Figure 4

Assessment of fluorescence intensity obtained with 25(OH)D₃. (a,b) Fluorescent spectra and fluorescent intensity of the aptamer with different conc. of 25(OH)D₃ and 3% agarose gel image confirming the increase in fluorescence in presence of 25(OH)D₃ using GO. Inset: Peak fluorescence change shows a linear relationship with 25(OH)D₃ concentration (0–1.25 µg/mL). (c,d) Fluorescent spectra and fluorescent intensity of the aptamer with different conc. of 25(OH)D₃ using GO-COOH. Inset: Peak fluorescence change shows a linear relationship with 25(OH)D₃ concentration (0–1.25 µg/mL). (Apt –100 nM, GO and GO-COOH-50 µg/mL) F0: Aptamer + GO (b) and Aptamer + GO-COOH (d); and F1: Apt + GO + 25(OH)D₃ (b) and Apt + GO-COOH + 25(OH)D₃ (d).