Microfluidic Cantilever Biosensors

Abstract

Although a microfabricated cantilever with a high quality factor can detect changes in its mass with unprecedented sensitivity, severe damping reduces it mass sensitivity when operated in a liquid medium thus restricting its use as a mass sensor for biomolecular detection. However, fabrication of cantilevers with embedded microfluidic channel allows confining liquids within them and enables their operation even in vacuum conditions for greatly reduced damping. Operating the microfluidic cantilever in vacuum allows mass-based detection of biomolecules in the liquid environment with unprecedented sensitivity. Although biomolecular detection based on mass using microfluidic cantilever is extremely sensitive, it cannot provide any molecular selectivity. However, coupling the cantilever with capillary gel electrophoresis for separation of biomolecules prior to detection provides an ideal technique for biomolecular detection. Making the cantilever bi-material will also allow infrared photothermal spectroscopy of molecules inside the cantilever. Mid-IR spectroscopy together with mass measurements of confined biomolecules in liquids offers molecular recognition in their native state without using any receptors.