ANALYTICAL CHEMISTRY
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2013
·
IF 5.695
Chun Yang,Lei Liu,Tao Zeng,Daowu Yang,Zhiyi Yao,Yuliang Zhao,Hai-Chen Wu
Both Pb2+ and Ba2+ can bind with high affinity to some specific DNA sequences, inducing the formation of unimolecular G-quadruplex structures. Translocation of a DNA probe containing such sequences through an α-hemolysin nanopore in the presence of Pb2+ or Ba2+ would result in much prolonged DNA translocation events. Quantification of these events can reveal the concentrations of Pb2+ or Ba2+ at as low as 0.8 nM. Besides, Pb2+ and Ba2+ in the solution can be simultaneously detected and individually identified. Furthermore, the probe is highly selective for Pb2+ and Ba2+ detection without interference from other metal ions. This sensing strategy can be extended to many other analytes which can bind to DNA molecules with high affinity.
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ACS Applied Materials & Interfaces
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2013
·
IF 5.008
Yong Liu,Peiyi Wu
Gold nanoparticles (Au NPs) are very attractive candidate nanoparticles in biological assay because of their high chemical stabilities, high homogeneities, good biocompatibilities, and low toxicities. However, molecular beacon assays via encapsulating the combined fluorescence or surface-enhanced Raman scattering (SERS) signals of reporters and Au NPs in nanobarcodes particles usually suffer from fluorescence quenching or weak Raman enhancement when Au NPs are employed (especially with size smaller than 15 nm). Herein, we present a new design of simultaneously realizing metal-enhanced fluorescence and coenhanced surface-enhanced Raman scattering by facilely embedding Ag nanoparticle into the shell of two kinds of Au nanoaggregate (5 and 10 nm), meanwhile, fluorophore is located between the silver core and gold nanoparticle layers and the distance among them is adjusted by SiO2 spacer (Ag@first SiO2 spacer@FiTC+SiO2@second SiO2 spacer@Au nanoaggregate). In this architecture, Ag nanoparticle not only is utilized as an efficient fluorescence enhancer to overcome the common fluorescence quenching around Au nanoaggregates but also behaves like a mirror. Thus, incident light that passes through the SERS-active Au nanoaggregate and the intervening dielectric layer of SiO2 could be reflected multiply from the surface of Ag nanoparticle and coupled with the light at the nanogap between the Au nanoaggregates to further amplify Raman intensity. This results in enhancement factors for fluorescence and SERS ∼1.6-fold and more than 300-fold higher than the control samples without silver core under identical experimental conditions, respectively. Moreover, fluorophore and SERS reporters are assembled onto different layers of the concentric hybrid microsphere, resulting in a feasible fabrication protocol when a large number of agents need to be involved into the dual-mode nanobarcodes. A proof-of-concept chip-based DNA sandwich hybridization assay using genetically modified organisms as a model system has been investigated based on the concentric hybrid microsphere. The high specificity and sensitivity of the assays suggest that the new architecture has a potential for various bioanalytical applications and provides opportunities for other similar metal nanoparticles to realize coenhancement effect.
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BIOMACROMOLECULES
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2015
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IF 5.75
Hua He,Yugang Bai,Jinhui Wang,Qiurong Deng,Lipeng Zhu,Fenghua Meng,Zhiyuan Zhong,Lichen Yin
Polycations often suffer from the irreconcilable inconsistency between transfection efficiency and toxicity. Polymers with high molecular weight (MW) and cationic charge feature potent gene delivery capabilities, while in the meantime suffer from strong chemotoxicity, restricted intracellular DNA release, and low stability in vivo. To address these critical challenges, we herein developed pH-responsive, reversibly cross-linked, polyetheleneimine (PEI)-based polyplexes coated with hyaluronic acid (HA) for the effective and targeted gene delivery to cancer cells. Low-MW PEI was cross-linked with the ketal-containing linker, and the obtained high-MW analogue afforded potent gene delivery capabilities during transfection, while rapidly degraded into low-MW segments upon acid treatment in the endosomes, which promoted intracellular DNA release and reduced material toxicity. HA coating of the polyplexes shielded the surface positive charges to enhance their stability under physiological condition and simultaneously reduced the toxicity. Additionally, HA coating allowed active targeting to cancer cells to potentiate the transfection efficiencies in cancer cells in vitro and in vivo. This study therefore provides an effective approach to overcome the efficiency-toxicity inconsistence of nonviral vectors, which contributes insights into the design strategy of effective and safe vectors for cancer gene therapy.
