Search Results (427)

Photodynamic therapy (PDT) is a non-invasive therapeutic method with over a century of medical use, especially in dermatology, ophthalmology, dentistry, and, notably, cancer treatment. With an increasing number of clinical trials, there is growing demand for innovation in PDT. Despite being a promising treatment for cancer and bacterial infections, PDT faces limitations such as poor water solubility of many photosensitizers (PS), limited light penetration, off-target accumulation, and tumor hypoxia. This review focuses on chlorins—well-established macrocyclic PSs known for their strong activity and clinical relevance. We discuss how nanotechnology addresses PDT’s limitations and enhances therapeutic outcomes. Nanocarriers like lipid-based (liposomes, micelles), polymer-based (cellulose, chitosan, silk fibroin, polyethyleneimine, PLGA), and carbon-based ones (graphene oxide, quantum dots, MOFs), and nanospheres are promising platforms that improve chlorin performance and reduce side effects. This review also explores their use in Antimicrobial Photodynamic Therapy (aPDT) against multidrug-resistant bacteria and in oncology. Recent in vivo studies demonstrate encouraging results in preclinical models using nanocarrier-enhanced chlorins, though clinical application remains limited. Full article

The main objective of this study is to improve heat transfer in hydrocarbon- and geothermal-energy coproduction systems using carbon quantum dots (CQDs). Two types of 0D nanoparticles (synthesized and commercial CQDs) were used for the formulation of nanofluids to increase the heat transfer from depleted wells for the coproduction of oil and electrical energy. The synthesized and commercial CQDs were characterized in terms of their morphology, zeta potential, density, size, and heat capacity. The nanofluids were prepared using brine from an oil well of interest and two types of CQDs. The effect of the CQDs on the thermophysical properties of the nanofluids was evaluated based on their thermal conductivity. In addition, a mathematical model based on heat transfer principles to predict the effect of nanofluids on the efficiency of the organic Rankine cycle (ORC) was implemented. The synthesized and commercial CQDs had particle sizes of 25 and 16 nm, respectively. Similarly, zeta potential values of 36 and 48 mV were obtained. Both CQDs have similar functional groups and UV absorption, and the fluorescence spectra show that the study CQDs have a maximum excitation–emission signal around 360–460 nm. The characterization of the nanofluids showed that the addition of 100, 300, and 500 mg/L of CQDs increased the thermal conductivity by 40, 50, and 60 %, respectively. However, the 1000 mg/L incorporated decreased the thermal conductivities of the nanofluids. The observed behavior can be attributed to the aggregate size of the nanoparticles. Furthermore, a new thermal conductivity model for CQD-based nanofluids was developed considering brine salinity, particle size distribution, and agglomeration effects. The model showed a remarkable fit with the experimental data and predicted the effect of the nanofluid concentration on the thermal conductivity and cycle efficiency. Coupled with an ORC cycle model, CQD concentrations of approximately 550 mg/L increased the cycle efficiency by approximately 13.8% and 18.6% for commercial and synthesized CQDs, respectively. Full article

Wastewater management has a direct impact on the supply of drinking water. New cutting-edge technologies are crucial to the ever-growing demand for tailored solutions for pollutant removal, but these pollutants first need to be detected. Traditional techniques are costly and are no longer competitive in the wastewater cleaning market. One sustainable and economically viable alternative is the fabrication of integrated nanosensors composed of conducting polymers. These include polyaniline doped with various types of nanomaterials such as nanocarbons (carbon nanotubes and graphene), metal oxide nanoparticles/nanostructures, and quantum dots. The synergistic properties of these components can endow sensing materials with enhanced surface reactivity, greater electrocatalytic activity, as well as tunable redox activity and electrical conductivity. This review covers key recent advances in the field of non-enzyme electrochemical conductive polymer nanosensors for pollutant detection in aqueous environments or simulated polluted samples. It provides an introduction to these sensors, their preparation, applications, the environmental and economic hurdles impeding the large-scale development of PANI-based nanomaterials in sensing applications, and future directions for research and real-world applications. Full article

