluidic chip serve as robust and inert nanolitre PCR reactors for single copy DNA molecule amplification. After PCR, agarose droplets are gelated to form agarose beads, trapping all amplicons in each reactor to maintain the monoclonality of each droplet. This method does not require cocapsulation of primer labeled microbeads, allows high throughput generation of uniform droplets and enables high PCR efficiency, making it a promising platform for many single copy genetic studies.National Scientific Foundation of China [20805038, 21075104, 20620130427]; National Basic Research Program of China [2007CB935603, 2010CB732402

A T7 exonuclease-assisted cyclic enzymatic amplification method coupled with rolling circle amplification: a dual-amplification strategy for sensitive and selective microRNA detection

National Basic Research Program of China [2010CB732402, 2013CB933703]; National Science Foundation of China [21205100, 21275122, 21075104]; National Instrumentation Program [2011YQ03012412]; Fundamental Research Funds for the Central Universities [2012121025]; Natural Science Foundation of Fujian Province for Distinguished Young Scholars [2010J06004]A T7 exonuclease-assisted cyclic enzymatic amplification method (CEAM) was combined with rolling circle amplification (RCA) to develop a RCA-CEAM dual amplification method for ultrasensitive detection of microRNA with excellent selectivity

Carbon nanoparticle-protected aptamers for highly sensitive and selective detection of biomolecules based on nuclease-assisted target recycling signal amplification

National Basic Research Program of China [2010CB732402, 2013CB933703]; National Science Foundation of China [91313302, 21205100, 21275122, 21075104]; National Science Foundation for Distinguished Young Scholars of China [21325522]; NFFTBS [J1030415]; Open Funding Project of the State Key Laboratory of Bioreactor EngineeringBased on the protective properties of carbon nanoparticles for aptamers against the digestion of nuclease, we have developed a nuclease-assisted target recycling signal amplification method for highly sensitive detection of biomolecules, such as ATP and kanamycin. The high binding specificity between aptamers and targets leads to excellent selectivity of the assay

An Improved SVM Based on Similarity Metric

Abstract: A novel support vector machine method for classification is presented in this paper. A modified kernel function based on the similarity metric and Riemannian metric is applied to the support vector machine. In general, it is believed that the similarity of homogeneous samples is higher than that of inhomogeneous samples. Therefore, in Riemannian geometry, Riemannian metric can be used to reflect local property of a curve. In order to enlarge the similarity metric of the homogeneous samples or reduce that of the inhomogeneous samples in the feature space, Riemannian metric is used in the kernel function of the SVM. Simulated experiments are performed using the databases including an artificial and the UCI real data. Simulation results show the effectiveness of the proposed algorithm through the comparison with four typical kernel functions without similarity metric