Bifunctional magnetic–plasmonic nanoparticles (NPs)—Fe 3 O 4 @SiO 2-Ag were successfully synthesi... more Bifunctional magnetic–plasmonic nanoparticles (NPs)—Fe 3 O 4 @SiO 2-Ag were successfully synthesized by an ultrasound assisted chemical method. Silver ions were absorbed and then reduced by sodium borohydride on the surface of 3-aminopropyltriethoxysilane (APTES) functionalized silica-coated magnetic NPs, then they were reduced under the influence of a 200 W ultrasonic wave for 60 min. When the amount of precursor silver ions increased, the relative intensity of diffraction peaks of silver crystals in all samples increased with the atomic ratio of silver/iron increasing from 0.208 to 0.455 and saturation magnetization (M s) decreasing from 44.68 emu/g to 34.74 emu/g. The NPs have superparamagnetic properties and strong surface plasmon absorption at 420 nm, which make these particles promising for biomedical applications.
Tantalum-doped tin oxide transparent conductive thin films were deposited on glass substrates by ... more Tantalum-doped tin oxide transparent conductive thin films were deposited on glass substrates by radio frequency and direct current reactive magnetron cosputtering methods in an argon and oxygen environment. Optimization of the thin films for photovoltaic applications was performed using a dimensionless figure of merit by combining electrical and transparency properties. The optimized thin film showed a weight-averaged transmittance of 83%, a band gap value of 3.2 eV, resistivity of 5.2 9 10 À3 X cm, and bulk carrier concentration of 1.2 9 10 20 cm À3 . The lowest resistivity among all films was 2.1 9 10 À3 X cm, corresponding to a weight-averaged transmittance of 62%. The optimized deposition condition was carried out by co-sputtering on heated substrates at 270°C. Thin films deposited under this optimized condition were applied for our perovskite solar cells, and demonstrated promising power conversion efficiency.
We present an efficient experimental method to investigate the photocatalytic activity of Nb-dope... more We present an efficient experimental method to investigate the photocatalytic activity of Nb-doped TiO 2 (TNO) polycrystalline film deposited on glass sub-strate by sputtering. The photocatalytic activity of the thin film was evaluated by oxidative photodegradation of methylene blue (MB) solution at wavelength of 292 nm in the ultraviolet (UV) region. Two ways of installing a UV light source to illuminate the sample were demonstrated: (a) with UV light coming from the front of the thin film through the MB solution, and (b) with UV light coming from the back of the thin film through the glass substrate. Compared with installation (a), which is often applied for photocatalytic activity investigation , the influence of the UV light on the dye solution is removed in installation (b), resulting in significantly improved illuminating light intensity. The results show that the photocatalytic efficiency of the thin film with installation (b) was two times higher than that with installation (a). Thus the proposed approach (b) for installing the UV light source is more promising for investigation of photocatalytic properties.
PbS nanoparticles with average size of 12 nm have been synthesized by a novel time-saving method ... more PbS nanoparticles with average size of 12 nm have been synthesized by a novel time-saving method that combines sonochemical and laser postanneal-ing processes, the latter being important for improved crystal quality of the nanoproduct. The crystalline quality and morphology of the PbS nanoparticles were characterized using several techniques such as Raman spectroscopy, x-ray diffraction analysis, transmission electron microscopy, diffuse re-flectance spectroscopy, and energy-dispersive x-ray analysis. The as-produced PbS nanoproduct was then used to make a glucose sensor. Electrochemical measurements showed that the sensitivity of the glucose sensor based on PbS nanoparticles was 546.2 lA cm À2 mM À1 , much higher than for glucose sensors based on other semiconductor materials reported in literature.
