ANALYST
·
2012
·Vol. 138
·期 3
·887-893
·
IF 4.23
Lu Zhang,Kao Zhu,Tao Ding,Xianyun Hu,Qingjiang Sun,Chunxiang Xu
We have developed a new fluorescent probe based on direct conjugation between 1,10-phenanthroline (Phen) and water-soluble thioglycolic acid (TGA) capped CdTe quantum dots (QDs) for the detection of double-stranded DNA (dsDNA). Phen could directly adsorb onto the QDs surface by metal-affinity driven coordination, quenching the photoluminescence (PL) of QDs via the photoinduced hole transfer process; addition of dsDNA would bring the restoration of QDs PL, as Phen could intercalate into dsDNA followed by its dissociation from the QDs surface. The dependence of QDs PL on the dsDNA amount as well as temperature was utilized to investigate the Phen–dsDNA interaction. The obtained binding constant of the QD–Phen dyad was 2–3 orders of magnitude higher than that of Phen-based metal complexes. Both the binding constant and the binding site of dsDNA with Phen increased with the elevated temperature, owing to an endothermic process. At 37 °C, sensitive detection of dsDNA with a detection limit of ∼3 nmol L−1 was achieved. Therefore, the QD-molecule direct conjugation based fluorescent probe could provide an effective alternative to those based on QD-bioconjugation and QD-ionic conjugation.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2013
·
IF 3.535
Ting Wen,Nian Bing Li,Hong Qun Luo
A novel sensing system has been designed for the Cu 2+ detection based on the quenched fluorescence signal of 6-carboxyfluorescein (FAM)-labeled DNA/polyethyleneimine. The FAM-labeled DNA showed weak fluorescence at the emission wavelength of 530 nm in a pH 4.8 acetic acid-sodium acetate buffer solution. When the polyethyleneimine was introduced to the FAM-labeled DNA solution, the fluorescence signal was greatly amplified. Subsequently, upon the addition of Cu 2+ , Cu 2+ can be captured by the amino groups of the polyethyleneimine to form an absorbent complex, resulting in a strong quenching of the fluorescence of FAM-labeled DNA/polyethyleneimine via a fluorescence resonance energy transfer effect. Herein, we have demonstrated that this facile methodology can offer a rapid, reliable, and selective detection of Cu 2+ with a detection limit as low as 20 nM and a linear range of 100–1600 nM. Furthermore, the detection results for Cu 2+ in a lake water sample obtained by this sensing system agreed well with that by atomic absorption spectroscopy, suggesting the potential application of this sensing system.
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ANALYTICA CHIMICA ACTA
·
2013
·
IF 4.387
Qingxiang Wang,Yingtao Ding,Feng Gao,Shulian Jiang,Bin Zhang,Jiancong Ni,Fei Gao
A novel DNA biosensor was fabricated through a facile sulfamide coupling reaction. First, the versatile sulfonic dye molecule of 1-amino-2-naphthol-4-sulfonate (AN-SO 3 − ) was electrodeposited on the surface of a glassy carbon electrode (GCE) to form a steady and ordered AN-SO 3 − layer. Then the amino-terminated capture probe was covalently grafted to the surface of SO 3 − -AN deposited GCE through the sulfamide coupling reaction between the amino groups in the probe DNA and the sulfonic groups in the AN-SO 3 − . The step-by-step modification process was characterized by electrochemistry and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. Using Ru(NH 3 ) 6 3+ as probe, the probe density and the hybridization efficiency of the biosensor were determined to be 3.18 × 10 13 strands cm −2 and 86.5%, respectively. The hybridization performance of the biosensor was examined by differential pulse voltammetry using Co(phen) 3 3+/2+ (phen = 1,10-phenanthroline) as the indicator. The selectivity experiments showed that the biosensor presented distinguishable response after hybridization with the three-base mismatched, non-complementary and complementary sequences. Under the optimal conditions, the oxidation peak currents of Co(phen) 3 3+/2+ increased linearly with the logarithm values of the concentration of the complementary sequences in the range from 1.0 × 10 −13 M to 1.0 × 10 −8 M with a regression coefficient of 0.9961. The detection limit was estimated to be 7.2 × 10 −14 M based on 3 σ .
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Analytical Methods
·
2014
·Vol. 6
·期 16
·6536-6540
·
IF 1.938
Jing Cao Si,Lu Lu,Zhong Feng Gao,Yu Zhang,Hong Qun Luo,Nian Bing Li
A sensitive and selective biosensor has been developed to detect the hydroxyl radical (˙OH), which was generated through the Fenton reaction. ˙OH could oxidatively damage DNA and cleave it into pieces. Based on this, taking [Ru(NH3)6]3+ as the electrochemical indicator, ˙OH was determined on a gold electrode with self-assembled DNA. The resulting electrochemical biosensor showed a wide linear range of detection from 125 pM to 625 nM with a detection limit of 80 pM and satisfactory selectivity.
