Influence of Surface States on the Optical and Cellular Property of Thermally Stable Red Emissive Graphitic Carbon Dots

Influence of PEGylation on WS2 Nanosheets and Its Application in Photothermal Therapy

Photothermal therapy (PTT) is an alternative cancer therapy with minimal side effects and higher efficiency and selectivity. In this study, WS2 nanosheets were developed by ultrasonic exfoliation with different ratios of polyethylene glycol (PEG), and their effects on physicochemical properties were studied. The utilization of PEG during sonication significantly influenced the size and thickness of the resulting WS2 nanosheet layers, which was confirmed through scanning electron microscopy, atomic force microscopy, and dynamic light scattering analyses. PEG functionalization also improved the dispersibility of WS2 in aqueous solution by making its surface hydrophilic, which resulted in better biocompatibility. The intrinsic near-infrared absorbance of the nanosheets positions them as valuable agents for PTT. The study further explores the efficacy of these nanosheets as photothermal agents in the ablation of MDAMB-231 breast cancer cells. Although the use of PEG to demonstrate exfoliation and biocompatibility for WS2 has been reported previously, the effect of PEGylation on various physicochemical properties has not been studied in-depth until now. This study paves the way for the use of highly versatile PEG across a range of 2D material systems.

Perspectives of different colour-emissive nanomaterials in fluorescent ink, LEDs, cell imaging, and sensing of various analytes

In the past 2 decades, multicolour light-emissive nanomaterials have gained significant interest in chemical and biological sciences because of their unique optical properties. These materials have drawn much attention due to their unique characteristics towards various application fields. The development of novel nanomaterials has become the pinpoint for different application areas. In this review, the recent progress in the area of multicolour-emissive nanomaterials is summarized. The different emissions (white, orange, green, red, blue, and multicolour) of nanostructure materials (metal nanoclusters, quantum dots, carbon dots, and rare earth-based nanomaterials) are briefly discussed. The potential applications of different colour-emissive nanomaterials in the development of fluorescent inks, light-emitting diodes, cell imaging, and sensing devices are briefly summarized. Finally, the future perspectives of multicolour-emissive nanomaterials are discussed.

Preclinical safety assessment of red emissive gold nanocluster conjugated crumpled MXene nanosheets: a dynamic duo for image-guided photothermal therapy

Red emissive gold nanoclusters have potential as biological fluorescent probes, but lack sufficient light-to-heat conversion efficiency for photothermal therapy (PTT). MXene nanomaterials, on the other hand, have shown promise in PTT due to their strong near-infrared absorption abilities, but their instability caused by restacking of the sheets can decrease their available surface area. One approach to address this issue is to design sheets with wrinkles or folds. However, the crumpled or 3D MXene materials reported in the literature are actually aggregates of multiple nanosheets rather than a single sheet that is folded. In this study, a modified method for crumpling a single MXene sheet and further conjugating it with red emissive gold nanoclusters and folic acid was developed. A detailed in vitro toxicity study was performed in various cell lines and cellular uptake in cancer cells was studied using AFM to understand its interaction at the nano-bio interface. The material also demonstrated excellent utility as a bioimaging and PTT agent in vitro, with its high fluorescence allowing bioimaging at a lower concentration of 12 μg mL^-1 and a photothermal conversion efficiency of 43.51%. In vitro analyses of the cell death mechanisms induced by PTT were conducted through studies of apoptosis, cell proliferation, and ROS production. In vivo acute toxicity tests were conducted on male and female Wistar rats through oral and intravenous administration (20 mg kg^-1 dose), and toxicity was evaluated using various measures including body weight, hematology, serum biochemistry, and H&E staining. The findings from these studies suggest that the MXene gold nanoconjugate could be useful in a range of biomedical applications, with no observed toxicity following either oral or intravenous administration.

Synthesis and degradation mechanism of renally excretable gold core-shell nanoparticles for combined photothermal and photodynamic therapy

Photothermal therapy (PTT) has emerged as a very potent therapeutic approach in the treatment of tumors. Gold nanoparticles have gained considerable scientific interest as a photosensitizer due to their absorbance in the near-infrared regions. However, their biodegradation and excretion from the body is a challenge. Various biodegradable systems consisting of liposomes and polymers have been synthesized, but their precise manufacturing and decomposition mechanisms have not yet been explored. Using zein nanoparticles as a template, we have fabricated a glutathione-functionalized gold core shell type of formulation. The scalability of the one-step seedless gold coating process is also reported. The synthesis procedure of these tunable nanoparticles is understood with TEM. The thermal degradation of the material under the physiological conditions is thoroughly examined using UV and TEM. In vitro PTT effectiveness on breast cancer cells is assessed after an extensive in vitro toxicity research. The mechanism of cell death is studied using ROS and cell cycle analysis. The material exhibited good efficacy as a PTT agent in mice and showed non-toxicity up to 14 days. The renal clearance study of the material in mice shows its disintegration into renal clearable minute gold seeds. All the findings suggest biodegradable glutathione-functionalized gold core-shell nanoparticles as potential photothermal cancer treatment agents.

Ultrasonic-Assisted Synthesis of N-Doped, Multicolor Carbon Dots toward Fluorescent Inks, Fluorescence Sensors, and Logic Gate Operations

Over past decades, the multicolor carbon dots (M-CDs) have attracted enormous attentions due to their tunable photoluminescence and versatile applications. Herein, the nitrogen-doped (N-doped) M-CDs including green, chartreuse, and pink emissive CDs are successfully synthesized by ultrasonic treatment of kiwifruit juice with different additive reagents such as ethanol, ethylenediamine, and acetone. Owing to their strong fluorescence upon irradiation with 365 nm UV light, the highly water-soluble M-CDs present great potential in the anticounterfeit field as fluorescent inks. Particularly, the resulting green emission CDs (G-CDs) with excellent fluorescence and stability are applied as a label-free probe model for “on–off” detection of Fe3+. The fluorescence of G-CDs is significantly quenched by Fe3+ through static quenching. The nanoprobe demonstrates good selectivity and sensitivity toward Fe3+ with a detection limit of ~0.11 μM. Besides, the quenched fluorescence of G-CDs by Fe3+ can be recovered by the addition of PO43− or ascorbic acid (AA) into the CDs/Fe3+ system to realize the “off–on” fluorescent process. Furthermore, NOT and IMPLICATION logic gates are constructed based on the selection of Fe3+ and PO43− or AA as the inputs, which makes the G-CD-based sensors utilized as various logic gates at molecular level. Therefore, the N-doped M-CDs hold promising prospects as competitive candidates in monitoring the trace species, applications in food chemistry, anticounterfeit uses, and beyond.