The surface-enhanced Raman signals of 4-aminothiophenol (4-ATP) attached to the surface of colloi... more The surface-enhanced Raman signals of 4-aminothiophenol (4-ATP) attached to the surface of colloidal gold nanoparticles with size distribution of 2 to 5 nm were used as a labeling agent to detect basal cell carcinoma (BCC) of the skin. The enhanced Raman band at 1075 cm-1 corresponding to the C-S stretching vibration in 4-ATP was observed during attachment to the surface of the gold nanoparticles. The frequency and intensity of this band did not change when the colloids were conjugated with BerEP4 antibody, which specifically binds to BCC. We show the feasibility of imaging BCC by surface-enhanced Raman spectroscopy, scanning the 1075 cm-1 band to detect the distribution of 4-ATP-coated gold nanoparticles attached to skin tissue ex vivo.
This work focuses on synthesis, functionalization, and application of gold and silver nanopartcle... more This work focuses on synthesis, functionalization, and application of gold and silver nanopartcles, magnetic nanoparticles Fe3O4, combination of 4-ATP-coated silver nanoparticles and Fe3O4 nanoparticles. The synthesis methods such as chemical reduction, seeding, coprecipitation, and inverse emulsion will be outline. Silica- and amino-coated nanoparticles are suitable for several applications in biomedicine and the environment. The application of prepared nanoparticles for early detection of breast cancer, basal cell carcinoma, antibacterial test, arsenic removal from water, Herpes DNA seperation, CD4+ seperation and isolatioin of DNA of Hepatitis virus type B (HBV) and Epstein-Barr virus (EBV) are discussed. Finally, some promissing perspectives will be pointed out.
4-Aminothiophenol (4-ATP) functionalized silver nanoparticles and magnetic Fe3O4 nanoparticles we... more 4-Aminothiophenol (4-ATP) functionalized silver nanoparticles and magnetic Fe3O4 nanoparticles were combined in a bi-functional nanocolloids which were covered by an approximately 5nm SiO2 layer by inverse emulsion method in order to apply to biomedicine. High saturated magnetization Ms indicated that the colloids are easy to be controlled by external magnetic field, while the characteristic Surface Enhanced Raman peak positions of 4-ATP absorbed on the metal particles were occurred without any alterations, which significantly predicted attractive applicability of the colloids for biomedical labeling.
In this study, the fast DNA diagnostics was successfully developed using high fluorescent Mn dope... more In this study, the fast DNA diagnostics was successfully developed using high fluorescent Mn doped ZnS nanoparticles and NH2-modified SiO2 coated Fe3O4 nanoparticles in a sandwich structure. In one end of the sandwich structure, we employed NH2-modified SiO2 coated Fe3O4 nanoparticles as a docking matrix. A so-called capture probe oligonucleotide chain, that specifically identifies the target DNA, linked to the docking magnetic particles. In the other end, other oligonucleotide chain – named detector probe – contacted with the signaling semiconductor particles. The complementary hybridization of the detector probe – target – capture probe formed the sandwich configuration that attached the fluorescent particles to the docking matrix. This configuration was used to detect DNA of Epstein-Bar virus (EBV) and as the result, a fine affinity between the luminescent intensity at 586 nm of Mn doped ZnS colloids showed with the initially added DNA target concentration, which could detect the presence of target DNA within 2×106 copies/ml (~0.3 fM). The mobility of the as-prepared solutions used in this methodology promised an attractive applicability for designing a DNA detecting fast KIT
Gold nanoparticles (GNPs) have been synthesized by a chemical reduction method using sodium boroh... more Gold nanoparticles (GNPs) have been synthesized by a chemical reduction method using sodium borohydride and functionalized with amino groups on their surface. The GNPs were then conjugated with the anti-HER2 human antibody (trastuzumab) for detecting breast cancer cells. The specific binding of trastuzumab-conjugated GNPs onto the breast cancer cells (KPL4 line) were observed by bright-field and dark-field microscopy and were for the first time observed by scanning electron microscopy and energy dispersive X-ray scanning.
Electronic structure of a surface-activated PbS by a bio-active molecule 4-aminothiophenol (4-ATP... more Electronic structure of a surface-activated PbS by a bio-active molecule 4-aminothiophenol (4-ATP) was investigated using density functional theory (DFT). The obtained results demonstrated the importance of charge transfer which accounted for the flipping of surface rumpling and the nature of the binding between the activated surface and the capping agent. The influence of 4-ATP-PbS topology on bonding nature between surface atoms was discussed. The capping-induced bonding nature shift was interpreted as surface core level shifts (SCLSs) of PbS.
