JOURNAL OF HAZARDOUS MATERIALS
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2017
·
IF 6.065
Wang Ren,Ying Zhang,Yu Zhu Fan,Jiang Xue Dong,Nian Bing Li,Hong Qun Luo
A resonance Rayleigh scattering (RRS) aptasensor was fabricated for detection of Pb 2+ via hairpin-like label-free substrate and G-wire for signal amplification. A hairpin-like DNA substrate contains a sequence in the loop labeled with ribonucleobase A and c-myc sequence in the stem. When hybridized with 8–17 DNAzyme in the presence of Pb 2+ , the sequence in the loop was activated and cleaved. Hundreds of c-myc sequences departing from the 8–17 DNAzyme yield nanowires superstructure called G-wire in the presence of Mg 2+ . The polymer G-wire was demonstrated by the RRS spectrum, polyacrylamide gel electrophoresis, and AFM. The RRS intensity was enhanced by the product G-wires, and the RRS signal at 370 nm was linear with the logarithm of Pb 2+ concentration in the range of 2.0 nM to 5.0 μM. This method was selective for Pb 2+ even coexisting with other metal ions at high concentrations and was successfully applied to the determination of Pb 2+ in real samples. The aptasensor holds a great promise for universal RRS sensing platform for sensitive detection of various metal ions just by changing the sequence of the probe in the loop and DNAzyme.
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SENSORS
·
2017
·Vol. 17
·期 1
·80
·
IF 2.677
Changwu Lv,Zhenhong Jia,Jie Lv,Hongyan Zhang,Yanyu Li
N-type macroporous silicon microcavity structures were prepared using electrochemical etching in an HF solution in the absence of light and oxidants. The CdSe/ZnS water-soluble quantum dot-labeled DNA target molecules were detected by monitoring the microcavity reflectance spectrum, which was characterized by the reflectance spectrum defect state position shift resulting from changes to the structures’ refractive index. Quantum dots with a high refractive index and DNA coupling can improve the detection sensitivity by amplifying the optical response signals of the target DNA. The experimental results show that DNA combined with a quantum dot can improve the sensitivity of DNA detection by more than five times.Keywords:N-type porous silicon;quantum dot labeling;QD-DNA;reflectance spectrum
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Open Life Sciences
·
2016
·Vol. 11
·期 1
·542-551
·
IF 0
Huanan Wang,Ming Yao,Wenqing Xu
Cancer is the second leading cause of death worldwide. Traditional antitumor drugs exhibit severe cytotoxic and side effects. Lung cancer needs new and more effective treatment approaches. Coumarin derivatives can act on various tumor cells and show anti-proliferative activity through various mechanisms, including mitochondrial signaling cascades that regulate development and apoptosis of cells. Mitochondria-targeted coumarin derivatives have not been reported yet. Taking advantage of the fact that cancer cells frequently have higher mitochondria membrane potential, we synthesized a mitochondria-targeted 6-(nicotinamide) methyl coumarin by coupling 6-methyl coumarin to nicotinamide. Our results demonstrate that 6-(nicotinamide) methyl coumarin preferentially kills A549 cells through inducing A549 cells apoptosis, mediated by increasing ROS level and causing mitochondrial depolarization. Strikingly, the viability of the A31 cells treated with 6-(nicotinamide) methyl coumarin did not decrease, indicating that 6-(nicotinamide) methyl coumarin preferentially accumulates in A549 cells and A549 cells are much more susceptible to 6-(nicotinamide) methyl coumarin treatment compared with A31 cells.
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Nanoscale
·
2016
·Vol. 8
·期 11
·6071-6078
·
IF 7.76
Hao Liang,Shuhui Jiang,Qipeng Yuan,Guofeng Li,Feng Wang,Zijie Zhang,Juewen Liu
Preserving enzyme activity and promoting synergistic activity via co-localization of multiple enzymes are key topics in bionanotechnology, materials science, and analytical chemistry. This study reports a facile method for co-immobilizing multiple enzymes in metal coordinated hydrogel nanofibers. Specifically, four types of protein enzymes, including glucose oxidase, Candida rugosa lipase, α-amylase, and horseradish peroxidase, were respectively encapsulated in a gel nanofiber made of Zn2+ and adenosine monophosphate (AMP) with a simple mixing step. Most enzymes achieved quantitative loading and retained full activity. At the same time, the entrapped enzymes were more stable against temperature variation (by 7.5 °C), protease attack, extreme pH (by 2-fold), and organic solvents. After storing for 15 days, the entrapped enzyme still retained 70% activity while the free enzyme nearly completely lost its activity. Compared to nanoparticles formed with AMP and lanthanide ions, the nanofiber gels allowed much higher enzyme activity. Finally, a highly sensitive and selective biosensor for glucose was prepared using the gel nanofiber to co-immobilize glucose oxidase and horseradish peroxidase for an enzyme cascade system. A detection limit of 0.3 μM glucose with excellent selectivity was achieved. This work indicates that metal coordinated materials using nucleotides are highly useful for interfacing with biomolecules.
