Biocompatible fluorescent carbon quantum dots prepared from beetroot extract for in vivo live imaging in C. elegans and BALB/c mice

Highly fluorescent hybrid nanofibers as potential nanofibrous scaffolds for studying cell-fiber interactions

In this study, we report on the fabrication of hybrid nanofibers for labeling and bioimaging applications. Our approach is involved for developing highly fluorescent nanofibers using a blend of polylactic acid, polyethyleneglycol, and perylenediimide dyes, through the solution blow spinning technique. The nanofibers are exhibited diameters ranging from 330 nm to 420 nm. Nanofibers showed excellent red and near-infrared fluorescence emissive properties in fluorescent spectroscopy. Moreover, the strong two-photon absorption phenomenon was observed for nanofibers under confocal microscopy. To assess the applicability of these fluorescent nanofibers in bioimaging settings, we employ two types of mammalian cells B16F1 melanoma cells and J774.A1 macrophages. Both cell types exhibit negligible cytotoxicity after 24 h incubation with the nanofibers, indicating the suitability of nanofibers for cell-based experiments. We also observe strong interactions between the nanofibers and cells, as evidenced by two major events: a) the acquisition of an elongated cellular morphology with the major cellular axis parallel to the nanofibers and b) the accumulation of actin filaments along the points of contact of the cells with the fibers. Our findings demonstrate the suitability of these newly developed fluorescent nanofibers in cell-based applications for guiding cellular behavior. We expect that these fluorescent nanofibers have the potential to serve as scaffold materials for long-time tracking of cell-fiber interactions in fluorescence microscopy.

A review on green synthesis, biological applications of carbon dots in the field of drug delivery, biosensors, and bioimaging

Since the beginning of nanoscience and nanotechnology, carbon dots (CDs) have been the foundational idea and have dominated the growth of the nano-field. CDs are an intriguing platform for utilization in biology, technology, catalysis, and other fields thanks to their numerous distinctive structural, physicochemical, and photochemical characteristics. Since several carbon dots have already been created, they have been assessed based on their synthesis process, and luminescence characteristics. Due to their biocompatibility, less toxic effects, and most significantly their fluorescent features in contrast to other carbon nanostructures, CDs have several benefits. This review focuses on the most recent advancements in the characterization, applications, and synthesis techniques used for CDs made from natural sources. It will also direct scientists in the creation of a synthesis technique for adjustable carbon dots that is more practical, effective, and environmentally benign. With low toxicity and low cost, CDs are meeting the new era's requirements for more selectivity and sensitivity in the detection and sensing of various things, such as biomaterial sensing, enzymes, chemical contamination, and temperature sensing. Its variety of properties, such as optical properties, chemiluminescence, and morphological analysis, make it a good option to use in bioimaging, drug delivery, biosensors, and cancer diagnosis.

Carbon dots as versatile nanomaterials in sensing and imaging: Efficiency and beyond

Carbon dots (CDs) have emerged as a versatile and promising carbon-based nanomaterial with exceptional optical properties, including tunable emission wavelengths, high quantum yield, and photostability. CDs are appropriate for various applications with many benefits, such as biocompatibility, low toxicity, and simplicity of surface modification. Thanks to their tunable optical properties and great sensitivity, CDs have been used in sensing as fluorescent probes for detecting pH, heavy metal ions, and other analytes. In addition, CDs have demonstrated potential as luminescence converters for white organic light-emitting diodes and light emitters in optoelectronic devices due to their superior optical qualities and exciton-independent emission. CDs have been used for drug administration and bioimaging in the biomedical field due to their biocompatibility, low cytotoxicity, and ease of functionalization. Additionally, due to their stability, efficient charge separation, and low recombination rate, CDs have shown interesting uses in energy systems, such as photocatalysis and energy conversion. This article highlights the growing possibilities and potential of CDs as adaptable nanomaterials in a variety of interdisciplinary areas related to sensing and imaging, at the same time addressing the major challenges involved in the current research and proposing scientific solutions to apply CDs in the development of a super smart society.

Biofilm Inhibition on Medical Devices and Implants Using Carbon Dots: An Updated Review

Biofilms are an intricate community of microbes that colonize solid surfaces, communicating via a quorum-sensing mechanism. These microbial aggregates secrete exopolysaccharides facilitating adhesion and conferring resistance to drugs and antimicrobial agents. The escalating global concern over biofilm-related infections on medical devices underscores the severe threat to human health. Carbon dots (CDs) have emerged as a promising substrate to combat microbes and disrupt biofilm matrices. Their numerous advantages such as facile surface functionalization and specific antimicrobial properties, position them as innovative anti-biofilm agents. Due to their minuscule size, CDs can penetrate microbial cells, inhibiting growth via cytoplasmic leakage, reactive oxygen species (ROS) generation, and genetic material fragmentation. Research has demonstrated the efficacy of CDs in inhibiting biofilms formed by key pathogenic bacteria such as Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. Consequently, the development of CD-based coatings and hydrogels holds promise for eradicating biofilm formation, thereby enhancing treatment efficacy, reducing clinical expenses, and minimizing the need for implant revision surgeries. This review provides insights into the mechanisms of biofilm formation on implants, surveys major biofilm-forming pathogens and associated infections, and specifically highlights the anti-biofilm properties of CDs emphasizing their potential as coatings on medical implants.

Nitrogen-doped biomass-derived carbon dots for fluorescence determination of sunset yellow

Sunset Yellow (SY) is a widely used food coloring in the food industry. However, exceeding the allowable limit of this dye poses a significant threat to human health. To address this issue, we developed Lycium ruthenicum-derived nitrogen-doped carbon dots (N-CDs) with a stable blue fluorescence through hydrothermal treatment for SY determination. The quantum yield (QY) of these N-CDs was found to be up to 10.63%. Physical characterization of N-CDs was performed using various spectroscopic techniques to confirm their excellent photostability and non-toxic properties. Furthermore, the presence of SY had a substantial quenching effect on the fluorescence intensity (F0/F) of the N-CDs. Leveraging this observation, we developed a fluorescent sensor for the determination of SY in the concentration range of 0.05 to 35.0 μM, with a limit of detection (LOD, 3σ/K) of 17 nM. The excellent fluorescent sensor also showed satisfactory results in the practical drink samples. Moreover, the stability and cytotoxicity of N-CDs as a fluorescent probe were studied. Finally, the N-CDs were applied to cell imaging using A549 cells.