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Small
·
2015
·Vol. 12
·期 6
·756-769
·
IF 8.368
Yundong Zang,Yanchun Wei,Yujiao Shi,Qun Chen,Da Xing
A multifunctional nanoparticle based on gold nanorod (GNR), utilizing mRNA triggered chemo-drug release and near-infrared photoacoustic effect, is developed for a combined chemo-photoacoustic therapy. The constructed nanoparticle (GNR-DNA/FA:DOX) comprises three functional components: (i) GNR as the drug delivery platform and photoacoustic effect enhancer; (ii) toehold-possessed DNA dressed on the GNR to load doxorubicin (DOX) to implement a tumor cell specific chemotherapy; and (iii) folate acid (FA) modified on GNR to guide the nanoparticle to target tumor cells. The results show that, upon an effective and specific delivery of the nanoparticles to the tumor cells with overexpressed folate receptors, the cytotoxic DOX loaded on the GNR-DNA nanoplatform can be released through DNA displacement reaction in melanoma-associated antigen gene mRNA expressed cells. With 808 nm pulse laser irradiation, the photoacoustic effect of the GNR leads to a direct physical damage to the cells. The combined treatment of the two modalities can effectively destroy tumor cells and eradicate the tumors with two distinctively different and supplementing mechanisms. With the nanoparticle, photoacoustic imaging is successfully performed in situ to monitor the drug distribution and tumor morphology for therapeutical guidance. With further in-depth investigation, the proposed nanoparticle may provide an effective and safe alternative cancer treatment modality.
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BIOSENSORS & BIOELECTRONICS
·
2017
·
IF 7.78
Fenglei Gao,Taotao Fan,Jing Wu,Sha Liu,Yan Du,Yao Yao,Fuyi Zhou,Yu Zhang,Xianjiu Liao,Deqin Geng
We describe a novel label-free and signal-on electrochemical DNA sensing platform via proximity hybridization triggered hemin/G-quadruplex formation based on the direct electron transfer of hemin . The thiolated modified G-DNA1 was first immobilized onto the Au electrode surface . In the presence of target DNA, Y-junction-structure ternary complex can be formed to trigger the proximity assembly of G-DNA1, hemin, and G-DNA2, which leads to the formation of hemin/G-quadruplex for generation an amplified electrochemical signal by differential pulse voltammetry . The observed signal gain was sufficient to achieve a demonstrated detection limit of 54 fM, with a wide linear dynamic range from 10 −13 to 10 −9 M and discriminated mismatched DNA from perfect matched target DNA with a high selectivity. Benefiting from the one step proximity dependent hemin/G-quadruplex formation, the assay method is extremely simple and can be carried out within 40 min. The advantages of free of any label conjugation step, and versatility make it a promising candidate for point-of-care testing and commercial application.
