Full text loading...
A selection of periodic patterns that can trap and transport superparamagnetic particles by rotation of an external magnetic field. The vertical sequence of micrographs below each schematic representation of the pattern and particle movement shows the position of an diameter superparamagnetic particle (highlighted by gray circles) as the external field of 40 mT is rotated steps clockwise. (c) The micrographs illustrate the movement of two particles in antiparallel directions for the same field rotation, the top bead (gray) moving left to right and the lower bead (white) moving right to left on the opposite side of the pattern. (d) The micrographs illustrate two particles moving in the same direct in phase with each other.
Schematic and micrograph of the microfluidic setup. (a) Schematic representation of the cross section of the microfluidic channel. (b) Micrograph of a merged white light and fluorescence image to illustrate the laminar flow from the three inlets perpendicular to the saw-tooth pattern. The concentration of the secondary antibody was increased to to collect this image. Dotted white lines have been added to emphasize the boundaries of the channel. (c) Average force and standard deviation from fluid drag in the microfluidic channel required to detach diameter superparamagnetic beads from the setup in (b) depending on the orientation and magnitude of the external magnetic field.
Sequential brightfield micrographs illustrating the trapping and controlled transport of magnetic beads between streams in a microfluidic channel. (a) Superparamagnetic beads are captured from the lower stream in the micrographs and transported into the middle stream [(a)–(d)] where the bead is held for 5 min to accumulate complementary fluorescent secondary antibody, as illustrated in the enlarged fluorescent images of the bead. These antibodies can be dissociated from the bead by moving it into the upper stream [(e)–(f)] and holding it there for 5 min. This process can be repeated by first rotating the external field clockwise [(g)–(h)] to move the bead back into the middle stream, holding it for 5 min and then rotating the field anticlockwise [(i)–(j)] to move the bead back to the upper stream. The progress of the bead has been highlighted by a dotted white circle.
Article metrics loading...