Devices, systems, and methods for microscale isoelectric fractionation

A microfluidic system comprising:

• a substrate;
• a preparation module including a fractionation microchannel defined in part by the substrate, wherein the fractionation microchannel has at least one cross-sectional dimension equal to or less than 1 mm, the preparation module further comprising:
• a plurality of membranes disposed in the fractionation microchannel, including a first and second membrane, the first membrane having a first pH and the second membrane having a second pH different from the first pH, the second membrane positioned a distance from the first membrane;
• the fractionation microchannel configured such that a target analyte having a pH between the first and the second pH is collected in a region of the fractionation channel between the first and second membranes following isoelectric fractionation;
• and
• a first analyte collection channel in fluid communication with the fractionation microchannel between the first and second membranes, the first analyte collection channel configured to receive the target analyte following fractionation;
• a transport module supported by the substrate, the transport module including a transport channel in fluid communication with the first analyte collection channel;
• an analysis module supported by the substrate, the analysis module configured to receive the target analyte from the transport module and analyze the target analyte;
• and
• an electric field generator configured to apply an electric field perpendicular to the fractionation microchannel to retain analytes within the fractionation microchannel.