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IUBMB LIFE
·
2017
·Vol. 69
·期 7
·500-509
·
IF 3.141
Yanbin Su,Lei Chen,Yanwen Su,Zhengqiang Li,Chuang Zhang,Tongxing Mu
The purpose of this study is to probe the spectroscopic evidences of toxic trans-crotonaldehyde (TCA) trapped and transformed by resveratrol (Res) to prevent the damage of mitochondrial DNA. In aldehyde dehydrogenase (ALDH) at the different pH or mitochondria, the spectroscopic characteristics of TCA trapped and transformed by Res were observed by means of both UV-vis and Raman spectra. When Res interacted with TCA, TCA peak at 316 nm immediately disappeared while Res main peak at 305 nm and shoulder peak at 320 nm were dramatically changed, Raman peaks of TCA at 1,688 cm −1 assigned to CHO and 1,641 cm −1 affiliated to CC were strikingly shifted, Raman peaks of Res itself were significantly displaced or disappeared, especially in mitochondria and ALDH at different pH. The active groups of Res were the OH at C 5 and C 10 . The results of theoretical calculations are in agreement on the whole with the experimental data. The Res plays undoubtedly an important role via the structural change in TCA. The toxic CHO of TCA was effectively trapped and transformed by Res by means of itself OH at C 5 and C 10 . The mitochondrial alkaline microenvironment and ALDH promoted the elimination of toxic TCA. © 2017 IUBMB Life, 69(7):500–509, 2017
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ANALYTICAL CHEMISTRY
·
2017
·
IF 6.32
Na Li,Meimei Wang,Xiaonan Gao,Zhengze Yu,Wei Pan,Hongyu Wang,Bo Tang
Multicomponent quantitative detection in living samples is becoming increasingly important; however, the current detection strategy may cause fluorescence self-quenching and reduce the sensitivity of detection. To solve the problem, we develop a DNA tetrahedral nanoprobe to control the dyes distance for simultaneous detection of multiple analytes. Compared to mesoporous silica nanoparticles based nanoprobes, the DNA tetrahedral nanoprobes display enhanced fluorescence intensities due to partially avoiding the fluorescence resonance energy transfer. Confocal fluorescence images show that the nanoprobes are capable of detecting and visualizing pH and O2•– in living cells under a single wavelength excitation. In an inflammation model for mice, the nanoprobes simultaneously image the down-regulation of pH and up-regulation of O2•–. We expect that the current strategy can provide new opportunities in designing probes for multiplexed detection with reduced self-quenching and enhanced sensitivity.
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COLLOIDS AND SURFACES B-BIOINTERFACES
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2016
·
IF 3.902
Jianwei Du,Bangbang Li,Peng Zhang,Youxiang Wang
In this research, BSA, one of the natural rigid globular proteins with ca. 51% of α-helix secondary structure, was utilized to prepare cationized BSA (cBSA) as gene carrier. Tetraethylenepentamine (TEPA) or polyethylenimine (PEI 1800 ) was grafted to BSA with different grafting levels. Based on the circular dichoism (CD) spectra, all cBSA remained α-helical structure to some degree. This was exciting to endow cBSA with quite different DNA complexibility and cellular biology behavior from the random coiled and flexible polycations such as PEI and poly- l- lysine (PLL). Strangely, the DNA condensability decreased with the increment of TEPA or PEI 1800 grafting level. Also, the cBSA could condense DNA effectively to form irregular nanoparticles around 50–200 nm above N/P ratio of 10. On account of the excellent hydration of BSA, the cBSA/DNA complexes revealed good colloidal stability under physiological salt condition. Cell culture experiments indicated this BSA-based gene carrier possessed good cellular compatibility. Surprisingly, cBSA/DNA complexes could be uptaken excellently by up to 90% cells. This might be owing to the agitation effect of α-helical structure and the positive potential of these complexes. BSA-PEI 1800 /DNA complexes with quick endosome escape even had transfection efficiency as high as PEI 25k /DNA complexes. Overall, this paper provided us the potential of cBSA as gene carrier and might have some instructions in the design of protein-based gene delivery system.
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TALANTA
·
2017
·
IF 4.162
Fangfang Li,Xuan Hu,Fengyi Wang,Baozhan Zheng,Juan Du,Dan Xiao
A simple, rapid, and ultrasensitive fluorescence strategy for adenosine triphosphate (ATP) detection was developed by using a FAM (carboxyfluorescein) labeled DNA (FAM-DNA). In this strategy, highly fluorescent FAM-DNA was used as a probe, and nanoceria (CeO 2 NPs) acted as an efficient quencher. FAM-DNA attached to the surface of nanoceria through the coordination between the phosphate group of DNA and NP surface, which induced complete quenching in the FAM-DNA fluorescence due to a photo induced electron transfer (PET) process. It was found that ATP can readily displace adsorbed DNA from nanoceria surface because of the stronger coordination ability of ATP with nanoceria, and the nanoceria-based competitive binding resulted in over 7-fold fluorescence enhancement. Over a wide range from 0.1 nM to 1.5 μM, a good linear relationship between the fluorescence intensity and the concentration of ATP was obtained and the detection limit was estimated to be as low as 54 pM. This method was successfully used to analyze ATP in a single drop of blood and human urine.
