Integrated lab-on-chip biosensing systems based on magnetic particle actuation – a comprehensive review

Abstract

The demand for easy to use and cost effective medical technologies inspires scientists to develop innovative lab-on-chip technologies for point-of-care in vitro diagnostic testing. To fulfill medical needs, the tests should be rapid, sensitive, quantitative, and miniaturizable, and need to integrate all steps from sample-in to result-out. Here, we review the use of magnetic particles actuated by magnetic fields to perform the different process steps that are required for integrated lab-on-chip diagnostic assays. We discuss the use of magnetic particles to mix fluids, to capture specific analytes, to concentrate analytes, to transfer analytes from one solution to another, to label analytes, to perform stringency and washing steps, and to probe biophysical properties of the analytes, distinguishing methodologies with fluid flow and without fluid flow (stationary microfluidics). Our review focuses on efforts to combine and integrate different magnetically actuated assay steps, with the vision that it will become possible in the future to realize integrated lab-on-chip biosensing assays in which all assay process steps are controlled and optimized by magnetic forces.

Magnetic interaction of Janus magnetic particles suspended in a viscous fluid

“…Integrated microfluidic systems utilizing magnetic particles have drawn attention because of their potential chemical and biomedical applications [1][2][3][4]. In these systems, functionalized magnetic particles have been adopted for use as actuators, stirrers to enhance mixing, capturers and carriers of target analytes, and biosensors for diagnostic applications.…”

Biological Magnetometry: Torque on Superparamagnetic Beads in Magnetic Fields

“…Micrometer-sized superparamagnetic beads are ubiquitously used in biochemistry and biotechnology, finding applications in, e.g., diagnostics that rely on capturing and detecting analytes or mixing microliter-sized volumes [1]. In addition, superparamagnetic beads are routinely employed in single-molecule magnetic tweezers (MT) as force [2] and torque [3] transducers.…”

Distance within colloidal dimers probed by rotation-induced oscillations of scattered light

“…In selfassembly studies of colloidal particles, this could enable more detailed information on the forces acting on the particles in the early stages of assembly. Also in the field of particlebased biosensing [7,8,25], knowing the distance between particles can serve to distinguish e.g. specifically bound from non-specifically bound particles, thereby improving the performance of these bioanalytical assays.…”