Tuning the photoluminescence by engineering surface states/size of S, N co-doped carbon dots for cellular imaging applications

Abstract

In this research, we have synthesized carbon dots (CDs) co-doped with nitrogen and sulfur by facile hydrothermal method, using citric acid and cysteine as carbon source. The effect of solid-state thermic treatment (STT) at 303 to 453 K on the size, surface, fluorescence and cellular cytotoxicity of the CDs were systematically investigated. Through a simple STT, it was possible to tune surface states and the average size of the CDs, causing a permanent red shift. Initially, CDs showed a decrease in cell viability with increasing concentration. However, after STT, its viability remained constant with an increase in concentration. Here, we show the possibility to label the cells cytoplasm according to the CDs fluorescence emission before (blue emission) and after STT (red emission). The CDs studied in this paper show selective luminescence properties, which are fundamental for any cell imaging application.

Facile synthesis of graphene quantum dots with red emission and high quantum yield

“…[14][15][16] However, most of these GQDs emit blue-light or have long-wavelength emission with low fluorescence QY, which greatly impedes their further development, especially in the bioimaging field. 17 It is mainly due to the strong background fluorescence of the cell/tissue environment and the side-effects of high-energy light on the bio-system. [18][19][20][21][22] Fortunately, long-wavelength emission can provide a deeper penetration and show less damage to cells/ tissues.…”

In situ synthesis of S‐doped coal‐based carbon quantum dots and its application to Cr6+ detection

“…The “top‐down” approach uses carbon‐rich materials such as coal and graphite as carbon sources and is prepared by electric arc discharge, 1 ultrasonic synthesis, 2,3 chemical oxidation, 4,5 electro‐chemical oxidation, 6,7 and laser ablation 8,9 . The ‘bottom‐up’ method is prepared by hydrothermal treatment, 10 thermal decomposition, 8,11 microwave synthesis, 12,13 using organic minor macromolecules, such as glucose and citric acid as carbon sources. In recent years, carbon quantum dots have been extensively applied in the field of photocatalysis, 14 chemical and biological sensing fields, 15,16 bioimaging, 17 biomedical materials, 18 and ion detection 19 …”

Development of biomass waste-based carbon quantum dots and their potential application as non-toxic bioimaging agents

“…40–42 The optical and electronic properties of the CQDs can be adjusted by varying the concentration of precursor, type and concentration of dopant, reaction time, reaction temperature, pH of the reaction system, and the most critical parameter is the type of solvent used. 43–49…”

“…[40][41][42] The optical and electronic properties of the CQDs can be adjusted by varying the concentration of precursor, type and concentration of dopant, reaction time, reaction temperature, pH of the reaction system, and the most critical parameter is the type of solvent used. [43][44][45][46][47][48][49] Citric acid (CA) is a common and easily obtainable weak organic acid widely used as a carbon precursor for producing uorescent CQDs. There is a wealth of scientic literature on this subject, making it a popular choice for researchers.…”