Recent advances in green carbon dots (2015-2022): synthesis, metal ion sensing, and biological applications

Honeycomb waste-derived carbon dots as a sensitive sensing probe for detection of capecitabine chemo drug

Anticancer medication provoked concerns owing to its adverse health effects from overdose and henceforth, its sensitive monitoring is crucial. Carbon dots (CDs), as a pioneering carbon nanomaterial, have particles lower than 10 nm. CDs have an extensive multitude of applications based on their luminous qualities. The present era is focused on turning waste into economically viable products. The current research demonstrates a feasible method for preparing green fluorescent CDs from honeycomb waste (HCCDs). The HCCDs display excitation-dependent emission properties, exhibiting a blue shift with a change in excitation wavelength, and acquiring good stability with a zeta potential of -14.8 mV. Nevertheless, the particle size ranges between 2-5 nm. It is noteworthy that the fluorescence intensity of HCCDs was remarkably enhanced by the addition of increasing concentrations of capecitabine due to complex formation. Additionally, the sensor shows a determined detection limit of 1.04 μmolL-1 without interference from ions. This demonstrates exclusive selectivity and sensitivity which paves a new way for the determination of the capecitabine drug.

Carbon dots: An emerging food analysis nanoprobes for detection of contaminants

Carbon dots are the new class of nanomaterials with a size range of 10 nm or less. These are associate with the important material properties such as good biocompatibility, fluorescent nature, small size and easy to synthesize with low toxicity which make them the first choice over the fluorescent inorganic materials and dyes, to be used as biocompatible nanoprobes for the detection of food adulterations. Herein, we have focused on the methods of synthesis of these tiny zero dimensions, fluorescent nanomaterials (CDs), their properties, mechanism of fluorescence, and lastly their wide applications in food analysis which include the detection of additives, heavy metal ions, organic pollutants, foodborne microbes, antibiotic and pesticides. Further, these nanomaterials open the scope to be used as nanoprobes in the food safety concern. Additionally, we discussed the challenges and future scope of CDs as an auspicious and emerging nanomaterial to be used in the food industries.

L-Arginine Doped Carbon Nanodots from Cinnamon Bark for Improved Fluorescent Yeast Cell Imaging

In this study, we present an economical and efficient synthesis method for carbon nanodots (CNDs) derived from cinnamon bark wood powder, with the incorporation of L-arginine as a dopant at varying ratios (Cinnamon : L-Arginine - 1:0.25, 1:0.5) via a hydrothermal reaction. Extensive structural and optical characterization was conducted through techniques such as FTIR, XRD, HR-TEM, DLS, UV-Vis, and PL spectra, providing a comprehensive understanding of the properties of CNDs and doped-CNDs. Quantum yields (QY) were quantified for synthesized materials, contributing to the assessment of their fluorescence efficiency. The synthesized CNDs were successfully applied for bioimaging of yeast cells, employing fluorescence microscopy to visualize their interaction. Remarkably, L-arginine-doped CNDs exhibited enhanced fluorescence, showcasing the influence of the dopant. The nature of these CNDs was rigorously investigated, confirming their biocompatibility. Notably, this work presents a novel approach to synthesizing CNDs from a renewable and sustainable source, cinnamon bark wood powder, while exploring the effects of L-arginine doping on their optical and biological properties. This work not only contributes to the synthesis and characterization of CNDs but also highlights their potential for diverse applications, emphasizing their structural, optical, and biological attributes. The findings underscore the versatility of CNDs derived from cinnamon bark wood powder and their potential for advancing biotechnological and imaging applications.

Modified carbon dot-mediated transient transformation for genomic and epigenomic studies in wheat

Genotype restriction poses a significant bottleneck to stable transformation in the vast majority of plant species, thereby severely impeding advancement in plant bioengineering, particularly for crops. Nanoparticles (NPs) can serve as effective carriers for the transient delivery of nucleic acids, facilitating gene overexpression or silencing in plants in a genotype-independent manner. However, the applications of NP-mediated transient systems in comprehensive genomic studies remained underexplored in plants, especially in crops that face challenges in genetic transformation. Consequently, there is an urgent need for efficient NP-mediated delivery systems capable of generating whole plants or seedlings with uniformly transformed nucleic acids. We have developed a straightforward and efficient modified carbon dot (MCD)-mediated transient transformation system for delivering DNA plasmids into the seeds of wheat, which is also applicable to other plant species. This system facilitates the generation of whole seedlings that contain the transferred DNA plasmids. Furthermore, our study demonstrates that this system serves as an excellent platform for conducting functional genomic studies in wheat, including the validation of gene functions, protein interactions and regulation, omics studies, and genome editing. This advancement significantly enhances functional genomic research for any plants or crops that face challenges in stable transformation. Thus, our study provides for the first time evidence of new applications for MCDs in functional genomics and epigenomic studies, and bioengineering potentially leading to the improvement of desirable agronomic traits in crops.

