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Enhanced photocatalytic performance of TiO2 NTs decorated with chrysanthemum-like BiOI nanoflowers
摘要： The BiOI nanosheets/chrysanthemum-like nanoflowers were successfully deposited on the surface of TiO2 nanotube arrays (TiO2 NTs) by the successive ionic layer adsorption and reaction (SILAR) method, and the morphology and visible light response of samples with different SILAR deposition cycles were investigated in detail. The as-prepared BiOI/TiO2 NTs significantly enhanced photoelectrocatalytic (PEC) activity for the removal of Methyl orange (MO), Rhodamine B (RhB), Methylene blue (MB) and Cr(VI). The as-prepared Sample-7 with chrysanthemum-like nanostructures showed the high visible light photocurrent density of 120.06 μA/cm2, photovoltage of ?203.61 mV/cm2, PEC efficiencies of 45%, 62%, 79% and 77% for the removal of MO, RhB, MB and Cr(VI), respectively. The high PEC performances could be ascribed to the excellent visible light response and charge carrier transportation in chrysanthemum-like BiOI nanoflowers. By further probing the charge separation and transportation behaviors, the experiments of the energy band structure and active species trapping were carried out. A possible p-n heterojunction photocatalytic mechanism was proposed, which not only benefited the efficient separation of photogenerated electrons but also demonstrated the advanced capacity for the PEC removal of organic dyes and heavy metal ions.
关键词： BiOI,Photoelectrochemical performance,TiO2 nanotube arrays,Nanoflowers
更新于2025-11-19 16:56:35
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Gold nanoparticles of different shape for bicolor lateral flow test
摘要： Spherical gold nanoparticles are the most commonly used marker in lateral flow assays. However, the widespread practice of using identical coloration for the test and control zones of test strips can lead to erroneous interpretations of the assay’s results. We propose an immunochromatographic test strip with lines of different colors. For this purpose, gold nanoparticles of different shapes were used, namely blue nanoflowers in the test zone and red gold nanospheres in the control zone. A detailed synthesis procedure for nanoparticles and their conjugates is considered and design parameters for optimal results are described. For the first time, nanoparticles of different shapes have been combined in the test strip with indirect labeling of specific antibodies (via their interaction with labeled secondary antibodies). Using the T-2 toxin (T2T) as an example, an instrumental detection limit of 30 pg/mL and a working range 0.06-0.9 ng/mL were achieved in an analysis of water-organic corn extracts.
关键词： gold nanoparticles,Immunochromatography,test strip,mycotoxin,indirect labeling,gold nanoflowers
更新于2025-09-23 15:23:52
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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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Silver nanoflowers-enhanced Tb(III)/La(III) co-luminescence for the sensitive detection of dopamine
摘要： A sensitive fluorescent analytical method for the detection of dopamine (DA) was developed based on surface-enhanced Tb(III)/La(III) co-luminescence using silver nanoflowers (AgNFs). Anisotropic AgNFs show strong surface-enhanced fluorescence effect owing to the abundant sharp tips. Tb(III)/La(III)-DA complexes mainly bind to the sharp tips of AgNFs and thus shorten the distance between the complexes. The shortened distance gives rise to obvious surface-enhanced Tb(III)/La(III) co-luminescence effect. In this work, AgNFs offer many superior properties, such as enhanced intrinsic green fluorescence of Tb(III) (λex/λem = 310/546 nm), increased fluorescence lifetime, and improved energy transfer efficiency. Under the optimum conditions, the fluorescence intensity is linearly correlated with the concentration of DA in the range of 0.80–10 nM (R2 = 0.9970), and the detection limit is 0.34 nM (S/N = 3). The fluorescent nanoprobe was successfully applied to the determination of DA in human serum samples with recoveries ranging from 99.1 to 102.6%.
关键词： Co-luminescence,Anisotropic nanoparticles,Surface-enhanced fluorescence,Rare earth elements,Dopamine,Silver nanoflowers
更新于2025-09-23 15:22:29
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Rationally Designed Multifunctional Carbon-Palladium Nanohybrids for Wide Applications: From Electrochemical Catalysis/Nonenzymatic Sensor to Photothermal Tumor Therapy
摘要： Palladium nanomaterials have been widely investigated in many areas due to their high activity of catalysis and surface plasmon resonance (SPR) resulting from their special configuration of outer electron. Herein, the novel nanoparticles, reduced graphene oxide modified with palladium nanoflowers (rGO/PdNFs), were designed and synthesized by seeded growth. Their application potentials in three areas were explored, including electrochemical ethanol catalysis, nonenzymatic glucose sensor and photothermal tumor therapy. The hybrids of PdNFs and rGO increased the conductivity and active sites of PdNFs, and then enhanced the activity of catalysis. Interestingly, through control of morphologies, the absorption of PdNFs in near infrared region was enhanced compared with common palladium nanoparticles, which showed excellent potential in photothermal tumor therapy. These results indicated the stronger activity of catalysis to ethanol of rGO/PdNFs compared with the commercial Pd/C catalyst, superior sensitivity and selectivity of glucose, and effective photothermal antitumor efficacy. Overall, it is demonstrated that the multifunctional rGO/PdNFs nanohybrids could possess more application potentials.
