Investigation of photo-induced electron transfer between amino-functionalized graphene quantum dots and selenium nanoparticle and it's application for sensitive fluorescent detection of copper ions

• Published in: Talanta (Oxford) Vol. 197; pp. 341 - 347
• Main Authors: Li, Yi, Zhang, Weilu, Jiang, Xiangmei, Kou, Yanxia, Lu, Jiajia, Tan, Liang
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15-05-2019
• Subjects: Amino-functionalized graphene quantum dots; Cellular uptake; Copper ions; Fluorescence quenching; Photo-induced electron transfer; Selenium nanoparticles; Photo-induced electron transfer; Cellular uptake; Copper ions; Amino-functionalized graphene quantum dots; Selenium nanoparticles; Fluorescence quenching
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2019.01.036

Copper ions play an essential role in some biological processes. Currently, there is a need for the development of convenient and reliable analytical methods for the Cu2+ measurement. In the present work, a sensitive fluorescence method was developed for the determination of copper ions. Amino-functionalized graphene quantum dots (af-GQDs) and selenium nanoparticles (Se NPs) were synthetized, respectively, and they were characterized via transmission electron microscope, infrared spectrum analysis and X-ray photoelectron spectrum measurement. Photo-induced electron transfer (PET) between the prepared two nanomaterials could effectively quench the fluorescence of af-GQDs. Cu(II) was reduced to Cu(I) in the presence ascorbic acid and Cu2Se was finally generated on Se NPs surface, which led to the declined PET efficiency and inhibited the fluorescence quenching of af-GQDs. The change in fluorescence intensity was linearly correlated to the logarithm of the Cu2+ concentration from 1 nM to 10 μM, with a detection limit of 0.4 nM under the optimal conditions. The detections of copper ions in water samples were realized via standard addition method and the recovery values varied from 98.7% to 103%. The proposed fluorescence method was also employed to analyze the uptake of Cu2+ into human cervical carcinoma HeLa cells and cisplatin-resistant HeLa cells (HeLa/DDP cells). The experimental results indicate that the decreased hCTR1 expression level in HeLa/DDP cells weakened the uptake of copper ions into these drug-resistant tumor cells.
[Display omitted]
•Af-GQDs and Se NPs were synthetized and characterized.•PET between the two nanomaterials led to the fluorescence quenching of af-GQDs.•The generation of Cu2Se on nanoSe0 inhibited the fluorescence quenching.•A highly sensitive fluorescence method for the detection of Cu2+ was proposed.•The uptake amount of Cu2+ into HeLa/DDP cells was less than that into HeLa cells.