Compared with acute wounds, typical chronic wounds (infection, burn, and diabetic wounds) are susceptible to bacterial infection and hard to heal. As for the complexity of chronic wounds, biocompatible hydrogel dressings can be employed to regulate the microenvironment and accelerate wound healing with their controllable physical and chemical properties. Recently, various nanomaterials have been introduced into hydrogel networks to prepare functional nanocomposite hydrogels. Among them, carbon-based nanomaterials (CBNs) have attracted wide attention in the biomedical field due to their outstanding physicochemical properties. However, comprehensive reviews on the use of CBNs for multifunctional hydrogel wound dressings in the past 10 years are very scarce. This review focuses on the research progress on hydrogel dressings made with typical CBNs. Specifically, a series of CBNs (carbon dots, graphene quantum dots, fullerenes, nanodiamonds, carbon nanotubes, graphene, graphene oxide and reduced graphene oxide) employed in the preparation of hydrogels are described as well as carbon-based nanocomposite hydrogels (CBNHs) with versatility (conductivity, antibacterial, injectable and self-healing, anti-inflammatory and antioxidant properties, substance delivery, stimulus response and real-time monitoring). Moreover, applications of CBNHs in treating different chronic wounds are concretely discussed. This review may provide some new inspirations for the future development of CBNHs in wound care and tissue engineering. Full article

Graphene quantum dots (GQDs) show significant promise as antibacterial agents, but their application is hindered by several limitations, including potential cytotoxicity at high concentrations, as well as concerns regarding aggregation and reusability. In this study, sodium titanate (NTO) ultralong nanotubes were utilized as both a photocatalyst and support for GQDs. The NTO/GQDs heterojunction was formed by embedding GQDs nanoplates onto the walls of NTO nanotubes. This integration significantly improved the visible light absorption and enhanced the separation and transfer of electron–hole pairs, leading to an efficient photocatalytic antibacterial process. The NTO/GQD-8 self-supporting membrane composed of these ultralong nanotubes demonstrated outstanding antibacterial efficiency (99.99%) against E. coli and exhibited remarkable cycling stability. Radical scavenging experiments revealed that ∙OH and e⁻ were the primary reactive species driving the photocatalytic antibacterial process. Notably, NTO and NTO/GQDs-8 exhibited distinct antibacterial outcomes. After photocatalytic treatment with NTO/GQDs-8, E. coli cells were completely fragmented, with no intact cell structures remaining due to the synergy effect of GQDs’ physical cutting during photocatalytic treatment. Full article

Ensuring effective water purification is essential for addressing freshwater scarcity and achieving the United Nations Sustainable Development Goals (SDGs). An efficient hybrid mixture, composed of FeCr quantum dots doped into mesoporous silica SBA-15 support and activated carbon (AC) derived from olive mill solid wastes, has been developed for treating high optical density polluted aqueous environments. This hybrid, denoted as FeCr-SBA-15/AC, was examined for its efficacy in the adsorption and photo-Fenton degradation of met orange dye (MO), a model high-optical-density pollutant, under visible light exposure. Characterization of the prepared samples was conducted using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Brunauer–Emmett–Teller (BET) surface area analysis, diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Key parameters investigated included catalyst dosage, dye concentration, solution pH, and H₂O₂ concentration. Remarkably, the FeCr-SBA-15/AC hybrid exhibited superior photocatalytic activity, achieving a degradation efficiency of 97% for MO under optimized conditions (catalyst dosage = 0.75 g L⁻¹, dye concentration = 20 mg L⁻¹, pH = 5.47, and 0.5 mL H₂O₂) after 180 min of irradiation with visible light. This performance surpassed that of FeCr-SBA-15 alone by 20%, due to the synergistic effects of adsorption and photo-Fenton. The adsorption of MO onto AC followed the Freundlich model equilibrium isotherm, while the experimental data for the hybrid mixture aligned well with the pseudo-first-order Langmuir–Hinshelwood kinetic model with a rate constant of 0.0173 min⁻¹. The leaching of Cr in the solution was very low—0.1 ppm—which is below the detection limit. These findings underscore the potential of the synthesized FeCr-SBA-15/AC hybrid as a cost-effective, environmentally friendly, and highly efficient photo-Fenton catalyst for treating wastewater contaminated by industrial effluents. Full article

Arsenic is a well-known, highly toxic carcinogen element that is widely found in nature, with numerous studies highlighting its hazardous impact on human health and the environment. Therefore, considering its toxicity and adverse health effects on mammals and the environment, rapid, sensitive, and effective methods for the recognition of arsenic are necessary. Over the past decade, a variety of fluorescent probes, such as small molecules, nanomaterials, gold nanoparticles (AuNPs), carbon dots (CDs), quantum dots (QDs), and more, have been designed and successfully employed for the recognition of lethal arsenic. Compared to other conventional sensor materials, sensors based on metal-organic frameworks (MOFs) are advantageous due to their simple preparation, easy functional group modulation, large specific surface area, and excellent chemical stability. In recent years, MOFs have been utilized as dual-functional materials for the detection and adsorptive removal of arsenic from water. This unique functionality distinguishes MOF-based materials from conventional sensors and arsenic adsorbents. Herein, we provide an overview of the state-of-the-art knowledge on the current development of MOFs for the fluorogenic detection of arsenic in aqueous media. Furthermore, the underlying detection mechanisms are also summarized in this review. The existing challenges in this field and potential remedial strategies for improving detection are elaborated upon in the relevant sections. Full article