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INTERNATIONAL JOURNAL OF PHARMACEUTICS
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2016
·
IF 3.994
Hui-Yun Zhang,Wen-Qian Xu,Yuan-Wen Wang,Emmanuel Omari-Siaw,Yan Wang,Yuan-yuan Zheng,Xia Cao,Shan-Shan Tong,Jiang-nan Yu,Xi-ming Xu
Periplogenin (PPG), a cardiac glycoside prepared from Cortex periplocae , with similar structure to bufalin , has been found to induce apoptosis in many tumor cells. However, lots of cardiac glycosides possessing strong antitumor activity in vitro have still not passed phase I clinical trials , mostly due to poor tumor selectivity and systemic toxicity. To overcome this drawback, we designed octreotide-periplogenin (OCT-PPG) conjugate by coupling PPG–succinate to the amino-terminal end of octreotide . In comparison with free PPG, the conjugate exhibited significantly stronger cytotoxicity on HepG2 cells (SSTRs overexpression) but much less toxicity in L-02 cells. After intravenous injection of OCT-PPG conjugate into H 22 tumor-bearing mice, its total accumulation in tumor was 2.3 fold higher than that of free PPG, but was 0.71- and 0.84-fold lower in heart and liver, respectively, suggesting somatostatin-mediated target delivery of PPG into the tumor tissue and reduced distribution in heart and liver. In vivo studies using H 22 tumor model in mice confirmed the remarkable therapeutic effect of this conjugate. These results suggested that OCT-PPG conjugate could provide a new approach for clinical application of cardiac glycosides and as a targeting agent for cancer therapy.
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MICROCHIMICA ACTA
·
2016
·Vol. 183
·期 4
·1333-1339
·
IF 4.831
Wang Xiao-Feng,Xiang Li-Ping,Wang Yong-Sheng,Xue Jin-Hua,Zhu Yu-Feng,Huang Yan-Qin,Chen Si-Han,Tang Xian
The authors describe a strategy for fluorometric determination of lead(II) that is based on the suppression of the surface energy transfer that occurs between acridine orange and gold nanoparticles (AuNPs). As a result, the fluorescence of the system is recovered. Under optimized conditions, the enhancement of fluorescence intensity is related to the concentration of lead(II) in the 44 nM to 4.8 μM range, with a detection limit of 13 nM. The relative standard deviations for 11 determinations at concentrations of 0.386 μM, 1.93 μM and 2.89 μM are 1.02 %, 1.06 % and 1.75 %, respectively. This result suggests that the method can potentially be used to monitor the level of lead(II) in environmental samples.
Lead(II) ion is found to bind to citrate capped gold nanoparticles (AuNPs) which prevents binding of acridine orange (AO) to the AuNPs. As a result, the surface energy transfer from AO to AuNPs cannot occur and fluorescence is restored. This effect was used to quantify lead(II) ion.
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CARBOHYDRATE POLYMERS
·
2017
·
IF 4.811
Jie Wu,Yaping Wang,Hao Yang,Xiangyu Liu,Zhong Lu
Nanoparticles with size range of 10–500 nm can be efficiently delivered into cancer cells by the Enhanced Permeability and Retention (EPR) effect. Here, we prepared resveratrol (Res) loaded chitosan (CS) nanoparticles with the size of 172–217 nm by an ionic cross-linking method, with sodium tripolyphosphate (TPP) as the cross-linking agent, to improve the stability, solubility and tumors targeting of the natural anti-cancer drug Res. The prepared Res loaded CS-TPP nanoparticles presented long-term storage stability and UV light stability. The cumulative drug release from nanoparticles in mimetic tumor tissue condition (pH 6.5) was higher than that in physiological condition (pH 7.4). Further, Res-loaded CS-TPP nanoparticles maintained the antioxidant activity of Res even after UV light irradiation. Cell viability study shows that the as prepared drug loaded nanoparticles had similar antiproliferative activity on hepatocellular carcinoma cells SMMC 7721 and lower cytotoxicity on normal hepatocyte cells L02 compared with free Res. Fluorescence microscopy observation revealed that the nanoparticles were efficiently taken in by SMMC 7721 cells. This work indicates the potential use of drug loaded CS-TPP nanoparticles for the efficient delivery of bioactive Res for chemotherapy.
