%0 Journal Article
%T Surface Modification on Acoustic Wave Biosensors for Enhanced Specificity
%A Onursal Onen
%A Asad A. Ahmad
%A Rasim Guldiken
%A Nathan D. Gallant
%J Sensors
%D 2012
%I MDPI AG
%R 10.3390/s120912317
%X Changes in mass loading on the surface of acoustic biosensors result in output frequency shifts which provide precise measurements of analytes. Therefore, to detect a particular biomarker, the sensor delay path must be judiciously designed to maximize sensitivity and specificity. B-cell lymphoma 2 protein (Bcl-2) found in urine is under investigation as a biomarker for non-invasive early detection of ovarian cancer. In this study, surface chemistry and biofunctionalization approaches were evaluated for their effectiveness in presenting antibodies for Bcl-2 capture while minimizing non-specific protein adsorption. The optimal combination of sequentially adsorbing protein A/G, anti-Bcl-2 IgG and Pluronic F127 onto a hydrophobic surface provided the greatest signal-to-noise ratio and enabled the reliable detection of Bcl-2 concentrations below that previously identified for early stage ovarian cancer as characterized by a modified ELISA method. Finally, the optimal surface modification was applied to a prototype acoustic device and the frequency shift for a range of Bcl-2 concentration was quantified to demonstrate the effectiveness in surface acoustic wave (SAW)-based detection applications. The surface functionalization approaches demonstrated here to specifically and sensitively detect Bcl-2 in a working ultrasonic MEMS biosensor prototype can easily be modified to detect additional biomarkers and enhance other acoustic biosensors.
%K bioconjugation
%K microelectromechanical systems (MEMS)
%K point-of-care
%K sensor
%K early detection
%K ovarian cancer
%K Bcl-2
%K surface acoustic wave (SAW)
%K self-assembled monolayer (SAM)
%K polyethylene glycol (PEG)
%U http://www.mdpi.com/1424-8220/12/9/12317