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Article ; Online: Synthesis of a BC-Dihydrodipyrrin Building Block of Bacteriochlorophyll

Nguyen, Khiem Chau / Lindsey, Jonathan S

2023 Volume 88, Issue 15, Page(s) 11205–11216

Abstract: A strategy for the synthesis of ... ...

Abstract	A strategy for the synthesis of bacteriochlorophyll
MeSH term(s)	Porphyrins/chemistry ; Bacteriochlorophyll A ; Magnetic Resonance Spectroscopy ; Acids ; Tetrapyrroles
Chemical Substances	Porphyrins ; Bacteriochlorophyll A ; Acids ; Tetrapyrroles
Language	English
Publishing date	2023-07-20
Publishing country	United States
Document type	Journal Article ; Research Support, U.S. Gov't, Non-P.H.S.
ZDB-ID	123490-0
ISSN	1520-6904 ; 0022-3263
ISSN (online)	1520-6904
ISSN	0022-3263
DOI	10.1021/acs.joc.3c01216
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article ; Online: Myocardial Infarction During SARS-CoV-2 Infection: Another Piece in the Long-COVID Puzzle.

Nguyen, Thach / Zuin, Marco / Ngo, Khiem / Gibson, C Michael

The American journal of cardiology

2024 Volume 215, Page(s) 92–93

MeSH term(s)	Humans ; Post-Acute COVID-19 Syndrome ; COVID-19 ; SARS-CoV-2 ; Myocardial Infarction/epidemiology
Language	English
Publishing date	2024-01-24
Publishing country	United States
Document type	Editorial
ZDB-ID	80014-4
ISSN	1879-1913 ; 0002-9149
ISSN (online)	1879-1913
ISSN	0002-9149
DOI	10.1016/j.amjcard.2024.01.013
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Article: Simple and Label-Free Detection of Carboxylesterase and Its Inhibitors Using a Liquid Crystal Droplet Sensing Platform.

Nguyen, Duy-Khiem / Jang, Chang-Hyun

Micromachines

2022 Volume 13, Issue 3

Abstract: In this study, we developed a liquid crystal (LC) droplet-based sensing platform for the detection of carboxylesterase (CES) and its inhibitors. The LC droplet patterns in contact with myristoylcholine chloride (Myr) exhibited dark cross appearances, ... ...

Abstract	In this study, we developed a liquid crystal (LC) droplet-based sensing platform for the detection of carboxylesterase (CES) and its inhibitors. The LC droplet patterns in contact with myristoylcholine chloride (Myr) exhibited dark cross appearances, corresponding to homeotropic anchoring of the LCs at the aqueous/LC interface. However, in the presence of CES, Myr was hydrolyzed; therefore, the optical images of the LC patterns changed to bright fan-shaped textures, corresponding to a planar orientation of LCs at the interface. In contrast, the presence of CES inhibitors, such as benzil, inhibits the hydrolysis of Myr; as a result, the LC patterns exhibit dark cross textures. This principle led to the development of an LC droplet-based sensing method with a detection limit of 2.8 U/L and 10 μM, for CES detection and its inhibitor, respectively. The developed biosensor not only enables simple and label-free detection of CES but also shows high promise for the detection of CES inhibitors.
Language	English
Publishing date	2022-03-21
Publishing country	Switzerland
Document type	Journal Article
ZDB-ID	2620864-7
ISSN	2072-666X
ISSN	2072-666X
DOI	10.3390/mi13030490
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article ; Online: Ultrasensitive colorimetric detection of amoxicillin based on Tris-HCl-induced aggregation of gold nanoparticles.

Nguyen, Duy Khiem / Jang, Chang-Hyun

Analytical biochemistry

2022 Volume 645, Page(s) 114634

Abstract: An ultrasensitive colorimetric aptasensor for the detection of amoxicillin (AMO) based on the Tris-HCl buffer-induced aggregation of gold nanoparticles (AuNPs) was developed. The AuNPs were aggregated by the addition of Tris-HCl buffer. The adsorption of ...