关键词： Nonenzymatic sensor,Photothermal tumor therapy,Reduced graphene oxide,Palladium nanoflowers,Electrochemical catalysis
更新于2025-09-23 15:22:29
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Novel Ag2O nanoparticles modified MoS2 nanoflowers for piezoelectric-assisted full solar spectrum photocatalysis
摘要： The separation of photoinduced electrons and holes can enhance the photocatalytic properties of photocatalysts. A piezoelectric field is created inside piezoelectric materials, such as ZnO and MoS2, by applying strain. The electrons and holes become separated under the driving force of the piezoelectric field. Here, we propose combining piezoelectric MoS2 nanoflowers (NFs) and full solar response Ag2O nanoparticles (NPs) to form a MoS2@Ag2O heterostructure and achieve high efficiency full solar (UV, visible, and near-infrared) photocatalysis. Under both full solar light and ultrasonic excitation, the MoS2@Ag2O heterostructures can rapidly degrade methyl orange (MO) in aqueous solution. A built-in electric field is formed by the spontaneous polarization potential of the MoS2 NFs during this process, and an ultrasonic wave as a driving force can consecutively change the potential created by the piezoelectric effect. Under light irradiation, electrons and holes are generated in the Ag2O NPs, and the photogenerated electrons and holes with opposite signs in the two Ag2O NPs at the two surfaces of the MoS2 NFs, can be separated respectively, along the spontaneous polarized direction. Therefore, the piezoelectric effect-induced enhancement of carrier separation under ultrasonic excitation can improve the full solar photocatalytic performance of the MoS2@Ag2O heterostructures.
关键词： Piezoelectric,MoS2 nanoflowers,Full solar light,Photocatalytic,Ag2O nanoparticles
更新于2025-09-23 15:21:21
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A Strategy for In-Situ Imaging of Cellular Alkaline Phosphatase Activity Using Gold Nanoflower Probe and Localized Surface Plasmon Resonance Technique
摘要： In this work, a simple and ultrasensitive localized surface plasmon resonance (LSPR) method that use Au nanoflowers (AuNFs) as probe was designed for in-situ monitoring of alkaline phosphatase (ALP) activity. The AuNFs was fabricated by hydrogen tetrechloroaurate-induced oxidative disruption of polydopamine-coated Au nanoparticles (AuNPs) and subsequently growth of Au nanopetals on AuNPs. The as-prepared AuNFs showed a much higher LSPR capability and stronger scattering color change than AuNPs. The strategy for in-situ cellular ALP activity detection relied on the deposition of Ag on AuNFs surface, which changed the morphology of AuNFs and led to a tremendous LSPR response and scattering color change. The deposition of Ag shell on AuNFs was related to ALP activity, where ALP catalyzed the hydrolysis of L-ascorbic acid 2-phosphate sesquimagnesium salt hydrate to form L-ascorbic acid (AA), then AA reduced Ag+ to Ag and deposited onto AuNFs. With this concept, the ALP activity could be monitored with a detection limit of 0.03 μU L-1. Meanwhile, the ALP activity of single HepG2 cells and HEK 293 cells was tracked with proposed approach, which indicated the trace expression level of ALP in HEK 293T cell and overexpressed level of ALP in HepG2 cells. After treated with drugs, the cellular ALP activity of HepG2 cells was decreased with the treating time and dose increasing. Therefore, the proposed strategy could be used for tracking the cellular ALP activity, which paved a new avenue for cell studies, and hold great potential for discovering novel ALP-based drugs applications.
