title: Quantum-dot-tagged microbeads for multiplexed optical coding of biomolecules.
abstract: Multicolor optical coding for biological assays has been achieved by embedding different-sized quantum dots (zinc sulfide-capped cadmium selenide nanocrystals) into polymeric microbeads at precisely controlled ratios. Their novel optical properties (e.g., size-tunable emission and simultaneous excitation) render these highly luminescent quantum dots (QDs) ideal fluorophores for wavelength-and-intensity multiplexing. The use of 10 intensity levels and 6 colors could theoretically code one million nucleic acid or protein sequences. Imaging and spectroscopic measurements indicate that the QD-tagged beads are highly uniform and reproducible, yielding bead identification accuracies as high as 99.99% under favorable conditions. DNA hybridization studies demonstrate that the coding and target signals can be simultaneously read at the single-bead level. This spectral coding technology is expected to open new opportunities in gene expression studies, high-throughput screening, and medical diagnostics.
authors: Department of Chemistry, Indiana University, Bloomington, IN 47405, USA.
authors: M
authors: M
authors: Han
authors: X
authors: X
authors: Gao
authors: J Z
authors: JZ
authors: Su
authors: S
authors: S
authors: Nie
mesh_terms: D001709:Biotechnology / Q000379:methods; D004247:DNA / Q000378:metabolism*; D005456:Fluorescent Dyes; D005821:Genetic Techniques; D008856:Microscopy, Fluorescence / Q000379:methods*; D009693:Nucleic Acid Hybridization / Q000379:methods*; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods*; D009841:Oligonucleotides / Q000737:chemistry; D013050:Spectrometry, Fluorescence / Q000379:methods*
chemical_list: D005456:Fluorescent Dyes; D009841:Oligonucleotides; D004247:DNA