Applications of Green Carbon Dots in Personalized Diagnostics for Precision Medicine

Green carbon dots (GCDs) have emerged as a revolutionary tool in precision medicine, offering transformative capabilities for personalized diagnostics and therapeutic strategies. Their unique optical and biocompatible properties make them ideal for non-invasive imaging, real-time monitoring, and integration with genomics, proteomics, and bioinformatics, enabling accurate diagnosis and tailored treatments based on patients' genetic and molecular profiles. This study explores the potential of GCDs in advancing individualized patient care by examining their applications in precision medicine. It evaluates their utility in non-invasive diagnostic imaging, targeted therapy delivery, and the formulation of personalized treatment plans, emphasizing their interaction with advanced genomic, proteomic, and bioinformatics platforms. GCDs demonstrated exceptional versatility in enabling precise diagnostics and delivering targeted therapies. Their integration with cutting-edge technologies showed significant promise in crafting personalized treatment strategies, enhancing their functionality and effectiveness in real-time monitoring and patient-specific applications. The findings underscore the pivotal role of GCDs in reshaping healthcare by advancing precision medicine and improving patient outcomes. The ongoing development and integration of GCDs with emerging technologies promise to further enhance their capabilities, paving the way for more effective, individualized medical care.

Selective Identification and Quantification of Microplastics Using Solid Fluorescent Green Carbon Dots (SFGCDs) - A Novel, Naked Eye Sensing Fluoroprobe

The current work presents a Novel, Carbon Dot fluoroprobe to selectively identify and quantify Microplastics (MPs) released from Surgical facemask and Cosmetic Personal Cleansers. Solid Fluorescent Green Carbon Dots (SFGCDs) are synthesized for the first time from a high carbon source natural resin, obtained from Araucaria araucana (Monkey puzzle tree). The increased carbon content is responsible for the green colour of the CDs. SFGCDs function as a TURN OFF fluoroprobe on detection of MPs through dynamic quenching mechanism, which is confirmed from Stern Volmer Plot with an R2 value of. The minimum LOD being 0.0063 g/l for ≥ 6 μm diameter MPs. The agglomeration of microplastics released from surgical mask and cosmetic cleansers on functions as an insulator on the surface of SFGCDs, forbidding ease of electron- hole transfer between the donor- SFGCDs and acceptor-MPs. The release of MPs from the donor surface results in reappearance of fluorescence obeying FRET mechanism. The detection of MPs/ microfibres released by disposable surgical mask is studied by the degradation of the surgical face mask for a period of 50 days, followed by detection. Turn- OFF in fluorescence of SFGCDs observed in presence of micro fibre Turns On, as remediation of MPs is done by a simple filtration technique. The results demonstrate the potential of the fluoroprobe towards real time detection of MPs and simple remediation of MPs to conserve the ecosystem. The SFGCDs is stable and can be reused for nearly 3 cycles for the detection of MPs. A single PL peak obtained on detection of MPs in presence of monovalent, divalent trivalent ions and biomolecules authenticates the selectivity and stability of SFGCDs to function as an efficient fluoroprobe towards sensing of MPs.

Enhanced chemiluminescence by carbon dots for rapid detection of bisphenol A and nitrite

Herein, a novel chemiluminescence (CL) sensor was successfully developed based on chlorine doped carbon dots (Cl/CDs) for the rapid determination of bisphenol A (BPA) and nitrite. The Cl/CDs were synthesized through a hydrothermal method, using ascorbic acid as the precursor and hydrochloric acid as the dopant. It was found that Cl/CDs significantly enhanced the CL intensity of the acid-KMnO4 system, while BPA and nitrite quenched the CL intensity of the Cl/CDs-sensitized acid-KMnO4 system. Under optimal conditions, BPA exhibited a linear detection range of 0.05-10 μM, with limits of detection (LOD) and quantification (LOQ) of 0.86 nM and 2.8 nM, respectively. Nitrite showed a linear detection range of 0.7-100 μM, with LOD and LOQ of 22.5 nM and 75 nM, respectively. The CL sensor was successfully use to determine BPA in water samples and nitrite in pickles, ham and celery, with spike recovery rates of 96.3 %-104.8 % and 96.0 %-104.9 %, respectively.

