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Colour-barcoded magnetic microparticles for multiplexed bioassays


Encoded particles have a demonstrated value for multiplexed high-throughput bioassays such as drug discovery and clinical diagnostics1,2. In diverse samples, the ability to use a large number of distinct identification codes on assay particles is important to increase throughput3. 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 method4. 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 environments5. A DNA hybridization assay is done using the colour-barcoded magnetic microparticles to demonstrate multiplexing capabilities.

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Figure 1: Single-material (M-Ink)-based colour-barcoded magnetic microparticles.
Figure 2: Magnetic multi-axis control of structural colour-barcoded magnetic microparticles for multistep biochemical assays.
Figure 3: Multiplexed DNA detection assay using colour-barcoded magnetic microparticles.


  1. Birtwell, S. & Morgan, H. Microparticle encoding technologies for high-throughput multiplexed suspension assays. Integr. Biol. 1, 345–362 (2009).

    CAS  Article  Google Scholar 

  2. Wilson, R., Cossins, A. R. & Spiller, D. G. Encoded microcarriers for high-throughput multiplexed detection. Angew. Chem. Int. Ed. 45, 6104–6117 (2006).

    CAS  Article  Google Scholar 

  3. Braeckmans, K., De Smedt, S. C., Leblans, M., Pauwels, R. & Demeester, J. Encoding microcarriers: Present and future technologies. Nature Rev. Drug Dis. 1, 447–456 (2002).

    CAS  Article  Google Scholar 

  4. Kim, H. et al. Structural colour printing using a magnetically tunable and lithographically fixable photonic crystal. Nature Photon. 3, 534–540 (2009).

    CAS  Article  Google Scholar 

  5. Ge, J. et al. Magnetochromatic microspheres: Rotating photonic crystals. J. Am. Chem. Soc. 131, 15687–15694 (2009).

    CAS  Article  Google Scholar 

  6. Alivisatos, A. P. Less is more in medicine — sophisticated forms of nanotechnology will find some of their first real-world applications in biomedical research, disease diagnosis and, possibly, therapy. Sci. Am. 285, 66–73 (2001).

    CAS  Article  Google Scholar 

  7. Fulton, R. J., McDade, R. L., Smith, P. L., Kienker, L. J. & Kettman, J. R. Advanced multiplexed analysis with the FlowMetrix(TM) system. Clin. Chem. 43, 1749–1756 (1997).

    CAS  Google Scholar 

  8. Han, M., Gao, X., Su, J. & Nie, S. Quantum-dot-tagged microbeads for multiplexed optical coding of biomolecules. Nature Biotechnol. 19, 631–635 (2001).

    CAS  Article  Google Scholar 

  9. Ma, Q., Wang, X., Li, Y., Shi, Y. & Su, X. Multicolor quantum dot-encoded microspheres for the detection of biomolecules. Talanta 72, 1446–1452 (2007).

    CAS  Article  Google Scholar 

  10. Medintz, I. L., Uyeda, H. T., Goldman, E. R. & Mattoussi, H. Quantum dot bioconjugates for imaging, labelling and sensing. Nature Mater. 4, 435–446 (2005).

    CAS  Article  Google Scholar 

  11. Braeckmans, K. et al. Encoding microcarriers by spatial selective photobleaching. Nature Mater. 2, 169–173 (2003).

    CAS  Article  Google Scholar 

  12. Keating, C. D. & Natan, M. J. Striped metal nanowires as building blocks and optical tags. Adv. Mater. 15, 451–454 (2003).

    CAS  Article  Google Scholar 

  13. Nicewarner-Pena, S. R. et al. Submicrometer metallic barcodes. Science 294, 137–141 (2001).

    CAS  Article  Google Scholar 

  14. Pregibon, D. C., Toner, M. & Doyle, P. S. Multifunctional encoded particles for high-throughput biomolecule analysis. Science 315, 1393–1396 (2007).

    CAS  Article  Google Scholar 

  15. Dejneka, M. J. et al. Rare earth-doped glass microbarcodes. Proc. Natl Acad. Sci. USA 100, 389–393 (2003).

    CAS  Google Scholar 

  16. Reiss, B. D. et al. Electrochemical synthesis and optical readout of striped metal rods with submicron features. J. Electroanal. Chem. 522, 95–103 (2002).

    CAS  Article  Google Scholar 

  17. Ge, J., Hu, Y. & Yin, Y. Highly tunable superparamagnetic colloidal photonic crystals. Angew. Chem. Int. Ed. 46, 7428–7431 (2007).

    CAS  Article  Google Scholar 

  18. Ge, J. & Yin, Y. Magnetically tunable colloidal photonic structures in alkanol solutions. Adv. Mater. 20, 3485–3491 (2008).

    CAS  Article  Google Scholar 

  19. Chung, S. E. et al. Optofluidic maskless lithography system for real-time synthesis of photopolymerized microstructures in microfluidic channels. Appl. Phys. Lett. 91, 041106 (2007).

    Article  Google Scholar 

  20. Dendukuri, D., Pregibon, D. C., Collins, J., Hatton, T. A. & Doyle, P. S. Continuous-flow lithography for high-throughput microparticle synthesis. Nature Mater. 5, 365–369 (2006).

    CAS  Article  Google Scholar 

  21. Yuet, K. P., Hwang, D. K., Haghgooie, R. & Doyle, P. S. Multifunctional superparamagnetic Janus particles. Langmuir 26, 4281–4287 (2009).

    Article  Google Scholar 

  22. Melle, S., Fuller, G. G. & Rubio, M. A. Structure and dynamics of magnetorheological fluids in rotating magnetic fields. Phys. Rev. E 61, 4111–4117 (2000).

    CAS  Article  Google Scholar 

  23. Wilhelm, C., Browaeys, J., Ponton, A. & Bacri, J. C. Rotational magnetic particles microrheology: The Maxwellian case. Phys. Rev. E 67, 011504 (2003).

    CAS  Article  Google Scholar 

  24. Pregibon, D. C. & Doyle, P. S. Optimization of encoded hydrogel particles for nucleic acid quantification. Anal. Chem. 81, 4873–4881 (2009).

    CAS  Article  Google Scholar 

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This work was supported by the Korea Science and Engineering Foundation (KOSEF) grant funded by the Korea government (MEST) (No. 2010-0017860 and 2009-0082694) and the System IC 2010 project of the Ministry of Knowledge Economy. We thank A. J. Heinz, W. Park, N. Kim and S. E. Choi for the experimental advice. We gratefully acknowledge Y. Yin at the University of California, Riverside, for valuable input and discussions on particle synthesis.

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S.K. proposed the concept of the work. H.L. and S.K. designed the experiment. J.K., H.K. and H.L. carried out the experiments and analysis. J.K. and J.K. carried out theoretical analysis.

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Correspondence to Sunghoon Kwon.

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The authors declare no competing financial interests.

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Lee, H., Kim, J., Kim, H. et al. Colour-barcoded magnetic microparticles for multiplexed bioassays. Nature Mater 9, 745–749 (2010).

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