Search

Introduction: Lung cancer is the most common cancer worldwide, among which non-small cell lung cancer (NSCLC) accounts for about 80% of all lung cancers. Chemotherapy, a mainstay modality for NSCLC, has demonstrated restricted effectiveness due to the emergence of chemo-resistance and systemic side effects. Studies have indicated that combining chemotherapy with phototherapy, such as photodynamic therapy (PDT) and photothermal therapy (PTT), can enhance efficacy of therapy. In this work, an aminated mesoporous graphene oxide (rPGO)-protoporphyrin IX (PPIX)-hyaluronic acid (HA)@Osimertinib (AZD) nanodrug delivery system (rPPH@AZD) was successfully developed for combined chemotherapy/phototherapy for NSCLC., Methods: A pH/hyaluronidase-responsive nanodrug delivery system (rPPH@AZD) was prepared using mesoporous graphene oxide. Its morphology, elemental composition, surface functional groups, optical properties, in vitro drug release ability, photothermal properties, reactive oxygen species production, cellular uptake and cell viability were evaluated. In addition, the in vivo therapeutic effect, biocompatibility, and imaging capabilities of rPPH@AZD were verified by a tumor-bearing mouse model., Results: Aminated mesoporous graphene oxide (rPGO) plays a role as a drug delivery vehicle owing to its large specific surface area and ease of surface functionalization. rPGO exhibits excellent photothermal conversion properties under laser irradiation, while PPIX acts as a photosensitizer to generate singlet oxygen. AZD acts as a small molecule targeted drug in chemotherapy. In essence, rPPH@AZD shows excellent photothermal and fluorescence imaging effects in tumor-bearing mice. More importantly, in vitro and in vivo results indicate that rPPH@AZD can achieve hyaluronidase/pH dual response as well as combined chemotherapy/PTT/PDT anti-NSCLC treatment., Conclusion: The newly prepared rPPH@AZD can serve as a promising pH/hyaluronidase-responsive nanodrug delivery system that integrates photothermal/fluorescence imaging and chemo/photo combined therapy for efficient therapy against NSCLC., Competing Interests: All authors have no conflicts of interest to disclose for this work., (© 2024 Zhang et al.)

A new type of polyethyleneimine-protected copper nanoclusters (PEI-CuNCs) is favorably developed by a one-pot method under mild conditions. The obtained PEI-CuNCs is characterized by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, Fourier-transform infrared (FTIR) spectroscopy and other techniques. It is worth noting that the proposed PEI-CuNCs demonstrate a selective response to chromium(VI) over other competitive species. Fluorescence quenching of PEI-CuNCs is determined to be chromium(VI) concentrations dependence with a low limit of detection of 8.9 nM. What is more, the as-developed PEI-CuNCs is further employed in building a detection platform for portable recognition of chromium(VI) in real samples with good accuracy. These findings may offer a distinctive strategy for the development of methods for analyzing and monitoring chromium(VI) and expand their application in real sample monitoring., (© 2024 John Wiley & Sons Ltd.)

Dopamine (DA) is the most abundant catecholamine neurotransmitter in the brain and plays an extremely essential role in the physiological activities of the living organism. There is a critical need for accurately and efficiently detecting DA levels in organisms in order to reflect physiological states. Carbon nitride quantum dots (C 3 N 4 ) were, in recent years, used enormously as electrochemical and fluorescence probes for the detection of metal ions, biomarkers and other environmental or food impurities due to their unique advantageous optical and electronic properties. 3-Aminophenylboronic acid (3-APBA) can specifically combine with DA through an aggregation effect, providing an effective DA detection method. In this work, 3-APBA modified carbon nitride quantum dots (3-APBA-CNQDs) were synthesized from urea and sodium citrate. The structure, chemical composition and optical properties of 3-APBA-CNQDs were investigated by XRD, TEM, UV-visible, and FT-IR spectroscopy. The addition of DA could induce fluorescence quenching of 3-APBA-CNQDs possibly through the inner filter effect (IFE). 3-APBA-CNQDs shows better selectivity and sensitivity to DA than other interfering substances. By optimizing the experiment conditions, good linearity was obtained at 0.10-51 μ M DA with a low detection limit of 22.08 nM. More importantly, 3-APBA-CNQDs have been successfully applied for the detection of DA in human urine and blood samples as well as for bioimaging of intracellular DA. This study provides a promising novel method for the rapid detection of DA in real biological samples., (© 2024 IOP Publishing Ltd.)

