title: Reduction of nonspecific protein adsorption on cantilever biosensors caused by transverse resonant mode vibration.
abstract: We examine if vibration of millimeter-sized cantilever sensors can release nonspecifically adsorbed proteins. Integrated electrochemical and mass-change measurement as well as fluorescence assays showed transverse surface vibration released nonspecifically bound proteins in samples prepared at 0.2-3.6 mg bovine serum albumin (BSA) per mL. Extent of release was directly related to magnitude of excitation voltage (Vex) applied to the self-actuating lead zirconate titanate (PZT) cantilever over three log units (0, 10 mV, 100 mV, and 1 V). Vibration-induced release was not instantaneous, but had an apparent first-order rate constant (kapp) which ranged from 0.02-0.1 min(-1). Results suggest significant serum albumin protein release could be achieved using excitation voltages of 1 V in millimeter-sized cantilever sensors. Complementary experiments with thiolated DNA, which binds to surface gold 〈111〉 sites with ∼ four times higher binding energy than BSA, showed negligible release under the same vibration magnitude. The results of the study suggest a direct correlation between surface-adsorbate binding energy and the effectiveness of vibration-induced release. We suggest that the release mechanism includes contributions from surface strain energy, body force, and acoustic streaming-associated hydrodynamic effects. The primary contribution of this study suggests that surface vibration of cantilever sensors may be useful in reducing nonspecific adsorption, especially for biosensing of analytes present in a complex background.
authors.affiliation: Department of Chemical and Biological Engineering, Drexel University, Philadelphia, PA 19104, USA. mutharasan@drexel.edu.
authors.forename: Blake N
authors.initials: BN
authors.lastname: Johnson
authors.forename: Raj
authors.initials: R
authors.lastname: Mutharasan
mesh_terms: D000327:Adsorption / Q000502:physiology; D000818:Animals; D015374:Biosensing Techniques / Q000379:methods*; D002417:Cattle; D055664:Electrochemical Techniques / Q000379:methods*; D006801:Humans; D011485:Protein Binding / Q000502:physiology; D012709:Serum Albumin / Q000032:analysis* / Q000378:metabolism; D013499:Surface Properties; D014732:Vibration
chemical_list: D012709:Serum Albumin