Abstract:
Biomolecules like cysteine and cytosine play a significant role in many physiological processes, and their
unusual level in biological systems can lead to many diseases including cancer. Indeed, the need for
selective detection of these moieties by a fluorescence probe is imperative. Thus, thiophene based Schiff
N,N’-bis(thiophene-2-ylmethylene)thiophenemethane (BMTM) was synthesized and then characterized
using several analytical techniques before converting it into organic nanoparticles (ONPs). Then, fluorescent organic inorganic nanohybrids (FONs) were obtained after decorating ONPs with AuNPs to yield
BMTM-Au-ONPs (FONPs). The morphology of the particles, analyzed using a Transmission Electron
Microscope (TEM), shows that AuNPs were embedded with low density organic matter (ONPs). FONPs
were employed to recognize cysteine and cytosine simultaneously. No interference was observed from
other moieties such as guanine, uracyl, NADH, NAD, ATP, and adenine during the detection. It means that
the intensity of the fluorescence signal was significantly changed (enhanced for cytosine and quenched
for cysteine). So, FONPs were used to detect cysteine and cytosine in real samples, like Saccharomyces
cerevisiae cells. As expected, no considerable fluorescence signal for cysteine was observed, while for
cytosine, strong fluorescence signals were detected in the cells. DFT was used to explain the interaction
of FONPs with cysteine or cytosine.
