Valorization of dragon fruit peel into advanced functional carbon quantum dot/betalain composite films for smart and active beef packaging.

Development of carbon quantum dot-human IgG fluorescent nanobioprobes for smartphone-enabled sensitive and quantitative immunodiagnostics.

Silicon dioxide in nano-luminescent materials: Enhancing stability, structural regulation, and functional expansion.

An "inside-outside" synergistic modification strategy is proposed to construct a photoelectrochemical (PEC) sensing platform based on a boron-doped carbon nitride/nitrogen-doped carbon quantum dot (BCN/NCQDs) heterojunction. The inside modification refers to boron doping within graphitic carbon nitride to modulate its electronic structure, narrowing the bandgap and extending visible light absorption. The outside modification involves the formation of a 0D/2D heterointerface with NCQDs, which establishes a built-in electric field to facilitate directional charge separation. Material characterization shows that the heterojunction exhibits a photocurrent response of approximately 1100 nA and enhanced charge separation efficiency. An aptamer-functionalized PEC sensor was fabricated for the detection of sulfadiazine, yielding a linear range from 0.01 to 1000ng/mL and a detection limit of 2.7pM. The sensor shows selectivity, reproducibility (RSD = 3.253%), and stability in operation. In real water and milk samples, recoveries range from 98.53 to 104.73%, consistent with chromatographic methods. This work presents a strategy for designing photoelectrochemical materials and biosensors.

Multifunctional red fluorescence−emitting carbon quantum dots functionalized with boronic acid groups for highly sensitive “on−off−on” detection of Fe3+ and L−cysteine, antibacterial and bacterial imaging

Synthesis of N,P co-doped carbon quantum dots for the ultrasensitive detection and enhanced visible-light photocatalytic degradation of atrazine

Evanescent wave-based fiber optic sensing of humidity with linear fast response via hierarchically assembled porous yttrium chloride-doped carbon quantum dot films

Enhanced capacity and selectivity of carbon quantum dots integrated NU-1000 MOF for CO2 capture

One-step microwave-assisted synthesis of nitrogen-doped carbon quantum dots for highly sensitive and selective fluorescence detection of mercury (II) ion in food.

Eco-friendly carbon quantum dots from agro-waste to enhance TiO2 photocatalytic and antibacterial efficiency

Advancements in nanocomposites of carbon quantum dots from kaffir lime leaves and zinc oxide nanoparticles for enhanced ultraviolet shielding and antioxidant applications

We developed N-doped carbon quantum dots (N-CQDs) as both photocathode modifiers and electrolytes for self-powered portable photoelectrochemical (PEC) cells to generate electricity under visible-light illumination. Using betaine-type Meldonium precursor, and either ethylenediamine, N,N-dimethylformamide or NH3·H2O as a nitrogen source deliver three different N-CQDs featuring both surface-negatively-charged and positively-charged groups. Due to structural-directing template functionality of ethylenediamine, N-CQDs(en) incorporates the highest pyridinic-N content, which facilitates the charge conductivity and fine-regulates the reaction selectivity within Csp2-frameworks. As semiconductor-coatings electrodeposited on Cu2O, N-CQDs(en) integrate with Cu2O into heterojunctions (N-CQDs(en)/Cu2O) to improve charge separation and promote 4e- oxygen-reduction into water. Importantly, encapsulating an aqueous solution containing N-CQDs(en) in a gelatin/sodium L-pyroglutamate-derived conductor gives a quasi-solid-state electrolyte that facilitates the charge migration, improving the electrodes-electrolytes interfacial incompatibility, while also possibly helping to in situ complement active sites on the modified photocathode. Coupled with a FeNiOOH/FeN-decorated BiVO4 photoanode, enabling the efficient 4e- water oxidation, the complete system establishes a self-sustaining H2O-O2-H2O cycle. The resulting PEC cell shows impressive electricity output for over 120h under irradiation, enough to power some small electronics. Unlike conventional photovoltaics, this cell is moisture-tolerant, oxidation-resistant and concurrently harnesses light and chemical energy, presenting a new paradigm for next-generation light-to-electricity conversion.

With the increasingly prominent role of information security in data confidentiality, a variety of information encryption strategies have emerged. Herein, a dual-channel information encryption strategy based on lanthanide ions and carbon quantum dots (CQDs) is proposed, which significantly enhances the security of information encryption. In this system, a luminescent lanthanide material is prepared through lanthanide ions and dynamic covalent bond surfactants. With further introduction of CQDs, the significant difference in excitation wavelengths between lanthanide ions and CQDs (365 nm for CQDs and 254 nm for Eu3+/Tb3+) enables the realization of excitation wavelength-channel information encryption. Owing to the chemical reaction and coordination effects at specific pH levels regulated by the hydrolysis time of d-(+)-gluconic acid δ-lactone (δ-GL), the fluorescence intensity exhibits time-dependent tunability, thus achieving the time-gated channel information encryption strategy. Decryption requires the simultaneous acquisition of wavelength and time keys, providing a novel strategy for the development of intelligent and high-security dynamic encryption materials.

