查找使用阿拉丁产品的科研文献

Different effects of titanium dioxide nanoparticles instillation in young and adult mice on DNA methylation related with lung inflammation and fibrosis

Yue Ma,Yinsheng Guo,Hailing Ye,Kaiqin Huang,Ziquan Lv,Yuebin Ke

Wide use of titanium dioxide nanoparticles (TiO 2 NPs) as white pigments induces unintentionally release in environment which increases concerns about their adverse health effects on respiratory system. So it is crucial to get a deep understanding of the disease process and molecular mechanism. Epigenetic mechanisms, such as DNA methylation, have been found to play a role in the development of lung diseases by affecting expression of key genes. In addition, there could be potential different toxic effects of TiO 2 NPs between young and adult. Thus, the comparative toxicity of TiO 2 NPs in 5-week (young) and 10-week (adult) old NIH mice is investigated in this study following nasal inhalation of TiO 2 NPs at dose of 20 mg/kg (body weight)/day for 30 days. Global DNA methylation and hydroxymethylation in lung were measured. Promoter methylation of inflammatory genes ( IFN-γ and TNF-α ) and tissue fibrosis gene ( Thy-1 ) were determined. Additional, RNA-sequencing runs were performed on the pulmonic libraries. We found the induced pulmonary inflammation and fibrosis were more severe in young mice. Decreased global methylation and hydroxymethylation were only found in the young group. The altered methylation in promoter of TNF-α and Thy-1 were found to play a role in the inflammatory response and fibration. RNA-sequencing showed that in pathways in cancer expression of 197 genes was up-regulated in the young mice more that in the adult mice. All these results suggested that the young ages are more sensitive to TiO 2 NP exposure and the potential of abnormal DNA methylation might be used as biomarkers of both exposure and disease development.

Development of a Highly Sensitive Colorimetric Method for Detecting 17β-Estradiol Based on Combination of Gold Nanoparticles and Shortening DNA Aptamers

Pu Hongbin,Huang Zhibin,Sun Da-Wen,Xie Xiaohui,Zhou Weibiao

Pollution of environmental endocrine disruptors has caused increasing concern globally. In the current study, a simple colorimetric method with high sensitivity and good selectivity for 17β-estradiol (E2) detection was developed, which employed gold nanoparticles (AuNPs) as colorimetric probe for specific recognition of shortening DNA aptamer. Visible color change from bright red to violet was observed for aggregation of AuNPs without the protection of DNA aptamer. After optimization, the method exhibited great performance for E2 detection with good linearity between E2 concentrations from 0.2 to 5 nM and the absorbance ratio at 620 and 523 nm, with the limit of detection of 0.1 nM. The method was also successfully applied to E2 determination in different spiked water samples including fishpond water, lake water, and tap water, in which good recoveries from 93.1 to 108.9% and acceptable relative standard deviations from 3.4 to 8.9% were obtained. This technique showed great potential for on-site fast determination of E2 in environmental water samples.

Colorimetric detection of single base-pair mismatches based on the interactions of PNA and PNA/DNA complexes with unmodified gold nanoparticles

Shu Xing,Xiaojun Xu,Pan Fu,Mengjia Xu,Tingting Gao,Xiaokang Zhang,Chao Zhao

Rapid and sensitive single nucleotide polymorphisms (SNPs) genotyping is of particular important for early diagnosis, prevention, and treatment of specific human diseases. A simple and low-cost SNP detection method would be valuable for routine analysis in resource-limited settings. Here, we demonstrated a novel and convenient gold nanoparticle (AuNPs) based colorimetric approach for efficient screening of SNPs at room temperature without instrumentation. SNP detection is performed in a single tube with one set of unmodified AuNPs, a label-free peptide nucleic acid (PNA) probe, a single exonuclease (S1 nuclease), and the target to be tested. S1 nuclease could digest DNAs in DNA/PNA duplexes involving a mismatch into small fragments, while DNAs in the fully-matched DNA/PNA duplexes can be effectively protected by PNA from enzymatic degradation. This difference could be easily discriminated by color changes associated with gold aggregation. PNA oligomers can induce immediate AuNP aggregation even in the presence of nucleoside monophosphates (dNMPs), the digestion products of DNA . Whereas PNA/DNA duplexes can effectively stabilize unmodified AuNPs, and the stabilization effect of PNA/DNA is better than single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA). Without the need of precise temperature control and extra salt addition, SNPs are detected with a detection limit of 2.3 nM in cell lysate. Moreover, this system can effectively discriminate a range of different mismatches even in spiked cell lysate, demonstrate the potential use of this biosensor for biological samples.

