Preparation of biocompatible and antibacterial carbon quantum dots derived from resorcinol and formaldehyde spheres

Abstract

Green or yellow emitting carbon quantum dots (CQDs) were prepared through the combination of bottomup and top-down approaches from resorcinol and formaldehyde. The prepared CQDs showed characteristic fluorescence behavior depending on the compositional or structural features. Both CQD-S (green emitting) and CQD-P (yellow-emitting) were physiologically stable and biocompatible as cancer cell bioimaging agents. Especially, silver nanoparticle (Ag NP)-decorated CQDs revealed very good antibacterial activity for Gram-positive S. aureus and Gram-negative E. coli.

Carbon Nanodots: A Review—From the Current Understanding of the Fundamental Photophysics to the Full Control of the Optical Response

“…Their non-toxicity is a key advantage to perform in vivo [118][119][120][121][122] and in vitro [41,67,113,[123][124][125] bioimaging experiments and drug delivery experiments [126]. Indeed, the range of applications of CDs is surprisingly wide: for example, antiviral [127,128] and antibacterial [129] properties of CDs were recently discovered, and CDs were even used as nanoweapons against mosquitos [130], or as a component of fluorescent inks [53,89]. So far, the majority of CDs-based devices have been developed and tested just in a laboratory environment.…”

“…This gave the basis for using CDs in the field of cancer therapy. Besides medical applications as anticancer or cancer targeting [120], CDs can be used as photo-activated [127] or not [128] antiviral agents, and photo-activated antibacterical [129] agents. For instance, they were used to reduce the entry of hepatitis C viruses into monkey kidney cancer cells and human lung cancer cells physically blocking the passage of the virus [128].…”

Bioimaging Applications of Carbon Nanodots: A Review

“…Since the serendipitous discovery of carbon dots over a decade ago, research into their formation and application has grown exponentially and an increased interest in introducing them into health-, environmental-, and technological-related applications has emerged [7]. Moreover, it was not until recently that CNDs were used as antibacterial agents, fluorescent agents, drug carriers, and probes for C 2019, 5, 19 of 19 the in vitro and in vivo detection of specific molecules, and they have even been proposed for human cancer theranostic and phototherapy applications [8][9][10][11][12]. Not surprisingly, therefore, CNDs can be considered to be the next generation platform for biomedical applications.…”

Microwave-assisted synthesis of fluorescent carbon quantum dots from an A2/B3 monomer set

“…[1][2][3] In addition to their comparable uorescence properties, CQDs are becoming comparable to those of inorganic quantum dots (QDs) through the exploitation of their biocompatibility, low toxicity, excellent photochemical stability, and facile surface functionalization. [4][5][6] Until now, CQDs have been widely examined in various applications such as bioimaging, [7][8][9][10][11][12] sensing, 13,14 photo/electrocatalysis, 15,16 light-harvesting, [17][18][19] and drug-delivery systems. [20][21][22] Although both "top-down" and "bottom-up" approaches have been routinely used for the synthesis of CQDs depending on the type of precursor materials, "bottom-up" approaches utilizing various small molecules, polymers, and even biocompatible materials have advantages in terms of low cost and environmental friendliness because carbon nanotubes, nanodiamonds, and graphene oxides, which are frequently used as carbon-rich precursor materials in "top-down" approaches, are not necessary.…”