Silver is widely used in medical materials, photography, electronics and other industries as a precious metal. The large-scale industrial production of silver-containing products and liquid waste emissions aggravate the environmental pollution. Silver ion is one of the most toxic metal ions, causing pollution to the environment and damage to public health. Therefore, the efficient and sensitive detection of Ag + in the water environment is extremely important. Sulfur-doped carbon nitride nanosheets (SCN Ns) were prepared by melamine and thiourea via high-temperature calcination. The morphology, chemical composition and surface functional groups of the SCN Ns were characterized by SEM, TEM, XRD, XPS, and FT-IR. The fluorescence of SCN Ns was gradually quenched as the Ag + concentration increased. The detection limit for Ag + was as low as 0.28 nM. The quenching mechanism mainly is attributed to static quenching. In this paper, SCN Ns were used as the fluorescent probe for detecting Ag + . SCN Ns have successfully detected Ag + in different environmental aqueous samples and cells. Finally, SCN Ns were further applied to the visual quantitative detection of intracellular Ag + ., (© 2022 IOP Publishing Ltd.)

A fluorescent sulfur and oxygen co-doped graphitic carbon nitride quantum dots (S,O-CNQDs) were prepared from ethylenediaminetetraacetic acid disodium salt dihydrate and thiourea as the carbon and sulfur sources. The morphology and surface functional groups of S,O-CNQDs were characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The fluorescence of S,O-CNQDs could be quenched efficiently by Cu 2+ under the optimum conditions. The S,O-CNQDs could function as an excellent fluorescent probe for Cu 2+ detection with a wide linear range of 0.50-15 μ M and a low detection limit of 0.58 nM. In addition, this fluorescent probe was employed for monitoring Cu 2+ in samples of tap water, lake water, human serum and urine with good recoveries from 99.0% to 110.0%. Moreover, the S,O-CNQDs with high cell penetration and low cytotoxicity were utilized for Cu 2+ detection in living cells. Owing to the excellent properties of S,O-CNQDs, the as-prepared S,O-CNQDs can be a potential candidate for biological applications., (© 2022 IOP Publishing Ltd.)

Recently, water-soluble gold nanoclusters (AuNCs) have attracted more and more attention due to their unique properties. In this study, penicillamine-protected gold nanoclusters (Pen-AuNCs) were synthesized and initially fractionated by sequential size-selective precipitation (SSSP). The crude Pen-AuNCs and SSSP fractions were separated by capillary zone electrophoresis (CZE) with a diode array detector. The effects of key parameters, including the concentration of phosphate buffer, pH value and the ethanol content were systematically investigated. The separation of water-soluble poly-disperse AuNCs were well achieved at 30 mM phosphate buffer with 7.5% EtOH, pH 12.0, and applied voltage of 15 kV. The linear correlation between AuNCs diameter and mobility was observed. This finding provides an important reference for CE separation and product purification of water-soluble AuNCs or other nanomaterials., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Polydisperse water-soluble gold nanoclusters (AuNCs) protected by penicillamine have been synthesized in this work. The sequential size-selective precipitation (SSSP) technique has been applied for the size fractionation and purification of the monolayer-protected AuNCs. Through continuously adding acetone to a crude AuNC aqueous solution and controlling the volume percentage of acetone, we successfully separated the polydisperse AuNCs with diameters ranging from 0.5 to 5.4 nm into four different fractions sequentially. High-resolution transmission electron microscopy (HRTEM) shows that the four fractions are well-dispersed spherical particles of diameter 3.0 ± 0.6, 2.3 ± 0.5, 1.7 ± 0.4, and 1.2 ± 0.4 nm. Proton nuclear magnetic resonance spectroscopy suggests that disulfide, excess ligands and gold(I) complexes were removed from the AuNCs fractions. These results demonstrate the considerable potential of the SSSP technique for size-based separation and purification of AuNCs, achieving not only the isolation of larger nanoclusters (NCs) from small NCs in a continuous fashion, but also for the removal of small-molecule impurities. Based on the results from the mass spectrometry and thermogravimetric analysis, the average composition of the four fractions can be represented by Au 38 (SR) 18 , Au 28 (SR) 15 , Au 18 (SR) 12 , and Au 11 (SR) 8 , respectively. This indicates that the SSSP separation is mainly dependent on the core size and the ratio of Au atoms to ligands of AuNCs. X-ray photoelectron spectroscopy (XPS) has also been applied to observe the molecular dependence on the gold and sulfur chemical state of organosulfur monolayers of the fractions. The photoluminescence spectra of these AuNCs in the range of 900-790 nm was investigated at room temperature. The results show that the peak emission energy of the size-selected AuNCs undergoes a blue shift when the size is decreased, which can be attributed to the quantum confinement effect.