The synthesis, characterization, DNA/protein interaction, molecular docking and catecholase activity of two Co(II) complexes constructed from the aroylhydrazone ligand

Yun Li,Yueqin Li,Xiaohui Liu,Yong Yang,Dong Lin,Qinwei Gao

Two Co(II) complexes, Co(BBH)phenMeCN (1) and Co(BSH)phenMeCN (2) (HBBH =  benzophenone benzoyl hydrazone, HBSH =  benzophenone salicylylhydrazone ligand and phen  = 1,10-phenanthroline) were prepared and characterized by single X-ray crystallography. The investigation of the complexes binding with herring sperm DNA (HS-DNA) revealed that stronger binding interaction exists between the complexes and HS-DNA compared to the corresponding free ligands. And both complexes can bind to DNA through intercalation of the phenyl rings between adjacent base pairs in the double helix. Meanwhile, bovine serum albumin (BSA) binding studies reveal the complexes can effectively interact with BSA and change the secondary structure of BSA. Superoxide dismutase (SOD) mimic activity of the complexes was investigated and the results showed that complex 2 showed a stronger radical scavenging potency against O 2 .- radical with an IC 50 value of 16.10 μM. The catecholase-like activity of both complexes has been investigated with 3,5-di- tert -butylcatechol (3,5-DTBC) as the substrate in methanol solution under completely aerobic conditions. The catalytic reaction follows Michaelis-Menten enzymatic reaction kinetics with turnover numbers ( k cat ) of 34.14 h −1 and 30.36 h −1 for complex 1 and complex 2, respectively.

Electrochemiluminescence sensing platform for ultrasensitive DNA analysis based on resonance energy transfer between graphitic carbon nitride quantum dots and gold nanoparticles

Zhimin Liu,Xing Zhang,Xianguo Ge,Leqian Hu,Yijie Hu

Electrogenerated chemiluminescence (ECL) of semiconductor quantum dots (QDs) is considered as a powerful technique in the fabrication of biosensor, however, the inherent toxicity of the heavy metal ion containing in QDs limits their further applications. Thus, searching for environment-friendly luminescent nanomaterials with high electrochemiluminescence (ECL) efficiency is an urgent goal. In this work, a solid-state method under low temperature was adopted to prepare graphitic carbon nitride quantum dots (g-CNQDs). By using coreactant K 2 S 2 O 8 , a strong cathodic ECL signal of g-CNQDs could be observed in phosphate buffer. A novel ECL resonance energy transfer procedure was constructed between g-CNQDs (emitter) and gold nanoparticles (acceptor). A signal probe was formed by connecting gold nanoparticles at the hairpin DNA (Hai-DNA) terminal. When the signal probe was anchored on g-CNQDs, ECL resonance energy transfer occurred due to the ECL quenching of gold nanoparticles to g-CNQDs. This phenomenon decreased the ECL signal. In the presence of target DNA (T-DNA), the looped structure of Hai-DNA could be destroyed by T-DNA, and gold nanoparticles were separated from g-CNQDs. Accordingly, the ECL resonance energy transfer procedure was hindered, and the ECL signal was recovered again. The ECL intensities exhibited linear correlation with the logarithm of T-DNA concentration from 0.02 fM to 0.1 pM, and the limit of detection was 0.01 fM (3σ). With the developed ECL resonance energy transfer system, good selectivity and high sensitivity were achieved in T-DNA detection.

Electrochemical aptasensing strategy for kanamycin detection based on target-triggered single-strand DNA adsorption on MoS2 nanosheets and enzymatic signal amplification

