(393k) Interaction of Carbohydrates With the Molecularly Imprinted Silica Particles

Carbohydrates draw significant attention in cell and molecular biology due to their pivotal roles in molecular transport, interactions with proteins and responsibly for disease transmission ^[1][2]. As a result, significant advances are being made based on glycobiology in the fields of bio-interface engineering, glycomics, saccharide sensors, carbohydrate drug discovery and refinement, enzyme mimics^[3][4] etc.  These fields would benefit from technologies to recognize and separate specific carbohydrates from mixtures of similar compounds. Carbohydrate separation is challenging due to the similarity in their structures; a difference in stereochemistry at one carbon can be biologically very significant while chemically difficult to utilize for separation. Among all the approaches reported in the literature for high selectivity adsorption, molecular imprinting is possibly the most interesting and promising approach to separate valuable carbohydrates from mixtures due to the high affinity ^[5] and selectivity towards the target molecules possible by this technique - comparable to natural receptors. By molecular imprinting we create molecular binding sites in a stable framework with specific size, shape and functional group arrangement complementary to the target molecule. Here we report one simple inexpensive technique to synthesize precipitated silica particles (Stoeber particles) whose surface is imprinted using mixed surfactants where one surfactant has the target carbohydrate as a headgroup.  We measure the adsorption kinetics and adsorption isotherms of different simple carbohydrates to demonstrate the selective binding of targeted molecules from carbohydrate mixtures due to molecular imprinting using nuclear magnetic resonance spectroscopy (NMR).  Capitalizing on the availability of isotopically labeled carbohydrates (e.g. with one ¹³C labeled) allows us to directly measure competitive binding from mixed solutions of carbohydrates to gain molecular-level insights into the interactions with the silica surface that lead to selective adsorption.

References

[1] Dinglasan, R. R.; Valenzuela, J. G.; Azad, A. F. Insect Biochemistry and Molecular Biology 2005, 35, 1.

[2] Mineo, H.; Hara, H.; Kikuchi, H.; Sakurai, H.; Tomita, F. The Journal of Nutrition 2001, 131, 3243.

[3] Fujie, T.; Matsutani, N.; Kinoshita, M.; Okamura, Y.; Saito, A.; Takeoka, S. Advanced Functional Materials 2009, 19, 2560.

[4] Di, L.; Wang, C.; Wu, J.; Wan, L.-S.; Xu, Z.-K. Chinese Journal of Analytical Chemistry 2011, 39, 592.

[5] G. Vlatakis, L. I. A., R. Moller, K. Mosbach. Nature 1993, 361, 645.