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ACS Applied Materials & Interfaces
·
2014
·
IF 5.9
Guilong Zhang,Minglei Yang,Dongqing Cai,Kang Zheng,Xin Zhang,Lifang Wu,Zhengyan Wu
An efficient enzyme-responsive controlled release carrier system was successfully fabricated using single-stranded DNA encapsulated functional mesoporous silica nanoparticles. Mesoporous silica nanoparticles were initially fabricated through hydrolysis of tetraethyl orthosilicate (TEOS) in cetyltrimethylammonium chloride (CTAC) solution, and the surface of nanoparticles could be encapsulated with single-stranded DNA. This nanomaterial has excellent bioactivity and its hydrolysate cannot cause damage to normal cell, thus the biocompatibility of the nanomaterial is improved. In addition, this nanomaterial showed an excellent drug release performance when loaded with drugs, which would be helpful to increase the treatment efficiency and decrease side effects of drugs.
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BIOSENSORS & BIOELECTRONICS
·
2014
·
IF 6.451
Hao Wu,Yaling Liu,Hongyong Wang,Jun Wu,Feifan Zhu,Pei Zou
Highly sensitive detection of DNA plays a crucial role in biomedical research and clinical diagnosis. Herein, we developed a simple, label-free, isothermal , and ultrasensitive colorimetric method for amplified detection of DNA on the basis of a new quadratic amplification strategy. With the presence of three ingeniously designed hairpin structures and Exonuclease III (Exo III), the target DNA can trigger two independent cycles of reactions: hairpin assembly reaction and Exo III cleavage reaction, which are designed to initiate target DNA recycling amplification and reporter DNA amplification, respectively. Therefore, the proposed method exhibits a high sensitivity toward target DNA with a detection limit of as low as 81 fM, and it can discriminate mismatched DNA from completely matched target DNA. Furthermore, this method could be used as a universal tool for the detection of various DNA sequences and might be further extended for the detection of aptamer-binding molecules.
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JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY
·
2014
·Vol. 30
·期 4
·888-894
·
IF 3.396
Jing Hu,Xiandeng Hou,Peng Wu
Hydride generation atomic fluorescence spectrometry (HG-AFS) has been widely used for highly sensitive determination of more than 10 elements that are capable of hydride generation in geological, environmental and biological samples, but its bioanalytical potential has not been well-exploited yet. With CdS quantum dots (QDs) as both the signal labels for DNA sandwiching and analytes for HG-AFS (acid-released Cd2+ from QDs), here we proposed an ultrasensitive indirect method for HIV DNA analysis by HG-AFS. After a conventional sandwich-type hybridization reaction between capture DNA, target DNA and signal DNA labelled with CdS QD assembled silica microspheres, nitric acid was added to dissolve QDs and release Cd2+ from the QD-labels, which were then detected by HG-AFS. This efficient signal amplification strategy, coupled with the highly sensitive HG-AFS detection, gave rise to an impressive limit of detection of 0.8 aM and a wide dynamic concentration range (1 aM to 1 fM). This HG-AFS-based DNA biosensing platform holds great promise in future tumor marker detection and early cancerous diseases diagnosis.
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BIOSENSORS & BIOELECTRONICS
·
2013
·
IF 5.437
Lan Ma,Zhijun Zhu,Tao Li,Zhenxin Wang
Herein, a double-stranded (ds) DNA microarray-based resonance light scattering (RLS) assay with multifunctional gold nanoparticle (GNP) probes has been developed for studying restriction endonuclease functionality and inhibition. Because of decreasing significantly melting temperature, the enzyme-cleaved dsDNAs easily unwind to form single-stranded (ss) DNAs. The ssDNAs are hybridized with multiplex complementary ssDNAs functionalized GNP probes followed by silver enhancement and RLS detection. Three restriction endonucleases (EcoRI, BamHI and EcoRV) and three potential inhibitors (doxorubicin hydrochloride (DOX), ethidium bromide (EB) and an EcoRI-derived helical peptide (α4)) were selected to demonstrate capability of the assay. Enzyme activities of restriction endonucleases are detected simultaneously with high specificity down to the limits of 2.0×10 −2 U/mL for EcoRI, 1.1×10 −2 U/mL for BamHI and 1.6×10 −2 U/mL for EcoRV , respectively. More importantly, the inhibitory potencies of three inhibitors are showed quantitatively, indicating that our approach has great promise for high-throughput screening of restriction endonuclease inhibitors.
