ACS Applied Materials & Interfaces
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2016
·
IF 7.145
Jing Sun,Dennis Curry,Qipeng Yuan,Xu Zhang,Hao Liang
Gold nanoparticle (AuNP)-templated spherical nucleic acids (SNAs) have been demonstrated as an important functional material in bionanotechnology. Fabrication of SNAs having high hybridization capacity to their complementary sequences is critical to ensure their applicability in areas such as antisense gene therapy and cellular sensing. The traditional salt-aging procedure is effective but tedious, requiring 1–3 days to complete. The rapid low-pH assisted protocol is efficient, but causes concerns related to nonspecific DNA adsorption to the AuNP core. To address these issues, we systematically compared the SNAs prepared by these two methods (salt-aging method and low-pH protocol). In terms of the number of complementary DNA that each SNA can bind and the average binding affinity of each thiolated DNA probe to its complementary strand, both methods yielded comparable hybridizability, although higher loading capacity was witnessed with SNAs made using the low-pH method. Additionally, it was found that nonspecific DNA binding could be eliminated almost completely by a simple glutathione (GSH) treatment of SNAs. Compared to conventional methods using toxic mercapto-hexanol or alkanethiols to remove nonspecific DNA adsorption, GSH is mild, cost-effective, and technically easy to use. In addition, GSH-passivated SNAs minimize the toxicity concerns related to AuNP-induced GSH depletion and therefore offer a more biocompatible alternative to previously reported SNAs. Moreover, rational design of probe sequences through inclusion of a polythymine spacer into the DNA sequences resulted in enhanced DNA loading capacity and stability against salt-induced aggregation. This work provides not only efficient and simple technical solutions to the issue of nonspecific DNA adsorption, but also new insights into the hybridizability of SNAs.
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Materials Science and Engineering B-Advanced Functional Solid-State Materials
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2016
·
IF 2.331
Hongyu Yang,Zhenghua Tang,Likai Wang,Weijia Zhou,Ligui Li,Yongqing Zhang,Shaowei Chen
Peptide A3-capped gold and silver nanoparticles were prepared by chemical reduction of metal salt precursors. The nanoparticles exhibited apparent but distinctly different color changes upon the addition of selected heavy metal ions. For gold nanoparticles, the solution color was found to change from red to blue in the presence of Hg 2+ or As 3+ ions, accompanied with broadening and a red-shift of the surface plasmon resonance peak. In contrast, silver nanoparticles showed an apparent color change from yellow to colorless only in the presence of Hg 2+ , along with a blue-shift and diminishment of the surface plasmon resonance peak. The Hg 2+ reaction concentration limit of silver nanoparticle was about 40 times lower than that of gold nanoparticle. Based on the dynamic light scattering, transmission electron microscopy and X-ray photoelectron spectroscopic results, the reaction mechanism has been proposed. Such a sensitive variation of the nanoparticle optical properties to selective ions might be exploited for ion detection for potential applications.
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Analytical Methods
·
2016
·Vol. 8
·期 43
·7755-7761
·
IF 1.915
Cong Wang,Junyong Sun,Han Mei,Feng Gao
In this work, the synthesis of carboxyl functionalized semiconducting polymer dots (PFBT-COOH Pdots) is achieved by a co-precipitation method. The PFBT-COOH Pdots show extraordinary fluorescence brightness and excellent photostability, and the fluorescence of PFBT-COOH Pdots is selectively quenched by ferric ions. Upon addition of phytic acid (PA) to the Pdots/Fe(III) system, PA is able to selectively and preferentially bind with the ferric ions, thus leading to fluorescence recovery of the PFBT-COOH Pdots. Therefore, a simple, selective and sensitive fluorescence probe for PA detection is designed based on the fluorescence quenching-recover process. This probe exhibits a good linear relationship (R = 0.9988) with a linear range from 2.5 μmol L−1 to 450 μmol L−1 and a limit of detection of 0.63 μmol L−1. The probe also shows good selectivity for PA and a good recovery ratio, and it is applied to the determination of PA in a corn grains sample with satisfactory results.
