Si-Doped Carbon Quantum Dots: A Facile and General Preparation Strategy, Bioimaging Application, and Multifunctional Sensor

Abstract

Heteroatom doping of carbon quantum dots not only enables great improvement of fluorescence efficiency and tunability of fluorescence emission, but also provides active sites in carbon dots to broaden their application in sensor. Silicon as a biocompatible element offers a promising direction for doping of carbon quantum dots. Si-doped carbon quantum dots (SiCQDs) were synthesized through a facile and effective approach. The as-prepared Si-doped carbon quantum dots possess visible fluorescence with high quantum yield up to 19.2%, owing to fluorescence enhancement effect of introduced silicon atoms into carbon dots. The toxicity test on human Hela cells showed that SiCQDs have lower cellular toxicity than common CQDs, and bioimaging experiments clearly demonstrated their excellent biolabelling ability and outstanding performance in resistance to photobleaching. Strong fluorescence quenching effect of Fe(III) on SiCQDs can be used for its selective detection among general metal ions. Specific electron transfer between SiCQDs and hydrogen peroxide enables SiCQDs as a sensitive fluorescence sensing platform for hydrogen peroxide. The subsequent fluorescence recovery induced by removal of hydrogen peroxide from SiCQDs due to formation of the stable adducts between hydrogen peroxide and melamine was taken advantage of to construct effective sensor for melamine.

Carbon Based Dots and Their Luminescent Properties and Analytical Applications

“…Therefore, it is impossible to say whether these CDs were layer like or spherical like. From the existing data, the heights of many CDs may be less than the lateral sizes [87,88,103,112,116]. In other words, many of the "bottom-up" obtained CDs, which were considered as carbon quantum dots may also be layer like.…”

Facile synthesis of N-rich carbon quantum dots from porphyrins as efficient probes for bioimaging and biosensing in living cells

“…[1][2][3] In the last decade, a variety of CQDs have been synthesized by two main methods: "top-down" and "bottom-up". 4 Among them, hydrothermal treatment of natural precursors is a low-cost and convenient route to prepare CQDs.…”

Nitrogen and sulfur co-doped carbon dots for highly selective and sensitive detection of Hg (Ⅱ) ions

“…For example, C-dots doped with ZnS and functionalized with oligomeric poly(ethylenelycol) diamine (PEG 1500N) have shown very high FLQY up to 78% (Anilkumar et al, 2011). Heteroatom (e.g., N, B, S, and Si) doping with or without surface modifications (Qian et al, 2014;Chandra et al, 2013;Hu, Y., et al, 2014), especially N-doping or co-doping with N and another element, has also been actively investigated to improve the FLQY of C-dots Zhang, Y.Q., et al 2012;Gao et al, 2014;Yang et al, 2014;Wei et al, 2014;Qu et al, 2014). By using citric acid and urea as C and N sources, respectively, Qu et al (2012) reported a one-step microwave synthesis of N-doped C-dots (N/C-dots) with FLQY of about 14%.…”