Emergence of Quantum Dots as Innovative Tools for Early Diagnosis and Advanced Treatment of Breast Cancer

Quantum dots (QDs) semiconducting nanomaterials, have garnered attention due to their distinctive properties, including small size, high luminescence, and biocompatibility. In the context of triple-negative breast cancer (TNBC), notorious for its resistance to conventional treatments, QDs exhibit promising potential for enhancing diagnostic imaging and providing targeted therapies. This review underscores recent advancements in the utilization of QDs in imaging techniques, such as fluorescence tomography and magnetic resonance imaging, aiming at the early and precise detection of tumors. Emphasis is placed on the significance of QD design, synthesis and functionalization processes as well as their use in innovative strategies for targeted drug delivery, capitalizing on their ability to selectively deliver therapeutic agents to cancer cells. As the research in this field advances rapidly, this review covers a classification of QDs according to their composition, the characterization techniques than can be used to determine their properties and, subsequently, emphasizes recent findings in the field of TNBC-targeting, highlighting the imperative need to address challenges, like potential toxicity or methodologies standardization. Collectively, the findings explored thus far suggest that QDs could pave the way for early diagnosis and effective therapy of TNBC, representing a significant stride toward precise and personalized strategies in treating TNBC.

Revolutionizing fuel production through biologically synthesized zero-dimensional nanoparticles

The sustainable management of wastewater and the production of clean fuel with a reduced carbon footprint require innovative methods, including photocatalytic degradation of pollutants and hydrogen generation. To achieve this, biosynthesized photocatalysts are necessary, with carbon quantum dots (CQDs) being a promising candidate for achieving this goal. In this study, CQDs were prepared from water caltrop peels and a composite of greenly synthesized CQDs with copper selenide (CuSe) was used for the photocatalytic degradation of pollutants and production of fuel. Thymol blue (TB) and Congo red (CR) were chosen as model dyes for degradation studies, with optimized reaction conditions being determined by varying the dose, pH, intensity, and concentration of dyes. The composite (CuSe@CQDs) showed a degradation rate of 99.4% and 97.8% for TB and CR, respectively, within 60 minutes, with a corresponding hydrogen production rate of 2360 and 1875 μmol g-1 h-1. The yield of hydrogen production using the composite was 35.7 and 29 times greater than that of CuSe alone for TB and CR, respectively. Spectroscopic techniques such as XRD, UV-Vis, FESEM, HRTEM, XPS, FTIR, BET, and TGA were used to characterize the composite, and the results revealed that the composite had superior degradation rates compared to CuSe alone, with the degradation rate being enhanced by about three times. GCMS analysis was used to investigate the intermediate and possible degradation pathways. Overall, this study highlights the potential of biosynthesized CQDs as effective photocatalysts for the sustainable management of wastewater and production of fuel.

Photodegradation of hazardous organic pollutants using titanium oxides -based photocatalytic: A review

Titanium oxide-based photocatalysts (TOBPs) have been widely utilized as potential materials for numerous applications, such as wastewater treatment, water-splitting reactions, carbon dioxide (CO₂) reduction and photosynthesis. However, the large bandgap of intrinsic TiO₂ limits their absorption toward visible light, which is the central part of the solar spectrum, resulting in low photocatalytic activities under sunlight. To overcome this obstacle, several strategies, such as doping with either metal or non-metal elements or combining with other compounds, are efficient ways to reduce the bandgap of TiO₂, leading to effectively extending their absorption toward the visible region and increasing their catalytic performance. In this review, we discussed the application of TOBPs for the photodegradation of hazardous organic pollutants in wastewater to produce quality reused water. The synthesis of TiO₂ and the enhancement of photocatalytic activities of TOBPs by different techniques with detailed information were provided. Application of TOBPs for decomposing hazardous organic pollutants such as dyes, phenolic compounds and pharmaceuticals under optimum conditions have been listed. Also, the photodegradation mechanisms of hazardous organic compounds have been investigated. This work also brings ideas for future perspectives and research plan to inhibit the disadvantages and expand the application of TOBPs to remove toxic organic pollutants.

