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Au nanoparticles supported on nanorod-like TiO2 as catalysts in the CO-PROX reaction under dark and light irradiation: Effect of acidic and alkaline synthesis conditions
摘要： Gold nanoparticles precipitated-deposited on titania nanostructures (1.0 wt% nominal loading) were studied in the preferential CO oxidation in excess of H2 at room temperature and atmospheric pressure, both in dark and under simulated solar light irradiation. Titania supports were synthesized by means of two hydrothermal methods markedly acid and basic, giving rise to rutile nanorods and anatase deformed nanorods structures, respectively. Characterization techniques such as N2 physisorption, XRD, XPS, DRUV-vis, HRTEM and XRF were performed in order to study the chemical, structural and optical properties of the catalysts. Well defined rutile nanorods structures were obtained from the acidic treatment allowing a regular distribution of gold nanoparticles and resulting quite active in the CO-PROX reaction. In particular the sample from the acidic synthetic approach calcined at 700 °C displayed the best results as it was highly selective to CO2 under both dark and simulated solar light irradiation.
关键词： Photocatalysis,CO preferential oxidation,Gold nanoparticles,Titania nanorods,Simulated solar light
更新于2025-09-23 15:22:29
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A thermo-responsive alginate nanogel platform co-loaded with gold nanoparticles and cisplatin for combined cancer chemo-photothermal therapy
摘要： The current interest in cancer research is being shifted from individual therapy to combinatorial therapy. In this contribution, a novel multifunctional nanoplatform comprising alginate nanogel co-loaded with cisplatin and gold nanoparticles (AuNPs) has been firstly developed to combine photothermal therapy and chemotherapy. The antitumor efficacy of the as-prepared nanocomplex was tested against CT26 colorectal tumor model. The nanocomplex showed an improved chemotherapy efficacy than free cisplatin and caused a significantly higher tumor inhibition rate. The in vivo thermometry results indicated that the tumors treated with the nanocomplex had faster temperature rise rate under 532 nm laser irradiation and received dramatically higher thermal doses due to optical absorption properties of AuNPs. The combined action of chemo-photothermal therapy using the nanocomplex dramatically suppressed tumor growth up to 95% of control and markedly prolonged the animal survival rate. Moreover, tumor metabolism was quantified by [18F]FDG (2-deoxy-2-[18F]fluoro-D-glucose)-positron emission tomography (PET) imaging and revealed that the combination of the nanocomplex and laser irradiation have the potential to eradicate microscopic residual tumor to prevent cancer relapse. Therefore, the nanocomplex can afford a potent anticancer efficacy whereby heat and drug can be effectively deliver to the tumor, and at the same time the high dose-associated side effects due to the separate application of chemotherapy and thermal therapy could be potentially reduced.
关键词： Alginate,Cisplatin,Gold nanoparticles,Chemo-photothermal therapy,Positron emission tomography
更新于2025-09-23 15:22:29
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Comparative Analysis to Explore the Suitability of a Short Chain Dyad in Its Pristine and Nanocomposite Forms for Designing Artificial Light Energy Conversion Device
摘要： From the UV-vis, steady state and time resolved spectroscopic investigations on the pristine dyad, dyad-spherical gold nanoparticles (GNP) and dyad-star shaped gold nanoparticles (GNS), it was observed that though in the ground state the dyad in its pristine form possesses trans-type (elongated and planar) isomer but on photoexcitation trans-form converts into cis-structure (folded). Interestingly, the dyad exhibits different behavior when it combines with GNP or GNS. In nanocomposite form, even on photoexcitation some ground state trans-structure still retains its identity in the excited state. The 60% of the trans-species remains unchanged in the excited state due to excitation of dyad-GNS system and possibly this configuration facilitates the hindrance of energy destructive charge recombination processes as in this conformer the donor and acceptor moieties tend to move far away from each other causing lack of overlapping of charge clouds within the two redox components. The dyad-GNS nanocomposite appears to be the best possible light energy conversion or storage device within the three system studied in the present investigation. Investigations are underway to examine how the degree of surface coverage of the dyad on the surface of gold nanoparticles affect its geometry or conformational changes on photoexcitation.
关键词： Nanocomposites,Time Resolved Spectroscopy,Light Energy Converter,Gold Nanoparticles,Short-Chain Dyad,Trans- and Cis-Conformer
更新于2025-09-23 15:22:29
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Polypyrrole microcapsules loaded with gold nanoparticles: Perspectives for biomedical imaging
摘要： We report the facile preparation of polypyrrole microcapsules with a hydrophobic liquid core that is loaded with gold nanoparticles. Through the oxidative polymerization of pyrrole, the polymer is deposited onto the surface of the droplets, which results in the encapsulation of both the liquid phase and the metal nanoparticles. We demonstrate the preparation of the microcapsules loaded with organic solvents (toluene, hexane) or 2-oxoheptyl isothiocyanate (new promising anticancer agent) as the liquid cores and stable or radioactive gold nanoparticles (Au-197 or Au-198 isotopes). The resulting microcapsules have been demonstrated as promising agents for medical applications such as computed tomography or gamma imaging. Moreover, the capsules can be applied as drug carriers, which has been shown in vitro on cancer and normal cell cultures.
