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: 5.64). 03/2008; 80(6):1902-9. DOI: 10.1021/ac7018574
Source: PubMed


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.

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    • "After fabrication, SU-8 particles retain surface epoxide functionality which can be used as a handle for further chemical functionalisations [6]. One example of the scope of this surface chemistry is the use of free radical polymerization to graft functionalised polymer brushes from the surface, allowing the loading density, spacing and type of functionality to be controlled (Figure 1). "
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