Luminescent silver nanoclusters for efficient detection of adenosine triphosphate in a wide range of pH values

Nano-engineering nanomedicines with customized functions for tumor treatment applications

Nano-engineering with unique "custom function" capability has shown great potential in solving technical difficulties of nanomaterials in tumor treatment. Through tuning the size and surface properties controllablly, nanoparticles can be endoewd with tailored structure, and then the characteristic functions to improve the therapeutic effect of nanomedicines. Based on nano-engineering, many have been carried out to advance nano-engineering nanomedicine. In this review, the main research related to cancer therapy attached to the development of nanoengineering nanomedicines has been presented as follows. Firstly, therapeutic agents that target to tumor area can exert the therapeutic effect effectively. Secondly, drug resistance of tumor cells can be overcome to enhance the efficacy. Thirdly, remodeling the immunosuppressive microenvironment makes the therapeutic agents work with the autoimmune system to eliminate the primary tumor and then prevent tumor recurrence and metastasis. Finally, the development prospects of nano-engineering nanomedicine are also outlined.

A dual-emission ratiometric fluorescent sensor based on copper nanoclusters encapsulated in zeolitic imidazolate framework-90 for rapid detection and imaging of adenosine triphosphate

Adenosine triphosphate (ATP) is the primary energy carrier for intracellular metabolic processes. Accurate and rapid detection of ATP has important implications for clinical diagnosis. In this work, we reported a dual-emission ratiometric fluorescent probe Cu NCs-Al@ZIF-90 formed by encapsulating copper nanoclusters (Cu NCs) into zeolitic imidazolate framework-90 (ZIF-90) using a simple one-pot method. Cu NCs exhibited a remarkable fluorescence enhancement in the presence of aluminum ions due to the aggregation-induced emission (AIE) properties. When ATP existed, the Zn²⁺ nodes in the MOF material acted as selective sites for ATP recognition, resulting in the cleavage of Cu NCs-Al@ZIF-90. As a consequence, two reverse fluorescence changes were observed from released Cu NCs at 620 nm and imidazole-2-carboxaldehyde (2-ICA) at 450 nm, respectively. With the dual-emission ratiometric strategy, efficient and rapid determination of ATP was realized, giving a detection limit down to 0.034 mM in the concentration range of 0.2 mM to 0.625 mM. The convenient synthesis process and the rapid ATP-responsive ability made the proposed Cu NCs-Al@ZIF-90 probe highly promising in clinical and environmental analysis.

Self-Cascade Nanoenzyme of Cupric Oxide Nanoparticles (CuO NPs) Induced in Situ Catalysis Formation of Polyelectrolyte as Template for the Synthesis of Near-Infrared Fluorescent Silver Nanoclusters and the Application in Glutathione Detection and Bioimaging

In this work, near-infrared fluorescent silver nanoclusters (Ag NCs) were prepared based on the in situ formed poly methacrylic acid (PMAA) as the template and stabilizer, which is synthesized by methacrylic acid (MAA) and hydroxyl radical (·OH) that is generated by the cascade nanoenzyme reaction of cupric oxide nanoparticles (CuO NPs). CuO NPs possess the intrinsic glutathione-like (GPx-like) and peroxidase-like (POD-like) activities, which can catalyze glutathione (GSH) and O₂ to produce hydrogen peroxide (H₂O₂), and then transform into ·OH. The fluorescence intensity of Ag NCs decreases with the addition of GSH, because the -SH can easily anchor on the surface, resulting in the PMAA leaving the Ag NCs, and the coeffect of GSH and PMAA results in the aggregation to form larger Ag NPs. A good linear relationship between the fluorescence quenching rate and the GSH concentration was found in the range 0.01-40 μM with the detection limit 8.0 nM. The Ag NCs can be applied in the detection of GSH in the serum, as well as bioimaging of endogenous and exogenous GSH in cells with high sensitivity. Moreover, the normal and cancer cells can be distinguished through bioimaging because of the different GSH levels. The new method for the preparation of biocompatible nanoprobe based on the nanozyme tandem catalysis and the in situ formed template can avoid the direct usage of polymers or protein templates that hinder preparation and separation, providing a reliable approach for the synthesis, biosensing, and bioimaging of nanoclusters.

High Biocompatible Poly(lactic-co-glycolic acid)-Based Nanosensitizer With Magnetic Resonance Imaging Capacity for Tumor Targeted Microwave Hyperthermia and Chemotherapy

Microwave (MW) hyperthermia has been widely studied in tumor therapy, while the lack of specificity, and the potential toxicity induced by instability or difficulty in degradation of existed MW thermal sensitizers still limits the application. Herein, a new biocompatible Poly(lactic-co-glycolic acid) (PLGA)-based nanosensitizer of Dtxl-Gd@PLGA-PEG-TPP (DGPPT) with capacities of magnetic resonance (MR) imaging and mitochondrial targeting for MW hyperthermia combined with chemotherapy was constructed via a double emulsion solvent evaporation method. The modified TPP significantly enhanced the specificity of sensitizer for targeting mitochondria, a heat-sensitive energy supply plant in cells. Thus the MW thermal damage induced by the loaded Gd in PLGA nanospheres was also strengthened. Together, the system could also achieve MR imaging due to the existence of Gd. In addition, the encapsulated Dtxl performed the chemotherapy of inhibiting mitochondrial function for assisting with MW hyperthermia. In vivo experiments demonstrated that PLGA had high biocompatibility that no obvious damage occurred even the dose was up to 200 mg/kg. Meanwhile, DGPPT+MW representing the combination of mitochondrial targeting and MW hyperthermia-chemotherapy has also been proved to shrink tumor size effectively. This study provides a new direction for building biosafe and multifunctional MW sensitizer with active targeting ability to impede tumor growth.

