Selective transport and concentration of molecules to specified regions on a substrate both enhances the potential to detect such molecules and provides a path to spatially localize such molecules prior to initiation of subsequent chemical reactions. Here, we first embed radially symmetric α-, β-, and γ-cyclodextrin gradients in a hydrogel matrix. Driven by host-guest interactions between the cyclodextrins and the target molecule, we observe these gradients can serve to direct 2D molecular transport. Using xanthene dyes and organophosphates as target molecules, we found the transport metrics, e.g., selectivity, rate, and concentration limits, are strongly dependent on the specific cyclodextrin forming the gradient. In all cases, as the concentrating power of the gradient increased, the rate of target concentration slowed, which we hypothesize is because stronger interactions between the target and the cyclodextrin decrease the rate of target diffusion. The concentration enhancement for the nerve agent simulant 4-methylumbelliferyl phosphate (15.8) is the greatest when the gradient is formed using β-cyclodextrin while directed concentration of cyanomethyl phosphonate, a smaller non-aromatic organophosphate, is observed only for the smaller α-CD. To provide a near real-time read-out of the concentration of the analyte, we used an array of IR resonant metallic nanoantennas tuned to a specific IR absorption band of the analyte to enhance the IR signal generated by the analyte.
|Original language||English (US)|
|Number of pages||6|
|Journal||Angewandte Chemie - International Edition|
|State||Published - Dec 9 2019|
Bibliographical noteFunding Information:
The work was supported by the Defense Threat Reduction Agency under award number HDTRA 1-12-1-0035, the Department of Defense/US Army W911NF-17-1-0351, the Alexander von Humboldt foundation (Bessel prize to P.V.B.), MWK BW (Spitzenforschung II), DFG, BMBF, ERC (ComplexPlas), and the Zeiss Foundation. We thank Dr. Brian Pate (DTRA), Dr. Tsung-Han Tsai, Dr. Mohammad Amdad Ali, Dr. Kali Miller, Dr. Dianwen Zhang, and Zheng Chen (Yale) for helpful discussions, technical advice and support.
© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
- chemical gradient
- molecular transport
- supramolecular interaction