Fluorescent Carbon Dots as Biosensor, Green Reductant, and Biomarker

Abstract

Carbon dots, the celebrated green material among the nanocarbon family, are blessed with several interesting features like biocompatibility, solubility, tunable luminescence, and so forth. Herein, carbon dots derived from Mint leaf extract (M-CDs) via a green method are exploited for versatile applications as a biosensor, reductant, and biomarker. M-CDs are applied for fluorimetric sensing of biologically relevant folic acid through quenching response originating from the inner filter effect, with a limit of detection of 280 nM. The carbon dots were highly selective toward folic acid in a collection of 16 biomolecules. The specificity of carbon dots toward folic acid is explained based on the interaction between the two. Along with sensing, herein, we project M-CDs as a green reducing agent by demonstrating the reduction of Fe(III) and noble metal nanoparticle synthesis from their salt solutions. The particles are found to be significantly non-cytotoxic, as evident from the MTT assay performed on primary H8 cells. The application of M-CDs in multicolor imaging is also illustrated using HeLa cells.

From Weed to Shining ‘Mystic Stars’: Value‐Added Applications of Siam Weed Derived Carbon Dots

“…The prepared system could act as an effective and selective sensor of folic acid realized through fluorescence quenching, with a limit of detection of 4.5 μM. The specific quenching [27] in the luminescence of CO‐CDs in presence of folic acid is credited to the inner filter effect [4b,28,4b,25,28b,29] . The practical use of the sensor has been confirmed by real sample analysis, by quantifying folic acid present in commercially available Folate tablets [30] .…”

“…Carbon dots are spheroid zero‐dimensional nanoparticles with a size of less than 10 nm, marked with a carbon core and associated functional groups. The above‐mentioned outstanding properties of C‐ dots have made it a comparitively eco‐friendly candidate for potential applications in nanotechnology [3] including bio‐imaging, [4] sensing [3,4b,,5e] photocatalysis, [6] and light‐emitting devices., [,7a,c–e,8] The exceptional chemical and photochemical stability of CDs accompanied by their biocompatibility enhances the potential of carbon dots as a promising attractive material for substantial application in bioimaging and selective detection of inorganic molecules., [,9c9b] This in turn signifies carbon dots as an excellent competitor for conventional toxic heavy metal‐based quantum dots [10] . Up to now, a variety of methods are employed for the development of CDs, which can be roughly sorted into two; as top‐down and bottom‐up [11] .…”

Synthesis of Doped/Hybrid Carbon Dots and Their Biomedical Application

“…Many reviews have been reported on nonmetal-doped CDs and their applications [ 10 , 27 , 41 , 48 , 49 , 50 , 53 ] However, we found no review on the advancement of metal/nonmetal-doped/hybrid CDs, describing their physical or chemical properties and biomedical applications. The current review describes the recent progress in metal/nonmetal-doped/hybrid CD-based technology, considering their bottom-up synthetic procedures, the effect of doping or conjugation on the structure and the physical properties of the nanocomposites and their biomedical applications, which includes bioimaging, antimicrobial activity, drug delivery, cancer therapy, neuron tissue engineering and bio-sensor applications.…”

“…Additionally, the presence of metal atoms in CDs results in an increase in their electrical conductivity as well as electron transfer and electron-acceptance capabilities, which facilitates electron transfer and increases their photocatalytic activity over pristine CDs [ 48 , 49 ]. Furthermore, CDs can act as an excellent reducing agent and reduce incorporated metal ions thus forming metal-doped CDs [ 50 ]. Conjugation of metal oxide nanomaterials with CDs or polymers improves their light-induced reactive oxygen species (ROS) production rate [ 5 , 51 , 52 ].…”

Immunosensor of Nitrofuran Antibiotics and Their Metabolites in Animal-Derived Foods: A Review

“…Both methods are suitable for effective high-throughput detection methods, and in contrast, FIA has higher sensitivity. Carbon dots (CDs) are a class of zero-dimensional fluorescent nanomaterials based on carbon, and have emerged in recent years ( Raveendran and Kizhakayil, 2021 ). Compared with traditional fluorescent nanomaterials (e.g., quantum dots), it can synthesize CDs in a simple way, and have the advantage of low cost, good photostability and low toxicity.…”