Oligomer Sensor Nanoarchitectonics for “Turn-On” Fluorescence Detection of Cholesterol at the Nanomolar Level

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Mechanism of nanoarchitectonic sensors based on glycoconjugated oligomer OFP-CD and dabsyl chloride quencher (Q) as functional nano-units. Schematic representation of the “Turn-On” fluorescence sensing of cholesterol. OFP oligomer grafted with pendant chains bearing β-CD units enables host-guest complexation with dabsyl chloride (quenching OFP’s fluorescence). When the complexation equilibrium is displaced by the presence of cholesterol, disruption of the energy transfer from OFP-CD to dabsyl chloride “turns-on” the fluorescence of the sensor.

Sensitive and rapid monitoring of cholesterol levels in the human body are highly desirable as they are directly related to the diagnosis of cardiovascular diseases. By using the nanoarchitectonic approach, a novel fluorescent conjugated oligofluorene (OFP-CD) functionalized with β-cyclodextrin (β-CD) was assembled for “Turn-On” fluorescence sensing of cholesterol. The appended β-CD units in OFP-CD enabled the forming of host-guest complexes with dabsyl chloride moieties in water, resulting in fluorescence quenching of the oligofluorene through intermolecular energy transfer. In the presence of cholesterol molecules, a more favorable host-guest complex with stoichiometry 1 cholesterol: 2 β-CD units was formed, replacing dabsyl chloride in β-CD’s cavities. This process resulted in fluorescence recovery of OFP-CD, owing to disruption of energy transfer. The potential of this nanoarchitectonic system for “Turn-On” sensing of cholesterol was extensively studied by fluorescence spectroscopy. The high selectivity of the sensor for cholesterol was demonstrated using biologically relevant interfering compounds, such as carbohydrates, amino acids, metal ions, and anions. The detection limit (LOD value) was as low as 68 nM, affirming the high sensitivity of the current system.

Vedant Joshi, Sameer Hussain, Sachin Dua, Nishtha Arora, Sajjad Husain Mir, Gaulthier Rydzek, Thangaraj Senthilkumar (2022) Oligomer Sensor Nanoarchitectonics for “Turn-On” Fluorescence Detection of Cholesterol at the Nanomolar Level. Molecules 27(9):2856. https://doi.org/10.3390/molecules27092

Featured picture credit: Szente & Szeman Anal. Chem. 2013, 85, 17, 8024–8030

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