A microfluidic aptasensor integrated with nanodrop generator for MALDI-TOF MS analysis in clinical applications

This paper presents an aptamer-based microchip for sensitive and quantitative detection of biomolecules using matrix-assisted laser desorption/ ionization time-of-flight mass spectrometry (MALDI-TOF MS). The device is capable of both isolating analyte from samples and dispensing purified samples onto a probe plate for a following MS analysis. Aptamers selectively captured and released target molecules for isocratic elution. An integrated nanodrop generator produced small sample spots (300 μm diameter), significantly minimizing spatial intensity variations. Repeated sample deposition on the same spot (50 times) induced on-spot analyte concentration improving the detection sensitivity. We also demonstrated that our integrated device coupled to MALDI MS analysis successfully performs the biomolecular quantification by calibrating relative intensities of analyte peak to its internal standard.