Cucurbiturils (CUs) are macromolecules with a cavity that is larger in diameter than its opening. The importance of this macromolecule is based on its ability to undergo host-guest chemistry, using its cavity to hold molecules without covalent bonds. It has been shown that guest molecules, when introduced in the CU, can change their emitting fluorescent signal enabling these host-guest complexes to function as sensors. The goal of this project was to determine the detection sensitivity of cucurbit[7]uril-berberine complex. Berberine is a quaternary ammonium salt extracted from the Berberis genus plants that increases in fluorescence emission intensity when introduced in cucurbit[7]uril. To analyze its sensor capability, the complex was immobilized on a glass slide that has been functionalized with (3-Glycidyloxypropyl) trimethoxysilane [GPTMS], where the epoxide reacts with the amine-functionalized end from the cucurbit[7]uril-berberine complex. To deposit the host-guest complex to the functionalized glass slide micro-channel cantilever spotting (µCS), a technique that uses quill-like pens, was used to dispense droplets that act as reaction vessels. Droplet size can vary between 10 µm to 20 µm radius and they can be freely arranged on the substrate, e.g. as a square array. Exposure of the array to different concentration of nandrolone, an anabolic steroid that has a greater binding capacity to the cucurbit[7]uril than berberine, resulted in the decrease of fluorescence due to the indicator displacement assay (IDA) mechanism. After confirming immobilization using fluorescent microscopy, the array was exposed to nandrolone in different concentrations to quantify the decrease of fluorescence. Immobilization of both of the inks (one with the CB7-Berberine complex and the other with the CB7-Pyronin Y complex) onto the GPTMS substrate was successful. Unfortunately, the fluorescence signal of the immobilized CB7-Berberine complex was insufficient, and a new complex, CB7-Pyronin Y, was immobilized and visualized. The immobilization involved the epoxide ring opening of the amine-functionalized cucurbit-berberine complex, which was characterized by Electrospray Ionization Mass Spectrometry.

Micro-channel cantilever spotting (µCS) and the immobilization of Cucurbit[7]uril complex for determination of sensitivity on analyte exposure

2019 Spring National Meeting

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