Planar zinc oxide (ZnO) based ultraviolet (UV) photodetectors are emerging for low-power optoelectronic applications but often suffer from limited responsivity due to surface recombination and inefficient carrier separation. In this work, we demonstrate vertically aligned ZnO nanorods (ZNRs) coated with nitrogen-doped carbon quantum dots (NCQDs) hybrid UV photodetector. Compared to the (zinc oxide thin film) ZTF device, which exhibits a photocurrent density on the order of 10-5 Acm-2 at ±1 V, the ZNR device shows improved light absorption and directional charge transport, yielding a photocurrent density of ∼10-4 Acm-2 and an external quantum efficiency (EQE) of ∼75%. Upon incorporation of NCQDs, the photocurrent density increases by more than two orders of magnitude, reaching the 10-2 Acm-2 range, accompanied by a responsivity exceeding 2 AW-1 and an EQE approaching 730%. This pronounced enhancement is attributed to stepwise conduction band alignment that promotes electron accumulation in the ZnO channel, along with CQD-induced surface passivation and long-lived interfacial trapping. These results highlight the importance of vertically oriented architecture, interfacial band engineering and controlled carrier trapping in realizing high-gain ZnO-based UV photodetectors, offering a scalable strategy for low-power next-generation optoelectronic platforms.

Carbon Quantum Dots (CQDs) represent a versatile class of biocompatible nanomaterials for photodynamic therapy (PDT). In present study, nitrogen-doped carbon quantum dots derived from the polyfloral resources of R. indica and H. rosa-sinensis (N-PFCQDs) were prepared and chemically characterized via different spectroscopic techiniques. N-PFCQDs were studied for their photodynamic antimicrobial and anticancer effects upon blue light exposure for different time intervals. Agar well diffusion assay demonstrated a light and time-dependent increase in their antimicrobial potential against Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Bacillus subtilis and Aspergillus niger with a zone of inhibition (mm) ranging from 14.8 ± 0.46 at 0min to 29.8 ± 0.44 at 90min of exposure time for bacterial strains and for fungal strains ranging from 13.8 ± 0.16 at 0min to 23.1 ± 0.21. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) analysis identified their potential for high levels of bactericidal action for Staphylococcus aureus (MIC: 15.2 to 7.3mg/L and MBC: 30.3 to 18.2mg/L) and Escherichia coli (MIC: 16.2 to 8.1mg/L and MBC: 29.8 to 19.3mg/L) upon exposure to blue light from 0 to 90min time interval. The combined treatment of conventional antibiotics with blue-light-activated N-PFCQDs revealed the enhancement of bacterial susceptibility. Under PDT, N-PFCQDs effectively inhibited Staphylococcus aureus and Pseudomonas aeruginosa biofilm formation, achieving up to 96.33 ± 1.20% and 98.67 ± 0.88% respectively. In addition, the concentration and time-dependent cytotoxicity effect was observed by utilizing the PDT approach with ROS generation on HepG2 cancer cells. Over all, these results demonstrate the effectiveness of N-PFCQDs as photosensitizing agents for therapeutic potential.

The high structural similarity of antibiotics and interference from complex environmental matrices significantly hinder the precise identification and detection. Herein, carbon quantum dots (CQDs) were synthesized using o-phenylenediamine and 2,2'-Azobis(2,4-dimethylvaleronitrile) as precursors via microwave-assisted pyrolysis, and two types of CQDs with distinct fluorescent properties (DIW-CQDs and FA-CQDs) were prepared by dispersion in deionized water (DIW) and formic acid (FA), respectively. S1-CQDs were synthesized by compositing CQDs with Rhodamine B (RhB), exhibiting dual-emission fluorescence properties. S2-CQDs were obtained by blending DIW-CQDs and FA-CQDs. A single-component dual-channel sensor array was constructed using S1-CQDs as the sensing unit. The array collect the signals of ultraviolet (UV) and fluorescence, enabling the discrimination and detection of fluoroquinolone antibiotics (norfloxacin (NOR), ciprofloxacin (CIP), and ofloxacin (OFX)). Furthermore, a two-component four-channel sensor array was developed by employing S1-CQDs and S2-CQDs as sensing units, generating four distinct signals for the discrimination and detection of three antibiotic categories: tetracycline (TC), cefixime (CFM), and fluoroquinolones (NOR, CIP, and OFX). Combined with pattern recognition methods including linear discriminant analysis (LDA), hierarchical cluster analysis (HCA), and principal component analysis (PCA), the array achieved 100% accurate identification and quantitative detection of five antibiotics, with detection limits ranging from 3.9-14.0 nM. The LDA score plots revealed well-separated clusters for single antibiotics and their binary, ternary, and quaternary mixtures with intercluster Euclidean distances exceeding 3.0. This work provides a fluorescence/ultraviolet dual-signal sensor array strategy coupled with machine learning-assisted pattern recognition for efficient and reliable antibiotic analysis in complex matrices.