Yunlei Zhou,Fei Li,Hanwen Wu,Yan Chen,Huanshun Yin,Shiyun Ai,Jun Wang

A selective and sensitive electrochemical aptasensing strategy was developed for kanamycin detection based on target-triggered single-strand DNA adsorption on MoS 2 nanosheets and enzymatic signal amplification. Firstly, a Y-shape double-stranded DNA (dsDNA) was designed containing probe DNA, assist DNA (labeled with biotin at its 3′-terminal) and aptamer DNA. Then, in the presence of kanamycin, aptamer DNA can be released from the Y-shape dsDNA structure due to its interaction with kanamycin to form stable conjugate, which will destroy the Y-shape dsDNA structure and lead to the presence of two-fragment of single-stranded DNA (ssDNA) on the remained half-hybrid DNA structure (containing probe DNA and assist DNA). Based on the strong interaction between ssDNA and MoS 2 nanosheets, the half-hybrid DNA structure can be captured on MoS 2 nanosheets modified electrode surface, which triggers the subsequent immobilization of streptavidin-alkaline phosphatase (SA-ALP) compound. Under the catalysis of ALP, p -nitrophenol phosphate (PNPP) is hydrolyzed to produce p -nitrophenol (PNP). Based on the linear relationship between the electrochemical oxidation signal of PNP and kanamycin concentration, kanamycin can be detected with the detection limit of 0.029 nM (S/N = 3). The aptamer-MoS 2 nanosheets based electrochemical biosensor shows good selectivity, reproducibility for kanamycin detection.

Probing the behavior of calf thymus DNA upon binding to a carboxamide fungicide boscalid: insights from spectroscopic and molecular docking approaches

Jie-Hua Shi,Yan-Yue Lou,Kai-Li Zhou,Dong-Qi Pan

Ultrasensitive electrochemiluminescence immunosensor for the transcriptional co-activator p300 by using a graphene oxide monolayer and tetrahedral DNA-mediated signal amplification

Hu Yufang,Zhang Qingqing,Hu Dandan,Wang Jiao,Rao Jiajia,Xu Lihua,Guo Zhiyong,Wang Sui,Liu Xin,Tang Shiyun,Shen Qinpeng

Protein p300 is a transcriptional co-activator that participates in many physiological processes including cell cycle control, differentiation and apoptosis. It serves (a) as a protein bridge that links specific transcription factors to the fundamental transcription machinery, (b) as a scaffold to complete multiple transcription cofactors, and (c) as an enzyme for acetylating histone and non-histone proteins. An ultrasensitive electrochemiluminescence (ECL) immunosensor is described here that is based on the use of a magnetic glassy carbon electrode modified with tetrahedral DNA with hollow structure, graphene oxide (GO) and gold nanocrystals. The use of a GO monolayer allows for greater carrying capacity and warrants a wider outer Helmholtz plane. Strong and stable ECL signals were achieved due to antigen-antibody interaction by using the ECL probe Ru(phen) 3 2+ . This immunosensor has a response that covers the 0.005 to 80 nM p300 concentration range and has a 1 pM detection limit. It was exploited for the determination of p300 in HeLa cell lysate and (spiked) serum. Schematic presentation of an ultrasensitive Faraday-cage electrochemiluminescence immunosensor toward the transcriptional co-activator p300 analysis is presented based on a graphene oxide monolayer and tetrahedral DNA-mediated signal amplification.

Enzyme-free fluorescent biosensor for the detection of DNA based on core–shell Fe3O4 polydopamine nanoparticles and hybridization chain reaction amplification

Na Li,Xia Hao,Bei Hua Kang,Zhen Xu,Yan Shi,Nian Bing Li,Hong Qun Luo

A novel, highly sensitive assay for quantitative determination of DNA is developed based on hybridization chain reaction (HCR) amplification and the separation via core–shell Fe 3 O 4 polydopamine nanoparticles (Fe 3 O 4 @PDA NPs). In this assay, two hairpin probes are designed, one of which is labeled with a 6-carboxyfluorescein (FAM). Without target DNA, auxiliary hairpin probes are stable in solution. However, when target DNA is present, the HCR between the two hairpins is triggered. The HCR products have sticky ends of 24   nt, which are much longer than the length of sticky ends of auxiliary hairpins (6   nt) and make the adsorption much easier by Fe 3 O 4 @PDA NPs. With the addition of Fe 3 O 4 @PDA NPs, HCR products could be adsorbed because of the strong interaction between their sticky ends and Fe 3 O 4 @PDA NPs. As a result, supernatant of the solution with target DNA emits weak fluorescence after separation by magnet, which is much lower than that of the blank solution. The detection limit of the proposed method is as low as 0.05   nM. And the sensing method exhibits high selectivity for the determination between perfectly complementary sequence and target with single base-pair mismatch. Importantly, the application of the sensor for DNA detection in human serum shows that the proposed method works well for biological samples.

