Browsing by Author Ngo, Xuan Dinh
Showing results [1 - 11] / 11
Thiram plays a critical role in protecting fruits and vegetables from damage by various crop diseases, but its residues significantly affect the environment, such as soil and water pollution, and becoming a serious threat to human health. Herein, Tween 80-capped copper nanoparticles (Tween 80-CuNPs) were developed as a convenient and low-cost colorimetric probe for selective detection of thiram pesticide. In the presence of thiram, the color of Tween 80-capped CuNPs changed from dark brown to olive green and colorless at high thiram concentrations. The Tween 80-capped CuNPs-based colorimetric probe exhibited good selectivity and high sensitivity (LOD about 0.17 μM) with a high lineari... |
In this study, we have developed, for the first time, a colorimetric and surface-enhanced Raman scattering (SERS) dual-mode sensing platform for sensitive amoxicillin (AMX) detection by employing electrochemically-synthesized copper nanoparticles (CuNPs) and copper-graphene oxide (Cu-GO) nanocomposites with low cost and high purity. The obtained results revealed that Cu-GO-based colorimetric nanosensor exhibited high sensitivity with AMX antibiotics in a linear working range from 5 to 50 µM with a limit of detection (LOD) of 1.71 µM, which was 1.3 times lower than that of CuNPs-based colorimetric nanosensor (2.17 µM). More interestingly, Cu-GO-based SERS nanosensor has a linear range ... |
In this study, silver nanoparticles (AgNPs) were functionalized by various molecules, including sodium borohydride (NaBH4), polyhexamethylene biguanide hydrochloride (PHMB), and Tween 80 to investigate the long-term stabilization of AgNPs in an aqueous dispersion. PHMB-functionalized silver nanoparticles (AgNPs/PHMB) exhibited better stability than others and could be stored at ambient temperature for at least 180 days. In addition to creating stabilization based on the electrostatic repulsion, the use of PHMB helped to increase the degree of stability of the colloidal AgNPs for a long time owing to strong interactions between Ag atoms on AgNPs with nitrogen (N) positions in PHMB mole... |
Modern society has been facing serious health-related problems including food safety, diseases and illness. Hence, it is urgent to develop analysis methods for the detection and control of food contaminants, disease biomarkers and pathogens. As the traditional instrumental methods have several disadvantages, including being time consuming, and having high cost and laborious procedures, optical nanosensors have emerged as promising alternative or complementary approaches to those traditional ones. With the advantages of simple preparation, high surface-to-volume ratio, excellent biocompatibility, and especially, unique optical properties, gold nanoparticles (AuNPs) have been demonstrat... |
Modern society has been facing serious health-related problems including food safety, diseases and illness. Hence, it is urgent to develop analysis methods for the detection and control of food contaminants, disease biomarkers and pathogens. As the traditional instrumental methods have several disadvantages, including being time consuming, and having high cost and laborious procedures, optical nanosensors have emerged as promising alternative or complementary approaches to those traditional ones. With the advantages of simple preparation, high surface-to-volume ratio, excellent biocompatibility, and especially, unique optical properties, gold nanoparticles (AuNPs) have been demonstrat... |
Electrochemically synthesized gold nanoparticles (e-AuNPs) were deposited on aluminum substrates to fabricate effective surface enhanced Raman spectroscopy (SERS) sensors for thiram and CAP monitoring in food samples, between which the thiram sensor showed better performance in terms of sensibility, reliability and practicability. Regarding that the differences in SERS performance of the two sensors were closely associated to the distinction in molecular structure of the two analytes, we investigated the effects of analyte molecular structure on the sensing performance, especially the enhancement factors (EFs), of the sensors. As the enhancement of SERS signal is explained by both che... |
We here invent an implicitly new optical device - cylindrical Fresnel lenses historically used in the decades-old lighthouse concentrator to find application in the field of concentrator photovoltaic, with numerous demonstrations of exotic features in optics. The precious attribute of such a solar concentrator is its ability to grant a focal point sequence, essentially distributed over an arc at any light incidence. The other striking merit of this design is its high acceptance angle, about 60°, at hand and even up to 90°, ideally. We have applied this approach to a simplified principle-of-concept model that closely depicts the octagonal cylindrical Fresnel lens in essence. This conve... |
In this work, we investigated the effect of morphology on the analytical performance of α-Fe2O3 nanostructures-based electrochemical sensors toward chloramphenicol (CAP) antibiotic using three designed morphologies including α-Fe2O3 nano-tube (α-Fe2O3-T), α-Fe2O3 nano-rice (α-Fe2O3-R), and α-Fe2O3 nano-plate (α-Fe2O3-P). Among these morphologies, α-Fe2O3-T displayed an outstanding electrochemical activity owing to the unique hollow structure and large specific surface area. However, due to the small pores size, α-Fe2O3-T showed the high steric hindrance (SD) effect towards an antibiotic with complex molecular structure, as CAP, leading to a significant decrease of their CAP electroche... |
In this work, we investigated the effect of morphology on the analytical performance of α-Fe2O3 nanostructures-based electrochemical sensors toward chloramphenicol (CAP) antibiotic using three designed morphologies including α-Fe2O3 nano-tube (α-Fe2O3-T), α-Fe2O3 nano-rice (α-Fe2O3-R), and α-Fe2O3 nano-plate (α-Fe2O3-P). Among these morphologies, α-Fe2O3-T displayed an outstanding electrochemical activity owing to the unique hollow structure and large specific surface area. However, due to the small pores size, α-Fe2O3-T showed the high steric hindrance (SD) effect towards an antibiotic with complex molecular structure, as CAP, leading to a significant decrease of their CAP electroche... |
In this study, we have investigated the influence of crystallinity, phase ratio, and heterojunction formation on the sensing performance of ZnO/ZnFe2O4 (ZnO/ZFO) nanocomposite-based electrochemical sensors for the detection of furazolidone (FZD) antibiotic drug. Results obtained show that the crystallinity and phase ratio of ZnO/ZFO nanocomposites have decisive effects on their electron transfer and active site density. Tuning the crystallinity and ZnO content of ZnO/ZFO nanocomposites is an effective way to enhance the FZD electrochemical sensing performance. Findings from this research suggested that the formation of ZnO/ZFO heterojunction could significantly improve their electroch... |
In this study, we have investigated the influence of crystallinity, phase ratio, and heterojunction formation on the sensing performance of ZnO/ZnFe2O4 (ZnO/ZFO) nanocomposite-based electrochemical sensors for the detection of furazolidone (FZD) antibiotic drug. Results obtained show that the crystallinity and phase ratio of ZnO/ZFO nanocomposites have decisive effects on their electron transfer and active site density. Tuning the crystallinity and ZnO content of ZnO/ZFO nanocomposites is an effective way to enhance the FZD electrochemical sensing performance. Findings from this research suggested that the formation of ZnO/ZFO heterojunction could significantly improve their electroch... |