Green synthesized β-caryophyllene oxide enriched fraction-derived carbon quantum dots trigger ROS production and p53 activation in HepG2 cells.

Biomass-derived carbon quantum dots (BCDs) have attracted considerable research attention as a novel category of sustainable fluorescent nanomaterials, attributed to their adjustable photoluminescence, superior biocompatibility, and eco-friendly synthesis methods. BCDs are made from renewable biomass sources like plants, algae, animal byproducts, and microorganisms, following the principles of green chemistry. This makes them much better for the environment and cheaper to make than carbon dots made in the traditional way. The field still has three big problems, though: the luminescence mechanism is still not well understood, with different pathways like carbon-core and surface-state emissions not having a single theoretical framework; optical modulation strategies are still not well developed, with quantum yields often falling below 30% and poor batch-to-batch consistency making it hard to standardize applications; and not enough is known about in vivo metabolic pathways and long-term toxicity to allow for systematic toxicological evaluation and clinical translation. The complex luminescence mechanisms, including carbon-core-state, surface-state, molecular-state, and cross-linked enhanced emission (CEE), are thoroughly examined to clarify the structure-property relationships that dictate their optical behavior. By using controlled synthesis and surface modification techniques, BCDs can be made to emit light in the visible to near-infrared (NIR) range. This makes them perfect for use in different types of multimodal imaging, such as single-photon, multi-photon, and photoacoustic bioimaging. Their natural ability to emit light, along with their low toxicity to cells and high stability in light, makes it possible to see cells and tissues in high detail. We talk more about the problems we are having right now with standardizing synthesis and controlling optical properties with precision. Future research should concentrate on refining reaction conditions and clarifying luminescence mechanisms to promote the clinical application of BCDs as next-generation, sustainable imaging agents.

Infectious diseases are a major global health issue despite the development of antibiotics and chemotherapy. There is an unmet need for the development of novel therapeutic and diagnostic agents to combat emerging and multi-drug-resistant microorganisms. To overcome these issues, carbon-based quantum dots (QDs), i.e., carbon quantum dots (CQDs) and graphene quantum dots (GQDs), can be an alternative approach due to their diverse and distinct properties, such as chemical inertness, low toxicity, biocompatibility, and photostability. Engineered QDs (EQDs) prepared by integrating various moieties through doping, functionalization, surface passivation, or combination with antimicrobial substances have vast biological applications in the management of infectious diseases. The current review aims to comprehensively discuss the recent progress on pharmacological mechanisms and detection strategies of native QDs (CQDs and GQDs), and EQDs against a wide range of infectious disease-causing pathogens, namely, bacteria, viruses, fungi, and parasites. The major mechanisms of their action involve cell wall/membrane disruption, replication and transcription inhibition, excessive ROS generation, immune response pathway activation, and synergistic interactions with antimicrobial agents. In addition, EQDs integrated diverse detection strategies, including optical, nucleic acid, immune, lateral flow assay, electrochemistry, emphasizing their potential use as sensitive probes for the rapid monitoring of pathogens in biological and environmental samples. Finally, the evolving scenarios of regulatory requirements, potential toxicity, and challenges in their clinical translation are addressed in this review. The current review will certainly be useful in advancing research activities for developing new affordable antimicrobial drugs and diagnostic agents using native QDs/EQDs.

A dual-mode platform combining dual-emission fluorescence and electrochemical detection was developed for the isomer-selective sensing of p-nitrophenol (p-NP). Nitrogen-doped carbon quantum dots (N-CQDs) were functionalized with phosphate pillar[5]arene to produce P-CQDs, and host-guest assembly with acridine orange yielded P-CQDs@AO with dual emissions at 422 and 525 nm. p-NP selectively quenched both emissions, allowing fluorescence quantification over 0-60 μM with limits of detection of 0.265 μM (422 nm) and 0.476 μM (525 nm), while P-CQDs-modified electrodes enabled differential pulse voltammetric detection (10-200 μM, detection limit 3.58 μM). Tap water tests showed spiked recoveries of 97-103% with RSDs below 5% for both methods, confirming reliability for real-world applications. The orthogonal fluorescence/electrochemical readouts of the supramolecular host-guest-mediated dual-mode platform with improved selectivity among isomers enable accurate identification of p-NP.