Application of biomass carbon dots in food packaging

Since its discovery, carbon quantum dots (CDs) have been widely applied in cell imaging, drug delivery, biosensing, and photocatalysis due to their excellent water solubility, chemical stability, fluorescence stability biocompatibility, low toxicity, and preparation cost. However, the low fluorescence yield and poor surface structure limit the application of CDs. Heteroatom doping is considered an ideal method to improve CDs' optical and electrical properties. From this perspective, eco-friendly biomass and its derivatives are perfect carbon precursors for CDs because they contain the heteroatoms needed to modify CDs, and their complex chemical composition gives CDs a wide variety of surface functional groups. Besides, converting biomass waste into high-value-added CDs is also an innovation in biomass waste treatment. Therefore, this paper focuses on the carbon precursors of biomass CDs. At the same time, food packaging occupies an essential position in the industry, and fluorescent CDs with good fluorescence properties, high chemical stability, and good photobleaching properties have great application potential in packaging innovation techniques that have emerged in recent years, but relevant reports are scarce and scattered. Considering that the surface morphology, chemical structure, and optical and electrical properties of biomass CDs are primarily affected by the carbon precursors' chemical structure and preparation method, this paper also focuses on the synthesis method of biomass CDs and its application in anti-counterfeiting packaging, intelligent packaging, antioxidant packaging, and antibacterial packaging.

Development of an accurate synchronous transport signal hand-held sensing platform for fluorescence-based berberine on-site detection

BACKGROUND

Berberine is widely used in clinical treatment because of its wide antibacterial spectrum and low toxic side effects. However, its abuse could lead to bacterial resistance and several other adverse effects. In addition, measuring the content of berberine in environmental water samples helps to monitor its accumulation and metabolism in ecosystems. Traditional detection methods usually need to be carried out in the laboratory, involving complex processing procedures, which are not only time-consuming, but also unfavorable for rapid response and decision-making. Therefore, it is necessary to develop portable instruments to provide reasonable guidance on the addition and intake of berberine to reduce the harm caused by its abuse.

RESULTS

In this work, an accurate synchronous transport signal hand-held sensing platform (STSHSP) with a low-cost, easy-to-manufacture, independent use was developed by using photoelectric conversion technology, Bluetooth technology, remote synchronous signal technology, electrical technology, and 3D printing technology. To verify the performance of STSHSP, a 5-oxo-2,3-dihydro-5H-thiazolo [3,2-a] pyridine-3,7-dicarboxylic acid (TPDCA) with ultra-high quantum yield was designed and synthesized as a probe. TPDCA exhibited bright blue fluorescence under the ultraviolet light of 365 nm which could be quenched by berberine through the inner filter effect. In the range of 0.1-80 μg/mL, the voltage displayed by the prepared STSHSP has a good linearity with the berberine concentration (R2 = 0.9997) with a detection limit of 28.32 ng/mL. The portable sensor demonstrated good stability, accuracy, and reliability in detecting actual river water, urine, traditional Chinese medicine, and its preparation samples.

SIGNIFICANCE

The sensor with its compact structure, portability, and simple operation was suitable for in-situ detection with accurate, reliable, and feasible results, which is beneficial for improving drug quality and ensuring human health. Fortunately, the device could transmit the information to the control center and/or a third-party supervision institution in real-time, which could effectively eliminate the trust crisis. The sensor has broad application prospects in the field of environmental water quality detection and drug safety.

Yam Carbon Dots Promote Bone Defect Repair by Modulating Histone Demethylase 4B

Introduction

Chronic apical periodontitis is a typical inflammatory disease of the oral cavity, the pathology is characterized by an inflammatory reaction with bone defects in the periapical area. Chinese medicine is our traditional medicine, Carbon Dots (CDs) are a new type of nanomaterials. The purpose of this study was to prepare Yam Carbon Dots (YAM-CDs) to investigate the mechanism of action of YAM-CDs on bone differentiation in vivo and in vitro.

Methods

We characterized YAM-CDs using transmission electron microscopy (TEM), Fourier Transform Infrared Spectrometer (FTIR), X-Ray Diffraction (XRD) and photoluminescence (PL). CCK-8 assay, Real-time qPCR, and Western Blot were conducted using bone marrow mesenchymal stem cells (BMSCs) to verify that YAM-CDs promote osteoblast differentiation. In addition, we investigated the role of YAM-CDs in promoting bone formation in an inflammatory setting in an in vivo mouse model of cranial defects.

