Fluorescence-Based Detection of Cholesterol Using Inclusion Complex of Hydroxypropyl-β-Cyclodextrin andl-Tryptophan as the Fluorescence Probe

Purpose The study is inspired by the fact that intravenous administration of 2-hydroxypropyl-beta-cyclodextrins (HP-beta-CD) in rats leads to a rapid decrease in plasma cholesterol levels. Further, HP-beta-CD being more water soluble than native beta-CD, HP-beta-CD forms soluble complex with cholesterol and higher affinity of cholesterol towards HP-beta-CD than native beta-CD leads to increase sensitivity. Hence, present work reports potential use of HP-beta-CD as a chemosensor to detect cholesterol aided withl-tryptophan (l-Trp) as a fluorescence probe. The purpose of the study is to develop fast, cost-effective, and high throughput fluorescence-based chemosensor as convenient point-of-care diagnostic method for cholesterol detection. Methods The host-guest interaction ofl-Trp with HP-beta-CD was elaborately studied using characterization techniques such as FT-IR, NMR, and DSC. Time and concentration dependent interactions were studied to determine the stoichiometry of molecular inclusion complexes of HP-beta-CD withl-Trp. Further, the inclusion complex of HP-beta-CD withl-tryptophan is explored to detect cholesterol based on the competitive displacement phenomenon and further explored for detecting different concentrations of cholesterol. Results Fluorescence spectroscopic data revealed that HP-beta-CD served as a quencher forl-Trp. Also, promising results of the displacement assay proved that the fluorescence ofl-Trp was quenched by HP-beta-CD followed by increase in fluorescence signals in quantitative relation with cholesterol as it replacesl-Trp from the HP-beta-CD host. Conclusion The present investigation is a proof-of-concept that proves the potential of HP-beta-CD withl-Trp as a novel fluorescence-based technique for cholesterol detection which is developed using competitive host-guest interaction.

Automated summary

This study explores the potential use of HP-beta-CD and l-tryptophan as a novel fluorescence-based technique for cholesterol detection. The interaction between HP-beta-CD and l-tryptophan was studied in depth, and promising results were obtained from the displacement assay showing quantitative relation with cholesterol levels. This investigation demonstrates the development of a fast and cost-effective chemosensor for cholesterol detection based on competitive host-guest interaction.