Microparticle encoding technologies for high-throughput multiplexed suspension assays

Abstract

The requirement for analysis of large numbers of biomolecules for drug discovery and clinical diagnostics has driven the development of low-cost, flexible and high-throughput methods for simultaneous detection of multiple molecular targets in a single sample (multiplexed analysis). The technique that seems most likely to satisfy all of these requirements is the multiplexed suspension (bead-based) assay, which offers a number of advantages over alternative approaches such as ELISAs and microarrays. In a bead based assay, different probe molecules are attached to different beads (of a few tens of microns in size), which are then reacted in suspension with the target sample. After reaction, the beads must be identifiable in order to determine the attached probe molecule, and thus each bead must be labelled (encoded) with a unique identifier. A large number of techniques have been proposed for encoding beads. This critical review analyses each technology on the basis of its ability to fulfil the practical requirements of assays, whilst being compatible with low-cost, high-throughput manufacturing processes and high-throughput detection methods. As a result, we identify the most likely candidates to be used for future integrated device development for practical applications.

Multiplexed Immunoassays

“…17,18 They are composed of encoded mciroparticles suspended in solution and pre-attached with capture ligands (Figure 1B). The nature of the capture ligands attached to each particle is revealed by deciphering the particle code.…”

Multiplexed protein analysis using encoded antibody-conjugated microbeads

“…There are many commercially available microbeads with a wide range of surface chemistries suitable for antibody conjugation and they can be encoded by a variety of techniques [32]. A large number of microbeads can be encoded using various combinations of fluorescent dyes or quantum dots with different emission wavelengths and intensity levels usually by entrapping the fluorescent moieties in the interior of the microbeads [33 -36], or by covalently attaching the dyes onto the surface of the microbeads [33,37].…”

Rapid microRNA Profiling on Encoded Gel Microparticles

“…Despite rapid developments in the synthesis of information-rich encoded micro-and nanoparticles, [15,16] there has been little progress in the creation of high-throughput systems for analyzing these complex entities. The emerging bead-based systems with the most promising detection performance lack a method for rapid decoding and target quantification, [16][17][18] while commercially available flow-through scanning systems constrain multiplexing capacity and provide only simple intensity measurements for inefficient, gatebased analysis (luminexcorp.com).…”

“…The emerging bead-based systems with the most promising detection performance lack a method for rapid decoding and target quantification, [16][17][18] while commercially available flow-through scanning systems constrain multiplexing capacity and provide only simple intensity measurements for inefficient, gatebased analysis (luminexcorp.com). Unlike bead systems that optically encode spheres and use arrays of lasers and photomultiplier tubes (PMTs), our particles have multiple distinct regions, making single-color, morphology-based scanning possible, with only one excitation source and one detector required.…”