Results

The results of TEM and PL showed that the YAM-CDs mostly consisted of the components C1s, O1s, and N1s. Additionally the average sizes of YAM-CDs were 2-6 nm. The quantum yield was 4.44%, with good fluorescence stability and biosafety. Real-time qPCR and Western blot analysis showed that YAM-CDs promoted osteoblast differentiation under an inflammatory environment by regulating expression of histone demethylase 4B (KDM4B). In vivo, results showed that YAM-CDs effectively repaired cranial bone defects in a mouse model and reduced the expression of inflammatory factors under the action of lipopolysaccharides (LPS).

Conclusion

YAM-CDs promoted the proliferation and differentiation of osteoblasts by regulating the expression of KDM4B to repair cranial bone defects in mice under an LPS-induced inflammatory milieu, which will provide a new idea for the treatment of clinical periapical inflammation and other bone defect diseases.

Engineering of Green Carbon Dots for Biomedical and Biotechnological Applications

Carbon dots (CDs) are attracting increasing research attention due to their exceptional attributes, including their biocompatibility, water solubility, minimal toxicity, high photoluminescence, and easy functionalization. Green CDs, derived from natural sources such as fruits and vegetables, present advantages over conventionally produced CDs, such as cost-effectiveness, stability, simplicity, safety, and environmental friendliness. Various methods, including hydrothermal and microwave treatments, are used to synthesize green CDs, which demonstrate strong biocompatibility, stability, and luminescence. These properties give green CDs versatility in their biological applications, such as bioimaging, biosensing, and drug delivery. This review summarizes the prevalent synthesis methods and renewable sources regarding green CDs; examines their optical features; and explores their extensive biological applications, including in bioimaging, biosensing, drug/gene delivery, antimicrobial and antiviral effects, formatting of mathematical components, cancer diagnosis, and pharmaceutical formulations.

Anticancer activity of quantum size carbon dots: opportunities and challenges

Research into the anticancer activity of quantum-sized carbon dots (CDs) has emerged as a promising avenue in cancer research. This CDs delves into the opportunities and challenges associated with harnessing the potential of these nanostructures for combating cancer. Quantum-sized carbon dots, owing to their unique physicochemical properties, exhibit distinct advantages as potential therapeutic agents. Opportunities lie in their tunable size, surface functionalization capabilities, and biocompatibility, enabling targeted drug delivery and imaging in cancer cells. However, we include challenges, a comprehensive understanding of the underlying mechanisms, potential toxicity concerns, and the optimization of synthesis methods for enhanced therapeutic efficacy. A succinct summary of the state of the research in this area is given in this review, emphasizing the exciting possibilities and ongoing challenges in utilizing quantum-sized carbon dots as a novel strategy for cancer treatment.

Exploring the potential of eco-friendly carbon dots in monitoring and remediation of environmental pollutants

Photoluminescent carbon dots (CDs) have garnered significant interest owing to their distinctive optical and electronic properties. In contrast to semiconductor quantum dots, which incorporated toxic elements in their composition, CDs have emerged as a promising alternative, rendering them suitable for both environmental and biological applications. CDs exhibit astonishing features, including photoluminescence, charge transfer, quantum confinement effect, and biocompatibility. Recently, CDs derived from green sources have drawn a lot of attention due to their strong photostability, reduced toxicity, better biocompatibility, enhanced fluorescence, and simplicity. These attributes have shown great promise in the areas of LED technology, bioimaging, photocatalysis, drug delivery, biosensing, and antibacterial activity. In contrast, this review offers a comprehensive overview of various green sources utilized to produce CDs and methodologies, along with their merits and demerits, with a notable emphasis on physiochemical properties. Additionally, the paper provides insight into the bibliometric analysis and recent advancements of CDs in sensing, photocatalysis, and antibacterial activity. In this field, extensive research is underway, and a total of 7,438 articles have been identified. Among these, 4242 articles are dedicated to sensing applications, while 1518 and 1678 focus on adsorption and degradation. Carbon dots demonstrate exceptional sensing capabilities within the nanomolar range with a selectivity of up to 95% for pollutants. They exhibit excellent degradation efficiency exceeding 90% within 10-130 min and possess an adsorption capacity from 100 to 800 mg/g. These fascinating qualities render them suitable for diverse applications.

