Detection of Vibrio cholerae O1 by Using Cerium Oxide Nanowires - Based Immunosensor with Different Antibody Immobilization Methods

Phuong Dinh Tam,Nguyen Luong Hoang,Hoang Lan,Pham Hung Vuong,Ta Thi Nhat Anh,Tran Quang Huy,Nguyen Thanh Thuy 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.68 No.10

In this work, we evaluated the effects of different antibody immobilization strategies on the response of a CeO2-nanowires (NWs)-based immunosensor for V ibrio cholerae O1 detection. Accordingly, the changes in the electron-transfer resistance (Ret) from before to after cells bind to an antibody-modified electrode prepared by using three different methods of antibody immobilization were determined. The values were 16.2%, 8.3%, and 6.65% for the method that utilized protein A, antibodies activated by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC)/Nhydroxysuccinimide (NHS), and absorption, respectively. Cyclic voltammetry confirmed that the change in the current was highest for the immunosensors prepared using protein A (11%), followed by those prepared with EDC/NHS-activated antibodies (9%), and finally, those prepared through absorption (7.5%). The order of the antibody immobilization strategies in terms of resulting immunosensor detection limit and sensitivity was as follows order: absorption (3.2 × 103 CFU/mL; 45.1 /CFU·mL−1) < EDC/NHS-activated antibody (1.0 × 103 CFU/mL; 50.6 /CFU·mL−1) < protein A (1.0 × 102 CFU/mL; 65.8 /CFU·mL−1). Thus, we confirmed that the protein A - mediated method showed significantly high cell binding efficiencies compared to the random immobilization method.

Genetically modified organism (GMO) detection by biosensor based on SWCNT material

Phuong Dinh Tam 한국물리학회 2015 Current Applied Physics Vol.15 No.3

This paper reports single-walled carbon nanotube-based biosensors for genetically modified organism (GMO) detection. Electrochemical electrode and single-walled carbon nanotube field effect transistor (SWCNT-FET)-based biosensors are used to determine the CaMV 35S promoter of Roundup Ready soybean. Given optimal conditions, both biosensors can effectively detect full complementarity with concentration as low as 1 nM. The sensitivity of the electrode-based biosensor is approximately 0.6 kU/nM while that of the SWCNT-FET-based biosensor is 0.32 nA/nM. Both biosensors were also used to determine a polymerase chain reaction-amplified sample. The obtained results showed that both sensors determined transgenic organisms well, thereby providing a useful tool for screening analysis of food samples.

High-performance nonenzymatic electrochemical glucose biosensor based on AgNP-decorated MoS2 microflowers

Dinh Van Tuan,Dang Thi Thuy Ngan,Dao Vu Phuong Thao,Nguyen Thi Nguyet,Nguyen Thi Thuy,Nguyen Phuong Thuy,Vu Van Thu,Vuong-Pham Hung,Phuong Dinh Tam 한국물리학회 2022 Current Applied Physics Vol.43 No.-

A facile hydrothermal route was used to synthesize silver nanoparticle (AgNP)-decorated microflower molybdenum disulfide (MoS2-MF) for bio-electrochemical platform fabrication to detect nonenzymatic glucose concentration. The morphologies of the materials were studied by scanning electron microscopy, and their structural characteristics were analyzed by X-ray diffractometry and energy-dispersive X-ray spectroscopy. The electrochemical characteristics of the AgNPs/MoS2-MF/PtE biosensor were studied by cyclic voltammetry. The obtained data indicated that the developed nonenzymatic glucose sensor has a large linear response between 1.0 and 15.0 mM, a limit of detection of as low as 1.0 mM, and a sensitivity of 46.5 μA nM-1 cm-2. The biosensor also displayed outstanding selectivity, stability, reproducibility, and repeatability. Additionally, the AgNPs/MoS2-MF/ PtE biosensor was utilized to detect glucose concentration in real sample and showed practical application potential for glucose detection.

Effect of nanostructured MoS2 morphology on the glucose sensing of electrochemical biosensors

Dinh Van Tuan,Dang Thi Thuy Ngan,Nguyen Thi Thuy,Hoang Lan,Nguyen Thi Nguyet,Vu Van Thu,Vuong-Pham Hung,Phuong Dinh Tam 한국물리학회 2020 Current Applied Physics Vol.20 No.9

