title: In situ detection of calcium ions with chemically modified microcantilevers.
abstract: We report a novel technique of micromechanical detection of trace amounts of calcium ions by using microcantilevers modified with ion-selective self-assembled monolayers (SAMs). The SAM-modified microcantilevers undergo bending due to selective adsorption of calcium ions. Experiments conducted under flow conditions show that the modified cantilevers respond sensitively to calcium ions (Ca(2+)); a Ca(2+) concentration of 10(-9) M can be detected with this technique. Other cations, such as Na(+) and K(+), do not have any effect on the deflection of these cantilevers. We demonstrate two different kinds of SAMs having selectivity for calcium ions.
authors.affiliation: Life Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6123, USA.
authors.forename: Hai Feng
authors.initials: HF
authors.lastname: Ji
authors.forename: Thomas
authors.initials: T
authors.lastname: Thundat
mesh_terms: D000327:Adsorption; D002118:Calcium / Q000032:analysis*; D004548:Elasticity; D006046:Gold; D018625:Microscopy, Atomic Force / Q000379:methods*; D008958:Models, Molecular; D008962:Models, Theoretical; D036103:Nanotechnology / Q000295:instrumentation; D012680:Sensitivity and Specificity; D012825:Silicon / Q000737:chemistry; D013314:Stress, Mechanical; D013500:Surface Tension
chemical_list: D006046:Gold; D002118:Calcium; D012825:Silicon