Abstract	An ultrasensitive colorimetric aptasensor for the detection of amoxicillin (AMO) based on the Tris-HCl buffer-induced aggregation of gold nanoparticles (AuNPs) was developed. The AuNPs were aggregated by the addition of Tris-HCl buffer. The adsorption of the aptamer on the AuNP surface increased its negative charge density, leading to the enhancement of the electrostatic repulsion between the nanoparticles, thus protecting AuNPs from aggregation in the Tris-HCl buffer. However, the specific binding of the aptamer with AMO induced conformational changes in the aptamer, which reduced the adsorption of the aptamer on the AuNP surface, diminishing the protective effect of the aptamer. This resulted in the aggregation of AuNPs by Tris-HCl buffer, and consequently, color change of the solution containing AuNPs from red to blue. Under optimized conditions, a linear relationship between the absorbance ratio variation (ΔA
MeSH term(s)	Amoxicillin ; Aptamers, Nucleotide/chemistry ; Biosensing Techniques/methods ; Colorimetry/methods ; Gold/chemistry ; Metal Nanoparticles/chemistry
Chemical Substances	Aptamers, Nucleotide ; Gold (7440-57-5) ; Amoxicillin (804826J2HU)
Language	English
Publishing date	2022-03-08
Publishing country	United States
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	1110-1
ISSN	1096-0309 ; 0003-2697
ISSN (online)	1096-0309
ISSN	0003-2697
DOI	10.1016/j.ab.2022.114634
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Article: A Label-Free Liquid Crystal Biosensor Based on Specific DNA Aptamer Probes for Sensitive Detection of Amoxicillin Antibiotic.

Nguyen, Duy Khiem / Jang, Chang-Hyun

Micromachines

2021 Volume 12, Issue 4

Abstract: We developed a liquid crystal (LC) aptamer biosensor for the sensitive detection of amoxicillin (AMX). The AMX aptamer was immobilized onto the surface of a glass slide modified with a mixed self-assembled layer of dimethyloctadecyl [3-(trimethoxysilyl) ... ...

Abstract	We developed a liquid crystal (LC) aptamer biosensor for the sensitive detection of amoxicillin (AMX). The AMX aptamer was immobilized onto the surface of a glass slide modified with a mixed self-assembled layer of dimethyloctadecyl [3-(trimethoxysilyl) propyl] ammonium chloride (DMOAP) and (3-aminopropyl) triethoxysilane (APTES). The long alkyl chains of DMOAP maintained the LC molecules in a homeotropic orientation and induced a dark optical appearance under a polarized light microscope (POM). In the presence of AMX, the specific binding of the aptamer and AMX molecules induced a conformational change in the aptamers, leading to the disruption of the homeotropic orientation of LCs, resulting in a bright optical appearance. The developed aptasensor showed high specificity and a low detection limit of 3.5 nM. Moreover, the potential application of the developed aptasensor for the detection of AMX in environmental samples was also demonstrated. Therefore, the proposed aptasensor is a promising platform for simple, rapid, and label-free monitoring of AMX in an actual water environment with high selectivity and sensitivity.
Language	English
Publishing date	2021-03-30
Publishing country	Switzerland
Document type	Journal Article
ZDB-ID	2620864-7
ISSN	2072-666X
ISSN	2072-666X
DOI	10.3390/mi12040370
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Article: A Simple and Ultrasensitive Colorimetric Biosensor for Anatoxin-a Based on Aptamer and Gold Nanoparticles.

Nguyen, Duy-Khiem / Jang, Chang-Hyun

Micromachines

2021 Volume 12, Issue 12

Abstract: Here, we designed a simple, rapid, and ultrasensitive colorimetric aptasensor for detecting anatoxin-a (ATX-a). The sensor employs a DNA aptamer as the sensing element and gold nanoparticles (AuNPs) as probes. Adsorption of the aptamer onto the AuNP ... ...

Abstract	Here, we designed a simple, rapid, and ultrasensitive colorimetric aptasensor for detecting anatoxin-a (ATX-a). The sensor employs a DNA aptamer as the sensing element and gold nanoparticles (AuNPs) as probes. Adsorption of the aptamer onto the AuNP surface can protect AuNPs from aggregation in NaCl solution, thus maintaining their dispersion state. In the presence of ATX-a, the specific binding of the aptamer with ATX-a results in a conformational change in the aptamer, which facilitates AuNP aggregation and, consequently, a color change of AuNPs from red to blue in NaCl solution. This color variation is directly associated with ATX-a concentration and can be easily measured using a UV/Vis spectrophotometer. The absorbance variation is linearly proportional to ATX-a concentration across the concentration range of 10 pM to 200 nM, with a detection limit of 4.45 pM and high selectivity against other interferents. This strategy was successfully applied to the detection of ATX-a in lake water samples. Thus, the present aptasensor is a promising alternative method for the rapid detection of ATX-a in the environment.
Language	English
Publishing date	2021-12-08
Publishing country	Switzerland
Document type	Journal Article
ZDB-ID	2620864-7
ISSN	2072-666X
ISSN	2072-666X
DOI	10.3390/mi12121526
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Article ; Online: A Cationic Surfactant-Decorated Liquid Crystal-Based Aptasensor for Label-Free Detection of Malathion Pesticides in Environmental Samples.