Dual-colored graphene quantum dots-labeled nanoprobes/graphene oxide: functional carbon materials for respective and simultaneous detection of DNA and thrombin

Zhao Sheng Qian,Xiao Yue Shan,Lu Jing Chai,Jian Rong Chen,Hui Feng

Convenient and simultaneous detection of multiple biomarkers such as DNA and proteins with biocompatible materials and good analytical performance still remains a challenge. Herein, we report the respective and simultaneous detection of DNA and bovine α-thrombin (thrombin) entirely based on biocompatible carbon materials through a specially designed fluorescence on-off-on process. Colorful fluorescence, high emission efficiency, good photostability and excellent compatibility enables graphene quantum dots (GQDs) as the best choice for fluorophores in bioprobes, and thus two-colored GQDs as labeling fluorophores were chemically bonded with specific oligonucleotide sequence and aptamer to prepare two probes targeting the DNA and thrombin, respectively. Each probe can be assembled on the graphene oxide (GO) platform spontaneously by π–π stacking and electrostatic attraction; as a result, fast electron transfer in the assembly efficiently quenches the fluorescence of probe. The presence of DNA or thrombin can trigger the self-recognition between capturing a nucleotide sequence and its target DNA or between thrombin and its aptamer due to their specific hybridization and duplex DNA structures or the formation of apatamer–substrate complex, which is taken advantage of in order to achieve a separate quantitative analysis of DNA and thrombin. A dual-functional biosensor for simultaneous detection of DNA and thrombin was also constructed by self-assembly of two probes with distinct colors and GO platform, and was further evaluated with the presence of various concentrations of DNA and thrombin. Both biosensors serving as a general detection model for multiple species exhibit outstanding analytical performance, and are expected to be applied in vivo because of the excellent biocompatibility of their used materials.

Ultrasensitive Electrochemical Biosensor for Detection of DNA from Bacillus subtilis by Coupling Target-Induced Strand Displacement and Nicking Endonuclease Signal Amplification

Yuhua Hu,Xueqin Xu,Qionghua Liu,Ling Wang,Zhenyu Lin,Guonan Chen

A simple, ultrasensitive, and specific electrochemical biosensor was designed to determine the given DNA sequence of Bacillus subtilis by coupling target-induced strand displacement and nicking endonuclease signal amplification. The target DNA (TD, the DNA sequence from the hypervarient region of 16S rDNA of Bacillus subtilis) could be detected by the differential pulse voltammetry (DPV) in a range from 0.1 fM to 20 fM with the detection limit down to 0.08 fM at the 3sblank level. This electrochemical biosensor exhibits high distinction ability to single-base mismatch, double-bases mismatch, and noncomplementary DNA sequence, which may be expected to detect single-base mismatch and single nucleotide polymorphisms (SNPs). Moreover, the applicability of the designed biosensor for detecting the given DNA sequence from Bacillus subtilis was investigated. The result obtained by electrochemical method is approximately consistent with that by a real-time quantitative polymerase chain reaction detecting system (QPCR) with SYBR Green.

“Turn-off-on” fluorescent sensor for (N-methyl-4-pyridyl) porphyrin -DNA and G-quadruplex interactions based on ZnCdSe quantum dots

Dan Zhao,Yao Fan,Fang Gao,Tian-ming Yang

As a new detection model, the reversible fluorescence “turn-off-on” sensor based on quantum dots (QDs) has already been successfully employed in the detections of many biochemical materials, especially in the researches on the interactions between anticancer drugs. The previous studies, however, mainly focused on simple-structured oligonucleotides and Calf thymus DNA . G-quadruplex, an important target for anti-cancer drug with special secondary structure , has been stimulating increasing research interests. In this paper, we report a new detection method based on the fluorescence “turn-off-on” model with water-soluble ZnCdSe QDs as the fluorescent probe , to analyze the interactions between anticancer drug (N-methyl-4-pyridyl) porphyrin (TMPyP) and nucleic acid , especially the G-quadruplex. The fluorescence of QDs can be quenched by TMPyP via photo-induced electron transfer and fluorescence resonance energy transfer , while on the other hand, the combination between TMPyP and G-quadruplex releases QDs from their quenchers and thus recovers the fluorescence. Most importantly, the fluorescence “turn-off-on” model has been employed, for the first time, to analyze the impacts of special factors on the interaction between TMPyP and G-quadruplex. The excellent selectivity of the system has been verified in the studies of the interactions between TMPyP and different DNAs (double-stranded DNA, single-stranded G-quadruplex, and different types of G-quadruplexes) in Na + or K + -containing buffer.