Abstract:
The detection and discrimination of Cys amino acid from numerous other related biomolecules has great importance
in clinical field for diagnosis of various diseases. Herein, to detect the Cys, we embedded the carbon
dots (CDs), gold, and naphthalimide (L1) into a single ratiometric fluorescence sensor assembly. Sensor assembly
works on the principle of FRET mechanism between CDs and naphthalimide when CDs and L1 adhered on gold
nanoparticles surface. Gold metal was turned into solid support by in situ reduction of HAuCl4 in the presence of
CDs and L1. When the assembly was excited at 360 nm, emission maxima at 568 nm corresponded to naphthalimide
emission was emerged that signifies the existence of a FRET between the CDs and naphthalimide
fluorophores. With the addition of Cys, the FRET mechanism eliminated and the change in the fluorescence
emission at two different wavelengths (450 nm and 568 nm) was recorded. The endogenous images of Cys was
recorded by collecting the fluorescence images of HeLa cells under fluorescence microscope and also applied for
the assay of Cys in blood serum. Cytotoxicity studies of CDs and sensor assembly were evaluated by performing
the MTT assay.