A rapid method has been developed for the determination of Hg(II) and sulfide by using graphitic carbon nitride quantum dots (g-CNQDs) as a fluorescent probe. The interaction between Hg(II) and g-CNQDs leads to the quenching of the blue g-CNQD fluorescence (with excitation/emission peaks at 390/450 nm). However, the fluorescence can be recovered after addition of sulfide such that the "turn-off" state is switched back to the "turn-on" state. The g-CNQDs were fully characterized by transmission electron microscopy, X-ray diffractometry, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, UV-vis absorption and fluorescence spectroscopy. Under the optimal experimental conditions, this probe is highly selective and sensitive to Hg(II). The linear response to Hg(II) extends from 0.20 to 21 μM with a detection limit of 3.3 nM. In addition, sulfide can be detected via the recovery of fluorescence. The linear response range for sulfide species is from 8.0 to 45 μM with a detection limit of 22 nM. The mechanism of the "turn-off-on" scheme is discussed. The methods have been applied to the analysis of spiked tap water, lake water and wastewater samples. Graphical abstract Schematic of an off-on fluorescent probe for mercury(II). The fluorescence of graphitic carbon nitride quantum dots (g-CNQDs) is quenched by Hg 2+ but is recovered after reacting with S 2- as it can combine with Hg 2+ on the surface of g-CNQDs.

Green fluorescent silver (Ag)-doped graphite carbon nitride (Ag-g-C 3 N 4 ) nanosheets have been fabricated by an ultrasonic exfoliating method. The fluorescence of the Ag-g-C 3 N 4 nanosheets is quenched by curcumin. The fluorescence intensity decreases with the increase in the concentration of curcumin, indicating that the Ag-g-C 3 N 4 nanosheets can function as a non-toxic and facile fluorescence probe to detect curcumin. The fluorescence intensity of Ag-g-C 3 N 4 nanosheets shows a linear relationship to curcumin in the concentration range 0.01-2.00 μM with a low detection limit of 38 nM. The fluorescence quenching process between curcumin and Ag-g-C 3 N 4 nanosheets mainly is based on static quenching. The fluorescent probe has been successfully applied to analyse curcumin in human urine and serum samples with satisfactory results., (© 2018 John Wiley & Sons, Ltd.)

In this work, a new assembled copper ions sensor based on the Mn metal-enhanced fluorescence of N-acetyl-l-cysteine protected CdS quantum dots (NAC-Mn:CdS QDs) was developed. The NAC and Mn:CdS QDs nanoparticles were assembled into NAC-Mn:CdS QDs complexes through the formation of CdS and MnS bonds. As compared to NAC capped CdS QDs, higher fluorescence quantum yields of NAC-Mn:CdS QDs was observed, which is attributed to the surface plasmon resonance of Mn metal. In addition, the fluorescence intensity of as-formed complexes weakened in the presence of copper ions. The decrease in fluorescence intensity presented a linear relationship with copper ions concentration in the range from 0.16-3.36μM with a detection limit of 0.041μM . The characterization of as-formed QDs was analyzed by photoluminescence (PL), ultra violet-visible (UV-vis), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and energy dispersive spectroscopy (EDS) respectively. Furthermore, the recoveries and relative standard deviations of Cu 2+ spiked in real water samples for the intra-day and inter-day analyses were 88.20-117.90, 95.20-109.90, 0.80-5.80 and 1.20-3.20%, respectively. Such a metal-enhanced QDs fluorescence system may have promising application in chemical and biological sensors., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Phosphorus doped graphitic carbon nitride (P-g-C 3 N 4 ) nanosheets were synthesized by calcination. P-g-C 3 N 4 nanosheets were characterized by XRD, XPS, TEM, fluorescence, ultraviolet-visible absorption and Fourier transform infrared spectroscopy. The fluorescence of the P-g-C 3 N 4 nanosheets was gradually quenched with the increase in the concentration of baicalein at room temperature. The proposed probe was used for the determination of baicalein in the concentration 2.0-30μM with a detection limit of 53nM. The quenching mechanism was discussed. The P-g-C 3 N 4 nanosheets have been successfully applied for effective and selective detection of baicalein in human urine samples and blood samples., (Copyright © 2018 Elsevier B.V. All rights reserved.)

