Green Synthesis of Multicolor Emissive Nitrogen-Doped Carbon Dots for Bioimaging of Human Cancer Cells

Pineapple stem starch-based films incorporated with pineapple leaf carbon dots as functional filler for active food packaging applications

Pineapple leaf waste, a byproduct of agricultural processes, was used as a novel raw material to synthesize carbon dots (CDs) through a simple hydrothermal method. The CDs were subsequently incorporated into pineapple stem starch (PSS)-based active food packaging films. The characterization of the CDs and PSS-CDs films was conducted using various techniques, including UV-light spectroscopy, fluorescence spectroscopy, and transmission electron microscopy. The results revealed that the CDs measured 2.36 ± 0.33 nm and exhibited antioxidant and antibacterial activities. The addition of the CDs led to notable enhancements in both mechanical strength and UV-barrier properties. Thus, PSS-CDs packaging film was successfully prepared, with the incorporation of CDs enhancing the antioxidant and antimicrobial properties of the film, thereby extending the shelf-life of fresh pork.

Luminous Insights: Harnessing Carbon Nanodots from Black Seed Powder via Pyrolysis for Bioimaging and Antifungal Investigations

This study delves into the fabrication of carbon nanodots (CNDs) through a bottom-up approach, utilizing black seed powder as the precursor material and employing the pyrolysis method. CNDs were synthesized across four distinct temperature settings. The investigation encompasses an extensive characterization of the CNDs, including optical and structural attributes. UV-visible and fluorescence spectroscopy were utilized to assess their optical properties, while FT-IR and XRD analyses confirmed their structural integrity. To elucidate size, shape, and nature, HR-TEM imaging was employed. Furthermore, the functional applications of the synthesized CNDs were explored. The material's antifungal potential was evaluated, and its viability for bioimaging was demonstrated by successfully labeling yeast cells with CNDs. This study underscores the multifaceted nature of CNDs, serving as a bridge between synthesis, comprehensive characterization, and practical applications. In summary, the investigation provides insights into the versatile applications of CNDs derived from black seed powder through pyrolysis. The study contributes to the understanding of their fundamental properties and establishes their potential for both antifungal treatments and cellular bioimaging.

Development of folate-conjugated polypyrrole nanoparticles incorporated with nitrogen-doped carbon quantum dots for targeted bioimaging and photothermal therapy

PPy nanoparticles are widely employed as PTT agents, because of their exceptional near-infrared absorption properties. Nonetheless, the efficacy of PTT with PPy nanoparticles is hindered by a challenge, specifically, a lack of precise targeting. In this study, a PTT imaging agent was developed by combining NCQDs having bright green fluorescent properties with PPy nanoparticles along with the masking of folic acid to overcome the challenge of targeting. The synthesized PPy:NCQDs:FA nanocomposite, characterized by extraordinary photothermal property, was utilized for imaging of folate receptor positive (FA+) MCF-7 cancer cells through the emission of green fluorescence by NCQDs incorporated within the nanocomposite. Additionally, these nanoparticles demonstrated a good level of cell viability, exceeding 82 %, even at a concentration of 600 μg mL-1. Even the in vivo toxicity inspection of the nanocomposite exemplified no observed acute toxicity at experimental dosages of 1 and 3 mg per kg body weight. By subjecting MCF-7 cells, inoculated with 100 μg mL-1 of nanocomposite, to NIR laser irradiation for 5 min, a significant decline in cell viability was witnessed, establishing the photothermal therapeutic potency of the nanocomposite. The death of cancer cells induced by nanocomposite was verified through MTT assay, imaging of cells by NCQDs alone, with nanocomposite, and by live/dead cell Calcein AM/PI staining assay. Quantification of induced apoptosis post-laser treatment is conducted through staining with Annexin V-FITC/PI. These findings establish potential use of PPy:NCQDs:FA nanocomposite as versatile theranostic agents, capable of targeted bioimaging and treatment for cancer cells exhibiting folate receptors.

Bioinspired theranostic quantum dots: Paving the road to a new paradigm for cancer diagnosis and therapeutics

Despite extensive research, a complete cure remains lacking for most types of cancer. Nanotechnology-based carriers, such as liposomes, nanoparticles (NPs), dendrimers, nanoemulsions, and other nanocarriers, can target cancer cells, but their in vivo fate is unpredictable. Bioinspired quantum dots (BQDs) offer enhanced aqueous solubility, exceptionally low toxicity, biocompatibility, easy biofunctionalization, and selective cancer targeting. Due to their photoluminescence, high longitudinal relaxation value, photothermal effect upon laser irradiation, generation of singlet oxygen, and production of H2S for gas therapy, BQDs are excellent cancer theranostic agents. In this review, we highlight the theranostic application of, and existing challenges relating to BQDs.

