Xiaolu Feng

Shanghai Jiao Tong University, Shanghai, Shanghai Shi, China

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Publications (4)5.65 Total impact

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    ABSTRACT: Detection of single nucleotide polymorphisms (SNPs) is critical for early stage diagnosis. However, available clinical methods for detecting SNPs require strict assay conditions or complicated enzyme reactions. DNA hybridization by Au nanoparticles is a new microscopic method for DNA detection, which offers many advantages over traditional ones. But currently, this method is limitedly used because of low yield of hybridization. Here we report novel strategies which use toehold-mediated strand displacement on DNA origami Chip by employing AuNPs, and we greatly improved the yield of hybridization to 80% from less than 10%. Based on the kinetic characteristic of toehold-mediated strand displacement reaction, DNA strands with unmatched sequences can be easily replaced by fully complementary ones, and the exchange rate depends on the length of the toehold region. Therefore, variation on ssDNA sequence can be differentiated by their different displacement time. With this approach we detect SNPs of age-related macular degeneration on DNA origami chip. This approach offers a new, simple and sensitive way to detect SNP.
    No preview · Article · Sep 2014 · Current Organic Chemistry
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    ABSTRACT: DNA origami is an emerging technology that assembles hundreds of staple strands and one single-strand DNA into certain nanopattern. It has been widely used in various fields including detection of biological molecules such as DNA, RNA and proteins. MicroRNAs (miRNAs) play important roles in post-transcriptional gene repression as well as many other biological processes such as cell growth and differentiation. Alterations of miRNAs' expression contribute to many human diseases. However, it is still a challenge to quantitatively detect miRNAs by origami technology. In this study, we developed a novel approach based on streptavidin and quantum dots binding complex (STV-QDs) labeled single strand displacement reaction on DNA origami to quantitatively detect the concentration of miRNAs. We illustrated a linear relationship between the concentration of an exemplary miRNA as miRNA-133 and the STV-QDs hybridization efficiency; the results demonstrated that it is an accurate nano-scale miRNA quantifier motif. In addition, both symmetrical rectangular motif and asymmetrical China-map motif were tested. With significant linearity in both motifs, our experiments suggested that DNA Origami motif with arbitrary shape can be utilized in this method. Since this DNA origami-based method we developed owns the unique advantages of simple, time-and-material-saving, potentially multi-targets testing in one motif and relatively accurate for certain impurity samples as counted directly by atomic force microscopy rather than fluorescence signal detection, it may be widely used in quantification of miRNAs.
    Full-text · Article · Aug 2013 · PLoS ONE
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    Chensheng Zhou · Heng Luo · Xiaolu Feng · Xingwang Li · Jie Zhu · Lin He · Can Li
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    ABSTRACT: DNA self-assembly is a nanotechnology that folds DNA into desired shapes. Self-assembled DNA nanostructures, also known as origami, are increasingly valuable in nanomaterial and biosensing applications. Two ways to use DNA nanostructures in medicine are to form nanoarrays, and to work as vehicles in drug delivery. The DNA nanostructures perform well as a biomaterial in these areas because they have spatially addressable and size controllable properties. However, manually designing complementary DNA sequences for self-assembly is a technically demanding and time consuming task, which makes it advantageous for computers to do this job instead. We have developed a web server, FOLDNA, which can automatically design 2D self-assembled DNA nanostructures according to custom pictures and scaffold sequences provided by the users. It is the first web server to provide an entirely automatic design of self-assembled DNA nanostructure, and it takes merely a second to generate comprehensive information for molecular experiments including: scaffold DNA pathways, staple DNA directions, and staple DNA sequences. This program could save as much as several hours in the designing step for each DNA nanostructure. We randomly selected some shapes and corresponding outputs from our server and validated its performance in molecular experiments.
    Full-text · Article · Sep 2012 · Journal of Nanotechnology
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    ABSTRACT: The aim of this study was to ascertain the anti-arthritic active fraction of Capparis spinosa L. (Capparidaceae) fruits and its chemical constituents. The adjuvant arthritic rat model was developed to evaluate the anti-arthritic effects of different fractions of ethanol extraction from C. spinosa L. The fraction eluted by ethanol-water (50:50, v/v) had the most significant anti-arthritic activity. The chemical constituents of this fraction were therefore studied; seven known compounds were isolated and identified as: P-hydroxy benzoic acid; 5-(hydroxymethyl) furfural; bis(5-formylfurfuryl) ether; daucosterol; α-D-fructofuranosides methyl; uracil; and stachydrine.
    Full-text · Article · Mar 2011 · Yakugaku zasshi journal of the Pharmaceutical Society of Japan