Carbon quantum dots as immune modulatory therapy in a Sjögren's syndrome mouse model

OBJECTIVES

The objective of the study was to evaluate the therapeutic effects of carbon quantum dots (CQDs) in immunomodulation on non-obese diabetic (NOD) mice, as the model for Sjögren's syndrome (SS).

METHODS

Carbon quantum dots were generated from Setaria viridis via a hydrothermal process. Their toxic effects were tested by cell viability and blood chemistry analysis, meanwhile therapeutic effects were investigated in NOD mice in the aspects of saliva flow, histology, and immune cell distribution.

RESULTS

Carbon quantum dots, with rich surface chemistry and unique optical properties, showed non-cytotoxicity in vitro or no damage in vivo. Intravenously applied CQDs alleviated inflammation in the submandibular glands in NOD mice after 6-week treatments. The inflammatory area index and focus score were significantly decreased in CQD-treated mice. Besides, the levels of anti-SSA and anti-SSB were decreased in the presence of CQDs. The stimulated saliva flow rates and weight of submandibular glands were significantly increased in CQD-treated mice by reducing the apoptosis of cells. The CD3+ and CD4+ T cells distributed around the ducts of submandibular glands were significantly decreased, while the percentage of Foxp3+ cells was higher in CQD-treated mice than that in the control group.

CONCLUSIONS

Our findings suggest that CQDs may ameliorate the dysregulated immune processes in NOD mice.

Carbon Dot Based Carbon Nanoparticles as Potent Antimicrobial, Antiviral, and Anticancer Agents

Antimicrobial and anticancer drugs are widely used due to increasing widespread infectious diseases caused by microorganisms such as bacterial, fungal, viral agents, or cancer cells, which are one of the major causes of mortality globally. Nevertheless, several microorganisms developed resistance to antibiotics as a result of genetic changes that have occurred over an extended period. Carbon-based materials, particularly carbon dots (C-dots), are potential candidates for antibacterial and anticancer nanomaterials due to their low toxicity, ease of synthesis and functionalization, high dispersibility in aqueous conditions, and promising biocompatibility. In this Review, the content is divided into four sections. The first section concentrates on C-dot structures, surface functionalization, and morphology. Following that, we summarize C-dot classifications and preparation methods such as arc discharge, laser ablation, electrochemical oxidation, and so on. The antimicrobial applications of C-dots as antibacterial, antifungal, and antiviral agents both in vivo and in vitro are discussed. Finally, we thoroughly examined the anticancer activity displayed by C-dots.

Development of amine-functionalized fluorescent silica nanoparticles from coal fly ash as a sustainable source for nanofertilizer

Scaling up the synthesis of fluorescent silica nanoparticles to meet the current demand in diverse applications involves technological limitations. The present study relates to the hydrothermal synthesis of water-soluble, crystalline, blue-emitting amine-functionalized silica nanoparticles from coal fly ash sustainably and economically. This study used tertiary amine (trimethylamine) to prepare amine-functionalized fluorescent silica nanoparticles, enhancing fluorescence quantum yield and nitrogen content for nanofertilizer application. The TEM and FESEM studies show that the silica nanoparticles have a spherical morphology with an average diameter of 4.0 nm. The x-ray photoelectron and Fourier transform infrared spectroscopy studies reveal the presence of the amine group at the surface of silica nanoparticles. The silica nanoparticles exhibit blue fluorescence with an emission maximum of 454 nm at 370 nm excitation and show excitation-dependent emission properties in the aqueous medium. With the perfect spectral overlap between silica nanoparticle emission (donor) and chlorophyll absorption (acceptor), fluorescent silica nanoparticles enhance plant photosynthesis rate by resonance energy transfer. This process accelerates the photosynthesis rate to improve the individual plant's quality and growth. These findings suggested that the fly ash-derived functionalized silica nanoparticles could be employed as nanofertilizers and novel delivery agents.

Structural Features of Carbon Dots and Their Agricultural Potential

Carbon dots (CDs) have drawn attention due to their enticing physical, chemical, and surface properties. Besides, good conductivity, low toxicity, environmental friendliness, simple synthetic routes, and comparable optical properties are advantageous features of CDs. Further, recently, CDs have been explored for biological systems, including plants. Among biological systems, only plants form the basis for sustainability and life on Earth. In this Review, we reviewed suitable properties and applications of CDs, such as promoting the growth of agricultural plants, disease resistance, stress tolerance, and target transportation. Summing up the available studies, we believe that the applications of CDs are yet to be explored significantly for innovation and technology-based agriculture.

Novel spectrofluorometric method utilizing functionalized carbon quantum dots for determining histamine levels in nasal secretions: Implications for allergic rhinitis

Histamine plays a crucial role in regulating various physiological functions and is significantly involved in the development of allergic rhinitis. Accurately measuring histamine levels in nasal secretions can serve as a specific indicator for studying mast cell activation and diagnosing allergic reactions. However, the controversy surrounding histamine levels in nasal secretions during allergenic stimulation suggests potential inaccuracies and imprecision in the analytical methods used, as well as the presence of substances that may interfere with the determination of histamine. In this study, a sensitive and selective spectrofluorometric method was developed using carbon quantum dots (CQDs) derived from beetroot slices, which are non-toxic and eco-friendly materials. These CQDs were functionalized with histamine tetra phenyl borate to determine histamine levels in nasal secretions. Various characterization techniques were employed to confirm the successful synthesis and functionalization of the CQDs. The functionalized CQDs demonstrated enhanced fluorescence and selective interaction with histamine, leading to concentration-dependent fluorescence quenching. The developed method was successfully utilized to compare histamine levels in nasal secretions of healthy individuals and patients with allergic rhinitis. The results showed that the histamine level was significantly higher in patients with allergic rhinitis than in healthy individuals, suggesting a potential association between allergic rhinitis and histamine, (normal vs. patient: 350 ± 20 ng/mL vs. 2520 ± 37 ng/mL, p < 0.05). Furthermore, the proposed spectrofluorometric method exhibited improved linearity range, dynamic range, and detection limit compared to a previously reported spectrophotometric method.