A recent update on development, synthesis methods, properties and application of natural products derived carbon dots

Natural resources are practically infinitely abundant in nature, which stimulates scientists to create new materials with inventive uses and minimal environmental impact. Due to the various benefits of natural carbon dots (NCDs) from them has received a lot of attention recently. Natural products-derived carbon dots have recently emerged as a highly promising class of nanomaterials, showcasing exceptional properties and eco-friendly nature, which make them appealing for diverse applications in various fields such as biomedical, environmental sensing and monitoring, energy storage and conversion, optoelectronics and photonics, agriculture, quantum computing, nanomedicine and cancer therapy. Characterization techniques such as Photoinduced electron transfer, Aggregation-Induced-Emission (AIE), Absorbance, Fluorescence in UV-Vis and NIR Regions play crucial roles in understanding the structural and optical properties of Carbon dots (CDs). The exceptional photoluminescence properties exhibited by CDs derived from natural products have paved the way for applications in tissue engineering, cancer treatment, bioimaging, sensing, drug delivery, photocatalysis, and promising remarkable advancements in these fields. In this review, we summarized the various synthesis methods, physical and optical properties, applications, challenges, future prospects of natural products-derived carbon dots etc. In this expanding sector, the difficulties and prospects for NCD-based materials research will also be explored.

Green synthesis of fluorescent carbon dots from Robinia hispida L. leaves for selective detection of Hg (II)

In this study, Robinia hispida L leaves (RH) was used as a precursor for the first time to synthesize fluorescent carbon dots (CDs) with stable blue fluorescence by a single-step hydrothermal synthesis method. Notably, the innovative approach eliminates the necessity for toxic chemicals or hazardous substances, marking a significant advancement in the field. The synthesized CDs demonstrate CDs demonstrates the predominance of spherical shapes with an average size of 11.63 ± 1.92 nm. The CDs not only exhibit an enhanced fluorescent efficiency with a relatively high quantum yield of up to 6.8%, but they also possess the potential for direct utilization in the selective determination of Hg(II) through fluorescence quenching, even without any functionalization. Under the optimized conditions at a pH of 7.0, a robust linear correlation was found to exist between the fluorescence intensity and the concentration of Hg (II) within the range of 5-17.5μM, exhibiting a detection limit (3σ) of 1.5μM. Additionally, this methodology was effectively employed to successfully detect Hg (II) ions in various aqueous samples, including tap water, spring water, drinking water, and a certified reference material (CRM-SA-C Sandy Soil C). The spike recoveries of 97.6%-101.6% with less than 2.7% variability were performed on all samples.

Synthesis of Temperature Sensing Nitrogen-Doped Carbon Dots and Their Application in Fluorescent Ink

With the discovery of research, many properties of carbon dots are getting better and better. People have taken advantage of this and utilized them interspersed in various fields. In the present study, water-soluble nitrogen-doped carbon dots (N-CDs) with excellent optical and fluorescence thermal properties were prepared by the hydrothermal method using 4-dimethylaminopyridine and N,N'-methylenebisacrylamide as precursors. Co2+ has a selective bursting effect on the fluorescence of N-CDs. The fluorescence of N-CDs is selectively burst by Co2+, and the high sensitivity is good in the range of 0-12 μM with a detection limit of 74 nM. In addition, the good temperature response (reversible and recoverable fluorescence in the temperature range of 20~90 °C) and excellent optical properties of the N-CDs also make them new potentials in the field of fluorescent inks and temperature sensing.

Metal-free auxiliary pyrophosphate detection based on near-infrared carbon dots

The excessive use of pyrophosphate (PPi) anions as additives poses a serious threat to human health and the environment. Considering the current status of PPi probes, the development of metal-free auxiliary PPi probes has important applications. In this study, a novel near-infrared nitrogen and sulfur co-doped carbon dots (N,S-CDs) were prepared. The average particle size of N,S-CDs was 2.25 ± 0.32 nm with average height was 3.05 nm. The probe N,S-CDs showed a special response to PPi, and a good linear relationship was obtained with PPi concentrations ranging from 0 to 1 μM, with the limit of detection being 0.22 nM. Tap water and milk were used for practical inspection, and ideal experimental results were acquired. In addition, the probe N,S-CDs also showed good results in biological systems, such as cell and zebrafish experiments.