title: Label-free sensing of adenosine based on force variations induced by molecular recognition.
abstract: We demonstrate a simple force-based label-free strategy for the highly sensitive sensing of adenosine. An adenosine ssDNA aptamer was bound onto an atomic force microscopy (AFM) probe by covalent modification, and the molecular-interface adsorption force between the aptamer and a flat graphite surface was measured by single-molecule force spectroscopy (SMFS). In the presence of adenosine, the molecular recognition between adenosine and the aptamer resulted in the formation of a folded, hairpin-like DNA structure and hence caused a variation of the adsorption force at the graphite/water interface. The sensitive force response to molecular recognition provided an adenosine detection limit in the range of 0.1 to 1 nM. The addition of guanosine, cytidine, and uridine had no significant interference with the sensing of adenosine, indicating a strong selectivity of this sensor architecture. In addition, operational parameters that may affect the sensor, such as loading rate and solution ionic strength, were investigated.
authors: Hybrid Materials Interfaces Group, Faculty of Production Engineering, University of Bremen, Am Fallturm 1, 28359 Bremen, Germany. jinfeng@uni-bremen.de.
authors: Jingfeng
authors: J
authors: Li
authors: Hybrid Materials Interfaces Group, Faculty of Production Engineering, University of Bremen, Am Fallturm 1, 28359 Bremen, Germany. qing_li@uni-bremen.de.
authors: Qing
authors: Q
authors: Li
authors: Hybrid Materials Interfaces Group, Faculty of Production Engineering, University of Bremen, Am Fallturm 1, 28359 Bremen, Germany. colombi@hmi.uni-bremen.de.|Center for Environmental Research and Sustainable Technology (UFT), University of Bremen, Leobener Str., 28359 Bremen, Germany. colombi@hmi.uni-bremen.de.
authors: Lucio Colombi
authors: LC
authors: Ciacchi
authors: Hybrid Materials Interfaces Group, Faculty of Production Engineering, University of Bremen, Am Fallturm 1, 28359 Bremen, Germany. wei@uni-bremen.de.
authors: Gang
authors: G
authors: Wei
mesh_terms: D000241:Adenosine / Q000032:analysis / Q000737:chemistry*; D052158:Aptamers, Peptide / Q000737:chemistry*; D001483:Base Sequence; D004277:DNA, Single-Stranded / Q000737:chemistry*; D018625:Microscopy, Atomic Force / Q000379:methods; D015336:Molecular Probe Techniques; D015394:Molecular Structure; D013057:Spectrum Analysis / Q000379:methods
chemical_list: D052158:Aptamers, Peptide; D004277:DNA, Single-Stranded; D000241:Adenosine