APPLIED SURFACE SCIENCE
·
2019
·
IF 5.155
Qiao Wang,Peng Xu,Guangshan Zhang,Limin Hu,Peng Wang
Visible-light responsive g-C 3 N 4 catalysts were successfully prepared by the calcination of urea, i.e., the thermal polycondensation method, and a series of ZnS/g-C 3 N 4 composite photocatalysts were then synthesized using a rapid microwave hydrothermal method . The physicochemical properties of the resulting g-C 3 N 4 and ZnS/g-C 3 N 4 catalysts were characterized via several microscopy and spectroscopy techniques . The reduction of Cr(VI) was used to evaluate the photocatalytic performance of the as-synthesized catalysts under visible light irradiation. The results showed that the calcination temperature substantially affected the crystallinity , specific surface area and photocatalytic performance of g-C 3 N 4 . The optimal temperature for thermal polycondensation in the g-C 3 N 4 synthesis was 600 °C. The bulk g-C 3 N 4 catalyst exhibited no Cr(VI) reduction ability, while a certain amount of ZnS nanoparticles coupling with g-C 3 N 4 significantly improved the Cr(VI) reduction efficiency, creating a synergistic effect between g-C 3 N 4 and ZnS. The simultaneous Cr(VI) reduction and rhodamine B decolorization by the ZnS/g-C 3 N 4 composite catalyst were also accomplished. In addition, a Cr(VI) reduction mechanism under visible light irradiation was proposed.
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MICROCHIMICA ACTA
·
2018
·Vol. 186
·期 1
·1-9
·
IF 5.705
Zou Wen-Sheng,Deng Ming-Yue,Wang Ya-Qin,Zhao Xiaoli,Li Wei-Hua,Huang Xian-Huai
A method is described for the detection of Cu(II). It is based on the use of a room-temperature phosphorescent probe consisting of alginate-capped and manganese(II)-doped ZnS quantum dots. The carboxy groups at the surface of the probe strongly coordinate Cu(II) to form a complex. As a result, the 4 T 1 - 6 A 1 transition of the Mn(II) ions in the probe is quenched, and the long decay time (~2.1 ms in the unquenched state) is accordingly reduced. At excitation/emission wavelengths of 316/590 nm and a delay time of 0.1 ms, the probe shows a linear response in the 0.01 to 12 μM Cu(II) concentration range. The detection limit is 6.0 nM and the RSD is 3.2% (for n = 5).
A two-step procedure is described to synthesize alginate capped manganese doped ZnS QDs. These coordinate with Cu(II) to form an absorbent complex and can be used as a phosphorescent probe for time-resolved detection of Cu(II).
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SENSORS AND ACTUATORS B-CHEMICAL
·
2018
·
IF 5.667
Dongxia Li,Jin Qin,Qiang Xu,Guiqin Yan
A convenient and efficient biosensor for detection of alkaline phosphatase (ALP) activity was built with Mn-ZnS quantum dots (QDs) as the phosphorescent probe and adenosine 5′-monophosphate (AMP) as the substrate. Eu 3+ , which could coordinate with surface carboxyl group of Mn-ZnS QDs, was added into Mn-ZnS QDs to form Mn-ZnS QDs/Eu 3+ nanocomposites, which quenched the RTP of Mn-ZnS QDs through photoinduced electron-transfer (PIET). After ALP and AMP were added into the system, under the hydrolytic catalysis of ALP, AMP was rapidly converted into adenosine and phosphate ions. The higher affinity of phosphate ions to Eu 3+ than QDs resulted in the formation of a more stable composite, and subsequently, Eu 3+ was desorbed from the surfaces of Mn-ZnS QDs, which restored the RTP of Mn-ZnS QDs. Under the optimal conditions, the RTP intensity of the Mn-ZnS QDs (ΔRTP) was well linearly related to the logarithm of the ALP activity, with a detection range of 0.15－18 U L −1 and a detection limit of 0.065 U L −1 . This phosphorescent sensor avoided interference from autofluorescent and scattering light in real biological samples and was highly sensitive to ALP.