Due to the relationship between compressibility and volume fluctuations, high-pressure studies pr... more Due to the relationship between compressibility and volume fluctuations, high-pressure studies provide vital insight into protein dynamics and function. Most high-pressure experiments were performed on small and fast folding proteins or model peptides. Here we show that a detailed kinetic study is necessary to extract reliable information from the high-pressure-induced structural conversion of large, slowly folding proteins. The pressure-jump unfolding kinetics of yeast phosphoglycerate kinase was recorded at pressures between 50 and 150 MPa. The time dependence of the conformational state of the protein was followed by tryptophan fluorescence measurements from 30 s to 2 h. The observed changes were described by a three-state model, and the volume change and the activation volume as well as the midpoint pressure of the transitions between the folded, intermediate, and unfolded states were determined. An interesting feature of the pressure unfolding of phosphoglycerate kinase was that the unfolding process speeds up with increasing pressure, which is the consequence of negative activation volumes for the folded f intermediate, intermediate f unfolded, and unfolded f intermediate transitions.
Colloidal gold nanoparticles (spheres) have been prepared from HAuCl 4 containing aqueous solutio... more Colloidal gold nanoparticles (spheres) have been prepared from HAuCl 4 containing aqueous solution by using X-ray irradiation and by chemical reduction method. Gold nanorods were synthesized according to the seed-mediated growth method. The colloidal gold nanoparticles were characterized by using transmission electron microscopy, X-ray diffraction, and UV-VIS absorption spectroscopy. It was found that the concentration of the precursors affects the size of the nanoparticles. In the chemical reduction approach the size of nanoparticles can be controlled by varying amount of trisodium citrate, but in the photochemical method the size of nanoparticles can been controlled by varying the ratio of HAuCl 4 to TX-100 and X-ray irradiation duration. Gold nanorods have been synthesized according to the seed-mediated growth method with two steps. The effect of silver acetate and CTAB on formation of gold nanorods has been studied.
Colloidal gold nanoparticles (spheres) have been prepared from HAuCl4 containing aqueous solution... more Colloidal gold nanoparticles (spheres) have been prepared from HAuCl4 containing aqueous solution by using X-ray irradiation and by chemical reduction method. Gold nanorods were synthesized according to the seed-mediated growth method. The colloidal gold nanoparticles were characterized by using transmission electron microscopy, X-ray diffraction, and UV-VIS absorption spectroscopy. It was found that the concentration of the precursors affects the size of the nanoparticles. In the chemical reduction approach the size of nanoparticles can be controlled by varying amount of trisodium citrate, but in the photochemical method the size of nanoparticles can been controlled by varying the ratio of HAuCl4 to TX-100 and X-ray irradiation duration. Gold nanorods have been synthesized according to the seed-mediated growth method with two steps. The effect of silver acetate and CTAB on formation of gold nanorods has been studied.
Electrochemical biosensor for glucose detection using zinc oxide nanotetrapods
International Journal of Nanotechnology, 2011
Faculty of Physics, Hanoi University of Science, Vietnam National University, 334 Nguyen Trai Roa... more Faculty of Physics, Hanoi University of Science, Vietnam National University, 334 Nguyen Trai Road, Thanh Xuan District, Hanoi, Vietnam E-mail: [email protected] E-mail: [email protected] E-mail: [email protected] E-mail: [email protected] * ...
h i g h l i g h t s < The initial Au particle size of 2e5 nm increased to 25 nm in one year of st... more h i g h l i g h t s < The initial Au particle size of 2e5 nm increased to 25 nm in one year of storage. < The main mechanisms of Au particle growth are Ostwald ripening and fusion. < The initial spherical morphology changed to regular shapes. < Twin boundaries have an important effect on the evolution of morphology.
