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Lock and key colloids

Abstract

New functional materials can in principle be created using colloids that self-assemble into a desired structure by means of a programmable recognition and binding scheme. This idea has been explored by attaching ‘programmed’ DNA strands to nanometre-1,2,3 and micrometre-4,5 sized particles and then using DNA hybridization to direct the placement of the particles in the final assembly. Here we demonstrate an alternative recognition mechanism for directing the assembly of composite structures, based on particles with complementary shapes. Our system, which uses Fischer’s lock-and-key principle6, employs colloidal spheres as keys and monodisperse colloidal particles with a spherical cavity as locks that bind spontaneously and reversibly via the depletion interaction. The lock-and-key binding is specific because it is controlled by how closely the size of a spherical colloidal key particle matches the radius of the spherical cavity of the lock particle. The strength of the binding can be further tuned by adjusting the solution composition or temperature. The composite assemblies have the unique feature of having flexible bonds, allowing us to produce flexible dimeric, trimeric and tetrameric colloidal molecules as well as more complex colloidal polymers. We expect that this lock-and-key recognition mechanism will find wider use as a means of programming and directing colloidal self-assembly.

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Figure 1: Fabrication of lock particles.
Figure 2: Lock–key interactions.
Figure 3: Selectivity of the lock–key reversible binding.
Figure 4: Temperature–controlled lock-key self-assembly and electric field manipulation.
Figure 5: Flexibility of the lock–key junctions in self-assembled colloidal molecules and polymers.

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References

  1. Mirkin, C., Letsinger, R., Mucic, R. & Storhoff, J. A DNA-based method for rationally assembling nanoparticles into macroscopic materials. Nature 382, 607–609 (1996)

    Article  ADS  CAS  PubMed  Google Scholar 

  2. Nykypanchuk, D., Maye, M. M., van der Lelie, D. & Gang, O. DNA-guided crystallization of colloidal nanoparticles. Nature 451, 549–552 (2008)

    Article  ADS  CAS  PubMed  Google Scholar 

  3. Park, S. Y. et al. DNA-programmable nanoparticle crystallization. Nature 451, 553–556 (2008)

    Article  ADS  CAS  PubMed  Google Scholar 

  4. Valignat, M., Theodoly, O., Crocker, J., Russel, W. & Chaikin, P. Reversible self-assembly and directed assembly of DNA-linked micrometer-sized colloids. Proc. Natl Acad. Sci. USA 102, 4225–4229 (2005)

    Article  ADS  CAS  PubMed  PubMed Central  Google Scholar 

  5. Rogers, P. et al. Selective, controllable, and reversible aggregation of polystyrene latex microspheres via DNA hybridization. Langmuir 21, 5562–5569 (2005)

    Article  CAS  PubMed  Google Scholar 

  6. Fischer, E. Einfluss der Configuration auf die Wirkung der Enzyme. Ber. deutsch. chem. Gesell. 27, 2985–2993 (1894)

    Article  CAS  Google Scholar 

  7. Obey, T. & Vincent, B. Novel monodisperse “silicone oil”/water emulsions. J. Colloid Interf. Sci. 163, 454–463 (1994)

    Article  ADS  CAS  Google Scholar 

  8. Asakura, S. & Oosawa, F. On interaction between two bodies immersed in a solution of macromolecules. J. Chem. Phys. 22, 1255–1256 (1954)

    Article  ADS  CAS  Google Scholar 

  9. Lekkerkerker, H., Poon, W., Pusey, P., Stroobants, A. & Warren, P. Phase-behavior of colloid plus polymer mixtures. Europhys. Lett. 20, 559–564 (1992)

    Article  ADS  CAS  Google Scholar 

  10. Odriozola, G., Jimenez-Angeles, F. & Lozada-Cassou, M. Entropy driven key-lock assembly. J. Chem. Phys. 129, 111101 (2008)