In this study, the effects of the morphological characteristics of MoS2 nanomaterials on the glucose sensing of electrochemical biosensors were explored. Nanostructured MoS2 materials, including nanoparticles (NPs), nanoflowers (NFs), and nanoplatelets (NPLs), were prepared via a simple hydrothermal method. The structure and morphological characteristics of MoS2 nanomaterials were examined through X-ray diffraction, field emission scanning electron microscopy, and Raman spectroscopy. Electrochemical properties were analyzed through cyclic voltammetry. Results showed that the obtained sensitivity was 64, 68.7, and 77.6 μAmM 1 cm 2 for MoS2 NP-, MoS2 NF-, and MoS2 NPL-based biosensors, respectively. The limit of detection (LOD) of all MoS2-based glucose biosensors was 0.081 mM. In addition, the pH, temperature, glucose oxidase (GOx) concentration, reproducibility, specificity, and stability of glucose biosensors with different MoS2 morphologies were also investigated and indicated the oxidation current response of the MoS2 NPL-based glucose biosensor was higher than that of MoS2 NF- and NP-based biosensors.

Rapid and label-free detection of H5N1 virus using carbon nanotube network field effect transistor

Vu Van Thu,Phuong Dinh Tam,Phuong Trung Dung 한국물리학회 2013 Current Applied Physics Vol.13 No.7

DNA hybridization-based detection techniques are widely used in genetics, medicine, and drug discovery. However, the current techniques are usually based on labels and reagents that are time consuming and complex to implement. In this study, we report a label-free DNA sensor based on single-walled carbon nanotube field effect transistor (SWCNTFET) for selective DNA hybridization detection of H5N1 virus. A network of single-walled carbon nanotubes (SWCNTs) acts as the conductor channel. ProbeDNA sequences were adsorbed onto SWCNTs. The developed DNA sensor can effectively detect full-complementary DNA with concentration as low as 1.25 pM. The sensitivity of the DNA sensor reached approximately 0.28 nM/nA. The effect of the parameters, including DNA probe concentration, its complementary concentration,mismatched sequence, and hybridization time, on the sensor response was also studied. The results showed the potential application of the DNA sensor for medical, environmental, and epidemic detection.

Detection of pathogenic microorganisms using biosensor based on multi-walled carbon nanotubes dispersed in DNA solution

Nguyen Thi Thuy,Phuong Dinh Tam,Mai Anh Tuan,Anh-Tuan Le,Le Thi Tam,Vu Van Thu,Nguyen Van Hieu,Nguyen Duc Chien 한국물리학회 2012 Current Applied Physics Vol.12 No.6

The present paper introduces a facile and cost-effective route for the direct dispersion of multi-walled carbon nanotubes (MWCNTs) in DNA solution. Their application in detecting Escherichia coli O157:H7using DNA biosensorwas demonstrated. The dispersion state of theMWCNTswas characterized via UVeVis spectroscopy, transmission electron microscopy, and field emission scanning electron microscopy. The interaction between DNA sequence and the MWCNTs was investigated using Raman spectroscopy and Fourier transform infrared spectroscopy. As-obtainedMWCNT solutionwas used in the preparation of DNA sensor. Results revealed that the developed DNA sensor can detect a DNA target as low as 1 nM in a buffer solution. The sensitivity of the DNA sensor reached approximately 0.19 nM/mV. The effect of dispersion parameters, including pH values, DNA concentration, ion strength, and sonication time, on sensor response was also studied. TheDNA sensor can respondwell to 120 min of sonication time, a pH value of 9, and 20 mM of DNA sequence concentration. The results of the present study showed a potential application of the DNA sensor in the detection of Escherichia coli O157:H7.

Green synthesis of finely-dispersed highly bactericidal silver nanoparticles via modified Tollens technique

Anh-Tuan Le,P.T. Huy,Phuong Dinh Tam,Tran Quang Huy,A.A. Kudrinskiy,Yu A. Krutyakov 한국물리학회 2010 Current Applied Physics Vol.10 No.3

In this article, we represent a versatile and effective technique which using non-toxic chemicals to prepare stable aqueous dispersions of silver nanoparticles (NPs) via modified Tollens process. It was shown that as-prepared silver colloids consisted of finely-dispersed NPs with average diameter about 10 nm and a relatively narrow size distribution. Moreover, they could be stored very stable after several months without observation of aggregates or sedimentation. In comparison with previous works where Tollens process was being used, we for the first time applied UV-irradiation simultaneously with glucose reduction of silver salt through NPs preparation. The colloidal solutions of silver NPs were found to exhibit a high antibacterial activity against gram-negative Escherichia coli. The concentration of silver leading to a complete inhibition of bacteria growth was revealed as low as at 1.0 ㎍ml-1 and found much lower compared to earlier reports. These advantages of aqueous dispersions of silver NPs make them ideal for green industrial, medicinal, microbiological and other applications.