Bifunctional magnetic–plasmonic nanoparticles (NPs)—Fe 3 O 4 @SiO 2-Ag were successfully synthesi... more Bifunctional magnetic–plasmonic nanoparticles (NPs)—Fe 3 O 4 @SiO 2-Ag were successfully synthesized by an ultrasound assisted chemical method. Silver ions were absorbed and then reduced by sodium borohydride on the surface of 3-aminopropyltriethoxysilane (APTES) functionalized silica-coated magnetic NPs, then they were reduced under the influence of a 200 W ultrasonic wave for 60 min. When the amount of precursor silver ions increased, the relative intensity of diffraction peaks of silver crystals in all samples increased with the atomic ratio of silver/iron increasing from 0.208 to 0.455 and saturation magnetization (M s) decreasing from 44.68 emu/g to 34.74 emu/g. The NPs have superparamagnetic properties and strong surface plasmon absorption at 420 nm, which make these particles promising for biomedical applications.
Tantalum-doped tin oxide transparent conductive thin films were deposited on glass substrates by ... more Tantalum-doped tin oxide transparent conductive thin films were deposited on glass substrates by radio frequency and direct current reactive magnetron cosputtering methods in an argon and oxygen environment. Optimization of the thin films for photovoltaic applications was performed using a dimensionless figure of merit by combining electrical and transparency properties. The optimized thin film showed a weight-averaged transmittance of 83%, a band gap value of 3.2 eV, resistivity of 5.2 9 10 À3 X cm, and bulk carrier concentration of 1.2 9 10 20 cm À3 . The lowest resistivity among all films was 2.1 9 10 À3 X cm, corresponding to a weight-averaged transmittance of 62%. The optimized deposition condition was carried out by co-sputtering on heated substrates at 270°C. Thin films deposited under this optimized condition were applied for our perovskite solar cells, and demonstrated promising power conversion efficiency.
We present an efficient experimental method to investigate the photocatalytic activity of Nb-dope... more We present an efficient experimental method to investigate the photocatalytic activity of Nb-doped TiO 2 (TNO) polycrystalline film deposited on glass sub-strate by sputtering. The photocatalytic activity of the thin film was evaluated by oxidative photodegradation of methylene blue (MB) solution at wavelength of 292 nm in the ultraviolet (UV) region. Two ways of installing a UV light source to illuminate the sample were demonstrated: (a) with UV light coming from the front of the thin film through the MB solution, and (b) with UV light coming from the back of the thin film through the glass substrate. Compared with installation (a), which is often applied for photocatalytic activity investigation , the influence of the UV light on the dye solution is removed in installation (b), resulting in significantly improved illuminating light intensity. The results show that the photocatalytic efficiency of the thin film with installation (b) was two times higher than that with installation (a). Thus the proposed approach (b) for installing the UV light source is more promising for investigation of photocatalytic properties.
PbS nanoparticles with average size of 12 nm have been synthesized by a novel time-saving method ... more PbS nanoparticles with average size of 12 nm have been synthesized by a novel time-saving method that combines sonochemical and laser postanneal-ing processes, the latter being important for improved crystal quality of the nanoproduct. The crystalline quality and morphology of the PbS nanoparticles were characterized using several techniques such as Raman spectroscopy, x-ray diffraction analysis, transmission electron microscopy, diffuse re-flectance spectroscopy, and energy-dispersive x-ray analysis. The as-produced PbS nanoproduct was then used to make a glucose sensor. Electrochemical measurements showed that the sensitivity of the glucose sensor based on PbS nanoparticles was 546.2 lA cm À2 mM À1 , much higher than for glucose sensors based on other semiconductor materials reported in literature.
