Recent Advances and Sensing Applications of Carbon Dots

Abstract

Carbon dots (C dots) with biocompatibility, brightness, stability against photoirradiation and salt, and ease in preparation have become important materials for sensing and imaging. They can be prepared from natural materials and small organic molecules through hydrothermal, microwave‐assistant, and electrochemical methods, with advantages of simplicity and low cost. To enhance the quantum yields of C dots in the red and near‐infrared regions, doping of C dots with heteroatoms such as nitrogen and sulfur has been suggested. C dots both with and without being functionalized recognition elements such as antibodies and aptamers are selective and sensitive for sensing of analytes, including metal ions (e.g., Fe3+, Hg2+, Cu2+), small molecules (e.g., H2O2, cysteine, glutathione), and biopolymers like proteins, as well as for in vitro and in vivo imaging. Depending on the size, charge, and surface ligands of C dots used to label cells, fluorescence images of different organelles are shown. Multicolor images of bacteria, mammalian cells, and plant tissues incubated with C dots are realized when excited at different wavelengths. In this review, many excellent sensing and imaging examples of C dots are presented to highlight their features and to show their challenges for analytical applications.

Carbon Dots-Based Logic Gates

“…CD-based logic gates show strong potential for optical sensing, leading to new avenues for future advancement of multidirectional memory devices. There are several reviews on CDs based on their forensic applications [31], synthesis [2], bioimaging [28], and sensing [6].…”

“…The photophysical, as well as chemical properties of CDs, can be tuned by changing their size and by doping with different heteroatoms such as nitrogen (N), oxygen (O), sulfur (S), and boron (B) [ 4 ]. Both the biological and electronic properties of CDs, such as water solubility and biocompatibility along with their electron donor and acceptor behavior, resulted in their application in the field of bioimaging, drug delivery, biosensors, optronics, catalysis, and sensors [ 5 , 6 , 7 , 8 , 9 ]. Initially, CDs were considered as an amorphous allotrope of carbon.…”

“…CD-based logic gates show strong potential for optical sensing, leading to new avenues for future advancement of multidirectional memory devices. There are several reviews on CDs based on their forensic applications [ 31 ], synthesis [ 2 ], bioimaging [ 28 ], and sensing [ 6 ]. In addition, there are reviews on molecular logic gates based on their past, present, and future [ 32 ], fluorescent sensors [ 33 ], and biological logic gates [ 34 ].…”

Synthesis of N-doped carbon dots and application in vanillin detection based on collisional quenching

“…The hydrothermal method has been widely used for CD synthesis. [31][32][33] Briey, 0.5 g glucose and 0.5 g tyrosine were rstly dissolved and completely mixed in 6 mL deionized water. The mixture was transferred into a 25 mL Teon stainless steel autoclave and heated at 180 C for 9 h. The resultant product was puried in a centrifuge (5000 rpm) for 30 min to remove the agglomerated particles.…”

The analytical and biomedical applications of carbon dots and their future theranostic potential: A review

“…These properties arise from their inherent structural features such as low toxicity, biocompatibility and permeability, weak interactions with proteins, resistance to swelling and photobleaching, easy clearance from the body, low cost, and immune system evasion [4]. To exploit the unique properties of C-dots and their low cost and ease of synthesis, much work has been done in areas such as optical sensing [5,6], bioimaging [7], photocatalysis [8][9][10][11] and electrocatalysis [12][13][14]. Interestingly, imaging agents have played an essential role as a platform for real-time multimodal imaging-associated cancer therapy [15][16][17].…”