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  • Authors: Nguyen, Ha Anh; Mai, Quan Doan; Ngo, Xuan Dinh;  Advisor: -;  Co-Author: - (2022)

    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 demonstrated as excellent transducers for optical sensing systems.

  • Authors: Nguyen, Ha Anh; Mai, Quan Doan; Ngo, Xuan Dinh; Tran, Quang Huy; Doa,n Quang Tri; Le, Thi Ngoc Loan; Bui, Van Hao; Le, Anh Tuan;  Advisor: -;  Co-Author: - (2022)

    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 demonstrated as excellent transducers for optical sensing systems. Herein, we provide an overview of the synth...

  • Authors: Nguyen, Ha Anh; Mai, Quan Doan; Ngo, Xuan Dinh;  Advisor: -;  Co-Author: - (2022)

    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 chemical and electromagnetic mechanisms (CM and EM), the investigation was also carried out in two dire...

  • Authors: Nguyen, Tuan Anh; Ngo, Xuan Dinh; Hoang, Van Tuan; Mai, Quan Doan; Nguyen, Ha Anh; Nguyen, Tien Khi; Vu, Thi Trang | Doan, Quang Tri; Lê, Tuan Anh;  Advisor: -;  Co-Author: - (2021)

    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 from 0.01 to 1000 µM and a LOD value ∼x223C 0.0012 µM, which was ∼x223C 13 times lower than CuNPs-ba...

  • Authors: Nguyen, Ha Anh; Mai, Quan Doan; Ngo, Xuan Dinh; Tran, Quang Huy; Doan, Quang Tri; Le, AnhTuan;  Advisor: -;  Co-Author: - (2022)

    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 convergence feature was evidenced in a mock-up model through optical simulation and further consolidated ...