Comprehensive advances in the synthesis, fluorescence mechanism and multifunctional applications of red-emitting carbon nanomaterials

Red emitting fluorescent carbon nanomaterials have drawn significant scientific interest in recent years due to their high quantum yield, water-dispersibility, photostability, biocompatibility, ease of surface functionalization, low cost and eco-friendliness. The red emissive characteristics of fluorescent carbon nanomaterials generally depend on the carbon source, reaction time, synthetic approach/methodology, surface functional groups, average size, and other reaction environments, which directly or indirectly help to achieve red emission. The importance of several factors to achieve red fluorescent carbon nanomaterials is highlighted in this review. Numerous plausible theories have been explained in detail to understand the origin of red fluorescence and tunable emission in these carbon-based nanostructures. The above advantages and fluorescence in the red region make them a potential candidate for multifunctional applications in various current fields. Therefore, this review focused on the recent advances in the synthesis approach, mechanism of fluorescence, and electronic and optical properties of red-emitting fluorescent carbon nanomaterials. This review also explains the several innovative applications of red-emitting fluorescent carbon nanomaterials such as biomedicine, light-emitting devices, sensing, photocatalysis, energy, anticounterfeiting, fluorescent silk, artificial photosynthesis, etc. It is hoped that by choosing appropriate methods, the present review can inspire and guide future research on the design of red emissive fluorescent carbon nanomaterials for potential advancements in multifunctional applications.

Carbon Dots Derived from Traditional Chinese Medicines with Bioactivities: A Rising Star in Clinical Treatment

In the field of carbon nanomaterials, carbon dots (CDs) have become a preferable choice in biomedical applications. Based on the concept of green chemistry, CDs derived from traditional Chinese medicines (TCMs) have attracted extensive attention, including TCM charcoal drugs, TCM extracts, and TCM small molecules. The design and preparation of CDs from TCMs (TCMs-CDs) can improve the inherent characteristics of TCMs, such as solubility, particle size distribution, and so on. Compared with other precursor materials, TCMs-CDs have outstanding intrinsic bioactivities and potential pharmacological effects. However, the research of TCMs-CDs in biomedicine is not comprehensive, and their mechanisms have not been understood deeply either. In this review, we will provide concise insights into the recent development of TCMs-CDs, with a major focus on their preparation, formation, precursors, and bioactivities. Then we will discuss the perfect transformation from TCMs to TCMs-CDs. Finally, we discuss the opportunities and challenges for the application of TCMs-CDs in clinical treatment.

Development of fluorescent carbon nanoparticles from Madhuca longifolia flower for the sensitive and selective detection of Cr6+: a collective experimental-computational approach

Herein, blue-emitting carbon nanoparticles (CNPs) were synthesized using the Madhuca longifolia flower for the highly selective and sensitive detection of Cr6+ ions in aqueous media using a simple, green, and cost-effective approach, and computational experiments were also performed. The prepared CNPs were well-dispersed in water with an average diameter of 12 nm and functionalized with carbonyl, hydroxyl and carboxylic acid groups. The decrease in the fluorescence intensity of the CNPs with an increase in the content of Cr6+ provided an important signal for the sensitive and selective detection of Cr6+ in aqueous media. The limit of detection for Cr6+ in an aqueous medium was found to be 103 ppb, which is more sensitive in comparison with the previously reported study. Furthermore, the validation of the proposed higher sensing feature and more selective nature of the CNPs towards Cr6+ was also explained using an in silico approach. The results from the theoretical calculations based on the DFT approach demonstrated that the binding energy (BE) of the CNPs with three transition metal (TM) cations (Cr6+, Fe3+, and Hg2+) follows the order of Cr6+ > Fe3+ > Hg2+, where the Cr6+ TM cation associated with the CNPs possesses the highest valence state, showing the highest sensing feature and highest selectivity among the investigated ions, as expected. The metal ions associated with the CNPs having a higher charge and a smaller radius indicated a higher BE and larger degree of deformation of the CNPs. Moreover, to achieve new insights into the structural, stability/energetics, and electronic features, some useful tools, such as NCI-plot, HOMO-LUMO gap, MESP, and QTAIM analysis were employed, which facilitated noteworthy outcomes.

Progress in drug delivery and diagnostic applications of carbon dots: a systematic review

Carbon dots (CDs), which have particle size of less than 10 nm, are carbon-based nanomaterials that are used in a wide range of applications in the area of novel drug delivery in cancer, ocular diseases, infectious diseases, and brain disorders. CDs are biocompatible, eco-friendly, easy to synthesize, and less toxic with excellent chemical inertness, which makes them very good nanocarrier system to deliver multi-functional drugs effectively. A huge number of researchers worldwide are working on CDs-based drug delivery systems to evaluate their versatility and efficacy in the field of pharmaceuticals. As a result, there is a tremendous increase in our understanding of the physicochemical properties, diagnostic and drug delivery aspects of CDs, which consequently has led us to design and develop CDs-based theranostic system for the treatment of multiple disorders. In this review, we aim to summarize the advances in application of CDs as nanocarrier including gene delivery, vaccine delivery and antiviral delivery, that has been carried out in the last 5 years.

Understanding the aggregation of excitation wavelength independent emission of amphiphilic carbon dots for bioimaging and organic acid sensing

Herein, excitation wavelength-independent, tunable emissive and amphiphilic CDs with high quantum yield were synthesized by a low-temperature oxidation method employing banana peel waste as a carbon source. These CDs showed longer wavelength emissions (green to yellow) independent of the excitation wavelength when dispersed in different polar to non-polar solvents. The quantum yields of the same CDs were 9-32% in different solvent polarities for different emissions. On the other hand, a large stokes-shifted emission (∼9606 cm^-1) was observed for CDs in the non-polar and weak polar solvents. The particle size of CDs increases from a hydrophobic to a hydrophilic environment with the change in emission colour from yellow to green. A polar and a non-polar host matrix were used to overcome the limitation of aggregation-caused quenching of CDs in the solid state to obtain bright emissions. These CDs were potentially used for naked-eye detection of trifluoroacetic acid (TFA) by changing the emission colour from yellow to orange under UV 365 nm. Sensing of TFA was also shown reversibly switch emission colour and average lifetime for multiple cycles. Additionally, the highly emissive CDs show negligible cytotoxicity in 3T3 fibroblast cells, indicating possible bioimaging applications in 3T3 cells.

