BIOSENSORS & BIOELECTRONICS
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2013
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IF 5.437
Sai Bi,Yangyang Cui,Ying Dong,Ningbo Zhang
A biosensing system is established for the multi-amplified detection of DNA or specific substrates of aptamers under isothermal conditions , which combines nicked rolling circle amplification (N-RCA) and beacon assisted amplification (BAA) with sensitive colorimetric technique by using DNAzymes as reporter units. According to the configuration, the analysis of DNA is accomplished by recognizing the target to capture nucleic acid-functionalized magnetic particles, followed by the self-assembly of the other two nucleic acids into multicomponent DNA supramolecular structure on magnetic particles. After magnetic separation, the circularization with ligase and the fragmentation with polymerase activate N-RCA and BAA in the presence of polymerase, dNTPs , and the nicking endonuclease , successively producing horseradish peroxidase (HRP)-mimicking DNAzymes that act as colorimetric reporter to catalyze the oxidation of ABTS 2− by H 2 O 2 in the presence of hemin . Under the optimized conditions, we obtain a wide dynamic range for DNA analysis over 6 orders of magnitude from 1.0×10 −14 to 1.0×10 −9 M with a low limit of detection of 6.8×10 −15 M. In the absence of a target, neither self-assembly of nucleic acids nor amplification process can be initiated, indicating an excellent selectivity of the proposed strategy. Similarly, an analogous system is activated by cancer cells or lysozyme through cooperative self-assembly of nucleic acids on magnetic particles in the presence of respective substrates of aptamers to synthesize HRP-mimicking DNAzymes that give the readout signal for the recognition events, achieving LODs of 81 Ramos cells and 7.2×10 −15 M lysozyme, respectively.
研究领域:
生物传感
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纳米技术
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分子生物学
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分析化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ELECTROANALYSIS
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2021
·Vol. 34
·期 5
·911-918
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IF 3.223
Qiaoling Sun,Xiaojun Liu,Haowen Tang,Yuying Qian,Haiying Gu,Hong He
A sandwich-type electrochemical immunosensor was developed for sensitive detection of Salmonella Typhimurium ( S . Typhimurium) in milk and eggs. According to the antigen-antibody specific binding, Anti- S . Typhimurium antibody was used to recognize the S . Typhimurium, while the HRP-Anti- S . Typhimurium antibody as signal probe was used to catalyze H 2 O 2 with the assistance of thionine. The immunosensor showed wide linear range from 5.6×10 1 to 5.6×10 8 CFU/mL and low detection limit of 35 CFU/mL. The immunosensor also exhibited excellent specificity, reproducibility and stability, indicating that it had practicability in quality control of complex food samples and potential in clinical applications.
研究领域:
食品科学
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分析化学
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生物技术
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微生物学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL ANALYSIS
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2018
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IF 2.831
Xin Liu,Dan Wang,Jinshen Chu,Yang Xu,Wenjun Wang
Prostate-Specific Antigen (PSA) is a crucial biomarker for screening prostate cancer, but a sensitive and selective immunosensor for rapid quantification of serum PSA remains to be developed. In this study, a sandwich pair of nanobodies (Nbs) (i.e., Nb2 and Nb40) against PSA surface antigen was obtained from an alpaca-derived immune phage display library. A sandwich-type immunosensor for the sensitive and selective detection of PSA in serum samples was ingeniously designed based on the pair of Nbs. The small size of Nb40 allowed high capture densities on the surface of reduced graphene oxide (rGO) nanocomposed with massive Au nanoparticles ( [email protected] ), which significantly improved the conductivity and provided a large area to anchor many primary antibodies. The secondary antibody Nb2 fused with streptavidin -binding peptide (SBP) cooperated with Nb40 for PSA sandwiching. Accompanying introduction of horseradish peroxidase-streptavidin (HRP-SA) coupled with Nb2-SBP, the faradaic current was linearly correlated with the logarithm of PSA concentration in a range of 0.1–100 ng mL −1 . More importantly, this immunosensor exhibited excellent selectivity, stability, and reproducibility due to the sandwich pair Nbs. The proposed immunosensor was successfully applied in determining PSA in serum samples and could be used for the sensitive and specific detection of PSA.
