Facile approach for green synthesis of fluorescent carbon dots from Manihot esculenta and their potential applications as sensor and bio-imaging agents

Synthesis of Carbon Dots from Peltophorum Pterocarpum Flowers for Selective Fluorescence Detection of Carbendazim

In this study, carbon dots (CDs) were synthesized from Peltophorum pterocarpum flowers as the precursor material using the hydrothermal method. The fluorescence emission spectra of the resulting Peltophorum pterocarpum CDs (PP-CDs) exhibited excitation-independent behavior, showing the fluorescence emission peak at 410 nm when excited at 330 nm. This method is simple, rapid and well consistent with the green chemistry and sustainable analytical method development. The as-synthesized PP-CDs acted as a promising fluorescent probe for detecting carbendazim (CBZ) via aggregation-induced emission mechanism, showing a linear response to CBZ concentrations ranging from 1 to 30 μM, with a detection limit of 5.41 nM. This method was successfully applied to quantify CBZ in food samples, achieving excellent recoveries of 99% with a relative standard deviation (RSD) of less than 2%.

Investigation of Anticancer Therapy Using pH-Sensitive Carbon Dots-Functionalized Doxorubicin in Cubosomes

Cancer remains a highly lethal disease due to its elusive early detection, rapid spread, and significant side effects. Nanomedicine has emerged as a promising platform for drug delivery, diagnosis, and treatment monitoring. In particular, carbon dots (CDs), a type of fluorescent nanomaterial, offer excellent fluorescence properties and the ability to carry multiple drugs simultaneously through covalent bonding. In this work, CDs with carbonyl groups on the surface were prepared by aldol condensation and reacted with amine groups in the structure of doxorubicin (DOX) through Schiff base reaction to generate pH-responsive CDs-DOX. On the other hand, cubosomes with three-dimensional lattice structures formed by lipid bilayers have advantageous capabilities of encapsulating various hydrophilic, amphiphilic, and hydrophobic substances. The pH-responsive CDs-DOX are subsequently loaded into cubosomes to form an anticancer therapeutic nanosystem, CDs-DOX@cubosome. Leveraging the unique properties of CDs-DOX and cubosomes, our CDs-DOX@cubosome can enter tumor tissue through the enhanced permeation and retention effect first and conduct membrane fusion with tumor cells to intracellularly release CDs-DOX. Then, the imine bond in CDs-DOX breaks under acidic conditions within human cancer cell lines (HeLa and HepG-2 cells), releasing DOX and achieving enhanced treatment of tumors. Additionally, fluorescent CDs can synchronously achieve real-time in situ diagnosis of tumor tissue. We demonstrate that our CDs-DOX@cubosome works as an excellent drug delivery system with therapeutic efficiency enhancement to the tumor and reduced side effects.

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.

Assessment of biomass-derived carbon dots as highly sensitive and selective templates for the sensing of hazardous ions

Access to safe drinking water and a hygienic living environment are the basic necessities that encourage healthy living. However, the presence of various pollutants (especially toxic heavy metal ions) at high concentrations in water renders water unfit for drinking and domestic use. The presence of high concentrations of heavy-metal ions (e.g., Pb2+, Hg2+, Cr6+, Cd2+, or Cu2+) greater than their permissible limits adversely affects human health, and increases the risk of cancer of the kidneys, liver, skin, and central nervous system. Therefore, their detection in water is crucial. Due to the various benefits of "green"-synthesized carbon-dots (C-dots) over other materials, these materials are potential candidates for sensing of toxic heavy-metal ions in water sources. C-dots are very small carbon-based nanomaterials that show chemical stability, magnificent biocompatibility, excitation wavelength-dependent photoluminescence (PL), water solubility, simple preparation strategies, photoinduced electron transfer, and the opportunity for functionalization. A new family of C-dots called "carbon quantum dots" (CQDs) are fluorescent zero-dimensional carbon nanoparticles of size < 10 nm. The green synthesis of C-dots has numerous advantages over conventional chemical routes, such as utilization of inexpensive and non-poisonous materials, straightforward operations, rapid reactions, and renewable precursors. Natural sources, such as biomass and biomass wastes, are broadly accepted as green precursors for fabricating C-dots because these sources are economical, ecological, and readily/extensively accessible. Two main methods are available for C-dots production: top-down and bottom-up. Herein, this review article discusses the recent advancements in the green fabrication of C-dots: photostability; surface structure and functionalization; potential applications for the sensing of hazardous anions and toxic heavy-metal ions; binding of toxic ions with C-dots; probable mechanistic routes of PL-based sensing of toxic heavy-metal ions. The green production of C-dots and their promising applications in the sensing of hazardous ions discussed herein provides deep insights into the safety of human health and the environment. Nonetheless, this review article provides a resource for the conversion of low-value biomass and biomass waste into valuable materials (i.e., C-dots) for promising sensing applications.

