A microfludic aptasensor with integrated sample preconcentration, isocratic elution and mass spectrometric detection

We present a microfluidic biosensor suitable for selective detection of analytes with integrated analyte preconcentration, isocratic elution and mass spectrometric detection. The device uses an aptamer (i.e., oligonucleotide that binds specifically to an analyte via affinity coupling) immobilized on microbeads to achieve highly selective analyte capture and concentration. Here, we demonstrate specific extraction and concentration of arginine vasopressin (a peptide hormone) by a vasopressin specific atpamer. In addition, the aptasensor is capable of isocratic elution and microbead regeneration via thermally-induced reversibility of the aptamer-analyte binding mechanism, which renders the aptamer functionalized microbeads functional for repeated use. Furthermore, a microvalve directs the analyte onto an analysis plate for label-free detection by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS).