Microcantilever biosensor: sensing platform, surface characterization and multiscale modeling
Resource
Smart Structures and Systems, 8(1), 17-37
Journal
Smart Structures and Systems
Pages
17-37
Date Issued
2011
Date
2011
Author(s)
Abstract
The microcantilever (MCL) sensor is one of the most promising platforms for next-generation label-free biosensing applications. It outperforms conventional label-free detection methods in terms of portability and parallelization. In this paper, an overview of recent advances in our understanding of the coupling between biomolecular interactions and MCL responses is given. A dual compact optical MCL sensing platform was built to enable biosensing experiments both in gas-phase environments and in solutions. The thermal bimorph effect was found to be an effective nanomanipulator for the MCL platform calibration. The study of the alkanethiol self-assembly monolayer (SAM) chain length effect revealed that 1-octanethiol (C8H17SH) induced a larger deflection than that from 1-dodecanethiol (C12H25SH) in solutions. Using the clinically relevant biomarker Creactive protein (CRP), we revealed that the analytical sensitivity of the MCL reached a diagnostic level of 1∼500 μg/ml within a 7% coefficient of variation. Using grazing incident x-ray diffractometer (GIXRD) analysis, we found that the gold surface was dominated by the (111) crystalline plane. Moreover, using X-ray photoelectron spectroscopy (XPS) analysis, we confirmed that the Au-S covalent bonds occurred in SAM adsorption whereas CRP molecular bindings occurred in protein analysis. First principles density functional theory (DFT) simulations were also used to examine biomolecular adsorption mechanisms. Multiscale modeling was then developed to connect the interactions at the molecular level with the MCL mechanical response. The alkanethiol SAM chain length effect in air was successfully predicted using the multiscale scheme.
Type
journal article
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