Thiosemicarbazide chemical functionalized carbon dots as a fluorescent nanosensor for sensing Cu²⁺and intracellular imaging

Abstract

Surface functionalization of nanomaterials with specific recognition units is a promising strategy to structure novel nanosensors for target analysis and bioimaging. In this study, a fluorescent nanosensor has been successfully synthesized by conjugating thiosemicarbazide with carbon dots (CDs) through amide bonds. The functional CDs own a relatively narrow size distribution of about 1.6-4.0 nm. The CDs exhibit highly specific recognition capability towards copper ions (Cu 2+ ) over the other competing metal ions, and the maximum quenching rate reaches to 68.7%. A good linear correlation is also established between F0/F and the Cu 2+ concentrations ranging from 0 to 0.4 µM and the detection limit is 3.47 nM. On account of their strong fluorescence intensity, excellent water solubility, low toxicity and good biocompatibility the nanosensor demonstrates their biolabeling potential in vivo, which might be high significance in bioanalysis and biomedical detection in the future.

Thiosemicarbazide functionalized carbon quantum dots as a fluorescent probe for the determination of some oxicams: application to dosage forms and biological fluids

“…This may be resulting from multiple C-, N-, O-, and S-containing functional groups on the surface of N, S-CQDs leading to numerous surface states with varied energy levels and emissive traps. 51 At higher excitation wavelength, it was observed that emission peak spectra were red shifted and the fluorescence intensity decreased. As demonstrated in Fig.…”

Biogreen Synthesis of Carbon Dots for Biotechnology and Nanomedicine Applications

“…The LOD was reported to be 115 nM with a detection range from 0.333 to 66.6 µM. Fu et al [ 144 ] functionalized CDs with thiosemicarbazide through amine bonds for the detection of copper ions. The attachment of thiosemicarbazide on CDs played a key role in cupric ion sensing as it provided abundant nitrogen-containing functional groups.…”

A highly selective fluorescent chemosensor for Cu2+ based on a diarylethene with a 2,1,3‐benzoxadiazole unit

“…Furthermore, a considerable accumulation of copper will cause serious environmental pollution and disrupt natural ecosystems, especially in drinking water . Hence, selective detecting and monitoring of Cu 2+ in biological and environmental samples are highly meaningful for human health and environmental protection …”