Kilogram-scale fabrication of TiO2 nanoparticles modified with carbon dots with enhanced visible-light photocatalytic activity

Incorrect discharge of dye wastewater will cause environment pollution and be very harmful to human health. Visible-light photocatalysis over large-scale synthesized semiconductor materials can become one of the feasible solutions for the practical application of purifying dye wastewater. As a new candidate, carbon dots (CDs) with unique fluorescence were fabricated on a tens of grams scale and then further applied to the kilogram-scale synthesis of a CDs/TiO₂ composite by one-step heat treatment. Compared with single TiO₂ nanoparticles (NPs), the CDs/TiO₂ composite with a large specific surface area exhibits enhanced photo-degradation performance for methyl orange (MO). This phenomenon can be attributed to the loading of CDs in the TiO₂ NPs, which is conducive to broadening the light absorption spectrum and improving absorption intensity, narrowing the band gap, charge carrier trapping, up-converting properties, and charge separation. The kilogram-scale synthesis of the CDs/TiO₂ photocatalyst does not affect the morphology, structure, optical properties and photocatalytic performance of the composite, which opens up a new avenue to construct elaborate heterostructures for enhanced photocatalytic performance using visible light as the light source.

Natural N-Doped Carbon Quantum Dots Derived from Straw and Adhered onto TiO2 Nanospheres for Enhancing the Removal of Antibiotics and Resistance Genes

Antibiotics and antibiotic resistance genes (ARGs) are emerging environmental contaminants. TiO₂ photocatalytic degradation has been proved an important removal technique, but its photocatalytic ability needs be improved. In our work, natural N-doped carbon quantum dots (N-SCQDs) were extracted from hydrothermal carbonization waste liquid of straw and were attached onto TiO₂ nanospheres for remediating antibiotics [sulfadiazine (SA)] and ARGs (sul1, sul2, and intl1). The maximum SA reduction rates were close to 100%, and the ARG reduction rates were 52.91-83.52%/lg10 (sul1), 32.10-68.23%/lg10 (sul2), and 46.29-76.55%/lg10 (inlt1). The temperature of the straw derivatives would influence their photoelectric properties. N-SCQDs@TiO₂ expands the application range of a novel potential high-efficiency degradation catalyst and offers a new way of hydrothermal carbonization waste liquid of agricultural waste.

Preparation of novel fluorescent probe based on carbon dots for sensing and imaging Fe(III) and pyrophosphate in cells and zebrafish

Ferric ions (Fe³⁺) and pyrophosphate anions (PPi) are involved in many physiological processes and play important roles in biological systems. The abnormal level of Fe³⁺ and PPi will cause serious damage to the environment and life. At present, the application of such probes in life, especially in vivo, is still very scarce. So, the development of a fluorescent probe to simultaneously detect Fe³⁺ and PPi has great significance to the health of the environment and organisms. Herein, nitrogen-doped carbon quantum dots (N-CDs) were synthesized via solvothermal treatment, using biuret and citric acid as precursors. The synthesized N-CDs showed highly selective and sensitive detection of Fe³⁺ through a photoluminescence quenching effect. The fluorescence of N-CDs quenched by Fe³⁺ could be restored with PPi, rendering the N-CDs/Fe³⁺ sensor promising for PPi detection ('OFF-ON'). The linear ranges of detection for Fe³⁺ and PPi were 3-30 and 2-12 μM, and the limits of detection were 2.71 and 1.12 μM, respectively. The practical applications of N-CDs were tested using tap water samples. Furthermore, N-CDs can be used for the detection and imaging of Fe³⁺ and PPi in HeLa cells and zebrafish owing to their excellent optical properties.

Photocatalytic removal of pharmaceutical water pollutants by TiO2 - Carbon dots nanocomposites: A review

Pharmaceuticals are becoming increasingly more relevant water contaminants, with photocatalysts (such as TiO₂) being a promising approach to remove these compounds from water. However, TiO₂ has poor sunlight-harvesting capacity, low photonic efficiency, and poor adsorption towards organic pollutants. One of the emerging strategies to enhance the photocatalytic performance of TiO₂ is by conjugating it with fluorescent carbon dots. Herein, we performed a critical review of the development of TiO₂ - carbon dots nanocomposites for the photocatalytic removal of pharmaceuticals. We found that carbon dots can improve the photocatalytic efficiency of the resulting nanocomposites, mostly due to increasing the adsorption of organic pollutants and enhancing the absorption in the visible range. However, while this approach shows significant promise, we also identified and discussed several aspects that need to be addressed before this strategy could be more widely used. We hope that this review can guide future studies aiming to the development of enhanced photocatalytic TiO₂ - carbon dots nanocomposites.

Photocatalytic activity study of ZnO modified with nitrogen–sulfur co-doped carbon quantum dots under visible light

Enhanced degradation rate of RhB under visible light by N,S-CQDs-modified ZnO.