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TALANTA
·
2018
·
IF 4.244
Zhihua Wang,Yafang Zhang,Bing Zhang,Xiaoquan Lu
A newly fluorescence probe for detection of Serotonin based on a Mn-doped ZnS quantum dots@silica nanoparticle@molecularly imprinted polymers (QDs@SiO 2 @MIPs) was successfully created. QDs@SiO 2 @MIPs were characterized by scanning electron microscope, transmission electron microscope, Fourier transform infrared spectroscopy, UV spectroscopy , X-ray powder diffraction, and fluorescence spectroscopy. A complex was produced between the amino group of QDs@SiO 2 @MIPs and the hydroxyl group of 5-HT when 5-HT rebinding, the energy of the QDs would be transferred to the complex, which led to its fluorescence quenching . The composite material has a high selectivity with an imprinting factor of 5.96. The linear regression equation is F 0 /F = 0.0036Cq-0.0512 , with a correlation coefficient of 0.9928 in a liner range from 50 to 500 ng/mL. The limit of detection(LOD) was 0.69 ng/mL. The probe exhibited simple preparation process, high sensitivity, good selectivity, low detection limit, short analysis time and could be applied to detect 5-HT in human serum successfully.
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Polymers
·
2018
·Vol. 10
·期 11
·1217
·
IF 2.935
Jinku Xu,Dongmei Li
Transparent nanocomposite films containing quantum dots are popular because of their extensive applications. However, nanoparticles tend to aggregate, resulting in phase separation of the nanoparticles in the polymer matrix. Herein, we present a bulk thermo-curing copolymerization method to fabricate poly(methyl methacrylate)-based nanocomposite films with ultra-high-loading ZnS quantum dots (ZnS/PMMA), utilizing polymerizable group-capped ZnS and monomer of methyl methacrylate (MMA). We found that the nanocomposite film is highly transparent, although the transmittance decreases with the ZnS content, especially at the wavelength between 300 nm and 400 nm. The results from X-ray diffraction (XRD), transmission electron microscopy (TEM), and dynamic mechanical thermal analysis (DMTA) show that the ZnS quantum dots maintain their original crystal structure, and are uniformly dispersed in the nanocomposite films, even with a very high ZnS content (41 wt %, determined by thermogravimetric analysis). The thermogravimetric analysis shows that the nanocomposite films possess a better thermal stability than that of pure PMMA film. The photoluminescence measurements show that ZnS/PMMA nanocomposite films have good optical properties. The fluorescence intensity increases with the increment of free ZnS content to 30 wt %, and then decreases due to self-reabsorption at a higher ZnS content. The transparent ZnS/PMMA nanocomposite films have a potential application as photoluminescence material.Keywords:nanocomposites;Quantum dots;poly(methyl methacrylate);photoluminescence
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JOURNAL OF NANOPARTICLE RESEARCH
·
2015
·Vol. 17
·期 11
·1-8
·
IF 2.184
Chen Jun,Yang Xiao-Quan,Qin Meng-Yao,Zhang Xiao-Shuai,Xuan Yang,Zhao Yuan-Di
In this paper, polyethylene glycol-phospholipid structure is used to synthesize hybrid cluster of 40–50 nm diameter that contains hydrophobic bismuth sulfide nanoparticles and CdSe/ZnS quantum dots. The composite probe’s toxicity, CT imaging, and fluorescence imaging performance are also studied. Experimental results show that the nanocomposite hybrid cluster has obvious CT contrast enhancement and fluorescence imaging capability in vitro even after cellular uptake. It gives a CT number of 700 (Hounsfield units) at 15 mg/mL, higher than that of the current iobitridol CT contrast agent. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide experiment reveals that it has low cytotoxicity at concentration up to of 3.14 mg/mL of Bi, indicating the composite probe has potential ability for CT and fluorescence bimodal imaging.