关键词： Targeted drug delivery,Gold nanoparticles doped with Au-198,Computed tomography,Anticancer agents,Polypyrrole microcapsules,Gamma imaging
更新于2025-09-23 15:22:29
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Photophysicochemical properties and photodynamic therapy activity of chloroindium(III) tetraarylporphyrins and their gold nanoparticle conjugates
摘要： Novel chloroindium(III) complexes of tetra(4-methylthiophenyl)porphyrin (2a) and tetra-2-thienylporphyrin (2b) dyes have been synthesized and characterized. The main goal of the project was to identify fully symmetric porphyrin dyes with Q-band regions that lie partially in the therapeutic window that are suitable for use in photodynamic therapy (PDT). 2a and 2b were found to have fluorescence quantum yield values ≤ 0.01 and moderately high singlet oxygen quantum yields (0.54?0.73) due to heavy atom effects associated with the sulfur and indium atoms. The dark toxicity and PDT activity against epithelial breast cancer cells (MCF-7) were investigated over a dose range of 3.0?40 mg . mL-1. The in vitro dark cytotoxicity of 2a is significantly lower than that of 2b at ≤ 40 mg . mL-1. 2a was conjugated with gold nanoparticles (AuNPs) to form a nanoconjugate (2a-AuNPs), which exhibited a higher singlet oxygen quantum yield (FD) value and PDT activity than was observed for 2a alone. The results suggest that the AuNPs nanoconjugates of readily synthesized fully symmetric porphyrin dyes are potentially suitable for PDT applications, if meso-aryl substituents that provide scope for nanoparticle conjugation can be introduced that shift the Q bands into the therapeutic window.
关键词： porphyrins,photophysics,dark toxicity,singlet oxygen,gold nanoparticles,photodynamic therapy
更新于2025-09-23 15:22:29
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Formation of Growth-Mediated Gold Nanoflowers: Roles of the Reducing Agent and Amine-Modified, Single-Strand DNA Sequences
摘要： The formation of growth-mediated structures from gold nanoparticle seeds was studied in the presence of amine-modified single-strand DNA sequences and reducing agents such as hydroxylamine and hydroquinone. In the case of hydroxylamine, gold nanoparticle seeds (0.45 nM) were incubated with amine-modified single-strand DNA probes PMR (amine-5’-ACATCAGT-3’) and PML (amine-5’-GATAAGCT-3’), which resulted in gold nanoflowers and nanospheres, respectively. When the concentration of the nanoparticle seeds was varied (0.15–0.45 nM), only the PMR sequence showed growth-mediated development of gold nanoflowers. The size of the gold nanoparticles obtained is independent of the seed concentration for both PMR and PML sequences. In contrast, in the presence of the reducing agent hydroquinone, the growth processes are identical for both the sequences. At a lower seed concentration (0.15 nM), gold nanoflowers of larger size were observed for both sequences, whereas at higher seed concentrations (0.45 nM), much smaller gold nanospheres resulted. The formation and stability of nanoflowers and nanospheres for PMR and PML with hydroxylamine-based reduction were further studied in detail with diverse controlled amine-modified (5’-, 3’- and both end-modified) and non-modified DNA sequences with other mutants of these two sequences.
关键词： DNA structures,gold nanoparticles,reducing agents,growth factors,nanoflowers
更新于2025-09-23 15:22:29
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Ultrastructural and optical characteristics of cancer cells treated by a nanotechnology based chemo-photothermal therapy method
摘要： The current chemotherapy method demonstrates the need for improvement in terms of efficacy and safety. Given the beneficiary effect of heat in combination with chemotherapy, the purpose of this study is to develop a multifunctional nanoplatform by co-incorporating gold nanoparticles (AuNPs) as photothermal agent and cisplatin as anticancer drug into alginate hydrogel (named as ACA) to enable concurrent thermo-chemotherapy. The in vitro cytotoxicity experiment showed that the as-developed nanocomplex was able to induce greater cytotoxicity in KB human nasopharyngeal cancer cells compared to free cisplatin at the same concentration. Moreover, the interaction of ACA and laser irradiation acted synergistically and resulted in higher cell death rate compared to separate application of photothermal therapy and chemotherapy. The micrograph of KB cells also revealed that ACA was able to selectively accumulate into the mitochondria, so that laser irradiation of KB cells pre-treated with ACA resulted in intensive morphological damages such as plasma membrane disruption, chromatin condensation, autophagic vacuoles formation and organelle degeneration. Moreover, the sign and magnitude of altered optical nonlinear refractive index measured by Z-scan technique was shown to be significantly in cells exposed to irradiation. Consequently, the nanocomplex developed herein could be a promising platform to combine photothermal therapy and chemotherapy effectively, thereby achieving synergistic therapeutic outcome.