Fluorescent carbon dots tailored iron oxide nano hybrid system forin vivooptical imaging of liver fibrosis

Hybrid nanoparticles are innovative invention of last decade designed to overcome limitations of single-component nanoparticles by introducing multiple functionalities through combining two or more different nanoparticles. In this study, we are reporting development of magneto-fluorescent hybrid nanoparticles by combining iron oxide and carbon nanoparticles to enablein vivofluorescence imaging which also has all the required characteristic properties to use as Magnetic Resonance Imaging (MRI) contrast agent. In order to achieve dual-functional imaging, alginate and pullulan coated super paramagnetic iron oxide nanoparticles (ASPION and PSPION) and Carbon dots (Cdts) were synthesised separately. ASPIONs and PSPIONs were further chemically conjugated with Cdts and developed dual-functional nanohybrid particles ASPION-Cdts and PSPION-Cdts. Subsequently, evaluation of the materials for its size, functionalisation efficiency, fluorescence and magnetic properties, biocompatibility and cellular uptake efficiency has been carried out. Fluorescence imaging of liver fibrosis was performedin vivoin rodent model of liver fibrosis using the two nanohybrids, which is further confirmed by high fluorescence signal from the harvested liver.

Water Soluble PMPC-Derived Bright Fluorescent Nitrogen/Phosphorous-Doped Carbon Dots for Fluorescent Ink (Anti-Counterfeiting) and Cellular Multicolor Imaging

Here, a simple one-step hydrothermal-assisted carbonization process was adopted for the preparation of nitrogen/phosphorous-doped carbon dots from a water-soluble polymer, poly 2-(methacryloyloxy)ethyl phosphorylcholine (PMPC). By the free-radical polymerization method, PMPC was synthesized using 2-(methacryloyloxy)ethyl phosphorylcholine (MPC) and 4,4′-azobis (4-cyanovaleric acid). The water-soluble polymers, PMPC, that have nitrogen/phosphorus moieties are used to prepare carbon dots (P-CDs). The resulting P-CDs were thoroughly characterized by various analytical techniques such as field emission-scanning electron microscopy (FESEM) with energy-dispersive X-ray spectroscopy (EDS), high-resolution transmittance electron microscopy (HRTEM), X-ray diffraction (XRD), Raman spectroscopy, attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), Ultraviolet-visible (UV-vis) spectroscopy and fluorescence spectroscopy to determine their structural and optical properties. The synthesized P-CDs displayed bright/durable fluorescence, were stable for long periods, and confirmed the enrichment of functionalities including oxygen, phosphorus, and nitrogen heteroatoms in the carbon matrix. Since the synthesized P-CDs showed bright fluorescence with excellent photostability, excitation-dependent fluorescence emission, and excellent quantum yield (23%), it has been explored as a fluorescent (security) ink for drawing and writing (anti-counterfeiting). Further, cytotoxicity study results advised for biocompatibility and thus were used for cellular multicolor imaging in nematodes. This work not only demonstrated the preparation of CDs from polymers that can be used as advanced fluorescence ink, a bioimaging agent for anti-counterfeiting, and cellular multicolor imaging candidate, but additionally prominently opened a new perspective on the bulk preparation of CDs simply and efficiently for various applications.

Carbon-Based Fluorescent Nano-Biosensors for the Detection of Cell-Free Circulating MicroRNAs

Currently, non-communicable diseases (NCDs) have emerged as potential risks for humans due to adopting a sedentary lifestyle and inaccurate diagnoses. The early detection of NCDs using point-of-care technologies significantly decreases the burden and will be poised to transform clinical intervention and healthcare provision. An imbalance in the levels of circulating cell-free microRNAs (ccf-miRNA) has manifested in NCDs, which are passively released into the bloodstream or actively produced from cells, improving the efficacy of disease screening and providing enormous sensing potential. The effective sensing of ccf-miRNA continues to be a significant technical challenge, even though sophisticated equipment is needed to analyze readouts and expression patterns. Nanomaterials have come to light as a potential solution as they provide significant advantages over other widely used diagnostic techniques to measure miRNAs. Particularly, CNDs-based fluorescence nano-biosensors are of great interest. Owing to the excellent fluorescence characteristics of CNDs, developing such sensors for ccf-microRNAs has been much more accessible. Here, we have critically examined recent advancements in fluorescence-based CNDs biosensors, including tools and techniques used for manufacturing these biosensors. Green synthesis methods for scaling up high-quality, fluorescent CNDs from a natural source are discussed. The various surface modifications that help attach biomolecules to CNDs utilizing covalent conjugation techniques for multiple applications, including self-assembly, sensing, and imaging, are analyzed. The current review will be of particular interest to researchers interested in fluorescence-based biosensors, materials chemistry, nanomedicine, and related fields, as we focus on CNDs-based nano-biosensors for ccf-miRNAs detection applications in the medical field.

Picomolar Detection of Lead Ions (Pb2+) by Functionally Modified Fluorescent Carbon Quantum Dots from Watermelon Juice and Their Imaging in Cancer Cells

Water contamination due to the presence of lead is one of the leading causes of environmental and health hazards because of poor soil and groundwater waste management. Herein we report the synthesis of functionally modified luminescent carbon quantum dots (CQDs) obtained from watermelon juice as potential nanomaterials for the detection of toxic Pb²⁺ ions in polluted water and cancer cells. By introducing surface passivating ligands such as ethanolamine (EA) and ethylenediamine (ED) in watermelon juice, watermelon-ethanolamine (WMEA)-CQDs and watermelon-ethylenediamine (WMED)-CQDs exhibited a remarkable ~10-fold and ~6-fold increase in fluorescence intensity with respect to non-doped WM-CQDs. The relative fluorescence quantum yields of WMEA-CQDs and WMED-CQDs were found to be 8% and 7%, respectively, in an aqueous medium. Among various functionally-modified CQDs, only WMED-CQDs showed high selectivity towards Pb²⁺ ions with a remarkably good limit of detection (LoD) of 190 pM, which is less than that of the permissible limit (72 nM) in drinking water. The functionally altered WMED-CQDs detected Pb²⁺ metal ions in polluted water and in a human cervical cancer cell line (HeLa), thus advocating new vistas for eco-friendly nanomaterials for their use as diagnostic tools in the environment and biomedical research areas.

