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Control of functional materials and supramolecular network dynamics at both the molecular and colloidal length scales
Cucurbit[n]urils (CB[n]) are macrocyclic molecules made of glycoluril monomers linked by methylene bridges, where n is the number of glycoluril units. CB[n] are excellent host molecules as they form stable yet dynamic complexes with guest compounds in aqueous media with extremely high affinity. The larger homologue CB[8] is capable of simultaneously accommodating two guests to form either 1:1:1 heteroternary or 2:1 homoternary complexes with association constants up to 1015 M−2 through multiple non-covalent interactions.[1] Our group has exploited CB[8]’s unique host-guest binding properties as a linking motif to prepare supramolecular polymers, micelles, hydrogels, microcapsules, hierarchical structured colloids and colloid/polymer hybrid materials.[1-5] The interactions of CB[n] with gold colloids has also been an area of interest within the group.
The use of CB[n] as a molecular ruler to control the aggregation of Au NPs and subsequently bind and detect analyte molecules at room temperature within their cavity is a major area of research in the group.6 Simple, robust CB[7]-AuNP constructs have shown the ability to detect neurotransmitters through the formation of 1:1 complexes using SERS. Moreover, this system is capable of performing quantitative multiplexing in biological media such as urine.7 In this lecture I will highlight recent advances we have made in controlling dynamic functional materials and sensors based on CB-mediated host-guest interactions.
- Figure 1 : Functional materials based on CB[8]-mediated host-guest interactions at interfaces.
Figure 2: (Left) Multiplexing of neurotransmitters in CB[7]-Au NP aggregates. (Right) Single molecule detection at RT.
About the author :
© University of Cambridge
Oren Scherman graduated from Cornell University in Ithaca, New York, with a BA in Chemistry in 1999. He then moved to Pasadena, California, where he completed a PhD in 2004 in the area of olefin metathesis and controlled polymerisation, under the supervision of Professor Robert H. Grubbs at the California Institute of Technology (Caltech). After finishing his PhD, Oren moved to the Netherlands to work on supramolecular polymers with Professors E.W. Meijer and Rint P. Sijbesma at the Eindhoven University of Technology. In 2006, he moved to the University of Cambridge to take up an academic appointment as a University Lecturer and Next Generation Fellow in the Melville Laboratory for Polymer Synthesis in the Department of Chemistry. In 2012, he was promoted to Reader in Supramolecular and Polymer Chemistry and in March 2013, he was appointed as the Director of the Melville Laboratory ; Oren was promoted to Professor in 2015. During the 2013-2014 academic year, Oren was on sabbatical at Tsinghua University as the Xuetang Visiting Professor in Chemistry. His research group is interested in dynamic supramolecular self-assembly at interfaces. Oren’s current research projects include the application of macrocyclic host-guest chemistry using cucurbit[n]urils in the development of novel supramolecular hydrogels and microcapsules, drug-delivery systems based on dynamic hydrogels, the conservation and restoration of important historical artefacts through the exploitation of supramolecular polymer chemistry and sensing and catalysis using self-assembled nanophotonic systems.
[1] Barrow. S. J., Kasera. S., Rowland. M. J., del Barrio. J., Scherman, O. A., Chem. Rev. 2015, 12320.
[2] Liu, J., Tan, C. S. Y., Lan, Y. Scherman, O. A., Macromol. Chem. Phys., 2016, 319.
[3] Zhang. J., Coulston. R. J., Jones. S.T., Geng. J., Scherman, O. A., Abell. C., Science, 2012, 690.
[4] Yang. H., Yuan. B., Zhang. X., Scherman. O. A., Acc. Chem. Res. 2014, 2106.
[5] Appel. E. A., del Barrio. J., Xian. J. L., Scherman, O. A., Chem. Soc. Rev. 2012, 6195.
[6] R. Chikkaraddy, B. de Nijs, F. Benz, S. J. Barrow, O. A. Scherman, J. J. Baumberg, et al. Nature, 2016, 535, 127.
[7] S. Kasera, L. O. Herrmann, J. D. Barrio, J. J. Baumberg and O. A. Scherman, Sci. Rep., 2014, 4, 6785.