Nanomechanical identification of liquid reagents in a microfluidic channel

Abstract

Integration of promising technologies that can enhance sensitivity, selectivity, and throughput into micro total analysis systems (μTAS) are important in making them useful in precise screening of reaction byproducts in analytical chemistry, cellular biology and pharmaceutical industries. But unfortunately so far a method to precisely determine molecular signatures of reagents is missing in μTAS. We have developed a technique whereby molecular signatures of 50 pL of liquid reagents confined within a bimetallic microchannel cantilever can be obtained. This is achieved using wavelength dependent mechanical bending of the cantilever under infrared (IR) radiation. This technique also allows simultaneous physical characterization of the liquid reagent using variations in resonance frequency. It is useful in lab-on-a-chip devices and has a myriad of applications in drug screening, bioreactor monitoring, and petrochemical analysis.

Microfluidic cantilever detects bacteria and measures their susceptibility to antibiotics in small confined volumes

“…A suspended microchannel resonator, where a microfluidic channel is embedded inside a microcantilever, overcomes the limitations of liquid damping and achieves unprecedented mass resolution 13 . Since the liquid is inside the cantilever, the cantilever can be excited into resonance in a vacuum for increased mass resolution and higher reproducibility 14 15 . Despite its extraordinarily high mass sensitivity, this resonator still lacks selectivity in detection.…”

Beyond biology: alternative uses of cantilever-based technologies

“…Also, a bi-material U-shaped microchannel cantilever (16 μm wide, 1050 μm long and 3 μm high) was developed on top of a plain cantilever to perform both the physical and chemical analysis of 50 pL volume samples of liquid reagents. 213 The system, which was turned into a bimaterial beam by depositing a 500 nm thick layer of aluminum on its bottom side using e-beam evaporation, was conceived to be potentially used in micro-bioreactors.…”

Review—Nanomechanical Calorimetric Infrared Spectroscopy using Bi-Material Microfluidic Cantilevers

“…In order to demonstrate the selectivity in the detection of analytes in small volumes of liquid, we have fabricated and demonstrated a BMC for various applications. 28 The cantilever was fabricated on a 500 μm Si wafer with diameter of 100 mm. 29 First, unreleased cantilever beams with dimensions of 44 μm width, 500 μm length and 500 nm thickness were fabricated using a 500 μm thick silicon wafer.…”