Green synthesis of multifunctional carbon quantum dots: An approach in cancer theranostics

Carbon quantum dots (CQDs) have gained significant growing attention in the recent past due to their peculiar characteristics including smaller size, high surface area, photoluminescence, chemical stability, facile synthesis and functionalization possibilities. They are carbon nanostructures having less than 10 nm size with fluorescent properties. In recent years, the scientific community is curiously adopting biomass precursors for the preparation of CQDs over the chemical compounds. These biomass sources are sustainable, eco-friendly, inexpensive, widely available and convert waste into valuable materials. Hence in our work the fundamental understating of diverse fabrication methodologies of CQDs, and the types of raw materials employed in recent times, are all examined and correlated comprehensively. Their unique combination of remarkable properties, together with the ease with which they can be fabricated, makes CQDs as promising materials for applications in diverse biomedical fields, in particular for bio-imaging, targeted drug delivery and phototherapy for cancer treatment. The mechanism for luminescence is of considerable significance for leading the synthesis of CQDs with tunable fluorescence emission. Therefore, it is aimed to explore and provide an updated review on (i) the recent progress on the different synthesis methods of biomass-derived CQDs, (ii) the contribution of surface states or functional groups on the luminescence origin and (iii) its potential application for cancer theranostics, concentrating on their fluorescence properties. Finally, we explored the challenges in modification for the synthesis of CQDs from biomass derivatives and the future scope of CQDs in phototherapy for cancer theranostics.

An insight into the potentials of carbon dots for in vitro live-cell imaging: recent progress, challenges, and prospects

Carbon dots (CDs) are a strong alternative to conventional fluorescent probes for cell imaging due to their brightness, photostability, tunable fluorescence emission, low toxicity, inexpensive preparation, and chemical diversity. Improving the targeting efficiency by modulation of the surface functional groups and understanding the mechanisms of targeted imaging are the most challenging issues in cell imaging by CDs. Firstly, we briefly discuss important features of fluorescent CDs for live-cell imaging application in this review. Then, the newest modulated CDs for targeted live-cell imaging of whole-cell, cell organelles, pH, ions, small molecules, and proteins are elaborately discussed, and their challenges in these fields are explained.

A Review on Carbon Quantum Dot Based Semiconductor Photocatalysts for the Abatement of Refractory Pollutants

Photocatalysis is a green approach frequently utilised to eliminate a variety of environmentally hazardous refractory pollutants. Accordingly, the modification of semiconductor photocatalysts with Carbon Quantum Dots (CQDs) is of great importance for the treatment of such pollutants due to their attractive physical and chemical properties. CQDs are a perfect candidate to handle photocatalysts of high-performance since they operate as co-catalysts and as visible light harvesters. The higher separation rate of electron-hole pairs in the photocatalytic system is attributable to better photodegradation efficiency. This review classifies CQD based photocatalysts as pure, doped and composite materials and discusses the specific advantages of CQDs in visible light-driven photocatalysis. In this work, the versatile roles of CQDs in CQD-based photocatalytic systems are thoroughly discussed and s u mmarised.

Alternative animal models in predictive toxicology

Toxicity testing relies heavily on animals, especially rodents as part of the non-clinical laboratory testing of substances. However, the use of mammalians and the number of animals employed in research has become a concern for institutional ethics committees. Toxicity testing involving rodents and other mammals is laborious and costly. Alternatively, non-rodent models are used as replacement, as they have less ethical considerations and are cost-effective. Of the many alternative models that can be used as replacement models, which ones can be used in predictive toxicology? What is the correlation between these models and rodents? Are there standardized protocols governing the toxicity testing of these commonly used predictive models? This review outlines the common alternative animal models for predictive toxicology to address the importance of these models, the challenges, and their standard testing protocols.

Designing of a pH-activatable carbon dots as a luminescent nanoprobe for recognizing folate receptor-positive cancer cells

During recent years, cancer has been recognized as a well-known disorder all over the world. One of the important factors to tackle this problem better than past decades is early diagnosis that takes into practice by state-of-the-art visual equipment for detection cancer cells. Herein, in this research, we synthesized carbon dots with pH-dependent behavior from a green source by hydrothermal method with high quantum yield and blue fluorescence. Folic acid-conjugated carbon dots by an efficient and optimal conjugation method were set upped which determined cancer cells visually. These synthesized and conjugated nanoparticles entered into the cancer cells more comprehensive than normal cells by receptor-mediated endocytosis and could distinguish cancer cells from normal ones by fluorescence imaging. Ultimately, synthesized nanoparticles in this research can be considered as an efficient fluorescent nanoprobe for cancer pre-diagnosis.

Beta vulgaris Assisted Fabrication of Novel Ag-Cu Bimetallic Nanoparticles for Growth Inhibition and Virulence in Candida albicans

Beta vulgaris extract contains water-soluble red pigment betanin and is used as a food colorant. In this study, the biogenic Ag-Cu bimetallic nanoparticles were synthesized and characterized by different spectroscopic and microscopic techniques, including UV-Visible, FTIR, TEM. SEM-EDX, XRD, and TGA. Further, Ag-Cu bimetallic nanoparticles capped with Beta vulgaris biomolecules were evaluated for their antifungal activity against Candida albicans via targeting its major virulence factors, including adherence, yeast to hyphae transition, extracellular enzyme secretion, biofilm formation, and the expression of genes related to these pathogenic traits by using standard methods. C. albicans is an opportunistic human fungal pathogen that causes significant morbidity and mortality, mainly in immunocompromised patients. The current antifungal therapy is limited with various shortcomings such as host toxicity and developing multidrug resistance. Therefore, the development of novel antifungal agents is urgently required. Furthermore, NPs were screened for cell viability and cytotoxicity effect. Antifungal susceptibility testing showed potent antifungal activity of the Ag-Cu bimetallic NPs with a significant inhibitory effect on adherence, yeast to hyphae transition, extracellular enzymes secretion, and formation of biofilms in C. albicans at sub-inhibitory and inhibitory concentrations. The RT-qPCR results at an MIC value of the NPs exhibited a varying degree of downregulation in expression levels of virulence genes. Results also revealed the dose-dependent effect of NPs on cellular viability (up to 100%) using MUSE cell analyzer. Moreover, the low cytotoxicity effect of bimetallic NPs has been observed using haemolytic assay. The overall results indicated that the newly synthesized Ag-Cu bimetallic NPs capped with Beta vulgaris are proven to possess a potent anticandidal activity, by affecting the vital pathogenic factors of C. albicans.