Prosopis juliflora hydrothermal synthesis of high fluorescent carbon dots and its antibacterial and bioimaging applications

Carbon dots have stimulated the curiosity of biomedical researchers due to their unique properties, such as less toxicity and high biocompatibility. The synthesis of carbon dots for biomedical application is a core area in research. In the current research, an eco-friendly hydrothermal technique was employed to synthesize high fluorescent, plant-derived carbon dots from Prosopis juliflora leaves extract (PJ-CDs). The synthesized PJ-CDs were investigated by physicochemical evaluation instruments such as fluorescence spectroscopy, SEM, HR-TEM, EDX, XRD, FTIR, and UV-Vis. The UV-Vis absorption peaks obtained at 270 nm due to carbonyl functional groups shifts of n→π*. In addition, a quantum yield of 7.88 % is achieved. The synthesized PJ-CDs showing the presence of carious functional groups O-H, C-H, C=O, O-H, C-N and the obtained particles in spherical shape with an average size of 8 nm. The fluorescence PJ-CDs showed stability against various environmental factors such as a broad range of ionic strength and pH gradient. The antimicrobial activity of PJ-CDs was tested against a Staphylococcus aureus, and a Escherichia coli. The results suggest that the PJ-CDs could substantially inhibit the growth of Staphylococcus aureus. The findings also indicate that PJ-CDs are effective materials for bio-imaging in Caenorhabditis elegans and they can be also used for pharmaceutical applications.

Green-derived carbon dots: A potent tool for biosensing in food safety

The impact of food contaminants on ecosystems and human health has attracted widespread global attention, and there is an urgent need to develop reliable food safety detection methods. Recently, carbon dots (CDs) have been considered as a powerful material to construct sensors for chemical analysis. Based on the concept of resource conversion and sustainable development, the use of natural, harmless, and renewable materials for the preparation of CDs without the involvement of chemical hazards is a current hot topic. This paper reviews the research progress of green-derived CDs and their application in food safety biosensing. The fabrications of green-derived CDs using various biomasses are described in detail, and the application of CDs especially the sensing mechanisms of photoluminescence, colorimetric, electrochemiluminescence and other sensors are provided. Finally, existing shortcomings and current challenges as well as prospects for food safety monitoring are discussed. We believe that this work provides strong insight into the application of CDs in the sensing of various contaminants.

Nano-probe for determination of phenobarbital of green synthesized fluorescent carbon dots using Scrophularia striata

In this study, using a thirsty plant extract and a simple hydrothermal method, a nano-probe was introduced to detect the phenobarbital based on fluorescence. Functional groups, particle size, surface morphology, and types of elements were identified using analysis such as FTIR, TEM, SEM, EDX, respectively. The excitation at 355 nm and emission intensity at 446 nm for nano-probe, the nano-probe shows that various parameters such as pH, temperature, and time were investigated for optimization conditions. After optimizing the factors affecting the sensor's response, a linear range between 0 and 750 µM with a detection limit of 5 µM was obtained. Then, the effect of interfering with other materials was investigated and finally, the ability of this sensor to measure the phenobarbital in real samples has been studied.