In this present study, a fluorescent probe was developed to detect curcumin, which is derived from the rhizomes of the turmeric. We used a simple and economical way to synthesize boron and nitrogen co-doped carbon dots (BNCDs) by microwave heating. The maximum emission wavelength of the BNCDs was 450 nm at an excitation wavelength of 360 nm. The as-prepared BNCDs were characterized by multiple analytical techniques such as transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and infrared spectroscopy. The synthesized carbon nanoparticles had an average particle diameter of 4.23 nm. The BNCDs exhibited high sensitivity to the detection of curcumin at ambient conditions. The changes of BNCDs fluorescent intensity show a good linear relationship with the curcumin concentrations in the range 0.2-12.5 μM. This proposed method has been successfully applied to detect the curcumin in urine samples with the recoveries of 96.5-105.5%., (Copyright © 2017 John Wiley & Sons, Ltd.)

A fast and accurate ultra-performance liquid chromatography coupled with electrospray ionisation quadrupole time-of-flight tandem mass spectrometry (UPLC-ESI-Q-TOF-MS/MS) method was developed for the separation and structural elucidation of fluorescent carbon nanoparticles (CNP). The CNP was synthesised from microwave-assisted pyrolysis of citric acid (CA) and 1,2-ethylenediamine (EDA). By using UPLC separation, the CNP product was well separated into ten fractions within 4.0 min. Based on high-accuracy MS and MS/MS analyses, the CNP species were revealed to display six kinds of chemical formulas, including (C10H20N4O5)n, (C8H12N2O5)n, (C16H22N4O9)n, (C6H8O7)n, (C14H18N2O11)n, and (C14H16N2O10)n. In particular, our study revealed for the first time that the CNP species exist as supramolecular clusters with their individual monomers units linked together through non-covalent bonding forces. These findings clearly indicated the usefulness of UPLC-ESI-Q-TOF-MS/MS in identifying the chemical composition of CNP product. It is anticipated that our proposed methodology can be applied to study the structure-property relationships of CNP, facilitating in the production of CNP with desirable spectral features., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Phosphorous and nitrogen co-doped carbon dots (P,N-CDs) with satisfactory quantum yield have been prepared through one-step acidic oxidation of pumpkin by H 3 PO 4 at low temperature (90 °C). The as-prepared P,N-CD is relatively monodisperse with a narrow size distribution. The P,N-CD displays a remarkable emission enhancement in the yellow fluorescence region (λ em = 550 nm) when the pH is increased from 1.5 to 7.4. The pK a value of P,N-CDs was found to be 4.17 and it shows linear response to the physiological range of pH 4.7-7.4, which is valuable for near-neutral cytosolic pH research. It is observed that P,N-CDs are superior fluorescent bioimaging agents in animals and cells thanks to their excellent solubility and ultra-low toxicity. In addition, P,N-CDs display a notably large Stokes shift of 125 nm, good reversibility and could effectively avoid the influence of autofluorescence in biological systems. The confocal fluorescent microscopic images of subcellular distribution and the detection of pH in MCF-7 cells were achieved successfully, suggesting that P,N-CDs have excellent cell membrane permeability and are further applied successfully to monitor pH fluctuations in live cells with negligible autofluorescence.