Multifunctional N-Doped Carbon Dots for Bimodal Detection of Bilirubin and Vitamin B12, Living Cell Imaging, and Fluorescent Ink

A N-doped carbon dot (NCD) has been synthesized via a simplistic one-step hydrothermal technique using l-aspartic acid and 3,6-diaminoacridine hydrochloride. The NCDs exhibit a high quantum yield (22.7%) and excellent optical stability in aqueous media. Additionally, NCDs display good solid-state yellowish-green emission and are suitable for security ink applications. The remarkable fluorescence (FL) properties of NCDs are further applied to develop a multifunctional sensor for bilirubin (BR) and vitamin B₁₂ (VB12) via fluorescence quenching. We have systematically studied the FL quenching mechanisms of the two analytes. The primary quenching mechanism of BR is via the Förster resonant energy transfer (FRET) pathway facilitated by the H-bonding network between the hydrophilic moieties existing at the surface of BR and NCDs. In contrast, the inner filter effect (IFE) is mainly responsible for the recognition of VB12. The practicability of the nanoprobe NCDs is further tested in real-sample analysis for BR (human serum and urine samples) and VB12 (VB12 tablets, human serum, and energy drink) with a satisfactory outcome. The in vitro competency is also verified in the human cervical cancer cell line (HeLa cell) with negligible cytotoxicity and significant biocompatibility. This result facilitates the application of NCDs for bioimaging and recognition of VB12 in a living organism.

Review of gut nanotoxicology in mammals: Exposure, transformation, distribution and toxicity

Nanomaterials are increasingly used in food processing, daily necessities and other fields due to their excellent properties, and increase the environmental contamination. Human beings will inevitably come into contact with these nanomaterials through multiple exposure routes especially oral exposure. The intestine is an important organ for nutrient absorption and physiologic barrier, which may be the main target of nanoparticles (NPs) exposure. However, for a long time, research on the toxicity of NPs has mainly focused on organs such as liver, kidney and brain. There are few assessment data over the intestinal safety. Recently, as reported, NPs can be translocated to the intestinal part in mammals and would be distributed in different substructures of intestines, thus causing damage to the structure and function of the intestine, in which the gut microbiota and its metabolites play important roles. In addition, due to the special physiological environment of gut, nanomaterials will undergo complex transformations that may cause different biological effects from their original form. Therefore, this review aims to assess the potential adverse effects of NPs on intestine and its possible mechanisms through the results of in vivo mammalian experiments. In addition, the exposure pathway, biodistribution and biotransformation of NPs in the intestine are also considered. We hope this review will arouse people's attention to the intestinal nanotoxicology and provide basic information for further related studies.

You Don't Learn That in School: An Updated Practical Guide to Carbon Quantum Dots

Carbon quantum dots (CQDs) have started to emerge as candidates for application in cell imaging, biosensing, and targeted drug delivery, amongst other research fields, due to their unique properties. Those applications are possible as the CQDs exhibit tunable fluorescence, biocompatibility, and a versatile surface. This review aims to summarize the recent development in the field of CQDs research, namely the latest synthesis progress concerning materials/methods, surface modifications, characterization methods, and purification techniques. Furthermore, this work will systematically explore the several applications CQDs have been subjected to, such as bioimaging, fluorescence sensing, and cancer/gene therapy. Finally, we will briefly discuss in the concluding section the present and future challenges, as well as future perspectives and views regarding the emerging paradigm that is the CQDs research field.

Biocompatibility assessment of silver chloride nanoparticles derived from Padina gymnospora and its therapeutic potential

The objective of the present work was to improve the biological activity of Padina gymnospora. In the current study, silver chloride nanoparticles have been synthesized using the aqueous extract of Padina gymnospora and further characterized by ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy, x-ray powder diffraction, scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy and atomic force microscope. Further, the hemolytic activity and eco-toxicity of silver chloride nanoparticles analyzed. The synthesized silver chloride nanoparticles were found to be mono-dispersed and spherical with an average size of 11.5–32.86 nm. The particles showed an anticancer effect in a dose-dependent manner against breast cancer cell line (MCF-7 cell lines) (IC50 = 31.37 μg ml−1). In addition, it showed the larvicidal activity against Aedes aegypti at a lower dose (3.92 μg ml−1) than that of the aqueous extract (13.01 μg ml−1). Nanoparticles also exhibited greater antimicrobial activity for both bacterial and fungal pathogens. The synthesized silver chloride nanoparticles showed a maximum zone of inhibition, i.e., 31 mm for Candida albicans followed and 27 mm for vancomycin resistance Enterococcus faecalis.The results suggest the possible use of synthesized silver nanoparticles with P. gymnospora as therapeutic agent for breast cancer, dengue vector control and as antimicrobial agent.

Physiological effect of colloidal carbon quantum dots on Bursaphelenchus xylophilus

Bursaphelenchus xylophilus (B. xylophilus) is a dangerous plant pest which could result in Pine Wild Disease (PWD).

Carbon dots-based nanocarrier system with intrinsic tumor targeting ability for cancer treatment

Doxorubicin (DOX) is a traditional broad-spectrum antitumor drug, which has a wide range of clinical applications, but has no tumor non-specificity. Nanoparticles have been explored as drug delivery agents to enhance the therapeutic efficacy and reduce toxic and side effects. Carbon dots (CDs), a carbon-based nanomaterial, has many unique advantages such as easy synthesis, good biocompatibility, and low toxicity. In this study, folic acid was used as raw material to prepare new CDs, and DOX was loaded on the surface of CDs through electrostatic interaction. The prepared nano-drugs CDs/DOX could effectively release DOX under mild acidic pH stimulation. Cell imaging showed that CDs/DOX could transport doxorubicin (DOX) to cancer cells and make them accumulated in nucleus freely. Flow cytometry tests and cellular toxicity assay together confirmed that CDs/DOX could target tumor cells with high expression of folate receptor and increase anti-tumor activity. The therapeutic effect on 4T1 tumor-bearing mice model indicated that CDs/DOX could alleviate DOX-induced toxicity, effectively inhibit tumor growth, and prolong the survival time. Hence, such a targeting nanocarrier is likely to be a candidate for cancer treatment.

