Droplet microfluidics with magnetic beads: a new tool to investigate drug–protein interactions

• Published in: Analytical and bioanalytical chemistry 2011, Vol.399 (1), p.347-352
• Main Authors: Lombardi, Dario, Dittrich, Petra S.
• Format: Article
• Language: English
• Subjects: Affinity labeling; Analysis; Analytical Chemistry; Anticoagulants - chemistry; Biochemistry; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Design and construction; Dimethylpolysiloxane; Drops; Exact sciences and technology; Food Science; Humans; Iron oxides; Kinetics; Laboratory Medicine; Magnetic materials; Magnetic properties; Magnetics; Methods; Microelectromechanical systems; Microfluidic Analytical Techniques - instrumentation; Microfluidic Analytical Techniques - methods; Microfluidics; Monitoring/Environmental Analysis; Nanoparticles; Original Paper; Physiological aspects; Properties; Protein Binding; Separation (Technology); Serum albumin; Serum Albumin - chemistry; Warfarin; Warfarin - chemistry
• ISSN: 1618-2642; 1618-2650
• DOI: 10.1007/s00216-010-4302-7

In this study, we give the proof of concept for a method to determine binding constants of compounds in solution. By implementing a technique based on magnetic beads with a microfluidic device for segmented flow generation, we demonstrate, for individual droplets, fast, robust and complete separation of the magnetic beads. The beads are used as a carrier for one binding partner and hence, any bound molecule is separated likewise, while the segmentation into small microdroplets ensures fast mixing, and opens future prospects for droplet-wise analysis of drug candidate libraries. We employ the method for characterization of drug–protein binding, here warfarin to human serum albumin. The approach lays the basis for a microfluidic droplet-based screening device aimed at investigating the interactions of drugs with specific targets including enzymes and cells. Furthermore, the continuous method could be employed for various applications, such as binding assays, kinetic studies, and single cell analysis, in which rapid removal of a reactive component is required.