Selective toxicity of hydroxyl-rich carbon nanodots for cancer research

Abstract

Authors are required to submit a graphic entry for the Table of Contents (TOC) in conjunction with the manuscript title. This graphic should capture the readers' attention and give readers a visual impression of the essence of the paper. Labels, formulae, or numbers within the graphic must be legible at publication size. Tables or spectra are not acceptable. Color graphics are highly encouraged. The resolution of the figure should be at least 600 dpi. The size should be at least 50 mm × 80 mm with a rectangular shape (ideally, the ratio of height to width should be less than 1 and larger than 5/8). One to two sentences should be written below the figure to summarize the paper. To create the TOC, please insert your image in the template box below. Fonts, size, and spaces should not be changed.Highly biocompatible carbon nanodots were synthesized, which are abundant in hydroxyl functional groups on particle surface. Interestingly, the nanoparticles display divergent antiproliferative activities against two ovarian choriocarcinoma cell lines, which may be further explored for cancer drug discovery. ABSTRACTThe toxicity of nanoparticles in a biological system is an integration of effects arising from surface functionality, particle size and ionic dissolution etc. Its complexity suggests that generalization on a material's toxicity may be inappropriate. Moreover, from medicinal point of view, toxicity can be used for treatment of malignant cells, such as cancer. In this study, highly biocompatible carbon nanodots (named gCDs) were synthesized by reacting citric acid and urea in glycerol, which resulted in abundant hydroxyl functional groups on particle surface. gCDs show excitation-dependent photoluminescence, but with brighter green to yellow emission. Importantly, a series of toxicity assessments showed that as-synthesized gCDs possess exceptional biocompatibilities to various biological entities including 18 bacteria species, Petunia axillaris seedlings and Artemia franciscana nauplii. Furthermore, the particles were shown to have low-to non-toxic effects on human embryonic kidney (HEK-293) cell lines, breast (MCF-7), oral squamous (CAL-27) carcinoma cell lines. Of particular interest, the gCDs display antiproliferative activities against ovarian choriocarcinoma cells (JAr / Jeg-3 cell lines), which may be further explored for cancer drug discovery.

Combating Antibiotic‐Resistant Gram‐Negative Bacteria Strains with Tetracycline‐Conjugated Carbon Nanoparticles

“…The biocompatibility of carbon‐based nanoparticles is widely known as nontoxic, [ 17 ] and CNPs have demonstrated no toxic and/or inhibitory effects on the bacteria. [ 24 ] Corresponding to the previous reports, the bare CNPs prepared in this study also showed no activities against the bacteria assessed regardless of the synthetic routes. The results from the bacteria cells incubated with TC alone indicated very low inhibitory activities owing to the efficient efflux system (Figure 4e).…”

“…No bacterial inhibitory activities were observed from either the CNP‐BUp or CNP‐TDn when tested alone on both Gram‐positive and Gram‐negative species, representative of the high degree of biocompatibility of the bare, unmodified CNPs ( Table 1 ; Tables S5 and S6, Supporting Information), and are consistent with a previous report on the antibacterial activities of CNPs of this type. [ 24 ] However, as presented in Table 1 and Figure 2 , K. pneumonia , A. baylyi , and P. vulgaris were inhibited strongly in comparison with P. aeruginosa and P. mirabilis . The lowest MIC (2 × 10 −6 m equivalent TC concentration ) was exhibited by the TC–CNP‐BUp conjugate against A. baylyi , whereas the MIC of TC alone in this cell line was 21 × 10 −6 m , an approximate tenfold potentiation in activity.…”

“…We prepared two types of CNPs using both bottom‐up and top‐down approaches, allowing the direct comparison of their respective biological properties and efficacies. The bottom‐up CNPs (CNP‐BUp) were prepared using propylene glycol and citric acid in a hydrothermal reactor [ 24 ] and the top‐down CNPs (CNP‐TDn) were prepared by a modified Hummer's method. [ 25 ] The as‐synthesized samples contained residual reaction products such as large agglomerates from the CNP‐BUp and graphene oxide sheets from the CNP‐TDn methods (Figure S1, Supporting Information).…”

Ecotoxicological impact of graphene oxide: toxic effects on the model organism Artemia franciscana

“…16 As for the production methods, Kim et al observed differences in mortality of A. franciscana stage I nauplii exposed for 24 and 48 h to carbon nanodots produced by the same synthetic method and precursors, but using different solvents. 44 Considering that, in our study, GO induced slight, but significant, mortality only in A. franciscana adults, only the organisms at this developmental stage were investigated for their susceptibility to GO, evaluating other biomarkers and parameters of toxicity. One of the main mechanisms of GBM toxicity appears to be an increased ROS production and consequent oxidative stress, as previously demonstrated in human cells exposed to GO.…”

The Puzzling Potential of Carbon Nanomaterials: General Properties, Application, and Toxicity

“…The carbon core structure is necessary for bioimaging, the effects of light-emitting diodes, mass spectrometry, and thermal therapy, whilst the nature of functional groups at the surface is responsible for enzyme and gene regulation effects, electro- and organo-catalysis, and drug delivery applications [ 48 , 49 , 50 ]. As photoluminescence is essential for bioimaging and biosensing applications, to date, enormous efforts are being made with the following final goal: To precisely define factors that enable the accurate and reproducible synthesis of materials with optimal photoluminescence properties [ 31 , 48 ].…”