Carbon Nanodots: Synthesis, Characterization, and Bioanalytical Applications

Abstract

Carbon dots (CDs) are a new class of carbon-rich nanoparticles with exciting physicochemical properties that make them an interesting material for bioanalytical applications. Since their first description in 2004, several preparation techniques have been developed and described in literature, either starting from carbon raw materials (e.g., soot, graphite) or molecular precursors (e.g., carbohydrates, citric acid). The resulting particles are typically only a few nanometers in size, and their surfaces are decorated with functional groups that are rich in oxygen. The presence of oxygenated functionalities on the surface renders the particles dispersible in water. Carbon dots contain a fraction of carbon atoms that are sp 2 hybridized with delocalized electrons on the surface -the basis for the particles' characteristic photoluminescence. The wavelength of the emitted light is dependent on the wavelength of the excitation source and shows remarkable photostability. Carbon dots are also readily excited in the NIR but still emit visible light (upconverted photoluminescence) which provides significant advantages for in vivo imaging. Nowadays CDs are considered as emerging tools in luminescence-based bioanalytics with their full potential yet to be discovered.

Molecularly Imprinted Polymers: Antibody Mimics for Bioimaging and Therapy

“…These FDA-approved nanotherapeutics will hopefully pave the way to more clinical investigation of targeted NPs for cancer imaging . An extensive coverage of the most commonly used NPs for fluorescence bioimaging, including quantum dots, − carbon dots, , upconverting nanoparticles, , polymer dots, , silicon NPs, polymer NPs, , and fluorescently doped silica, , can be found elsewhere. , …”

Advancement in science and technology of carbon dot-polymer hybrid composites: a review

“…In brief, these state-of-the-art features already turn the CDs into several applications, that is, sensing, as a nano-drug carrier, catalysis, cell-imaging, optoelectronics, antcounterfeiting, energy harvesting and so on [13][14][15][16][17][18][19][20][21]. Moreover, it has utmost importance to mention that their bright PL intensity, excellent photostability, and non-cytotoxic nature made them virile competitors of other available semiconductor quantum dots [22][23][24]. Despite this fact, a couple of reviews of the PL behaviours of quantum dots and their applications in a variety of fields have already been published [1,[25][26][27][28], but there is not a single, more focused review regarding the CDs and their affinity/mingling outcomes towards a polymer matrix.…”

Tracking Hyaluronan: Molecularly Imprinted Polymer Coated Carbon Dots for Cancer Cell Targeting and Imaging

“…Moreover, they can be prepared easily and economically, are highly water-dispersible, and do not contain heavy metals like QDs, and are thus rather environmentally friendly and less toxic. These properties render carbon dots serious competitors to the traditional QDs as they can be applied in chemical sensing, live-cell, and in vivo bioimaging and nanomedicine . However, until now, they have not been much amalgamated with MIPs, and the fluorescent CD-MIPs described in the literature have mostly been applied for optical sensing. − For additional information on the MIP-CD combination, see ref and references therein .…”