Nguyen, Duy Khiem / Jang, Chang-Hyun

Biosensors

2021 Volume 11, Issue 3

Abstract: We report a liquid crystal (LC)-based aptasensor for the detection of malathion using a cationic surfactant-decorated LC interface. In this method, LCs displayed dark optical images when in contact with aqueous cetyltrimethylammonium bromide (CTAB) ... ...

Abstract	We report a liquid crystal (LC)-based aptasensor for the detection of malathion using a cationic surfactant-decorated LC interface. In this method, LCs displayed dark optical images when in contact with aqueous cetyltrimethylammonium bromide (CTAB) solution due to the formation of a self-assembled CTAB monolayer at the aqueous/LC interface, which induced the homeotropic orientation of LCs. With the addition of malathion aptamer, the homeotropic orientation of LCs changed to a planar one due to the interactions between CTAB and the aptamer, resulting in a bright optical image. In the presence of malathion, the formation of aptamer-malathion complexes caused a conformational change of the aptamers, thereby weakening the interactions between CTAB and the aptamers. Therefore, CTAB is free to induce a homeotropic ordering of the LCs, which corresponds to a dark optical image. The developed sensor exhibited high specificity for malathion determination and a low detection limit of 0.465 nM was achieved. Moreover, the proposed biosensor was successfully applied to detect malathion in tap water, river water, and apple samples. The proposed LC-based aptasensor is a simple, rapid, and convenient platform for label-free monitoring of malathion in environmental samples.
MeSH term(s)	Aptamers, Nucleotide/chemistry ; Biosensing Techniques/methods ; Environmental Monitoring ; Environmental Pollutants/analysis ; Limit of Detection ; Liquid Crystals/chemistry ; Malathion ; Pesticides/analysis ; Surface-Active Agents/chemistry ; Water/chemistry
Chemical Substances	Aptamers, Nucleotide ; Environmental Pollutants ; Pesticides ; Surface-Active Agents ; Water (059QF0KO0R) ; Malathion (U5N7SU872W)
Language	English
Publishing date	2021-03-23
Publishing country	Switzerland
Document type	Journal Article
ZDB-ID	2662125-3
ISSN	2079-6374 ; 2079-6374
ISSN (online)	2079-6374
ISSN	2079-6374
DOI	10.3390/bios11030092
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article ; Online: An acetylcholinesterase-based biosensor for the detection of pesticides using liquid crystals confined in microcapillaries.

Nguyen, Duy Khiem / Jang, Chang-Hyun

Colloids and surfaces. B, Biointerfaces

2021 Volume 200, Page(s) 111587

Abstract: Here, we demonstrate a capillary-sensing platform based on liquid crystals (LCs) confined in microcapillaries for simple and sensitive detection of acetylcholinesterase (AChE) and its inhibitors. LC droplets were formed through sequential injection of ... ...

Abstract	Here, we demonstrate a capillary-sensing platform based on liquid crystals (LCs) confined in microcapillaries for simple and sensitive detection of acetylcholinesterase (AChE) and its inhibitors. LC droplets were formed through sequential injection of LCs and an aqueous solution into trichloro(octyl)silane (OTS)-treated microcapillaries. When the confined LC droplets make contact with a cationic surfactant solution, myristoylcholine chloride (Myr), the formation of a Myr monolayer at the aqueous/LC interface induces a horizontal orientation of the LCs at the interface along the microcapillary, producing an optical LC droplet texture of a four-petal shape. On the other hand, AChE can catalyze the hydrolysis of Myr into choline and myristic acid. The hydrolyzed Myr is unable to form a monolayer at the aqueous/LC interface, and therefore the confined LC droplets exhibit two bright-lined optical images when in contact with the pre-incubated mixture of Myr and AChE, corresponding to the homeotropic orientation of LCs at the interface. However, in the presence of AChE-inhibiting pesticides, such as fenobucarb and malathion, the activity of AChE is inhibited, and thus, the enzymatic hydrolysis of Myr cannot occur. As a result, the confined LC droplets present the four petal-shaped optical images when in contact with the pre-incubated mixture of Myr, AChE, and pesticides. Based on this principle, an LC-based microcapillary sensor was developed and utilized for the detection of pesticides. Using this sensing platform, fenobucarb and malathion were detected at limits of 5 pg/mL and 2.5 pg/mL, respectively. Moreover, the proposed biosensor was successfully applied to the determination of pesticides in real river water. Therefore, this LC-based microcapillary sensor is a promising platform for simple, rapid, and label-free detection of pesticides with very high sensitivity.
MeSH term(s)	Acetylcholinesterase ; Biosensing Techniques ; Liquid Crystals ; Pesticides/analysis ; Surface-Active Agents
Chemical Substances	Pesticides ; Surface-Active Agents ; Acetylcholinesterase (EC 3.1.1.7)
Language	English
Publishing date	2021-01-22
Publishing country	Netherlands
Document type	Journal Article
ZDB-ID	1500523-9
ISSN	1873-4367 ; 0927-7765
ISSN (online)	1873-4367
ISSN	0927-7765
DOI	10.1016/j.colsurfb.2021.111587
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Article ; Online: A novel machine learning approach to predict the export price of seafood products based on competitive information: The case of the export of Vietnamese shrimp to the US market.

