The use of "lab-on-a-chip" microfluidic SDS electrophoresis technology for the separation and quantification of milk proteins

The use of a microfluidic "lab-on-a-chip" technique for the separation and quantification of milk proteins is described and compared with traditional sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). The microfluidic chip technique could separate all major milk proteins when standard protein solutions were used. In a milk system, alpha-lactalbumin, beta-lactoglobulin, alpha(s)-casein, beta-casein and kappa-casein were readily separated; the resolution was comparable with SDS-PAGE. However, the immunoglobulins, lactoferrin and bovine serum albumin could not be resolved from the background in the microfluidic chip technique, but were easily resolved by SDS-PAGE. Standard curves for the major whey proteins were linear with both techniques and the calculated concentrations of the major proteins in a milk sample were comparable using both microfluidic chip and SDS-PAGE techniques. These results indicate that the microfluidic chip technology may be a rapid alternative for the separation and quantification of proteins in milk protein based systems. (C) 2008 Elsevier Ltd. All rights reserved.