Liquid Plasticine-Based Electrokinetic Enrichment of Proteins

Graphical An open liquid plasticine-based FASS system (FASS: field-amplified sample stacking) for protein enrichment was developed, with which proteins can be enriched 40–80-fold by LP-FASS within 40 min. Protein analysis is an important approach for disease diagnosis, in which sample pretreatment is an essential step since protein samples are often complex and many protein biomarkers are of low abundance. Here, given the good openness and light transmission of liquid plasticine (LP), which is a liquid entity formed by SiO 2 nanoparticles and encapsulated aqueous solution, we developed a LP-based field-amplified sample stacking (FASS) system for protein enrichment. The system was composed of a LP container, a sample solution and a Tris-HCl solution containing hydroxyethyl cellulose (HEC). The system design, mechanism investigation, optimization of experimental parameters and characterization of LP-FASS performance for protein enrichment were well studied. Under the optimized experimental conditions of 1 % HEC, 100 m m Tris-HCl and 100 V in the LP-FASS system, a 40–80 times enrichment of proteins was obtained in 40 min using bovine hemoglobin (BHb) as the model protein using the constructed LP-FASS system. The simultaneous enrichment of multiple proteins (phycocyanin, BHb and cytochrome C) was also realized using the system. The LP-FASS system can serve as a new platform for protein enrichment which is easy to be combined with online and offline detections.