The structure of nitrofen is stable and resistant to natural degradation, persisting in environments for extended periods. It can accumulate through the food chain, posing risks to human health. Here, we report a sensor based on carbon quantum dots (CQDs) and molecular imprinting technology (CQDs@MIPs). It not only possesses the specificity and stability of MIPs but also incorporates the environmental friendliness and signal amplification capabilities of CQDs, making it an ideal material for the specific detection of nitrofen residues in the environment. The interaction between CQDs@MIPs and nitrofen, as well as the successful removal of nitrofen, were confirmed through transmission electron microscopy (TEM) and Zeta potential analysis, which evaluated the morphology and particle size of the prepared CQDs@MIPs. After binding with nitrofen, the CQDs@MIP sensor exhibited a low detection limit (2.5 × 10⁻³ mg·L⁻¹), a wide detection range (0.01–40 mg·L⁻¹), a good linear relationship (R² = 0.9951), and a short detection time (5 min). The CQDs@MIP sensor also demonstrated excellent stability, with the fluorescence intensity of CQDs@MIPs remaining above 90% of the initial preparation after 20 days. At the same time, Red, Green, Blue (RGB) color model extraction technology is used to fit the color of the sample under different concentrations, and the smart phone application is integrated to realize the visual detection of nitrofen. Furthermore, acceptable accuracy was achieved in real water samples (recovery rates ranging from 84.1% to 115.7%), indicating that our CQDs@MIP sensor has high analytical potential for real samples. Full article

An electrically injected vertical-cavity surface-emitting laser (VCSEL) with quantum-well-embedded InGaN quantum dots (QDs) as the active region was designed. The InGaN QD size and cavity length were optimized using PICS3D simulation software to achieve a high-performance InGaN QD-embedded VCSEL. A comparative analysis between the InGaN QD VCSEL and the traditional InGaN quantum well VCSEL was conducted, and the results demonstrated that the InGaN QD VCSEL achieved higher stimulated recombination radiation and internal quantum efficiency. The threshold current was reduced to 4 mA, corresponding to a threshold current density of 5.1 kA/cm², and the output power reached 4.4 mW at an injection current of 20 mA. A stable single-longitudinal-mode output was also achieved with an output wavelength of 436 nm. The proposed novel quantum-well-embedded QD active-region VCSEL was validated through theoretical simulations, confirming its feasibility. This study provides theoretical guidance and key epitaxial structural parameters for preparing high-performance VCSEL epitaxial materials. Full article

Graphene quantum dots (GQDs) represent a class of promising nanomaterials characterized by adjustable optical properties, making them well suited for applications in biosensing and chemical detection. However, challenges persist in achieving scalable, cost-effective synthesis and enhancing detection sensitivity. In this study, we have developed a simple and environmentally friendly method to prepare blue graphene quantum dots, c-GQDs, using nitronaphthalene as a precursor, and yellow graphene quantum dots, y-GQDs, using nitronaphthalene doped acid. The quantum yield is 29.75%, and the average thickness is 2.08 nm and 3.95 nm, respectively. The synthesized c-GQDs exhibit a prominent cyan fluorescence at a wavelength of 490 nm under excitation at 380 nm, while the y-GQDs show a distinct yellow fluorescence at a wavelength of 540 nm under excitation at 494 nm. The introduction of p-aminobenzoic acid (PABA) introduced a marked red shift in fluorescence, attributed to the electron-withdrawing effect of the carboxyl groups on PABA. This key finding significantly enhanced the sensitivity of GQDs for detecting trace copper(II) ions (Cu²⁺), a heavy metal contaminant posing serious environmental risks. The fluorescence of the GQDs was selectively quenched in the presence of Cu²⁺, facilitating accurate and sensitive detection even in complex ion matrices. Mechanistic studies revealed that the quenching effect is driven by strong static quenching interactions, which inhibit non-radiative transitions. This work not only introduces a scalable method for producing high-performance GQDs but also highlights their potential as effective fluorescent probes for environmental monitoring and heavy metal ion detection. Full article

