In situ detection of calcium ions with chemically modified microcantilevers.
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.
Ji
Hai Feng
HF
Life Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6123, USA.
Thundat
Thomas
T
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
D006046:Gold; D002118:Calcium; D012825:Silicon