Diffractive micro bar codes for encoding of biomolecules in multiplexed assays

School of Chemistry, School of Electronics and Computer Science, Optoelectronics Research Centre, and School of Physics and Astronomy, University of Southampton, Highfield, Southampton, SO17 1BJ, UK.
Analytical Chemistry (Impact Factor: 5.83). 03/2008; 80(6):1902-9. DOI: 10.1021/ac7018574
Source: PubMed

ABSTRACT Microparticles incorporating micrometer-sized diffractive bar codes have been modified with oligonucleotides and immunoglobulin Gs to enable DNA hybridization and immunoassays. The bar codes are manufactured using photolithography of a chemically functional commercial epoxy photoresist (SU-8). When attached by suitable linkers, immobilized probe molecules exhibit high affinity for analytes and fast reaction kinetics, allowing detection of single nucleotide differences in DNA sequences and multiplexed immunoassays in <45 min. Analysis of raw data from assays carried out on the diffractive microparticles indicates that the reproducibility and sensitivity approach those of commercial encoding platforms. Micrometer-sized particles, imprinted with several superimposed diffraction gratings, can encode many million unique codes. The high encoding capacity of this technology along with the applicability of the manufactured bar codes to multiplexed assays will allow accurate measurement of a wide variety of molecular interactions, leading to new opportunities in diverse areas of biotechnology such as genomics, proteomics, high-throughput screening, and medical diagnostics.

Download full-text


Available from: David Holmes, Jul 02, 2015
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The language that cells use to communicate consists of the small molecules, peptides, and proteins that are released into the extracellular environment. To decipher this language, analytical assays are needed that have high selectivity, high sensitivity, and fast temporal resolution. Affinity assays are a group of analytical methodologies that are adept at studying this communication. In this overview, we highlight several examples from the literature on various types of affinity assays used in different platforms to monitor biological communication of peptides and proteins.
    Analytical and Bioanalytical Chemistry 09/2008; 393(2):459-65. DOI:10.1007/s00216-008-2347-7 · 3.58 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A novel magnetic encoding technique for performing high-throughput biological assays is presented. Electrodeposited Ni/Cu and Co/Cu multilayer pillar structures with a diameter of 15μm and a thickness up to 10μm are presented as “magnetic barcodes”, where the number of unique codes possible increases exponentially with a linear increase in length. A gold cap facilitates the growth of self-assembled monolayers (SAMs), while microdrop printing allows efficient generation of large libraries of tagged probes. Coercivity-tuning techniques are used to exploit a non-proximity encoding methodology compatible with microfluidic flow.
    Journal of Magnetism and Magnetic Materials 05/2009; 321(10):1662-1666. DOI:10.1016/j.jmmm.2009.02.109 · 2.00 Impact Factor
  • [Show abstract] [Hide abstract]
    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.
    Integrative Biology 06/2009; 1(5-6):345-62. DOI:10.1039/b905502a · 4.00 Impact Factor