Folic Acid Detection Using β-Cyclodextrin-Functionalized Copper Nanoclusters and Vitamin B<sub>6</sub> Cofactor Pyridoxal
Yagnik Vegad, Seshu Vardhan, A. Ghosh, Bigyan Ranjan Jali, Suban K. Sahoo
Abstract
The facile and reliable detection of folic acid (FA), also known as vitamin B 9, is crucial for the early diagnosis and prevention of FA-related physiological health problems. This article introduces a displacement approach for the fluorescent turn-off detection of FA by using β-cyclodextrin (β-CD) functionalized copper nanoclusters (β-CD-CuNCs) and vitamin B 6 cofactor pyridoxal (PY). With the addition of PY, the fluorescence emission of β-CD-CuNCs was blue-shifted and enhanced at 435 nm due to the inclusion complexation occurred between the PY and the β-CD functionalized over copper nanoclusters. The fluorescence study and density functional theory (DFT) calculations support the inclusion complexation occurring between the PY and the β-CD. Subsequently, the PY-decorated β-CD-CuNCs (β-CD-CuNCs_PY) were employed for the fluorescent turn-off detection of FA. Upon the addition of FA to β-CD-CuNCs_PY, PY gets displaced from the cavity of β-CD due to the higher inclusion complexing ability between FA and β-CD. Molecular dynamics simulation was performed to examine and visualize the pathways of FA-induced displacement of PY from the hydrophobic cavity of β-CD. The fluorescence quenching of β-CD-CuNCs_PY was observed to exhibit a linear relationship with the addition of FA in the range of 4.95 to 47.6 μM. The detection limit of β-CD-CuNCs_PY for FA was estimated as 0.47 μM. With high selectivity and sensitivity, the developed probe β-CD-CuNCs_PY was successfully employed to detect FA in blood serum.