Energy storage devices are essential for enhancing the effectiveness and sustainability of electrical energy. Lithium-ion batteries (LIBs) are one of the most efficient energy storage solutions available. The choice of electrode materials plays a vital role in defining the performance of an energy storage device. A range of electrode materials have been developed utilizing both organic and inorganic substances. Due to their notable electrochemical characteristics, strong chemical stability, and well-established technological approaches, inorganic materials have been extensively studied to achieve high-performance devices. This review paper aims to provide a thorough and analytical review of different materials ranging from zero- to three-dimensional (3D), like quantum dots, nanotubes, and nanosheets that have been proposed for high-performance LIBs. This study also includes challenges and future pathways to address the issues with inorganic materials utilized as electrode materials for high-performance energy storage LIBs. Full article

Nanomaterials, including quantum dots, have gained more and more attention in the past few decades due to their extraordinary properties that make them useful for many applications, ranging from catalysis, energy generation and storage, biotechnology, and medicine to quantum informatics. Mathematical descriptions of the phenomena in which nanostructures are involved are of great demand because they may be utilized for the purpose of controlling these phenomena (e.g., the growth of nanostructures with certain sizes, shapes, and other properties). Such models may be of distinct nature, including calculations from first principles, ordinary and partial differential equations, and machine learning models (including artificial intelligence) as well. The aim of this article is to review the most important and useful computational and mathematical approaches for the description and control of processes involving nanostructures. Full article

Silicon photodetectors are well developed, with the advantage of their low cost and easy fabrication. However, due to the semiconductor band gap limitation, their detection wavelength is limited in the visible and near-infrared ranges. To broaden the detection wavelength, we stacked a mercury telluride (HgTe) colloidal quantum dot (CQD) photodiode and a silicon PIN photodiode in series. This detector shows response spectra ranging from visible to short-wave infrared (430 nm to 2800 nm) at room temperature. At zero bias, the total photocurrents are 112.5 μA and 1.24 μA, with a tungsten lamp and a blackbody serving as light sources, respectively. The response speed can reach 1.65 μs, with the calculated detectivities of the visible wavelength D* = 1.01 × 10¹¹ Jones, and that of the short-wave infrared being D* = 2.66 × 10¹⁰ Jones at room temperature. At the same time, with a homemade trans-impedance amplifier (TIA) circuit, we demonstrate the device application for figuring out the amplified voltage of the VIS, SWIR, and the VIS-SWIR stacked layers. Full article

Nano-sized quantum dots (QDs) have the potential for the application of stress sensing materials based on their pressure-sensitive photoluminescence (PL) properties, while the influence of a more realistic loading environment on the PL characteristics of QDs under a high-temperature environment remains to be further studied. Herein, we studied the PL response of CdTe QDs under repetitive loading–unloading conditions under high-temperature coupling to explore the stability of its high temperature stress sensing potential. The results show that the CdTe QDs with size of 3.2 nm can detect pressure in the range of 0–5.4 GPa, and the pressure sensitivity coefficient of PL emission peak energy ($E_{PL}$) is about 0.054 eV/GPa. Moreover, the relationship between $E_{PL}$ and pressure of CdTe QDs is not sensitive to high temperature and repeated loading, which meets the stability requirements of the sensing function required for stress sensing materials under high temperature. However, the disappearance of PL intensity caused by spontaneous growth as well as the ligand instability of QDs induced by high temperature/high pressure affects the availability of $E_{PL}$, which has a great influence on the application of CdTe QDs as high-temperature-resistant nano-stress sensing materials. The research provides the mechanical luminescence response mechanism of CdTe QDs under high-temperature/high-pressure coupling conditions, which provides experimental support for the design of high-temperature/high-pressure-resistant QD structures. Full article

Quantum dots (QDs) are emerging as a new class of zero-dimensional nanomaterials with semiconducting properties. Among many applications, QDs find useful employment in high-capacity electrodes in secondary batteries by virtue of their nanodimension. The recent advancements of QDs and their application as QD-based nanocomposites in electrodes are published in numerous accounts. Well-dispersed QDs in conductive carbonaceous materials can lead to the formation of nanocomposites with excellent cyclic stabilities and large reversible capacities, which are suitable for applications in many batteries. Inorganic QDs are also being investigated as potential candidates to fabricate nanocomposites in different secondary batteries. However, there are not many review articles available detailing the synthetic methodologies used to fabricate such QD-based nanocomposites along with their electrochemical properties. In this article, we are documenting a comprehensive review of a variety of QD nanocomposites with their manufacturing processes and successful utilization in battery applications. We will be highlighting the application of QD-based nanocomposites as anode and cathode materials for applications in different secondary batteries and discussing the enhancement of the electrochemical performances of such batteries in terms of energy density and cyclability. Full article