Electrochemical and surface plasmon resonance characterization of beta-cyclodextrin-based self-assembled monolayers and evaluation of their inclusion complexes with glucocorticoids

Simple preparation of green fluorescent protein conjugated with β-cyclodextrin in a site specific manner

We have site-directedly linked a green fluorescent protein (GFP) variant and a β-cyclodextrin (β-CD) with a simple method to develop a basic complex for sophisticated supramolecules. We have confirmed β-CD grafting on GFP with several methods including matrix-assisted laser desorption/ionization linear time-of-flight mass spectrometry (MALDI-TOF MS) without protease digestion and characterized the complex as well. In consideration of the resulting properties, the product we plainly and efficiently obtained could have applications related to sensing devices and drug delivery systems.

Electrochemically controlled assembly and logic gates operations of gold nanoparticle arrays

The reversible assembly of β-cyclodextrin-functionalized gold NPs (β-CD Au NPs) is studied on mixed self-assembled monolayer (SAM), formed by coadsorption of redox-active ferrocenylalkylthiols and n-alkanethiols on gold surfaces. The surface coverage and spatial distribution of the β-CD Au NPs monolayer on the gold substrate are tuned by the self-assembled monolayer composition. The binding and release of β-CD Au NPs to and from the SAMs modified surface are followed by surface plasmon resonance (SPR) spectroscopy. The redox state of the tethered ferrocene in binary SAMs controls the formation of the supramolecular interaction between ferrocene moieties and β-CD-capped Au NPs. As a result, the potential-induced uptake and release of β-CD Au NPs to and from the surface is accomplished. The competitive binding of β-CD Au NPs with guest molecules in solution shifted the equilibrium of the complexation-decomplexation process involving the supramolecular interaction with the Fc-functionalized surface. The dual controlled assembly of β-CD Au NPs on the surface enabled to use two stimuli as inputs for logic gate activation; the coupling between the localized surface plasmon, associated with the Au NP, and the surface plasmon wave, associated with the thin metal surface, is implemented as readout signal for "AND" logic gate operations.