Colour-barcoded magnetic microparticles for multiplexed bioassays

Abstract

Encoded particles have a demonstrated value for multiplexed high-throughput bioassays such as drug discovery and clinical diagnostics. In diverse samples, the ability to use a large number of distinct identification codes on assay particles is important to increase throughput. Proper handling schemes are also needed to readout these codes on free-floating probe microparticles. Here we create vivid, free-floating structural coloured particles with multi-axis rotational control using a colour-tunable magnetic material and a new printing method. Our colour-barcoded magnetic microparticles offer a coding capacity easily into the billions with distinct magnetic handling capabilities including active positioning for code readouts and active stirring for improved reaction kinetics in microscale environments. A DNA hybridization assay is done using the colour-barcoded magnetic microparticles to demonstrate multiplexing capabilities.

Engineering fluid flow using sequenced microstructures

“…C ontrol of fluid streams is useful in biological processing [1][2][3] , chemical reaction control 4,5 , and creating structured materials [6][7][8] ; however, general strategies to engineer the cross-sectional form and motion of fluid streams have been limited. Strategies to mix fluids 1,9,10 and control particles 11,12 using engineered systems exist, often relying on chaotic fluid transformations as an effective tool 13,14 to disrupt sustained regions of order in the flow 10,15 .…”

High‐Throughput Contact Flow Lithography

“…The method was demonstrated on polyethylene glycol diacrylate (PEGDA) hydrogels, but is applicable to any free radical polymerization reaction 9, 10. Several research groups successfully applied flow lithography to synthesize particles with complex graphical codes based on shapes,11 1D‐barcodes,12 or even 2D‐barcodes 13. Recent studies also investigated 3D‐particle patterning 14…”

Microfluidic Generation of Multifunctional Quantum Dot Barcode Particles

“…One promising strategy is to use barcode particles, which are particles that encode information about their specific compositions and enable simple identification. Many encoding strategies have been proposed for these barcode particles; these include incorporation of segmented nanorods, 3 photo-patterning, [4][5][6] as well as the use of photonic crystals, 7,8 fluorescent silica colloids, 9 and semiconductor quantum dots (QDs). [10][11][12][13][14][15][16] In particular, the semiconductor QDs hold immense promise as barcode elements because of their excellent optical properties such as simultaneous excitation of multiple wavelength-and-intensity with a single light source, minimal spectral width, and remarkable photo-stability.…”

“…In addition, traditional processes used for generating such particles provide little control over the characteristics of the result particles, such as particle sizes and QDs number and distribution within each particles; thus the resultant QD barcodes often have high variability of fluorescence intensities. [13][14][15][16] This is exacerbated by the uncontrolled motion of these barcode particles, which reduces the sensitivity of the assay 6 and demands more complicated procedures for enriching the barcode particles during assay 17 . These, together with the debatable biocompatibility of such particles, have limited their applications.…”

“…Therefore, our barcode particles have great potential for use in high-throughput bioassays that requires barcode particles with high sensitivity and controllable motion. 6,17 In conclusion, we have developed a new approach to prepare barcode particles by encapsulating QDs in double emulsion templates generated in capillary microfluidic devices. The resultant particles exhibit uniform spectral characteristics and allow substantial number of coding levels for multiplexing.…”