Preparation of high-quality biocompatible carbon dots by extraction, with new thoughts on the luminescence mechanisms

Abstract

Recently, carbon dots (CDs) have been among the most promising emerging fluorescent labels for cellular imaging. In this work, a new facile synthesis method was developed for fabricating CDs from polystyrene foam waste and common organic solvents. The CDs obtained have tunable emission from blue to orange and are expected to be of use for labeling different cellular structures simultaneously. Transmission electron microscopy, x-ray diffraction, Raman spectra, Fourier transform infrared spectrometry, UV-vis, and fluorescence spectrophotometry (PL) were employed to investigate the structures and luminescence properties of CDs. The highest quantum yield (QY) achieved was 36%. The mechanisms for the formation and luminescence of the CDs are analyzed. The ability of the solvent to disperse the CDs plays a very important role in the origin of PL. The type of organic solvent has an important influence on the position of emission peaks and the QY. Different emissive traps play the dominant role in the luminescence of carbon materials. Furthermore, a hemolysis assay was performed to evaluate the biocompatibility of these CDs in vitro. The biocompatibility of the CDs, even at very high doses, ensures their potential in biomedical applications.

Engineering surface states of carbon dots to achieve controllable luminescence for solid-luminescent composites and sensitive Be2+ detection

“…Obviously, only one emission state dominated the PL properties of LCD-160 but two in LCD-240. The single emission state in LCD-160 brings about excitation-independent behavior4243. For LCD-240, two dominating states are believed to correspond to the energy gap and surface state transitions.…”

Glowing Graphene Quantum Dots and Carbon Dots: Properties, Syntheses, and Biological Applications

“…After exposure to PEG 1500N passivated C‐dots (40 mg, intravenously injected), the tested mice showed no abnormalities in their food intake, body weight, activities, kidney and liver functions, and serum biochemical indicators (e.g., alanine amino transferase, uric acid, blood urea nitrogen, etc.). It was found in another study that the hemolysis percentage was <1.8% for a C‐dot dosage of 60 μg mL −1 (<5% is considered non‐hemolytic by ISO guidelines) …”

Molecular imaging with nanoparticles: the dwarf actors revisited 10 years later

“…They have, therefore, been the object of numerous investigations, generating a large, detailed literature which has grown exponentially and now includes thousands of publications. Since theirs is a rapidly developing story, we note here a few of the many reviews, noting their dates of publication: in 2008: (Sun et al 2008a); in 2009: (Yang et al 2009a), in 2010: (Baker and Baker 2010; Wang et al 2010a, c); in 2011: (da Silva and Gonçalves 2011; Anilkumar et al 2011); in 2012: (Zhang et al 2012a, b); in 2013: (Luo et al 2013; Zhang et al 2013; Qu et al 2013; Zhu et al 2013); in 2014: (Wang and Hu 2014; Wei et al 2014); in 2015: (Zheng et al 2015); in 2016: (Sun et al 2016); in 2017: (De and Karak 2017; Wang et al 2017); there are numerous others. We note the admirable research contribution coming from the start from China.…”