关键词： cellular activity,alkaline phosphatase,localized surface plasmon resonance,in-situ imaging,gold nanoflowers
更新于2025-09-23 15:21:21
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A sensitive immunoassay for simultaneous detection of foodborne pathogens using MnO2 nanoflowers-assisted loading and release of quantum dots
摘要： In this study, a sensitive immunoassay using immunomagnetic nanobeads (MNBs), manganese dioxide nanoflowers (MnO2 NFs) and quantum dots (QDs) was developed for simultaneous detection of E. coli O157: H7 and Salmonella typhimurium. MnO2 NFs were synthesized, functionalized and incubated with QDs to obtain QDs@MnO2 nanocomposites, followed by modification with antibodies (pAbs) to obtain pAb-QDs@MnO2 nanocomposites (QM NCs). Target bacteria were first conjugated with MNBs and QM NCs to form MNB-bacteria-QM complexes. Then, QDs were quickly released from the complexes using glutathione to reduce MnO2 to Mn2+. Finally, fluorescent intensity at characteristic wavelength was measured by optical detector to determine target bacteria. This immunoassay could simultaneously and quantitatively detect E. coli from 1.5 × 101 to 1.5 × 106 CFU/mL with detection limit of 15 CFU/mL and Salmonella from 4.0 × 101 to 4.0 × 106 CFU/mL with detection limit of 40 CFU/mL in 2 h. The mean recovery for both bacteria in spiked chicken samples was ～96%.
关键词： Pathogenic bacteria,Quantum dots,Simultaneous detection,Manganese dioxide nanoflowers,Fluorescent immunoassay
更新于2025-09-23 15:21:01
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Photocatalytic degradation enhancements of dyes with bi-functionalized zones of modified nanoflower like TiO2 with Pt-C3N4 under sunlight irradiation
摘要： In this work, a novel method was proposed to photodegradation of organic dyes as important pollutants in wastewaters of textile industries. A one-step hydrothermal method was used to directly synthesis nanoflower like TiO2 on ordinary glass (OG) and modified with Pt-C3N4 nanotubes (NFs TiO2/Pt-C3N4) via electrophoretic deposition (EPD) method. Its photocatalytic activity investigated for degradation of three dyes under sunlight irradiation. The properties of NFs TiO2/Pt-C3N4 NTs were characterized by SEM, FT-IR, EDS, and XRD. Reduction of band gap energy and improvement of light absorption in the visible region for the modified photocatalyst were evaluated by using Tauc’s plot method. The experimental result showed that the NFs TiO2/Pt-C3N4 NTs achieved degradation efficiency of <97% at 240 min, towards methylene blue (MB), methyl violet (MV) and malachite green (MG) which are higher than pure TiO2 (68%, 83%, and 71%, respectively). Also as a new strategy, a part of the NFs TiO2/Pt-C3N4 NTs was used as a photoanode of the dye-sensitized solar cell (DSSC) and the other part, placed at a solution as a degradation zone. So with this bi-functionalized system, the degradation time was reduced from 240 min to 120 min with the same degradation efficiency.
关键词： Nanoflowers of TiO2,Pt-C3N4 nanotubes,dye-sensitized solar cells,photodegradation,bi-functionalized system
更新于2025-09-23 15:21:01
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A Microfluidic Biosensor Based on Magnetic Nanoparticle Separation, Quantum Dots Labeling and MnO2 Nanoflower Amplification for Rapid and Sensitive Detection of Salmonella Typhimurium
摘要： Screening of foodborne pathogens is an effective way to prevent microbial food poisoning. A microfluidic biosensor was developed for rapid and sensitive detection of Salmonella Typhimurium using quantum dots (QDs) as fluorescent probes for sensor readout and manganese dioxide nanoflowers (MnO2 NFs) and as QDs nanocarriers for signal amplification. Prior to testing, amino‐modified MnO2 nanoflowers (MnO2‐NH2 NFs) were conjugated with carboxyl‐modified QDs through EDC/NHSS method to form MnO2‐QD NFs, and MnO2‐QD NFs were functionalized with polyclonal antibodies (pAbs) to form MnO2‐QD‐pAb NFs. First, the mixture of target Salmonella Typhimurium cells and magnetic nanoparticles (MNPs) modified with monoclonal antibodies (mAbs) was injected with MnO2‐QD‐pAb NFs into a microfluidic chip to form MNP‐bacteria‐QD‐MnO2 complexes. Then, glutathione (GSH) was injected to dissolve MnO2 on the complexes into Mn2+, resulting in the release of QDs. Finally, fluorescent intensity of the released QDs was measured using the fluorescent detector to determine the amount of Salmonella. A linear relationship between fluorescent intensity and bacterial concentration from 1.0 × 102 to 1.0 × 107 CFU/mL was found with a low detection limit of 43 CFU/mL and mean recovery of 99.7% for Salmonella in spiked chicken meats, indicating the feasibility of this biosensor for practical applications.
关键词： quantum dots,manganese dioxide nanoflowers,Salmonella Typhimurium,Microfluidic biosensor,magnetic nanoparticles
更新于2025-09-23 15:19:57