    Article  ADS  CAS  PubMed  Google Scholar 

  11. König, P., Roth, R. & Dietrich, S. Lock and key model system. Europhys. Lett. 84, 68006 (2008)

    Article  ADS  Google Scholar 

  12. Saunders, B. & Vincent, B. Microgel particles as model colloids: theory, properties and applications. Adv. Colloid Interf. Sci. 80, 1–25 (1999)

    Article  CAS  Google Scholar 

  13. Stöber, W., Fink, A. & Bohn, E. Controlled growth of monodisperse silica spheres in micron size range. J. Colloid Interf. Sci. 26, 62–69 (1968)

    Article  ADS  Google Scholar 

  14. Ottewill, R. & Shaw, J. Studies on the preparation and characterisation of monodisperse polystyrene latices. Colloid Polym. Sci. 218, 34–40 (1967)

    CAS  Google Scholar 

  15. Pelton, R. H. & Chibante, P. Preparation of aqueous lattices with n-isopropylacrylamide. Colloids Surf. 20, 247–256 (1986)

    Article  CAS  Google Scholar 

Download references

Acknowledgements

This work was partially supported by National Science Foundation grants DMR 0706453 and the Keck Foundation. S.S. was supported by the Netherlands Organization for Scientific Research (NWO) through a Rubicon fellowship. W.T.M.I. acknowledges support from the English Speaking Union through a Lindemann Fellowship and Rhodia.

Author Contributions S.S. designed the lock synthesis, synthesized all the colloidal systems, designed and performed the experiments and analysed data. W.T.M.I. designed the experiments, performed field manipulation experiments, analysed data and theoretically modelled the system. D.J.P. and P.M.C. conceived of the depletion-induced colloidal lock-and-key interaction, initiated and supervised the research. The manuscript was written by S.S., W.T.M.I. and D.J.P.

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Correspondence to S. Sacanna or D. J. Pine.

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Supplementary information

Supplementary Information

This file contains Supplementary Data including Figure 1 and legend, Supplementary References and Supplementary Figures S1 and legend. (PDF 878 kb)

Supplementary Movie 1

This movie file shows the sequential self-assembly of a flexible colloidal molecule via our novel recognition mechanism. A lock-key complex forms only when a matching key particle (here a 1.57μm silica sphere) docks at the lock cavity site (green arrow). All other configurations result in repulsive interactions (red arrow). A key particle can accommodate more than one lock. The movie was acquired at 1 fr/s and it is displayed at 8.7 fr/s. (MOV 2937 kb)

Supplementary Movie 2

This movie file shows the simultaneous unbinding of two lock-key complexes controlled by temperature. When the temperature is raised the depletant shrinks (pNIPAM microgel particles not visible in the movie) and the attractive depletion potential falls below that required for binding. As a result, the locks release their bound keys. The movie was acquired at 10.7 fr/s and it is displayed at 12.8 fr/s. (MOV 2210 kb)

Supplementary Movie 3

This movie file shows self-assembled colloidal molecules with flexible bonds between their constituent particles. The flexibility is given by ball-and-socket joints held together by the depletion force. Movies were acquired at 1 fr/s and they are displayed at 10 fr/s (MOV 395 kb)

Supplementary Movie 4

This movie file shows self-assembled colloidal molecules with flexible bonds between their constituent particles. The flexibility is given by ball-and-socket joints held together by the depletion force. Movies were acquired at 1 fr/s and they are displayed at 10 fr/s (MOV 1062 kb)

Supplementary Movie 5

This movie file shows a freely diffusing flexible colloidal polymer consisting of interconnected locks. The movie was acquired at 10.7 fr/s and it is displayed at 23.5 fr/s. (MOV 1680 kb)

Supplementary Movie 6

This movie file is showing a typical, randomly selected "full field of view" of our sample containing ~60× lock-key assemblies. (MOV 4955 kb)

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Sacanna, S., Irvine, W., Chaikin, P. et al. Lock and key colloids. Nature 464, 575–578 (2010). https://doi.org/10.1038/nature08906

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