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ANALYTICAL CHEMISTRY
·
2017
·
IF 6.32
Shan Sun,Kai Jiang,Sihua Qian,Yuhui Wang,Hengwei Lin
Fluorescent carbon dots (CDs) are attracting much attention in sensing recently thanks to their superior optical properties and abundant surface functional groups. To take further advantages of these unique features, CDs are considered to be possible for facilely fabricating multichannel sensor arrays. As a proof-of-concept research, CDs-metal ions ensembles are screened and designed as a triple-channel fluorescent sensor array in this study for the identification of various phosphate anions (e.g., ATP, ADP, AMP, PPi, and Pi) for the first time. Further studies reveal that the selected three metal ions (i.e., Ce3+, Fe3+, and Cu2+) could induce aggregation of the CDs, resulting in quenching of their fluorescence. However, disaggregation or further aggregation of the CDs-metal ions ensembles occurs with the addition of phosphate anions. Consequently, fluorescence of the CDs is recovering or further quenching. On account of various numbers of phosphate group and steric hindrance effects of phosphate anions, their affinities to the sensor array can be distinguished through fluorescence changes of the CDs-metal ions ensembles. By means of statistical analysis methods, the as-developed array is shown excellent capabilities in the detection and discrimination of phosphate anions. Furthermore, practicability of the sensor array is validated by the successful identification of phosphates in serum and blind samples. Compared to previous reports, the as-developed multichannel sensor array manifests numerous advantages, such as simple fabrication process, flexible adjusting detection ranges, and possible extension to other analytes having similar chemical structures or properties.
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BIOSENSORS & BIOELECTRONICS
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2016
·
IF 7.476
Hao Wu,Yaling Liu,Hongyong Wang,Jun Wu,Feifan Zhu,Pei Zou
In this study, a simple, label-free, and enzyme-free colorimetric biosensor has been developed for amplified detection of let-7a microRNA (miRNA) on the basis of dual signal amplification strategy. The sensing system mainly consists of four unlabeled hairpin probes termed H1, H2, H3, and H4. Upon sensing of the target miRNA, hairpin H1 is opened. Then hairpin H2 hybridizes with H1 forming H1–H2 duplex and frees the target miRNA that can be recycled to trigger another reaction cycle. In addition, the newly formed H1–H2 duplex hybridizes with hairpin H3, and this triggers the autonomous cross-opening of the two hairpins H3 and H4 through hybridization chain reaction. During this process, numerous split G-quadruplex structures are generated and further associate with cofactor hemin to form massive peroxidase-mimicking DNAzymes. The resulting DNAzymes catalyze the H 2 O 2 -mediated oxidation of colorless 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS 2− ) to the green-colored ABTS •− , inducing a remarkably amplified colorimetric signal. This newly developed sensing system exhibits high sensitivity toward miRNA with a detection limit of 7.4 fM and a large dynamic range of 6 orders of magnitude from 10 fM to 10 nM. Furthermore, it exhibits a good performance to discriminate single-base difference among the miRNA family members and holds a great potential for early diagnosis in gene-related diseases.
