Amplified electrochemical aptasensor taking AuNPs based sandwich sensing platform as a model.

Here, we report a sensitive amplified electrochemical impedimetric aptasensor for thrombin, a kind of serine protease that plays important role in thrombosis and haemostasis. For improving detection sensitivity, a sandwich sensing platform is fabricated, in which the thiolated aptamers are firstly immobilized on a gold substrate to capture the thrombin molecules, and then the aptamer functionalized Au nanoparticles (AuNPs) are used to amplify the impedimetric signals. Such designed aptamer/thrombin/AuNPs sensing system could not only improve the detection sensitivity compared to the reported impedimetric aptasensors but also provide a promising signal amplified model for aptamer-based protein detection. In this paper, we realize a sensitive detection limit of 0.02 nM, with a linear range of 0.05-18 nM. Meanwhile, the effect of 6-mercaptohexanol (MCH) and 2-mercaptoethanol (MCE) on the modification of the electrode is investigated.

[1]  M. Tewes,et al.  Microfabricated high-performance microwave impedance biosensors for detection of aptamer-protein interactions , 2005 .

[2]  Tao Li,et al.  Adaptive recognition of small molecules by nucleic acid aptamers through a label-free approach. , 2007, Chemistry.

[3]  Jun Wang,et al.  Aptamer-based ATP assay using a luminescent light switching complex. , 2005, Analytical chemistry.

[4]  Yun Xiang,et al.  Quantum-dot/aptamer-based ultrasensitive multi-analyte electrochemical biosensor. , 2006, Journal of the American Chemical Society.

[5]  L. Marky,et al.  Folding of the thrombin aptamer into a G-quadruplex with Sr(2+): stability, heat, and hydration. , 2001, Journal of the American Chemical Society.

[6]  Hans Wolf,et al.  An aptamer-based quartz crystal protein biosensor. , 2002, Analytical chemistry.

[7]  I-Ming Hsing,et al.  Label-free protein recognition using an aptamer-based impedance measurement assay , 2006 .

[8]  Juewen Liu,et al.  A simple and sensitive "dipstick" test in serum based on lateral flow separation of aptamer-linked nanostructures. , 2006, Angewandte Chemie.

[9]  Chunhai Fan,et al.  A target-responsive electrochemical aptamer switch (TREAS) for reagentless detection of nanomolar ATP. , 2007, Journal of the American Chemical Society.

[10]  Juewen Liu,et al.  Preparation of aptamer-linked gold nanoparticle purple aggregates for colorimetric sensing of analytes , 2006, Nature Protocols.

[11]  P. He,et al.  A new amplification strategy for ultrasensitive electrochemical aptasensor with network-like thiocyanuric acid/gold nanoparticles. , 2007, Biosensors & bioelectronics.

[12]  Joseph Wang,et al.  Aptamer biosensor for label-free impedance spectroscopy detection of proteins based on recognition-induced switching of the surface charge. , 2005, Chemical communications.

[13]  A. Tulinsky,et al.  The structure of alpha-thrombin inhibited by a 15-mer single-stranded DNA aptamer. , 1994, The Journal of biological chemistry.

[14]  Milan N Stojanovic,et al.  Aptamer-based colorimetric probe for cocaine. , 2002, Journal of the American Chemical Society.

[15]  Andrew D. Ellington,et al.  Nucleic Acid Selection and the Challenge of Combinatorial Chemistry. , 1997, Chemical reviews.

[16]  Gerald F. Joyce,et al.  Selection in vitro of an RNA enzyme that specifically cleaves single-stranded DNA , 1990, Nature.

[17]  X. Le,et al.  Selection and analytical applications of aptamers , 2006 .

[18]  Martin Moskovits,et al.  A heterogeneous PNA-based SERS method for DNA detection. , 2007, Journal of the American Chemical Society.

[19]  M. Mascini,et al.  Aptamer-based biosensors for the detection of HIV-1 Tat protein. , 2005, Bioelectrochemistry.

[20]  Itamar Willner,et al.  Label-free and reagentless aptamer-based sensors for small molecules. , 2006, Journal of the American Chemical Society.

[21]  Itamar Willner,et al.  Nucleic acid-functionalized Pt nanoparticles: Catalytic labels for the amplified electrochemical detection of biomolecules. , 2006, Analytical chemistry.

[22]  Nobuko Hamaguchi,et al.  Aptamer-based biosensor arrays for detection and quantification of biological macromolecules. , 2003, Analytical biochemistry.

[23]  Bingling Li,et al.  Sensitive detection of protein by an aptamer-based label-free fluorescing molecular switch. , 2007, Chemical communications.

[24]  Kevin W Plaxco,et al.  A reagentless signal-on architecture for electronic, aptamer-based sensors via target-induced strand displacement. , 2005, Journal of the American Chemical Society.

[25]  Razvan Nutiu,et al.  In vitro selection of structure-switching signaling aptamers. , 2005, Angewandte Chemie.

[26]  E. Vermaas,et al.  Selection of single-stranded DNA molecules that bind and inhibit human thrombin , 1992, Nature.

[27]  Weihong Tan,et al.  Aptamer-modified gold nanoparticles for colorimetric determination of platelet-derived growth factors and their receptors. , 2005, Analytical chemistry.

[28]  Y. Shao,et al.  A chronocoulometric aptamer sensor for adenosine monophosphate. , 2007, Chemical communications.

[29]  J. Szostak,et al.  In vitro selection of RNA molecules that bind specific ligands , 1990, Nature.

[30]  Chad A. Mirkin,et al.  One-Pot Colorimetric Differentiation of Polynucleotides with Single Base Imperfections Using Gold Nanoparticle Probes , 1998 .

[31]  Ciara K O'Sullivan,et al.  Reusable impedimetric aptasensor. , 2005, Analytical chemistry.

[32]  Yi Xiao,et al.  Aptamer-functionalized Au nanoparticles for the amplified optical detection of thrombin. , 2004, Journal of the American Chemical Society.

[33]  Itamar Willner,et al.  Fluorescence detection of DNA by the catalytic activation of an aptamer/thrombin complex. , 2005, Journal of the American Chemical Society.

[34]  A. Steel,et al.  Electrochemical quantitation of DNA immobilized on gold. , 1998, Analytical chemistry.

[35]  X Chris Le,et al.  Ultrasensitive detection of proteins by amplification of affinity aptamers. , 2006, Angewandte Chemie.

[36]  L. Gold,et al.  Systematic evolution of ligands by exponential enrichment: RNA ligands to bacteriophage T4 DNA polymerase. , 1990, Science.

[37]  Chunli Bai,et al.  Signaling aptamer/protein binding by a molecular light switch complex. , 2004, Analytical chemistry.

[38]  R. Shafer,et al.  Effect of loop sequence and size on DNA aptamer stability. , 2000, Biochemistry.

[39]  Xiaobo Yu,et al.  Label-free electrochemical detection for aptamer-based array electrodes. , 2005, Analytical chemistry.