The surface-enhanced Raman signals of 4-aminothiophenol (4-ATP) attached to the surface of colloi... more The surface-enhanced Raman signals of 4-aminothiophenol (4-ATP) attached to the surface of colloidal gold nanoparticles with size distribution of 2 to 5 nm were used as a labeling agent to detect basal cell carcinoma (BCC) of the skin. The enhanced Raman band at 1075 cm-1 corresponding to the C-S stretching vibration in 4-ATP was observed during attachment to the surface of the gold nanoparticles. The frequency and intensity of this band did not change when the colloids were conjugated with BerEP4 antibody, which specifically binds to BCC. We show the feasibility of imaging BCC by surface-enhanced Raman spectroscopy, scanning the 1075 cm-1 band to detect the distribution of 4-ATP-coated gold nanoparticles attached to skin tissue ex vivo.
This work focuses on synthesis, functionalization, and application of gold and silver nanopartcle... more This work focuses on synthesis, functionalization, and application of gold and silver nanopartcles, magnetic nanoparticles Fe3O4, combination of 4-ATP-coated silver nanoparticles and Fe3O4 nanoparticles. The synthesis methods such as chemical reduction, seeding, coprecipitation, and inverse emulsion will be outline. Silica- and amino-coated nanoparticles are suitable for several applications in biomedicine and the environment. The application of prepared nanoparticles for early detection of breast cancer, basal cell carcinoma, antibacterial test, arsenic removal from water, Herpes DNA seperation, CD4+ seperation and isolatioin of DNA of Hepatitis virus type B (HBV) and Epstein-Barr virus (EBV) are discussed. Finally, some promissing perspectives will be pointed out.
4-Aminothiophenol (4-ATP) functionalized silver nanoparticles and magnetic Fe3O4 nanoparticles we... more 4-Aminothiophenol (4-ATP) functionalized silver nanoparticles and magnetic Fe3O4 nanoparticles were combined in a bi-functional nanocolloids which were covered by an approximately 5nm SiO2 layer by inverse emulsion method in order to apply to biomedicine. High saturated magnetization Ms indicated that the colloids are easy to be controlled by external magnetic field, while the characteristic Surface Enhanced Raman peak positions of 4-ATP absorbed on the metal particles were occurred without any alterations, which significantly predicted attractive applicability of the colloids for biomedical labeling.
In this study, the fast DNA diagnostics was successfully developed using high fluorescent Mn dope... more In this study, the fast DNA diagnostics was successfully developed using high fluorescent Mn doped ZnS nanoparticles and NH2-modified SiO2 coated Fe3O4 nanoparticles in a sandwich structure. In one end of the sandwich structure, we employed NH2-modified SiO2 coated Fe3O4 nanoparticles as a docking matrix. A so-called capture probe oligonucleotide chain, that specifically identifies the target DNA, linked to the docking magnetic particles. In the other end, other oligonucleotide chain – named detector probe – contacted with the signaling semiconductor particles. The complementary hybridization of the detector probe – target – capture probe formed the sandwich configuration that attached the fluorescent particles to the docking matrix. This configuration was used to detect DNA of Epstein-Bar virus (EBV) and as the result, a fine affinity between the luminescent intensity at 586 nm of Mn doped ZnS colloids showed with the initially added DNA target concentration, which could detect the presence of target DNA within 2×106 copies/ml (~0.3 fM). The mobility of the as-prepared solutions used in this methodology promised an attractive applicability for designing a DNA detecting fast KIT
Gold nanoparticles (GNPs) have been synthesized by a chemical reduction method using sodium boroh... more Gold nanoparticles (GNPs) have been synthesized by a chemical reduction method using sodium borohydride and functionalized with amino groups on their surface. The GNPs were then conjugated with the anti-HER2 human antibody (trastuzumab) for detecting breast cancer cells. The specific binding of trastuzumab-conjugated GNPs onto the breast cancer cells (KPL4 line) were observed by bright-field and dark-field microscopy and were for the first time observed by scanning electron microscopy and energy dispersive X-ray scanning.
Electronic structure of a surface-activated PbS by a bio-active molecule 4-aminothiophenol (4-ATP... more Electronic structure of a surface-activated PbS by a bio-active molecule 4-aminothiophenol (4-ATP) was investigated using density functional theory (DFT). The obtained results demonstrated the importance of charge transfer which accounted for the flipping of surface rumpling and the nature of the binding between the activated surface and the capping agent. The influence of 4-ATP-PbS topology on bonding nature between surface atoms was discussed. The capping-induced bonding nature shift was interpreted as surface core level shifts (SCLSs) of PbS.
