Electrophoresis assisted time-of-flow mass spectrometry using hollow nanomechanical resonators

Abstract

This report discusses the first demonstration of electrophoresis assisted time-of-flow mass spectrometry using ‘U’ shaped hollow nanomechanical resonators (HNR). Capillary electrophoresis was coupled with the HNR based mass detection to overcome low ionic conductivity of channels embedded in the HNR preventing direct in-situ electrophoretic separation. The flow of analytes through the HNR was achieved by balancing the hydrodynamic pressure to override the electromotive force and inhibit the motion of analytes towards the anode for capillary electrophoresis. The resonance frequency shifts of the HNR vibrating around 1.5 MHz were correlated with the time of the passage of the protein bands to construct the mass spectrum. The proposed concept was demonstrated by constructing a mass spectrum of egg white proteins in the molecular weight range of 14–250 kDa. When compared to regular polyacrylamide gel electrophoresis, our method not only provides a precise and fast readout but also avoids the use of chemical staining. This study paves a new route for low-cost and on-chip mass spectrometers with ultra-miniaturized dimensions.

Recent advances in capillary electrophoresis‐mass spectrometry: Instrumentation, methodology and applications

“…Chaudhari et al. presented the coupling of CGE to time‐of‐flight mass spectrometry in hollow nanomechanical resonators . Such a system allows the rough mass determination of proteins in a small portable instrument since it does not require vacuum.…”

Nanomechanical hydrodynamic force sensing using suspended microfluidic channels

“…Among all the common materials used in MEMS/NEMS and microfluidics, poly dimethyl siloxane (PDMS) is the most promising candidate for use as a hydrodynamic force sensor due to its Young’s modulus. Additionally, we deduce that the force effect has not been previously measured because the materials used in the fabrication of these devices (silicon 16 , silicon oxide 43 , silicon nitride 32 , or fused silica 17 , 38 , 39 , 44 ) need a flow rate at least three orders of magnitude higher than the usual experimental values.…”

Nanomechanical Molecular Mass Sensing Using Suspended Microchannel Resonators

“…In this regard, suspended microchannel resonators (SMR) have been demonstrated to be excellent tools for highly sensitive detection of both colloidal particles (measuring its buoyant mass) [ 14 , 15 , 16 , 17 ] and liquid properties (by measuring its mass density, viscosity, etc.) [ 18 , 19 , 20 , 21 , 22 ].…”