Enantioselective Sensors Based on Antibody-Mediated Nanomechanics

Dutta, Paramita; Ca, Tipple; Lavrik, Nickolay V.; Datskos, Panos G.; Hofstetter, Heike; Hofstetter, Oliver; Mj, Sepaniak

doi:10.1021/ac034031z

Cited by 97 publications

(72 citation statements)

References 30 publications

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“…The binding of this particular antigen generated absolute tensile stress of the sensor and reference cantilever, resulting in upward bending of the cantilever spring compared with its original position. Absolute tensile deflections have been also observed previously for physical adsorption of different proteins on a gold surface of a single-cantilever array (34)(35)(36). Note that the generated surface stress is not a result of mass loaded on a cantilever but of the sum of different processes taking place at the cantilever interface, such as protein-surface and proteinprotein interactions whereby the net charge of molecular counterparts plays a key role (35).…”

Section: Resultssupporting

confidence: 69%

A label-free immunosensor array using single-chain antibody fragments

Backmann

Zahnd

Huber

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

264

183

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We report a microcantilever-based immunosensor operated in static deflection mode with a performance comparable with surface plasmon resonance, using single-chain Fv (scFv) antibody fragments as receptor molecules. As a model system scFv fragments with specificity to two different antigens were applied. We introduced a cysteine residue at the C terminus of each scFv construct to allow covalent attachment to gold-coated sensor interfaces in directed orientation. Application of an array enabled simultaneous deflection measurements of sensing and reference cantilevers. The differential deflection signal revealed specific antigen binding and was proportional to the antigen concentration in solution. Using small, oriented scFv fragments as receptor molecules we increased the sensitivity of microcantilevers to Ϸ1 nM.cantilever arrays ͉ nanomechanics ͉ proteomics M icrocantilever-based sensors have attracted much interest as devices for fast and reliable detection of small amounts of molecules in air and solution. Over the last few years the application of the cantilever sensor concept was extended to the measurements of biocompounds in solution, resulting in a versatile biosensor (1, 2). Because of its label-free detection principle and small size, this kind of biosensor is advantageous for diagnostic applications, disease monitoring, and research in genomics or proteomics (3, 4). Multicantilever arrays would enable the detection of several analytes simultaneously.The main principle of the cantilever static mode is the transduction of the molecular interaction between analyte and receptors, immobilized as a layer on one surface of a cantilever, into a nanomechanical motion of the cantilever. Biomolecular interactions taking place on a solid-state interface produce a change in surface stress, because of changes in molecular configuration and intermolecular crowding (5). This process results in bending of the cantilever. Microcantilever-based biosensors operated in static mode have been successfully applied for the detection of various molecular interactions such as ssDNA-ssDNA (5-7) or protein-DNA (8, 9). Interactions between proteins were detected with cantilever-based immunosensors, where an antigen was recognized by its cognate antibody randomly immobilized on the sensor surface (10-12).The most critical step in preparation of any immunosensor is the immobilization of capture molecules on the support, a process where the orientation of the antigen-binding sites toward the analyte in solution plays a key role. Immunoglobulins can be either adsorbed on gold directly (10, 12) or attached covalently to the surface modified with hetero-bifunctional self-assembled monolayers of alkylthiols (11). However, these approaches produce a layer of randomly oriented antibody molecules on the cantilever surface, thereby generating conformational heterogeneity and inactive receptor molecules (13,14).As previously shown (13,(15)(16)(17)(18), the sensitivity of immunosensors can be improved by both maximizing the degree of functional ...

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Section: Resultssupporting

confidence: 69%

A label-free immunosensor array using single-chain antibody fragments

Backmann

Zahnd

Huber

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

264

183

View full text Add to dashboard Cite

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“…The ease of cantilever functionalisation allows for systems as varied as single molecules to whole cells to be studied. In addition, the ability to microfabricate compact arrays of cantilevers facilitates simultaneous and high throughput measurements [128,131].…”

Section: Micro-cantilever Immunosensorsmentioning

confidence: 99%

Trends and Perspectives in Immunosensors

2012

Antibodies Applications and New Developments

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Immunosensors are devices that comprise both a biomolecular recognition system, such as an antibody and its corresponding antigen, and a transducer to translate the high affinity and specific binding event into a physical signal.Antibodies are produced by an immunological response to the presence of a foreign substance called an antigen. Antibodies may be immobilised onto a variety of platforms including bulk planar surfaces and nanoparticles by either covalent or adsorption strategies. Different interfaces between the bio-components and the detector are available to monitor in 'real-time' the signal generated by biological interactions. The transducers detect, for example, the change in electron transfer, absorbance, fluorescence, refractive index, mass change or heat transfer as the antibody binds to the antigen of interest. Such analytical devices have allowed a wide range of analytes to be identified and quantified such as pathogens, toxins, environmental food contaminants and disease biomarkers.The demand for sensitive, rapid, 'on-site' techniques has taken advantage of the latest advances in microfluidics and nanotechnology. This chapter will highlight current trends in immobilisation, micro/nano-fluidics/ and transducers utilised. A number of examples outlining the exploitation of these elements in immunosensors and their successful applications will be described.

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“…It has been shown that the detection of <0.01% of the L enantiomers in samples of D enantiomers is possible in less than 5 minutes including regeneration of immunoreactor (Silvaieh et al 2002). Anti-D-AA was used in microfabricated cantilevers for enantioselective detection of amino acids based on inducing surface stress by intermolecular forces arising from analyte adsorption on surfaceimmobilized antibodies (Dutta et al 2003). The temporal response of the cantilever allowed the quantitative determination of enantiomeric purity up to an enantiomeric excess of 99.8%.…”

Section: Other Type Of Detectionmentioning

confidence: 99%