研究领域:
生物技术
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纳米技术
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免疫学
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癌症研究
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分析化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
RSC Advances
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2023
·Vol. 13
·期 19
·12966-12972
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IF 3.9
Min Dong,Zhihong Gao,Yating Zhang,Jiahui Cai,Jian Li,Panpan Xu,Hong Jiang,Jianmin Gu,Jidong Wang
There has been great interest in the enzymatic cascade amplification strategy for the electrochemical detection of circulating tumor cells (CTCs). In this work, we designed a highly efficient enzymatic cascade reaction based on a multiwalled carbon nanotubes–chitosan (MWCNTs–CS) composite for detection of CTCs. A high electrochemical effective surface area was obtained for a MWCNTs–CS-modified glassy carbon electrode (GCE) for loading glucose oxidase (GOD), as well as a high loading rate and high electrical activity of the enzyme. As a ‘power source’, the MWCNTs–CS composites provided a strong driving power for horseradish peroxidase (HRP) on the surface of polystyrene (PS) microspheres, which acted as probes for capturing CTCs and allowed the reaction to proceed with further facilitation of electron transfer. Aptamer, CTCs, and PS microspheres with HRP and anti-epithelial cell adhesion molecule (anti-EpCAM) antibody were assembled on the MWCNTs–CS/GCE to allow for the modulation of enzyme distance at the micrometer level, and thus ultra-long-range signal transmission was made possible. An ultrasensitive response to CTCs was obtained via this proposed sensing strategy, with a linear range from 10 cell mL−1 to 6 × 106 cell mL−1 and a detection limit of 3 cell mL−1. Moreover, this electrochemical sensor possessed the capability to detect CTCs in serum samples with satisfactory accuracy, which indicated great potential for early diagnosis and clinical analysis of cancer.
研究领域:
生物传感器
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癌症诊断
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电化学
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纳米技术
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生物医学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Omega
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2023
·
IF 4.1
Jie Dong,Laixi Zhang,Wei Li,Xin Hu,Anyi Chen,Chaorui Li
In this study, a facile and cost-effective hydrothermal synthesis method was used to synthesize zinc oxide nanoflowers modified by reduced graphene oxide, and subsequently, trimetallic AuPtRu nanoparticles(AuPtRuNPs) were supported via the reduction method for high-sensitivity colorimetric detection of H2O2 in weakly acidic solutions. Compared to monometallic and bimetallic nanoparticles, trimetallic nanoparticles exhibit significant synergistic effects and enhanced catalytic activity. After providing a three-dimensional structure with multiple pores by zinc oxide and enhancing electron transfer ability by reduced graphene, the trimetallic nanocomposites (AuPtRu/ZnO-rGO) exhibited excellent peroxidase-mimicking activity, which can effectively catalyze 3,3′,5,5′-tetramethylbenzidine (TMB) to produce a blue oxidation product (oxTMB) in the presence of H2O2. Compared to horseradish peroxidase (HRP), AuPtRu/ZnO-rGO demonstrated significantly enhanced catalytic velocity (Vmax = 6.16 × 10–8 M/s) and affinity (Km = 0.02) for H2O2. The study of the catalytic mechanism showed that trimetallic Au, Pt, and Ru could effectively catalyze H2O2 to produce hydroxyl radicals (•OH) to accelerate the oxidation of TMB and enhance the peroxidase-mimicking activity of the AuPtRu/ZnO-rGO nanocomposites. The results showed that the as-synthesized hydrangea-like AuPtRu/ZnO-rGO nanocomposites showed enhanced peroxidase-mimicking activity. It could be used for the colorimetric detection of H2O2 in the range 5–1000 μM with a LOD of 3.0 μM (S/N = 3), and the recoveries are 93.0–101.7%. In addition, the AuPtRu/ZnO-rGO nanocomposites have good applicability for sensitive colorimetric determination of H2O2 in milk, and it has broad application prospects as a multifunctional sensing platform in the food processing industry.
研究领域:
材料科学
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纳米技术
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分析化学
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生物催化
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环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Applied Polymer Materials
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2023
·
IF 5
Yongming Zeng,Tianchi Xu,Xiao-Fang Hou,Jiang Liu,Changqing Liu,Zhaosen Chang,Jianglin Fang,Dongzhong Chen
To achieve convenient storage of bioactive materials such as protein enzymes (proteases) at ambient temperature, with both their spatial structure and biocatalytic activity well retained, is highly appealing but challenging. Herein, a variety of amphiphilic random copolymers have been well synthesized via reversible addition–fragmentation chain transfer (RAFT) copolymerization of sulfobetaine methacrylate (SBMA) and various length fluoroalkyl methacrylate monomers. By simultaneously introducing fluoroalkyl and zwitterionic segments in random copolymerization, such kinds of amphiphilic random copolymers combined the advantages of both polyzwitterionic and fluoropolymers, which were capable of constructing uniform tiny single-chain nanoparticles (SCNPs) of around 10 nm in a wide range of compositions and fabrication conditions from aqueous solutions. Through intramolecular self-folding of the fluorinated alkyl segments to constitute the compact inner cores and the superhydrophilic zwitterionic SBMA polymer segments forming the outer passivated layer, the thus obtained SCNPs exhibited remarkable enzyme stabilizing capability through morphological adjustment, hydration, and heterocoagulation mechanisms for the investigated glucose oxidase (GOx) and horse radish peroxidase (HRP), acting like artificial molecular chaperones. Moreover, enzyme catalytic activity enhancement in the HRP@SCNPs system was well demonstrated with a representative enzyme-catalyzed cascade oxidization reaction for the synthesis of an azobenzene chromophore. Therefore, this work provides a facile fabricating strategy for SCNPs from well-synthesized amphiphilic random copolymers via RAFT, which may serve as promising stabilizers for ambient temperature storage and activity preservation of proteases.
研究领域:
聚合物化学
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生物化学
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材料科学
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纳米技术
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）