Microfluidic chip electrophoresis investigation of major milk proteins: study of buffer effects and quantitative approaching

Abstract

Results of microfluidic chip technology using SEP buffer were comparable to those of SDS-PAGE and previously reported data.

Effect of Somatic Cell Count on Bovine Milk Protein Fractions

“…Segundo Costa et al [31], milk was diluted in a 1 : 4 ratio with TPS buffer, SEP buffer and pure water (Ultrapure Milli-Q; Millipore Corp., USA) to compare and select the more efficient diluting agent. Samples were allowed for at least 2 h at 4°C for protein solubilization before application in microfluidic chip electrophoresis which was performed using an Agilent 2100 Bioanalyzer system (Agilent Technologies, Germany).…”

“…It was prepared according to the SOP (Standard Operating Procedure) available from the Food Standards Agency (FSA) of the United Kingdom [31,35]. The SEP buffer solution, pH 3.0, used to separate the proteins consisted of 6.0 mol L1 urea (USB, Germany), 20 mmol L1 trisodium citrate dehydrate (Synth, Brazil), 0.1 mol L -1 citric acid (Merck, Brazil) and 0.05% (w/w) hydroxypropylmethyl cellulose (Sigma-Aldrich, USA) [31,36].…”

“…The two buffers compared were a total protein solubilization buffer (TPS buffer) and a separating milk protein buffer (SEP buffer). The first one is recommended for the preparation of milk samples before application in microfluidic chip electrophoresis [31,35] while the latter is commonly used for the separation of protein fractions of milk during the sample preparation for analysis by CE [60].…”

“…Separation of individual milk proteins was performed using the microfluidic chip electrophoresis system (Agilent 2100 Bioanalyser -Technologies GmbH, Waldbronn, Germany) and the associated Protein 80 kit (Agilent Technologies, Germany). These kits contain the chips and proprietary reagents such as the gel matrix solution, proteins in a concentrated solution, a marker protein buffer solution and a protein molecular mass ladder solution to perform the electrophoresis [31,[33][34][35].…”

“…Therefore, accurate and rapid methods are profoundly important. The microfluidic chip technique is faster, and uses considerably fewer chemicals and materials traditional techniques [31].…”