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2015
·Vol. 408
·期 3
·683-693
·
IF 3.436
Chen Xing,Jiang Guimei,Wang Zhili,Hong Shanni,Zhang Yuanyuan,Guo Yahui,Cheng Hui,Wang Jine,Pei Renjun
Doxorubicin (Dox) is a DNA-targeting anthracycline antibiotic active against a wide spectrum of cancers. The interaction between Dox and double-stranded DNA (dsDNA) was used to load Dox using DNA duplexes as carriers. More importantly, the interesting DNA sequence-dependent fluorescence response of Dox could be exploited in the design of efficient Dox release systems and efficient fluorescence sensors. In this work, we demonstrated that separate introduction of G and C bases into T-rich single-stranded DNA (ssDNA) sequences afforded the best discrimination of Dox binding between dsDNA and ssDNA. For the first time, we successfully utilized this interesting DNA sequence-dependent fluorescence response of Dox as a signal transduction mechanism for the sensitive detection of biothiols in human serum. Cysteine, homocysteine, and glutathione were detected at as low as 26 nM, 37 nM, and 29 nM, respectively. The biosensors exhibited not only good selectivity, stability, and sensitivity in aqueous solutions but also a sensitive response in human serum, demonstrating their potential for diagnosis.
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Journal of Physical Chemistry C
·
2015
·
IF 4.772
Di Bao,Peng Gao,Yanbo Wang,Han Zhou,Yujin Chen,Guorui Chen,Piaoping Yang,Xitian Zhang
In this paper, Cd(OH)2 1D three-side nanobelt architectures have been fabricated through a facile two-phase reaction system. Considering their electropositive character proven by zeta potential measurement, the as-obtained Cd(OH)2 nanomaterials have been applied to capture negatively charged DNA. On the basis of the above results, the Cd(OH)2 nanomaterials have been employed for trapping negatively charged double-stranded DNA molecules (salmon sperm DNA). Assisted by the detailed observation of their DNA interaction results as well as through UV–vis spectroscopy, infrared imaging automatic target recognition (IRATR) and inductive coupled plasma atomic emission spectrometer (ICP-AES) measurements, it has been clearly shown that this 1D nanoarchitecture can effectively trap and release DNA molecules without use of any other organic reagents. In addition, a miniaturized electrochemical DNA-releasing device based on the Cd(OH)2 1D three-side nanobelt architectures has been fabricated. Using this device, it is possible to recycle the Cd(OH)2 nanostructures. In addition, the Cd(OH)2 nanomaterials maintain their nanostructures, and no Cd2+ ions were released in repeated DNA separation and transfer processes, which demonstrate their practicality for DNA trapping.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2017
·
IF 5.401
Na Li,Shi Gang Liu,Yu Die Zhu,Ting Liu,Shu Min Lin,Yan Shi,Hong Qun Luo,Nian Bing Li
DNA and carbon dots were utilized to co-mediate the growth of gold nanoparticles (AuNPs). The properties of grown AuNPs were discussed and applied to colorimetric biomolecule determination. When target biomolecules were absent, single-stranded oligonucleotides (ssDNA) were adsorbed on the surface of AuNP seeds. Branched AuNP solution of blue color was obtained after carbon dots reduction. In the presence of target DNA, it hybridized with the ssDNA and double-stranded oligonucleotides (dsDNA) were formed. As a result, a spherical AuNP solution of red color was achieved after growth as dsDNA would not be adsorbed by AuNP seeds. A similar situation was observed with thrombin. The complex of thrombin and its aptamer was formed, giving rise to spherical AuNPs after growth. The target biomolecule determination was realized by virtue of color change, consistent with the peak shift in UV–vis absorption spectrum. The detection limits were determined to be 5 nM for target DNA and 1.8 nM for thrombin, respectively. The biomolecule sensors showed the requisite selectivity against possible interferents, and the assay for target DNA exhibited the potential for distinguishing single-base mismatch. These results served as the basis for constructing future biomolecule sensors using DNA and carbon dots co-mediated growth of AuNPs.
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CURRENT APPLIED PHYSICS
·
2015
·
IF 2.212
Hongyan Zhang,Zhenhong Jia,Xiaoyi Lv
A technique is demonstrated to detect DNA hybridization based on surface layer of Au/porous silicon microcavity (Au/PSM) substrate for very small amount of biomolecules. Simulations show that the increase of effective refractive index for the first layer of PSM will cause a blue shift for its reflectance spectrum, and the blue shift becomes less with the increase of refractive index for one more layers. In experiments, such a blue shift of reflectance spectrum of PSM comes from the increase of refractive index by DNA hybridization on the surface. The detection limit of Au/PSM biosensor is 15.15 nM for 19-base pair DNA, which is comparable to that of reported biosensors based on porous silicon (PS). Therefore such an Au/PSM could be very useful to develop simple, rapid and sensitive optical biosensors when the amount of target is very small.
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