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BIOSENSORS & BIOELECTRONICS
·
2017
·
IF 7.78
Yufang Hu,Qingqing Zhang,Zhiyong Guo,Sui Wang,Chunnuan Du,Chunyang Zhai
A novel label-free electrochemical strategy was established based on the unique electro-catalytic activity of graphene oxide (GO)-supported terminal deoxynucleotidyl transferase (TdT)-generated C-rich DNA nanotail-templated silver nanoclusters (DNA-AgNCs). TdT can catalyze the deoxycytidine triphosphate (dCTP) to the 3′-OH terminus of single-stranded DNA (ssDNA) with no template; then, in the presence of Ag(I), TdT-generated C-rich DNA sequence was employed for the synthetic template of AgNCs because of the formed complexes of nitrogen atoms of cytosine based with silver atoms. We proved that in situ grown DNA nanotail-templated AgNCs can be adsorbed on GO-modified electrode and possess high electro-catalytic activity to H 2 O 2 reduction, presenting a good electrochemical indicator for signal readout. Under optimal conditions, the proposed biosensor could be employed for quantitatively monitoring TdT activity and within a dynamic range from 0.4 to 90 U/mL and a low limit of detection is 0.08 U/mL. With high sensitivity and excellent selectivity , this strategy offers a facile, convenient and specific electrochemical method for TdT activity detection and its relevant inhibitors screening. It holds a promising potential in the practical application of TdT-based biochemical research, disease diagnosis and drug discovery.
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Chemistry-An Asian Journal
·
2016
·Vol. 11
·期 14
·2041-2048
·
IF 4.592
Yuehua Hu,Fan Lin,Tao Wu,Ying Wang,Xiao-Shun Zhou,Yong Shao
Graphical Stranded : Induction and selective recognition of DNA triplex assembly have been achieved by using fluorescently activated chelerythrine as a multifuncational probe (see scheme). DNA triplex assembly has attracted a variety of interest in the regulation of genetic expression, drug screening, molecular switches, and sensors. However, these achievements are essentially dependent on the formation and stability of the triplex assembly. Herein, the recognition of DNA triplex assembly with various isoquinoline alkaloids was investigated. We found that natural chelerythrine (CHE) exhibits the highest selectivity in recognizing the triplex structure. The DNA triplex stability is substantially increased upon CHE binding, as opposed to the invariance in the stability of the duplex counterpart. CHE also favors the assembly of the triplex-forming oligonucleotide (TFO) with its duplex counterpart. The triplex binding switches CHE to a strong fluorescent emitter, which suggests CHE as a useful probe in following triplex assembly. As a unique triplex selector, inducer, and emitter, CHE successfully reports the wide pH- and metal-ion-dependent tunability of the triplex nanoswitch in a label-free manner.
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BIOSENSORS & BIOELECTRONICS
·
2016
·
IF 7.476
Ye Wang,Ning Gan,You Zhou,Tianhua Li,Yuting Cao,Yinji Chen
Herein, a smart single-stranded DNA binding protein (SSB)-assisted fluorescence aptamer switch based on fluorescence resonance energy transfer (FRET) was designed. The FRET switch was synthesized by connecting SSB labeled quantum dots ( [email protected] ) as donor with aptamer (apt) labeled gold nanoparticles ( [email protected] ) as acceptor, and it was employed for detecting chloramphenicol (CAP) in a homogenous solution. In the assay, the interaction between core-shell [email protected] and [email protected] leads to a dramatic quenching (turning off). After adding CAP in the detection system, [email protected] can bind the target specifically then separate [email protected] with [email protected] , resulting in restoring the fluorescence intensity of QDs (turning on). Consequently, the fluorescence intensity recovers and the recovery extent can be used for detection of CAP in homogenous phase via optical responses. Under optimal conditions, the fluorescence intensity increased linearly with increasing concentrations of CAP from 0.005 to 100 ng mL −1 . The limit of this fluorescence aptamer switch was around 3 pg mL −1 for CAP detection. When the analyte is changed, the assay can be applied to detect other targets only by changing relative aptamer in [email protected] probe. Furthermore, it has potential to be served as a simple, sensitive and portable platform for antibiotic contaminants detection in biological and environmental samples.
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