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SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
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2014
·
IF 2.129
Chang Shu,Li Ding,Wenying Zhong
In the current work, using ZnSe ZnS quantum dots (QDs) as representative nanoparticles, the affinities of seven anticancer drugs for bovine serum albumin (BSA) were studied using fluorescence resonance energy transfer (FRET). The FRET efficiency of BSA–QD conjugates can reach as high as 24.87% by electrostatic interaction. The higher binding constant (3.63 × 10 7 L mol −1 ) and number of binding sites (1.75) between ZnSe ZnS QDs and BSA demonstrated that the QDs could easily associate to plasma proteins and enhance the transport efficacy of drugs. The magnitude of binding constants (10 3 –10 6 L mol −1 ), in the presence of QDs, was between drugs–BSA and drugs–QDs in agreement with common affinities of drugs for serum albumins (10 4 –10 6 L mol −1 ) in vivo. ZnSe ZnS QDs significantly increased the affinities for BSA of Vorinostat (SAHA), Docetaxel (DOC), Carmustine (BCNU), Doxorubicin (Dox) and 10-Hydroxycamptothecin (HCPT). However, they slightly reduced the affinities of Vincristine (VCR) and Methotrexate (MTX) for BSA. The recent work will not only provide useful information for appropriately understanding the binding affinity and binding mechanism at the molecular level, but also illustrate the ZnSe ZnS QDs are perfect candidates for nanoscal drug delivery system (DDS).
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JOURNAL OF LUMINESCENCE
·
2014
·
IF 2.367
Xiao Wei,Zhiping Zhou,Jiangdong Dai,Tongfan Hao,Hongji Li,Yeqing Xu,Lin Gao,Jianming Pan,Chunxiang Li,Yongsheng Yan
In this paper, a simple procedure for the determination of 2,4,5-trichlorophenol (2,4,5-TCP) is reported. Mn-doped ZnS quantum dots (QDs) capped by molecularly imprinted polymers (MIPs) were prepared. MIPs were characterized by spectrofluorometer, UV–vis spectrophotometer , X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscope (TEM) and scanning electron microscope (SEM). Meanwhile, spectrofluorometer was used to the evaluation of optical stability, the effect of pH, and the selective and sensitive determination of 2,4,5-TCP. Under optical conditions, MIPs-capped Mn-doped ZnS QDs were successfully applied to the detection of 2,4,5-TCP in water selectively and sensitively, and a linear relationship was obtained to cover the concentration range of 5.0–50 μmol L −1 with a correlation coefficient of 0.9913. Moreover, 2,4,5-TCP could quench the room temperature phosphorescence of MIPs-capped Mn-doped ZnS QDs in a concentration-dependent manner, which was best described by a Stern–Volmer-type equation.
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MICROCHIMICA ACTA
·
2014
·Vol. 181
·期 13
·1591-1599
·
IF 3.719
Ban Rui,Zhu Jun-jie,Zhang Jianrong
We present a sensitive and selective method for the determination of organophosphorus pesticides (OPs) based on the inhibition of the enzyme acetylcholinesterase (AChE). It is making use of quantum dots QDs of the type Mn: ZnS that display long-lived phosphorescence emission and act as optical probes for hydrogen peroxide (H 2 O 2 ). In this assay, acetylcholine (ACh) is first hydrolyzed by AChE, and the enzyme choline oxidase (ChOx) further oxidizes choline under the formation of H 2 O 2 which quenches the phosphorescence of the QDs. If, however, OPs are added to the solution, the rate of enzymatic hydrolysis by AChE is retarded. This reduces the rate of production of H 2 O 2 and results in a reduced quenching efficiency. The slow decay time of the phosphorescence of the QDs also allows time-resolved luminescence intensity to be measured. This can eliminate background fluorescence from the sample and therefore improves analytical accuracy and the signal-to-noise ratio. Under optimized conditions, there is a linear relationship between luminescence intensity and the concentration of paraoxon in the 1 pM to 1 μM range, with an ~0.1 pM limit of detection which is much lower than that of most existing methods. The phosphorescent probe was applied to determine OPs in spiked real samples.
We present a sensitive and selective method for the determination of organophosphorus pesticides (OPs) based on the inhibition of the enzyme acetylcholinesterase (AChE). It is making use of quantum dots QDs of the type Mn-doped ZnS that display long-lived phosphorescence emission and act as optical probes for hydrogen peroxide (H 2 O 2 ).