Engineering the surface of graphene oxide with bovine serum albumin for improved biocompatibility in Caenorhabditis elegans

Graphene oxide (GO) has been extensively studied for its potential biomedical applications. However, its potential risk associated with the interactions of GO in a biological system hampers its biomedical applications. Therefore, there is an urgent need to enhance the biocompatibility of GO. In the present study, we decorated the surface of GO with bovine serum albumin (GO-BSA) to mitigate the in vivo toxic properties of GO. An in vivo model Caenorhabditis elegans has been used to study the potential protective effect of BSA decoration in mitigating GO induced toxicity. The BSA decoration on the surface of GO prevents the acute and prolonged toxicity induced by GO in primary and secondary organs by maintaining normal intestinal permeability, defecation behavior, development, and reproduction. Notably, GO-BSA treatment at 0.5-100 mg L^-1 does not affect the intracellular redox status and lifespan of C. elegans. Reporter gene expression analysis revealed that exposure to GO-BSA (100 mg L^-1) did not significantly influence the nuclear accumulation and expression patterns of DAF-16/FOXO and SKN-1/Nrf2 transcription factors and their downstream target genes sod-3, hsp-16.2, ctl-1,2,3, gcs-1, and gst-4 when compared to exposure to pristine GO. Also, quantitative real-time PCR results showed that GO-BSA did not alter the expression of genes involved in regulating DNA damage checkpoints (cep-1, hus-1 and egl-1) and core signaling pathways of apoptosis (ced-4, ced-3 and ced-9), in contrast to GO treatment. All these findings will have an impact on the future development of safer nanomaterial formulations of graphene and graphene-based materials for environmental and biomedical applications.

A Perspective on Application of Carbon Quantum Dots in Luminescence Immunoassays

Quantum dots (QDs) have been established in our daily life, for instance, in display screens and light-harvesting technologies, mainly owing to their peculiar opto-electronic features. However, toxicity of inorganic QDs, such as CdSe, CdTe, and perovskites, limits their applications in biological environments for medical diagnosis and bio-imaging purposes. A new generation of QDs called carbon quantum dots (CQDs) have been progressing rapidly over the past few years. CQDs have become as popular as other carbon-based nanomaterials such as carbon nanotubes (CNTs), due to their ease of preparation, ultra-small size, biocompatibility, and bright luminescence.

Sensor and Bioimaging Studies Based on Carbon Quantum Dots: The Green Chemistry Approach

Since carbon quantum dots have high photoluminescent efficiency, it has been a desired material in sensor and bioimaging applications. In recent years, the green chemistry approach has been preferred and the production of quantum dots has been reported in many studies using different precursors from natural, abundant, or waste sources. Hydrothermal, chemical oxidation, microwave supported, ultrasonic, solvothermal, pyrolysis, laser etching, solid-state, plasma, and electrochemical methods have been reported in the literature. In this review article, green chemistry strategies for carbon quantum dot synthesis is summarized and compared with conventional methods using methodologic and statistical data. Furthermore, a detailed discussion on sensor and bioimaging applications of carbon quantum dots produced with green synthesis approaches are presented with a special focus on the last decade.

Carbon quantum Dot@Silver nanocomposite-based fluorescent imaging of intracellular superoxide anion

Silver nanoparticle (Ag NP)-coated carbon quantum dot (CQD) core-shell-structured nanocomposites (CQD@Ag NCs) were developed for fluorescent imaging of intracellular superoxide anion (O₂^•-). The morphology of CQD@Ag NCs was investigated by transmission electron microscopy, and the composition was characterized by X-ray diffraction and X-ray photoelectron spectroscopy. CQDs display blue fluorescence with excitation/emission maxima at 360/440 nm, and the fluorescence was quenched by Ag NPs in CQD@Ag NCs. In the presence of O₂^•-, Ag NPs were oxide-etched and the fluorescence of CQDs was recovered. A linearity between the relative fluorescence intensity and O₂^•- solution concentration within the range 0.6 to 1.6 μM was found, with a detection limit of 0.3 μM. Due to their high sensitivity, selectivity, and low cytotoxicity, the as-synthesized CQD@Ag NCs have been successfully applied for imaging of O₂^•- in MCF-7 cells during the whole process of autophagy induced by serum starvation. In our perception, the developed method provides a cost-effective, sensitive, and selective tool in bioimaging and monitoring of intracellular O₂^•- changes, and is promising for potential biological applications. Graphical abstract Illustration of the synthesis of carbon quantum Dot@Silver nanocomposites (CQD@Ag NCs), and CQD@Ag NCs as a "turn-on" nanoprobe for fluorescent imaging of intracellular superoxide anion.

Fluorescent Carbon Dots for Selective Labeling of Subcellular Organelles

With the recent advancement in understanding and control of the structure and optical properties of fluorescent carbon dots (CDs), they have been shown to be valuable in biolabeling of bacteria, tumor cells, tissues, and organelles. Their extremely small size and tunable functional properties coupled with ultrastable fluorescence enable CDs to be used for easy and effective labeling of various organelles. In addition, CDs with advantages of easy preparation and functionalization with recognition elements and/or drugs have emerged as nanocarriers for organelle-targeted drug delivery. In this review, we mainly discuss the applications of fluorescent CDs for the labeling of organelles, including lysosome, nucleoli, nucleus, endoplasmic reticulum, and mitochondria. We highlight the importance of the surface properties (functional groups, hydrophobicity/hydrophilicity, charges, zwitterions) and the size of CDs for labeling. Several interesting examples are provided to highlight the potential and disadvantages of CDs for labeling organelles. Strategies for the preparation of CDs for specific labeling of organelles are suggested. With the edge in preparation of diverse CDs, their potential in labeling and drug delivery is highly expected.

A facile microwave-assisted synthesis of highly crystalline red carbon dots by adjusting the reaction solvent for white light-emitting diodes

Microwave approach has been widely used for the synthesis of fluorescent carbon dots (CDs) due to its advantages of short reaction time and homogeneous heating. Currently, it is still difficult to synthesize red light-emitting CDs (R-CDs) via the microwave-assisted method at atmospheric pressure. Herein, we report a solvent-controlled synthesis of R-CDs using domestic microwave. As a result, for an ammonium citrate tribasic, formamide and glycerol blend reaction solvent, the R-CDs with emission peak of 622 nm were achieved and exhibited a photoluminescence (PL) quantum yield of 37.4% and excitation-independent PL emission spectrum. During the formation process of R-CDs, glycerol and formamide not only promote the carbonization of ammonium citrate tribasic, but can also enhance the crystalline nature of CDs. Finally, the warm white light-emitting diode (WLED) with a high colour rendering index (CRI) of 90.9 and Commission Internationale de L'Eclairage (CIE) coordinates of (0.344, 0.333) was realized by combining conventional yellow YAG:Ce phosphor and R-CDs/mesoporous silica (MPS) composites with a blue chip. This result demonstrates a low-cost R-CD synthetic method for potential substitution for red phosphor materials in solid-state lighting applications.

