Universal process-inert encoding architecture for polymer microparticles

Nat Mater. 2014 May;13(5):524-9. doi: 10.1038/nmat3938. Epub 2014 Apr 13.


Polymer microparticles with unique, decodable identities are versatile information carriers with a small footprint. Widespread incorporation into industrial processes, however, is limited by a trade-off between encoding density, scalability and decoding robustness in diverse physicochemical environments. Here, we report an encoding strategy that combines spatial patterning with rare-earth upconversion nanocrystals, single-wavelength near-infrared excitation and portable CCD (charge-coupled device)-based decoding to distinguish particles synthesized by means of flow lithography. This architecture exhibits large, exponentially scalable encoding capacities (>10(6) particles), an ultralow decoding false-alarm rate (<10(-9)), the ability to manipulate particles by applying magnetic fields, and pronounced insensitivity to both particle chemistry and harsh processing conditions. We demonstrate quantitative agreement between observed and predicted decoding for a range of practical applications with orthogonal requirements, including covert multiparticle barcoding of pharmaceutical packaging (refractive-index matching), multiplexed microRNA detection (biocompatibility) and embedded labelling of high-temperature-cast objects (temperature resistance).

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Biocompatible Materials / chemistry
  • Chemical Engineering
  • Drug Packaging
  • Electrochemical Techniques
  • Hot Temperature
  • Magnetic Fields
  • Metal Nanoparticles / chemistry
  • Metals, Rare Earth / chemistry
  • MicroRNAs / analysis
  • Nanoparticles / chemistry
  • Particle Size
  • Polymers / chemical synthesis
  • Polymers / chemistry*


  • Biocompatible Materials
  • Metals, Rare Earth
  • MicroRNAs
  • Polymers