Thermally Responsive Aptamer Surfaces for Microfluidic Sample Preparation

For many bioanalytical systems, the quality of the sample under scrutiny greatly affects the success of its analysis by the analytical instrument. Thus, sample preparatory techniques such as solid-phase extraction (SPE), purification and concentration are used to improve the quality of the sample before introduction into the equipment. This work overviews our effort in developing microdevices which exploit thermally responsive aptamers for biomolecular sample extraction, purification and concentration. We demonstrate the feasibility of this approach with a model system which consists of an adenosine monophosphate (AMP) analyte and adenosine triphosphate derived aptamer. Through systematic experimentation, we demonstrate the extraction and enrichment of AMP at physiologically relevant concentrations, release of AMP and regeneration of the aptamer through thermal stimulation, and detection of AMP by either fluorescence or mass spectrometry. In addition, completely aqueous operation of the device eliminates the use of potentially harsh reagents.