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Nonspecific binding of proteins is an ongoing problem that dramatically reduces the sensitivity and selectivity of biosensors. We demonstrate that ultrasonic waves generated by surface acoustic wave (SAW) devices remove nonspecifically bound proteins from the sensing and nonsensing regions of the microarrays. We demonstrate our approach for controllably and nondestructively cleaning the microarray interface. In this work, SAWs were generated using 128 YX lithium niobate, chosen for its high coupling coefficient and efficient power transfer to mechanical motion. These waves propagating along the surface were coupled into specifically bound and nonspecifically bound proteins on a patterned surface of 40 mum feature size. Fluorescence intensity was used to quantify cleaning efficacy of the microarrays. Our results have shown that excess protein layers and aggregates are removed leaving highly uniform films as evidenced by fluorescence intensity profiles. Selected antigen-receptor interactions remained bound during the acoustic cleaning process when subjected to 11.25 mW of power and retained their efficacy for subsequent antigen capture. Results demonstrate near-complete fluorescence signal recovery for both the sensing and nonsensing regions of the microarrays. Of significance is that our approach can be integrated into existing array technologies where sensing and nonsensing regions are extensively fouled. We believe that this technology will be pivotal in the development and advancement of microsensors and their biological applications.
Date of Publication: March 2008