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TALANTA
·
2016
·
IF 4.035
Lijiang Lei,Jin Zhu,Gangqiang Xia,Hui Feng,Hongman Zhang,Yuwang Han
NGAL is a promising novel biomarker for acute kidney injury (AKI) and chronic kidney disease (CKD). More rapid and user-friendly methods are needed for the timely monitoring of NGAL in human urine and serum. UCP technology-based lateral flow assay (UPT-LFA) was developed for rapid, user-friendly and quantitative detection of the NGAL in human serum specimens and urine specimens. Under optimal conditions, the UPT-LFA displayed a rapid response to NGAL with a LOD of 7.68 ng/mL and detection range from 7.68 to 1000 ng/mL. The UPT-LFA method was compared with commercial immunoturbidimetry (103 urine specimens), and by ELISA (26 serum specimens), respectively. The results demonstrated that the UPT-LFA was consistent with immunoturbidimetry assay, reporting a 97.92% of positive and 92.73% of negative coincidence rates, respectively. Meanwhile, the concordance rate between UPT-LFA and ELISA, as shown by correlative regression analysis, was also high (R 2 =0.95). The whole assay can be completed within 30 min compared to 4 h consuming with ELISA. The research implies that, the UPT-LFA provides a potential to be used in point of care testing (POCT) to define early acute kidney injury with advantages of user-friendly and rapid testing, promising this new assay a bright future.
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2017
·Vol. 409
·期 21
·4951-4958
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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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CHIRALITY
·
2017
·Vol. 29
·期 7
·348-357
·
IF 1.956
Hao Wu,Xiaolin He,Huifen Dong,Qingyan Zhou,Yongsong Zhang
Imazethapyr (IM) is a chiral herbicide composed of an (−)-R-enantiomer and an (+)-S-enantiomer with differential herbicidal activity. In this study, the effects of microbial organisms, humidity, and temperature on the selective degradation of the (−)-R- and (+)-S-enantiomers of IM were determined in silty loam (SL) and clay loam (CL) soil with different pH values. The (−)-R-enantiomer of IM was preferentially degraded in two soils under different microorganism, humidity, and temperature conditions. The average half-lives of R-IM ranged from 43 to 66.1 days and were significantly shorter ( P < 0.05) than those of S-IM, which ranged from 51.4 to 79.8 days. The enantiomer fraction (EF = (+)-S-enantiomer/((−)-R-enantiomer + (+)-S-enantiomer)) values were used to describe the enantioselectivity of degradation of IM were >0.5 ( P < 0.05) in two unsterilized soils under different humidity and temperature conditions. The highest EF values were observed at unsterilized CL soil samples under 50% maximum water-holding capacity (MWHC) and 25 °C environmental conditions. The EF values of the IM enantiomers were significantly higher ( P < 0.05) in CL soils (higher pH = 5.81) and were 0.581 (unsterilized) and 0.575 (50% MWHC; 25 °C) compared with those recorded in SL soil (lower pH = 4.85). In addition, this study revealed that microbial organisms preferentially utilized the more herbicidal active IM enantiomer.
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JOURNAL OF HAZARDOUS MATERIALS
·
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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BIOSENSORS & BIOELECTRONICS
·
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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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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TALANTA
·
2016
·
IF 4.035
Yating Xu,Ju Liu,Hongyang Zhang,Min Jiang,Lingling Cao,Min Zhang,Wei Sun,Shengli Ruan,Ping Hu
In this study, hypercrosslinked strong cation-exchange polymer resins (HXLPP-SCX) were synthesized and employed as selective sorbents for the solid-phase extraction (SPE) of basic purine metabolites associated with gout. The HXLPP-SCX material was prepared based on hypercrosslinking reactions and sulfonated with concentrated H 2 SO 4 . This synthetic procedure is facile and efficient without using highly toxic reagent. The resulting resins were characterized in the form of monodisperse microspheres (mean diameters of 3‒5 μm) with narrow pore size (2.1 nm) and relatively high specific surface areas (801 m 2 /g). The polymers also possess high ion-exchange capacity (IEC, 2.22 mmol/g) and good adsorption and selectivity performances for basic compounds. The resins used as SPE sorbents permit the selective enrichment of three pivotal purine metabolites (hypoxanthine, xanthine and inosine) in human serum followed by HPLC analysis. Method validation including linearity range, sensitivity, accuracy and reproducibility were evaluated. This method was exemplarily applied in the analysis of serum purines in gout patients and healthy controls. The present results demonstrate a promising potential of this HXLPP-SCX material for the clinical sample pretreatment.
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