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Nanoscale Research Letters
·
2014
·Vol. 9
·期 1
·1-13
·
IF 2.481
Li Chao,Ji Yang,Wang Can,Liang Shujing,Pan Fei,Zhang Chunlei,Chen Feng,Fu Hualin,Wang Kan,Cui Daxiang
Successful development of safe and highly effective nanoprobes for targeted imaging of in vivo early gastric cancer is a great challenge. Herein, we choose the CdSe/ZnS (core-shell) quantum dots (QDs) as prototypical materials, synthesized one kind of a new amphiphilic polymer including dentate-like alkyl chains and multiple carboxyl groups, and then used the prepared amphiphilic polymer to modify QDs. The resultant amphiphilic polymer engineered QDs (PQDs) were conjugated with BRCAA1 and Her2 monoclonal antibody, and prepared BRCAA1 antibody- and Her2 antibody-conjugated QDs were used for in vitro MGC803 cell labeling and in vivo targeted imaging of gastric cancer cells. Results showed that the PQDs exhibited good water solubility, strong photoluminescence (PL) intensity, and good biocompatibility. BRCAA1 antibody- and Her2 antibody-conjugated QD nanoprobes successfully realized targeted imaging of in vivo gastric cancer MGC803 cells. In conclusion, BRCAA1 antibody- and Her2 antibody-conjugated PQDs have great potential in applications such as single cell labeling and in vivo tracking, and targeted imaging and therapeutic effects' evaluation of in vivo early gastric cancer cells in the near future.
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RSC Advances
·
2016
·Vol. 6
·期 111
·109386-109393
·
IF 3.289
Jian-Jun Shi,Lei Gong,Yan-Hong Zhang,Ping Yang,Jie He
A series of Cu and Mn doped glutathione (GSH)–ZnS polypeptide quantum dots (QDs) were successfully prepared by a facile one-pot microwave-assisted sonochemical synthesis approach. Herein, GSH acted as a sulfide source and dispersant, as well as a reducing agent to form polypeptide QDs. The products were characterized by high-resolution transmission electron microscope (HRTEM) and energy dispersive spectroscopy (EDS). Results show that the size of the polypeptides QDs was 2–3 nm. In Fourier transform infrared (FT-IR) spectra, the splitting of S–H bonds and substitution by S–Zn can be noticed. The bonding interaction between Cu, Mn and Zn ions toward S was further confirmed from X-ray photoelectron spectroscopy (XPS) analysis. The results confirmed the partial Cu(Mn) substitution of Zn. Fluorescence (FL) spectra and UV-vis absorption spectra were used to investigate the optical properties. It was found that the doping of Cu and Mn could decrease the band gap of GSH–ZnS from 3.67 eV to 2.86 eV. The photoelectrochemical (PEC) properties of GSH–ZnS were enhanced due to the doping of Cu and Mn which has excellent chemical stability. The possible photoelectrochemical reaction mechanism is discussed.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2025
·
IF 9.7
Asif Hassan Raza,Long Li,Shumail Farhan,Wenjing Fu,Yan Wu
Two dimensional (2D) photocatalytic materials are desirable to achieve synergistic charge transfer and segregation. Here, we have developed 2D ZnIn 2 S 4 nanosheet (3–4 nm) that generates more active sites for excellent photocatalytic activity. Further, we have fabricated ZnS quantum dots (QDs) and ZnS nanoparticles (NPs) embedded with ZnIn 2 S 4 nanosheet in the form of ZnS QDs/ZnIn 2 S 4 and ZnS NPs/ZnIn 2 S 4 heterostructures prepared via one step hydrothermal method. The optimal ZnS QDs/ZnIn 2 S 4 presents the hydrogen evolution rate (HER) of 4.5 mmol g −1 h −1 which was approximately 5 and 34 times higher than that of their counterparts as well as about 3 times more efficient than ZnS NPs/ZnIn 2 S 4 heterostructure. The apparent quantum efficiency (AQE) of 21.2% was observed at 350 nm. The work functions determined through Ultraviolet photoelectron spectroscopy (UPS) elaborate the charge transfer mechanism. In situ KPFM validated the surface potential difference between the ZnS QDs and ZnIn 2 S 4 interfaces estimated about 55 mV which was approximately 2 times higher than ZnS NPs/ZnIn 2 S 4 . Theoretical calculation confirms the significant reduction in Gibbs free energy about −0.6 eV. Electron paramagnetic resonance (EPR) spectra suggest the development of a novel S-scheme mechanism and provides a unique insight into the charge transfer, separation and the surface photovoltage of heterostructure photocatalysts.
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