Due to the relationship between compressibility and volume fluctuations, high-pressure studies pr... more Due to the relationship between compressibility and volume fluctuations, high-pressure studies provide vital insight into protein dynamics and function. Most high-pressure experiments were performed on small and fast folding proteins or model peptides. Here we show that a detailed kinetic study is necessary to extract reliable information from the high-pressure-induced structural conversion of large, slowly folding proteins. The pressure-jump unfolding kinetics of yeast phosphoglycerate kinase was recorded at pressures between 50 and 150 MPa. The time dependence of the conformational state of the protein was followed by tryptophan fluorescence measurements from 30 s to 2 h. The observed changes were described by a three-state model, and the volume change and the activation volume as well as the midpoint pressure of the transitions between the folded, intermediate, and unfolded states were determined. An interesting feature of the pressure unfolding of phosphoglycerate kinase was that the unfolding process speeds up with increasing pressure, which is the consequence of negative activation volumes for the folded f intermediate, intermediate f unfolded, and unfolded f intermediate transitions.
Colloidal gold nanoparticles (spheres) have been prepared from HAuCl 4 containing aqueous solutio... more Colloidal gold nanoparticles (spheres) have been prepared from HAuCl 4 containing aqueous solution by using X-ray irradiation and by chemical reduction method. Gold nanorods were synthesized according to the seed-mediated growth method. The colloidal gold nanoparticles were characterized by using transmission electron microscopy, X-ray diffraction, and UV-VIS absorption spectroscopy. It was found that the concentration of the precursors affects the size of the nanoparticles. In the chemical reduction approach the size of nanoparticles can be controlled by varying amount of trisodium citrate, but in the photochemical method the size of nanoparticles can been controlled by varying the ratio of HAuCl 4 to TX-100 and X-ray irradiation duration. Gold nanorods have been synthesized according to the seed-mediated growth method with two steps. The effect of silver acetate and CTAB on formation of gold nanorods has been studied.
Colloidal gold nanoparticles (spheres) have been prepared from HAuCl4 containing aqueous solution... more Colloidal gold nanoparticles (spheres) have been prepared from HAuCl4 containing aqueous solution by using X-ray irradiation and by chemical reduction method. Gold nanorods were synthesized according to the seed-mediated growth method. The colloidal gold nanoparticles were characterized by using transmission electron microscopy, X-ray diffraction, and UV-VIS absorption spectroscopy. It was found that the concentration of the precursors affects the size of the nanoparticles. In the chemical reduction approach the size of nanoparticles can be controlled by varying amount of trisodium citrate, but in the photochemical method the size of nanoparticles can been controlled by varying the ratio of HAuCl4 to TX-100 and X-ray irradiation duration. Gold nanorods have been synthesized according to the seed-mediated growth method with two steps. The effect of silver acetate and CTAB on formation of gold nanorods has been studied.
Electrochemical biosensor for glucose detection using zinc oxide nanotetrapods
International Journal of Nanotechnology, 2011
Faculty of Physics, Hanoi University of Science, Vietnam National University, 334 Nguyen Trai Roa... more Faculty of Physics, Hanoi University of Science, Vietnam National University, 334 Nguyen Trai Road, Thanh Xuan District, Hanoi, Vietnam E-mail: [email protected] E-mail: [email protected] E-mail: [email protected] E-mail: [email protected] * ...
h i g h l i g h t s < The initial Au particle size of 2e5 nm increased to 25 nm in one year of st... more h i g h l i g h t s < The initial Au particle size of 2e5 nm increased to 25 nm in one year of storage. < The main mechanisms of Au particle growth are Ostwald ripening and fusion. < The initial spherical morphology changed to regular shapes. < Twin boundaries have an important effect on the evolution of morphology.
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