title: Optical Manipulation of Single Magnetic Beads in a Microwell Array on a Digital Microfluidic Chip.
abstract: The detection of single molecules in magnetic microbead microwell array formats revolutionized the development of digital bioassays. However, retrieval of individual magnetic beads from these arrays has not been realized until now despite having great potential for studying captured targets at the individual level. In this paper, optical tweezers were implemented on a digital microfluidic platform for accurate manipulation of single magnetic beads seeded in a microwell array. Successful optical trapping of magnetic beads was found to be dependent on Brownian motion of the beads, suggesting a 99% chance of trapping a vibrating bead. A tailor-made experimental design was used to screen the effect of bead type, ionic buffer strength, surfactant type, and concentration on the Brownian activity of beads in microwells. With the optimal conditions, the manipulation of magnetic beads was demonstrated by their trapping, retrieving, transporting, and repositioning to a desired microwell on the array. The presented platform combines the strengths of digital microfluidics, digital bioassays, and optical tweezers, resulting in a powerful dynamic microwell array system for single molecule and single cell studies.
authors.affiliation: Department of Biosystems, MEBIOS-Biosensors, KU Leuven , Willem de Croylaan 42, 3001 Leuven, Belgium.
authors.forename: Deborah
authors.initials: D
authors.lastname: Decrop
authors.affiliation: Department of Electronics and Information Systems (ELIS) and Center for Nano and Biophotonics (NB-Photonics), UGent , Sint-Pietersnieuwstraat 41, 9000 Gent, Belgium.
authors.forename: Toon
authors.initials: T
authors.lastname: Brans
authors.affiliation: Department of Electrotechnical Engineering (ESAT-MICAS), KU Leuven , Kasteelpark Arenberg 10 Postbus 2440, 3001 Leuven, Belgium.
authors.forename: Pieter
authors.initials: P
authors.lastname: Gijsenbergh
authors.affiliation: Department of Biosystems, MEBIOS-Biosensors, KU Leuven , Willem de Croylaan 42, 3001 Leuven, Belgium.
authors.forename: Jiadi
authors.initials: J
authors.lastname: Lu
authors.affiliation: Department of Biosystems, MEBIOS-Biosensors, KU Leuven , Willem de Croylaan 42, 3001 Leuven, Belgium.
authors.forename: Dragana
authors.initials: D
authors.lastname: Spasic
authors.affiliation: Department of Biosystems, MEBIOS-Biosensors, KU Leuven , Willem de Croylaan 42, 3001 Leuven, Belgium.
authors.forename: Tadej
authors.initials: T
authors.lastname: Kokalj
authors.affiliation: Department of Electronics and Information Systems (ELIS) and Center for Nano and Biophotonics (NB-Photonics), UGent , Sint-Pietersnieuwstraat 41, 9000 Gent, Belgium.
authors.forename: Filip
authors.initials: F
authors.lastname: Beunis
authors.affiliation: Department of Biosystems, MEBIOS-Biosensors, KU Leuven , Willem de Croylaan 42, 3001 Leuven, Belgium.|Faculty of Applied Economics, University of Antwerp, Stadscampus , Prinsstraat 13, 2000 Antwerp, Belgium.
authors.forename: Peter
authors.initials: P
authors.lastname: Goos
authors.affiliation: Department of Electrotechnical Engineering (ESAT-MICAS), KU Leuven , Kasteelpark Arenberg 10 Postbus 2440, 3001 Leuven, Belgium.
authors.forename: Robert
authors.initials: R
authors.lastname: Puers
authors.affiliation: Department of Biosystems, MEBIOS-Biosensors, KU Leuven , Willem de Croylaan 42, 3001 Leuven, Belgium.
authors.forename: Jeroen
authors.initials: J
authors.lastname: Lammertyn
mesh_terms: D060526:Magnetic Fields; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation; D052898:Optical Tweezers; D019809:Streptavidin / Q000737:chemistry
chemical_list: D019809:Streptavidin