Development of an SDS‐gel electrophoresis method on SU‐8 microchips for protein separation with LIF detection: Application to the analysis of whey proteins

Abstract

This work describes the development of an SDS‐gel electrophoresis method for the analysis of major whey proteins (α‐lactalbumin, β‐lactoglobulin, and BSA) carried out in SU‐8 microchips. The method uses a low‐viscosity solution of dextran as a sieving polymer. A commercial coating agent (EOTrol LN) was added to the separation buffer to control the EOF of the chips. The potential of this coating agent to prevent protein adsorption on the walls of the SU‐8 channels was also evaluated. Additionally, the fluorescence background of the SU‐8 material was studied to improve the sensitivity of the method. By selecting an excitation wavelength of 532 nm at which the background fluorescence remains low and by replacing the mercury arc lamp by a laser in the detection system, an LOD in the nanomolar range was achieved for proteins derivatized with the fluorogenic reagent Chromeo P540. Finally, the method was applied to the analysis of milk samples, demonstrating the potential of SU‐8 microchips for the analysis of proteins in complex food samples.

Recent advances in the application of capillary electromigration methods for food analysis and Foodomics

“…Recently, interesting developments have been published on the use of LIF detection in MCE. For instance, Barrios-Romero et al [227] developed a SDS-gel electrophoresis method on SU8 microchips for the separation of three whey proteins (␣-lactalbumin, ␤-lactoglobulin, and BSA). Authors used a commercial coating to control the EOF and a low-viscosity solution of dextran as a sieving polymer.…”

Fabrication of universal serial bus flash disk type microfluidic chip electrophoresis and application for protein analysis under ultra low voltage

“…The RSD results were in accordance with the reported RSD value of similar protein separation by MCE. 33,34 The detection limits can be further improved if more sensitive detection technique is applied. [35][36][37][38][39] Additionally, the USB flash disk type MCE makes full use of the computer USB interface, and there is no need to carry an extra cumbersome high voltage power supply.…”

Recent advances in protein analysis by capillary and microchip electrophoresis

“…94–96 Such advances can improve the feasibility of microchip electrophoresis methods for clinical point-of-care applications, and polymeric materials for MCE allow for the selection of the most suitable material for particular applications. 97 …”