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Dry-mass sensing for microfluidics



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Müller, T 
White, DA 
Knowles, TPJ 


jats:pWe present an approach for interfacing an electromechanical sensor with a microfluidic device for the accurate quantification of the dry mass of analytes within microchannels. We show that depositing solutes onto the active surface of a quartz crystal microbalance by means of an on-chip microfluidic spray nozzle and subsequent solvent removal provides the basis for the real-time determination of dry solute mass. Moreover, this detection scheme does not suffer from the decrease in the sensor's quality factor and the viscous drag present if the measurement is performed in a liquid environment, yet allows solutions to be analysed. We demonstrate the sensitivity and reliability of our approach by controlled deposition of nanogram levels of salt and protein from a micrometer-sized channel.</jats:p>



Microfluidics, Mass measurement, Electromechanical transducers, QCM

Journal Title

Applied Physics Letters

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AIP Publishing
Biotechnology and Biological Sciences Research Council (BB/J002119/1)
We thank Alexander K. Buell, Igor Efimov, and Victor Ostanin for valuable discussions on QCM sensors and gratefully acknowledge financial support from the Swiss National Science Foundation (SNF), the Engineering and Physical Sciences Research Council (EPSRC), the Biotechnology and Biological Sciences Research Council (BBSRC), the European Research Council (ERC), as well as the Frances and Augustus Newman Foundation.