Copper nanocluster composites for analytical (bio)-sensing and imaging: a review

As an ideal substitute for traditional organic fluorescent dyes or up-conversion nanomaterials, copper nanoclusters (CuNCs) have developed rapidly and have been involved in exciting achievements in versatile applications. The emergence of novel CuNCs composites improves the poor stability and fluorescence intensity of CuNCs. With this in mind, great efforts have been made to develop a wide variety of CuNCs composites, and impressive progress has been made in the past few years. In this review, we systematically summarize absorption, fluorescence, electrochemiluminescence, and catalytic properties and focus on the multiple factors that affect the fluorescence properties of CuNCs. The fluorescence properties of CuNCs are discussed from the point of view of core size, surface ligands, self-assembly, metal defects, pH, solvent, ions, metal doping, and confinement effect. Especially, we illustrate the research progress and representative applications of CuNCs composites in bio-related fields, which have received considerable interests in the past years. Additionally, the sensing mechanism of CuNCs composites is highlighted. Finally, we summarize current challenges and look forward to the future development of CuNCs composites. Schematic diagram of the categories, possible sensing mechanisms, and bio-related applications of copper nanoclusters composites.

Evaluation of Apigenin Inhibiting Lactate Dehydrogenase Activity Based on CdTe Quantum Dots Fluorescence

Lactate dehydrogenase (LDH) is one of key enzymes in glucose metabolism pathway, which plays a critical role in cell metabolism. Inhibition of LDH can inhibit glycolysis process, thereby inhibiting the occurrence and development of tumor cells. Two kinds of LDH inhibitors, apigenin and emodin, were obtained by testing the IC₅₀ of several natural products in LDH enzyme reaction. The IC₅₀ of apigenin was about 1/3 of LDH inhibitor sodium oxalate. A new method to evaluate the performance of LDH inhibitors based on CdTe QDs was established at the same time, which provides a new idea for research on LDH enzyme inhibitors.

Noble metal-molybdenum disulfide nanohybrids as dual fluorometric and colorimetric sensor for hepatitis B virus DNA detection

Hepatitis B virus (HBV) infection is one of the global healthcare burdens, and its early diagnosis is crucial for the prevention of HBV-induced chronic hepatitis, liver fibrosis, cirrhosis, and hepatocellular carcinoma. Although different detection approaches have been reported, most of these methods either rely on sophisticated machines or procedures, which limit their use particularly in the high endemic, developing countries. In this work, we report a dual-sensing nanoplatform built on noble metal-molybdenum disulfide (MoS₂) nanohybrids, and this platform can detect the HBV DNA target through either fluorometric or colorimetric readouts. The design with the silver nanocluster (AgNC)-MoS₂ nanohybrid enables multiplex fluorescent detection, while the HBV DNA-regulated growth of platinum nanoparticles (PtNPs) on the MoS₂ nanosheets offers signal-on colorimetric detection. Both AgNC-MoS₂ and PtNP-MoS₂ nanohybrids show high sensitivity with pico-molar detection limit and single nucleotide specificity, even with the spiked human serum. Collectively, the proposed nanohybrids possess their potential in the use of early HBV diagnosis, particularly suitable for the high endemic areas with limited medical and instrumental supports.

A new method for cartap detection with high sensitivity and selectivity based on the inner filter effect between GSH-Cu NCs and Au NPs

Herein, a novel and sensitive fluorescence method for cartap determination is established on the basis of the inner filter effect (IFE) of gold nanoparticles (Au NPs) on the fluorescence of glutathione protected Cu NCs (GSH-Cu NCs). In the presence of Au NPs, the fluorescence of GSH-Cu NCs was strongly quenched by the IFE because the absorption spectra of Au NPs overlap well with the emission spectra of GSH-Cu NCs. Upon addition of cartap, cartap could induce the aggregation of Au NPs whose absorption spectrum does not overlap with the emission spectrum of GSH-Cu NCs. Then, with the increase in cartap concentration, the IFE-decreased fluorescence was gradually recovered, realizing the fluorescence sensing of cartap. Under optimal conditions, the proposed method has a good linear relationship with cartap concentration in the range of 7-100 nM, and the detection limit is 3.34 nM. In addition, satisfactory results were obtained for cartap analysis using tap water and cabbage as real samples, which demonstrated that the method as-developed would have great practical application prospects.