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COLLOIDS AND SURFACES B-BIOINTERFACES
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2016
·
IF 3.902
Farooq Ahmad,Xing Zhou,Hongzhou Yao,Ying Zhou,Chao Xu
The present study explored the interaction and kinetics of cobalt ferrite nanoparticles (NPs) with acid phosphatase (ACP) by utilizing diverse range of spectroscopic techniques. The results corroborate, the CoFe 2 O 4 NPs cause fluorescence quenching in ACP by static quenching mechanism. The negative values of van’t Hoff thermodynamic expressions (Δ H = −0.3293 J mol −1 K −1 and Δ G = −3.960 kJ mol −1 K −1 ) corroborate the spontaneity and exothermic nature of static quenching. The positive value of ΔS (13.2893 J mol −1 K −1 ) corroborate that major contributors of higher and stronger binding affinity among CoFe 2 O 4 NPs with ACP were electrostatic. In addition, FTIR, UV-CD, UV–vis spectroscopy and three dimensional fluorescence (3D) techniques confirmed that CoFe 2 O 4 NPs binding induces microenvironment perturbations leading to secondary and tertiary conformation changes in ACP to a great extent. Furthermore, synchronous fluorescence spectroscopy (SFS) affirmed the comparatively significant changes in microenvironment around tryptophan (Trp) residue by CoFe 2 O 4 NPs. The effect of CoFe 2 O 4 NPs on the activation kinetics of ACP was further examined in Chlorella vulgaris . Apparent Michaelis constant (Km) values of 0.57 and 26.5 mM with activation energy values of 0.538 and 3.428 kJ mol −1 were determined without and with 200 μM CoFe 2 O 4 NPs. Apparent Vmax value of −7 Umml −1 corroborate that enzyme active sites were completely captured by the NPs leaving no space for the substrate. The results confirmed that CoFe 2 O 4 NPs ceased the activity by unfolding of ACP enzyme. This suggests CoFe 2 O 4 NPs perturbed the enzyme activity by transitions in conformation and hence the metabolic activity of ACP. This study provides the pavement for novel and simple approach of using sensitive biomarkers for sensing NPs in environment.
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Journal of Materials Chemistry B
·
2017
·Vol. 5
·期 37
·7692-7700
·
IF 4.543
Jie Gao,Caihong Wang,Hongliang Tan
This work demonstrated the potential of lanthanide/nucleotide coordination polymers as a host platform for encapsulating enzymes and fluorescent nanoparticles to fabricate multifunctional composites. The self-adaptive assembly of terbium ions (Tb3+), adenosine monophosphate (AMP), glucose oxidase (GOx), and carbon dots (CDs) leads to the formation of a GOx&CDs@AMP/Tb composite with catalytic and fluorescence properties. Owing to the confinement effect, the GOx&CDs@AMP/Tb composite exhibited about 2-fold higher catalytic activity than free GOx. Meanwhile, significantly enhanced storage stability and negligible leakage of GOx were also achieved. On this basis, by considering the advantages of carboxyphenylboronic acid (CPBA) in the sensitization of Tb3+ fluorescence and specific recognition of hydrogen peroxide, a dual-emissive GOx&CDs@AMP/Tb-CPBA composite was further fabricated for the ratiometric sensing of glucose. Benefiting from the synergistic effect of GOx and CDs in the highly efficient transfer of intermediates and the elimination of environmental fluctuations, the presented ratiometric sensor not only displayed an ultrahigh sensitivity with a detection limit of 80 nM, but also allowed glucose to be easily identified by the naked eye under a UV lamp. We hope that this study will provide a new insight into the design and application of coordination polymer-based multifunctional composites.
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2017
·Vol. 409
·期 21
·4951-4958
·
IF 3.431
Zhu Yu-Feng,Wang Yong-Sheng,Zhou Bin,Yu Jun-Hui,Peng Li-Lan,Huang Yan-Qin,Li Xue-Jiao,Chen Si-Han,Tang Xian,Wang Xiao-Feng
We report a highly sensitive and selective strategy for Cd(II) assay using a singly labeled multifunctional probe consisting of a Cd(II)-specific aptamer (CAP), which acted as a recognition element for Cd(II) and a signal reporter. The presence of Cd(II) can induce the conformational switching of the CAP, accompanied by a change in fluorescence intensity. Thereby, a fluorescence strategy for Cd(II) assay was established. The proposed method has a detection limit of 2.15 nM, which is much lower than the detection limits reported in related literature. This strategy involves only an aptamer probe, and the use of such a G 4 -based quencher avoids the dual labeling of the CAP with fluorophore/quencher units. It is obviously more convenient and economical than the other aptamer-based biosensors for Cd(II) detection. The mechanism by which Cd(II) induces the CAP to change from a random coil sequence to a stem-loop structure was studied in a series of control experiments. This strategy would be helpful in the design of a sensitive analytical platform for various target assays in environmental and biomedical fields.
The presence of Cd 2+ leads to the conformational change of CAP from a random coil sequence to a stem-loop structure, resulting in a quenching in the fluorescence
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