Phaseguide assisted liquid lamination for magnetic particle-based assays

Abstract

We have developed a magnetic particle-based assay platform in which functionalised magnetic particles are transferred sequentially through laminated volumes of reagents and washing buffers. Lamination of aqueous liquids is achieved via the use of phaseguide technology; microstructures that control the advancing air-liquid interface of solutions as they enter a microfluidic chamber. This allows manual filling of the device, eliminating the need for external pumping systems, and preparation of the system requires only a few minutes. Here, we apply the platform to two on-chip strategies: (i) a one-step streptavidin-biotin binding assay, and (ii) a two-step C-reactive protein immunoassay. With these, we demonstrate how condensing multiple reaction and washing processes into a single step significantly reduces procedural times, with both assay procedures requiring less than 8 seconds.

Magnetic Particle Plug-Based Assays for Biomarker Analysis

“…Here, streptavidin-coated magnetic particles, having not undergone the 1° anti-CRP functionalisation step, were trapped in the capillary and flushed with CRP (10 µg·mL −1 ) and 2° anti-CRP-FITC (100 µg·mL −1 ). Image analysis showed no increase in fluorescence that confirmed a lack of unspecific binding, as previously demonstrated [ 69 , 70 ].…”

“…Immobilisation of biotinylated primary CRP antibodies (1° anti-CRP) onto streptavidin functionalised magnetic particles (Dynabeads M-270 Streptavidin) was achieved via the streptavidin-biotin interaction, as previously reported [ 69 , 70 ]. Briefly, 10 µL of stock particle suspension (6.5 × 10 8 particles·mL −1 ) was added to a 1.5 mL microcentrifuge tube (VWR, Leicester, UK), followed by 200 µL of 1° anti-CRP solution at a concentration of 10 µg·mL −1 , and incubated for 15 min with slow tilt rotation in order for the biotinylated antibodies to bind to the streptavidin-coated particles.…”

Symmetric surficial phaseguides: a passive technology to generate wall-less channels by two-dimensional guiding elements

“…Phaseguides consists either of a different material (Choi et al 2015;Vulto et al 2006) or of a different geometry (Phurimsak et al 2014;Podszun et al 2012;PuchbergerEnengl et al 2014;Vulto et al 2010Vulto et al , 2011Xu et al 2015). Phaseguides based on a different material consist usually of thin stripes of SU8 (Vulto et al 2006), Teflon (Vulto et al 2006) or SiO 2 (Choi et al 2015) which are patterned on the top or bottom plate of the chip.…”

Continuous Microfluidic Purification of DNA Using Magnetophoresis

“…The movement of beads is controlled through the static buffers by the motion of the external permanent magnet by hand [2,19], while beads cross the continuous flow under the influence of the inhomogeneous magnetic field. Magnetic beads across various continuous flows has been applied in cell sorting [14,20,21], bioanalysis [15,22,23], capsule assembly [24], etc. Kim et al [25] used "SIM-Chip" that comprised a magnetophoretic separator and a dispenser to enrich circulating tumor cells (CTCs).…”