Development of a biomimetic DNA delivery system by encapsulating polyethyleneimine functionalized silicon quantum dots with cell membranes

Quantum dots (QDs) are renowned for their remarkable optoelectronic properties, making them suitable for applications such as bioimaging and optoelectronics. However, their use in gene delivery has been restricted due to the low DNA loading capacity. This study aimed to develop a biomimetic DNA delivery system by encapsulating polyethyleneimine (PEI) functionalized silicon QDs (SiQDs) with cell membranes and evaluate its potential as a gene vector in vitro. To achieve this, hydrophilic dispersed silicon QDs (PQDs) were prepared through a one-pot hydrothermal reaction of PEI and 3-Aminopropyltrimethoxysilane (APTMS). Subsequently, red blood cell membrane (RBCM) encapsulated biomimetic QDs (CM-PQDs) was obtained through the extrusion method. The CM-PQDs exhibited higher DNA loading capacity and better stability than naked SiQDs. The CM-PQDs/DNA complex was effectively taken up by cells, as observed through the fluorescence characteristics of QDs themselves. Both CM-P10QDs (prepared with PEI10k) and CM-P25QDs (prepared with PEI25k) could deliver DNA into cells and express the reporter protein successfully. CM-P25QDs showed a higher transfection efficiency of 77.32% in 293 T cells and 47.11% in HeLa cells than SiQDs and CM-P10QDs. The results also indicated that cell membrane encapsulation could effectively reduce the cytotoxicity of SiQDs further. Therefore, the study concludes that CM-PQDs have the potential to serve as a safe and traceable biomimetic gene delivery system.

Metal-organic framework-based nanomaterials as opto-electrochemical sensors for the detection of antibiotics and hormones: A review

Increasing trace levels of antibiotics and hormones in the environment and food samples are concerning and pose a threat. Opto-electrochemical sensors have received attention due to their low cost, portability, sensitivity, analytical performance, and ease of deployment in the field as compared to conventional expensive technologies that are time-consuming and require experienced professionals. Metal-organic frameworks (MOFs) with variable porosity, active functional sites, and fluorescence capacity are attractive materials for developing opto-electrochemical sensors. Herein, the insights into the capabilities of electrochemical and luminescent MOF sensors for detection and monitoring of antibiotics and hormones from various samples are critically reviewed. The detailed sensing mechanisms and detection limits of MOF sensors are addressed. The challenges, recent advances, and future directions for the development of stable, high-performance MOFs as commercially viable next-generation opto-electrochemical sensor materials for the detection and monitoring of diverse analytes are discussed.

Ultrasmall and highly biocompatible carbon dots derived from natural plant with amelioration against acute kidney injury

BACKGROUND

Acute kidney injury (AKI) refers to a tricky clinical disease, known by its high morbidity and mortality, with no real specific medicine for AKI. The carbonization product from Pollen Typhae (i.e., Pu-huang in China) has been extensively employed in clinic, and it is capable of relieving the renal damage and other diseases in China since acient times.

RESULTS

Inspired by the carbonization process of Traditional Chinese Medicine (TCM), a novel species of carbon dots derived from Pollen Typhae (PT-CDs) was separated and then collected using a one-pot pyrolysis method. The as-prepared PT-CDs (4.85 ± 2.06 nm) with negative charge and abundant oxygenated groups exhibited high solubility, and they were stable in water. Moreover, the rhabdomyolysis (RM)-induced AKI rat model was used, and it was first demonstrated that PT-CDs had significant activity in improving the level of BUN and CRE, urine volume and kidney index, and histopathological morphology in RM-induced AKI rats. It is noteworthy that interventions of PT-CDs significantly reduced degree of inflammatory reaction and oxidative stress, which may be correlated with the basial potential mechanism of anti-AKI activities. Furthermore, cytotoxicity assay and biosafety evaluation exhibited high biocompatibility of PT-CDs.

CONCLUSION

This study offers a novel relieving strategy for AKI based on PT-CDs and suggests its potential to be a related candidate for clinical applications.

The Consequences of Water Interactions with Nitrogen-Containing Carbonaceous Quantum Dots-The Mechanistic Studies

Despite the importance of quantum dots in a wide range of biological, chemical, and physical processes, the structure of the molecular layers surrounding their surface in solution remains unknown. Thus, knowledge about the interaction mechanism of Nitrogen enriched Carbonaceous Quantum Dots' (N-CQDs) surface with water-their natural environment-is highly desirable. A diffusive and Stern layer over the N-CQDs, characterized in situ, reveals the presence of anionic water clusters [OH(H2O)n]-. Their existence explains new observations: (i) the unexpectedly low adsorption enthalpy (ΔHads) in a pressure range below 0.1 p/ps, and ΔHads being as high as 190 kJ/mol at 0.11 p/ps; (ii) the presence of a "conductive window" isolating nature-at p/ps below 0.45-connected to the formation of smaller clusters and increasing conductivity above 0.45 p/ps, (iii) Stern layer stability; and (iv) superhydrophilic properties of the tested material. These observables are the consequences of H2O dissociative adsorption on N-containing basic centers. The additional direct application of surfaces formed by N-CQDs spraying is the possibility of creating antistatic, antifogging, bio-friendly coatings.