Khiem, Nguyen Minh / Takahashi, Yuki / Yasuma, Hiroki / Dong, Khuu Thi Phuong / Hai, Tran Ngoc / Kimura, Nobuo

PloS one

2022 Volume 17, Issue 9, Page(s) e0275290

Abstract: Predicting the export price of shrimp is important for Vietnam's fisheries. It not only promotes product quality but also helps policy makers determine strategies to develop the national shrimp industry. Competition in global markets is considered to be ... ...

Abstract	Predicting the export price of shrimp is important for Vietnam's fisheries. It not only promotes product quality but also helps policy makers determine strategies to develop the national shrimp industry. Competition in global markets is considered to be an important factor, one that significantly influences price. In this study, we predicted trends in the export price of Vietnamese shrimp based on competitive information from six leading exporters (China, India, Indonesia, Thailand, Ecuador, and Chile) who, alongside Vietnam, also export shrimp to the US. The prediction was based on a dataset collected from the US Department of Agriculture (USDA), the Food and Agriculture Organization of the United Nations (FAO), and the World Trade Organization (WTO) (May-1995 to May-2019) that included price, required farming certificates, and disease outbreak data. A super learner technique, which combined 10 single algorithms, was used to make predictions in selected base periods (3, 6, 9, and 12 months). It was found that the super learner obtained results in all base periods that were more accurate and stable than any candidate algorithms. The impacts of variables in the predictive model were interpreted by a SHapley Additive exPlanations (SHAP) analysis to determine their influence on the price of Vietnamese exports. The price of Indian, Thai, and Chinese exports highlighted the advantages of being a World Trade Organization member and the disadvantages of the prevalence of shrimp disease in Vietnam, which has had a significant impact on the Vietnamese shrimp export price.
MeSH term(s)	Animals ; Asians ; Crustacea ; Humans ; Machine Learning ; Seafood ; Vietnam
Language	English
Publishing date	2022-09-29
Publishing country	United States
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	2267670-3
ISSN	1932-6203 ; 1932-6203
ISSN (online)	1932-6203
ISSN	1932-6203
DOI	10.1371/journal.pone.0275290
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article: Ultrasensitive colorimetric detection of amoxicillin based on Tris-HCl-induced aggregation of gold nanoparticles

Nguyen, Duy Khiem / Jang, Chang-Hyun

Analytical biochemistry. 2022 Feb. 28,

2022

Abstract	An ultrasensitive colorimetric aptasensor for the detection of amoxicillin (AMO) based on the Tris-HCl buffer-induced aggregation of gold nanoparticles (AuNPs) was developed. The AuNPs were aggregated by the addition of Tris-HCl buffer. The adsorption of the aptamer on the AuNP surface increased its negative charge density, leading to the enhancement of the electrostatic repulsion between the nanoparticles, thus protecting AuNPs from aggregation in the Tris-HCl buffer. However, the specific binding of the aptamer with AMO induced conformational changes in the aptamer, which reduced the adsorption of the aptamer on the AuNP surface, diminishing the protective effect of the aptamer. This resulted in the aggregation of AuNPs by Tris-HCl buffer, and consequently, color change of the solution containing AuNPs from red to blue. Under optimized conditions, a linear relationship between the absorbance ratio variation (ΔA₆₈₀/A₅₂₀) and the AMO concentration was observed in the concentration range of 0.1–125 nM, with a detection limit of 67 pM. The developed biosensor exhibited high selectivity toward AMO. Moreover, this strategy was successfully applied to the detection of AMO in lake water samples. Thus, the present aptasensor is a promising alternative for the simple and ultrasensitive detection of AMO in the environment.
Keywords	absorbance ; adsorption ; amoxicillin ; aptasensors ; color ; colorimetry ; detection limit ; electrostatic interactions ; lakes ; nanogold ; oligonucleotides ; protective effect
Language	English
Dates of publication	2022-0228
Publishing place	Elsevier Inc.
Document type	Article
Note	Pre-press version
ZDB-ID	1110-1
ISSN	1096-0309 ; 0003-2697
ISSN (online)	1096-0309
ISSN	0003-2697
DOI	10.1016/j.ab.2022.114634
Database	NAL-Catalogue (AGRICOLA)

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