Sensitive detection of carcinoembryonic antigen (CEA) by a sandwich-type electrochemical immunosensor using MOF-Ce@HA/Ag-HRP-Ab2 as a nanoprobe

Sandwich-type electrochemical immunosensor was one of the main methods for detecting carcinoembryonic antigen (CEA). In this work, using Ce-MoF as the skeleton precursor, hyaluronic acid (HA) was coated on the surface of Ce-metal organic framework (Ce-MoF), which loaded with silver nanoparticles (Ag NPs) and horseradish peroxidase (HRP) to catalyze H₂O₂ and double amplified the current signal. Thus, a sensitive sandwich-type electrochemical immunosensor (Ce-MoF@ HA/Ag-HRP) was designed to detect carcinoembryonic antigen (CEA). The designed immunosensor used Au NPs to enhance the ability of attach more the first antibody (Ab₁). This was due to Au NPs had good electrical conductivity and biocompatibility to accelerate electron transfer on the surface of the electrode. HA was riched in -COOH, -OH and had excellent biocompatibility, which can carry more Ag NPs to catalyze H₂O₂. Finally, the prepared sandwich-type electrochemical immunosensor had excellent biocompatibility and great catalytic performance. The immunosensor can be tested within 30 min and the logarithm of the current signal and CEA concentration showed a broad linear response range of 1 pg ml^-1-80 ng ml^-1, and the detection limit of CEA was 0.2 pg ml^-1. More importantly, the proposed immunosensor had good reproducibility, selectivity, stability and without matrix effect. This confirmed that the proposed immunosensor had broad prospects in early clinical trials.

High-quality quantum dots for multiplexed bioimaging: A critical review

Bioimaging done using two or more fluorophores possessing different emission wavelengths can be termed as a multicolor/multiplexed bioimaging technique. Traditionally, images are captured sequentially using multiple fluorophores having specific excitation and emission. For this purpose, multifunctional nanoprobes, such as organic fluorophores, metallic nanoparticles, semiconductor quantum dots, and carbon dots (CDs) are used. Among these fluorophores, quantum dots (QDs) have emerged as an ideal probe for multiplexed bioimaging due to their unique property of size tunable emission. However, the usage of quantum dots in bioimaging is limited due to their toxicity. Furthermore, the reproducibility of optical properties is cynical. These desirable properties, along with enhancement in quantum efficiency, photostability, fluorescence lifetime, etc. can be achieved by stringent control over synthesis parameters. This review summarizes the desirable properties and synthesis methods of such superior QDs followed by their application in multiplexed imaging.

In situ green synthesis of highly fluorescent Fe2 O3 @CQD/graphene oxide using hard pistachio shells via the hydrothermal-assisted ball milling method

In this study, highly photoluminescent and photocatalytic Fe₂ O₃ @carbon quantum dots/graphene oxide nanostructures were synthesized using ball milling-assisted hydrothermal synthesis with hard pistachio shells. Different analyses, such as X-ray diffraction, energy dispersive X-ray spectroscopy, and Fourier transform infrared spectroscopy were used to study the product structure. Scanning electron microscopy and transmission electron microscopy images were used to study product size and morphology. Optical properties of the as-synthesized nanomaterials were investigated using ultraviolet-visible light and photoluminescence analyses. To increase photoluminescence intensity, ethylene diamine tetraacetic acid, polyethylene glycol, polyvinylpyrrolidone, and acetylacetonate anions were used to modify the product surface. Thermal stability of the product was studied using thermal gravimetric analysis. Finally, photocatalytic activity and surface adsorption of the product were investigated; the produce was found to be highly photoluminescent with high photocatalytic and surface activities.

Transfer of orally administered ZnO:Eu nanoparticles through the blood-testis barrier: the effect on kinetic sperm parameters and apoptosis in mice testes

Zinc-based nanoparticles are promising materials for various applications, including in biomedicine. The aim of our study was to determine the effect of fluorescent europium-doped zinc oxide nanoparticles (ZnO:Eu NPs) on sperm parameters, cell apoptosis and integrity of the blood-testis barrier (BTB) in mice. Nanostructures were orally administered to adult mice (n = 34). Animals were sacrificed after 3 h, 24 h, 7 d and 14 d following oral administration. Sperm was collected and analysed for viability and kinetic parameters. Collected testes were quantitatively analysed for accumulation of ZnO:Eu NPs. Microscopic evaluation based on immunofluorescence and histopathological studies were also conducted. Results showed that ZnO:Eu NPs were able to overcome the BTB with their subsequent accumulation in the testis. No toxic or pro-apoptotic effects of nanoparticles on the male reproductive system were observed. The results suggested that ZnO:Eu NPs were able to accumulate in the testis with no negative impact on sperm parameters, tissue architecture or the integrity of the BTB.

Fabrication of carbon dots@restricted access molecularly imprinted polymers for selective detection of metronidazole in serum

A custom-tailored design was proposed for the fabrication of carbon dots coupled with restricted access materials and molecularly imprinted polymers (CDs@RAM-MIPs) to detect metronidazole (MNZ). Biomass carbon dots (CDs) were derived from longan peels assisted with high pressure microwave, and had the merits of eco-friendly, excellent photostability and low toxicity. In this work, glycidyl methacrylate was used as a co-polymeric monomer to increase hydroxyl groups on the surface of synthetic materials, which eliminated the interference of biological macromolecules. The specific binding cavities of CDs@RAM-MIPs were formed after removing the template molecule (MNZ). The obtained CDs@RAM-MIPs can selectively capture MNZ through the specific interaction between recognition sites and MNZ, and obey photoinduced electron transfer fluorescence quenching mechanism. The highly sensitive and selective fluorescent sensor based CDs@RAM-MIPs had a wide linear range (50-1200 ng mL^-1) and a low detection limit (17.4 ng mL^-1) for MNZ. It has been utilized to detect MNZ in serum with recoveries of 93.5%-102.7%, and the relative standards (RSDs) were 1.9%-3.6%, respectively. This work provides a thoughtful strategy for preparation and application of CDs@RAM-MIPs, which presages its great potential for detecting trace compounds in real samples.