关键词： Gold nanoparticles,Cisplatin,Chemotherapy,Photothermal therapy,Thermo-chemotherapy
更新于2025-09-23 15:22:29
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A far-red FRET fluorescent probe for ratiometric detection of l-cysteine based on carbon dots and N-acetyl-l-cysteine-capped gold nanoparticles
摘要： A novel far-red fluorescence resonance energy transfer (FRET) fluorescenct probe for ratiometric detection of L-cysteine (L-Cys) has been designed. The system was established a FRET assembly by positively charged carbon dots (CDs) and negatively charged N-acetyl-L-cysteine capped gold nanoparticles (NAC-AuNPs). The fluorescence of CDs at 539 nm could be effectively quenched in the presence of NAC-AuNPs owing to FRET process, while the emission of NAC-AuNPs at 630 nm was appeared. Subsequently, the interactions between L-Cys and NAC-AuNPs resulted in the decreased emission intensity of NAC-AuNPs, but the emission intensity of CDs kept almost constant due to the continuous FRET efficiency. The ratio of emission intensities at 539 and 630 nm (I539/I630) exhibited a linear correlation to the L-Cys concentration in the range of 1.0-110 μM with the detection limit of 0.16 μM. Moreover, this far-red ratiometric sensor also revealed excellent selectivity toward L-Cys over other amino acids, which showed very high potential in the practical application for diagnosing of cysteine-related disease.
关键词： Fluorescence resonance energy transfer,gold nanoparticles,L-cysteine,Carbon dots
更新于2025-09-23 15:22:29
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Development of Ion Exchange Ligands with High Separation Performance and Colorimetric Analysis Using Gold Nanoparticles Decorated with The Functional Ligands
摘要： Development of metal separating reagents with high selectivity is necessary for efficient separation and recovery of valuable metals contained in industrial wastes, and removal and detection of toxic metals. We have developed novel metal separating ligands with a diglycolamic acid (DGAA) framework. The ligands have a tridentate coordination structure consisting of an amide group and a carboxy group connected by an ether chain and provide a metal separation ability superior to that of commercial ligands. Since the ligands can be synthesized simply in one step, this helps to reduce the production costs of the ligands. In the present review article, we report the extraction characteristics of DGAA-type ligand for 56 kinds of metal ions, extraction separation of rare-earth metal ions, and removal of toxic metal ions. Furthermore, a one-pot biological approach to fabricate DGAA-decorated gold nanoparticles has been developed using the DGAA-type ligand fused to the N-terminus of a gold-binding peptide. It was found that the DGAA-decorated gold nanoparticles can act as a high-sensitive colorimetric sensor for detecting toxic metal ions with color change.
关键词： Ion-exchange materials,Gold nanoparticles,Diglycolamic acid,Colorimetric detection,Metal separating reagents,Separation and recovery
更新于2025-09-23 15:22:29
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A photoelectrochemical glucose and lactose biosensor consisting of gold nanoparticles, MnO2 and g-C3N4 decorated TiO2
摘要： In this study, an innovative light-sensitive hybrid material was used for photoelectrochemical (PEC) biosensor fabrication. Herein, gold nanoparticles modified mesoporous TiO2 was coated on an indium tin oxide substrate, after a layer of MnO2/g-C3N4 was introduced to develop a PEC biosensor that yielded a favorable electronic interface for photo-excited electron injection. Glucose oxidase and β-galactosidase were co-immobilized on the photoanode surface via silane/glutaraldehyde linkage chemistry for glucose and lactose determination. Au NPs, g-C3N4, and MnO2 were utilized to modify quintessential semiconductor TiO2 owing to their narrow band gaps, appropriate position of the valence and conduction bands, and high visible light absorption. The p–n heterojunction formation at the interface of MnO2 and g-C3N4/TiO2 was presumed, and the heterojunction facilitates the charge transport and inhibit the recombination of excited electrons. Direct electron transfer led to the hole scavenging by FADH2, which reinforced the photocurrent. The linear measurement ranges were calculated in the range of 0.004-1.75 mM, with a sensitivity of 1.54 μAmM?1cm?2 for glucose at 0 V, and 0.008-2.50 mM, with a sensitivity of 1.66 μAmM?1cm?2 for lactose at -0.4 V. To the best of our knowledge, we report the first PEC lactose biosensor, and this study opens the door to PEC multianalyte detection.
关键词： β-galactosidase,g-C3N4,Self-powered biosensor,Glucose oxidase,Gold nanoparticles
更新于2025-09-23 15:21:21