Dae Hong Jeong | Seoul National University (original) (raw)
Papers by Dae Hong Jeong
Nanomaterials, 2021
Prostate cancer can be detected early by testing the presence of prostate-specific antigen (PSA) ... more Prostate cancer can be detected early by testing the presence of prostate-specific antigen (PSA) in the blood. Lateral flow immunoassay (LFIA) has been used because it is cost effective and easy to use and also has a rapid sample-to-answer process. Quantum dots (QDs) with very bright fluorescence have been previously used to improve the detection sensitivity of LFIAs. In the current study, a highly sensitive LFIA kit was devised using QD-embedded silica nanoparticles. In the present study, only a smartphone and a computer software program, ImageJ, were used, because the developed system had high sensitivity by using very bright nanoprobes. The limit of PSA detection of the developed LFIA system was 0.138 ng/mL. The area under the curve of this system was calculated as 0.852. The system did not show any false-negative result when 47 human serum samples were analyzed; it only detected PSA and did not detect alpha-fetoprotein and newborn calf serum in the samples. Additionally, fluores...
Journal of Nanobiotechnology, 2021
Background Blood prostate-specific antigen (PSA) levels are widely used as diagnostic biomarkers ... more Background Blood prostate-specific antigen (PSA) levels are widely used as diagnostic biomarkers for prostate cancer. Lateral-flow immunoassay (LFIA)-based PSA detection can overcome the limitations associated with other methods. LFIAbased PSA detection in clinical samples enables prognosis and early diagnosis owing to the use of high-performance signal reporters. Results Here, a semiquantitative LFIA platform for PSA detection in blood was developed using Au–Ag nanoparticles (NPs) assembled on silica NPs (SiO2@Au–Ag NPs) that served as signal reporters. Synthesized SiO2@Au–Ag NPs exhibited a high absorbance at a wide wavelength range (400–800 nm), with a high scattering on nitrocellulose membrane test strips. In LFIA, the color intensity of the test line on the test strip differed depending on the PSA concentration (0.30–10.00 ng/mL), and bands for the test line on the test strip could be used as a standard. When clinical samples were assessed using this LFIA, a visual test line wi...
Physical Chemistry Chemical Physics, 2019
Gold nanocubes modified to form roughened structures with very strong and uniform single-particle... more Gold nanocubes modified to form roughened structures with very strong and uniform single-particle surface-enhanced Raman scattering intensity were developed.
Scientific reports, Jan 19, 2018
We have developed a sensitive colorimetric immunoassay with broad dynamic range using enzyme-cata... more We have developed a sensitive colorimetric immunoassay with broad dynamic range using enzyme-catalyzed Ag growth on gold nanoparticle (NP)-assembled silica (SiO@Au@Ag). To reduce Ag ion content and promote Ag growth on the assembled Au NPs, alkaline phosphatase (AP)-based enzymatic amplification was incorporated, which considerably increased the colorimetric read-out. As a model study, sandwich enzyme-linked immunosorbent assay (ELISA) was used to quantify target IgG. The immune complexes capture the Ab-IgG-AP-labeled detection Ab and trigger the enzyme-catalyzed reaction to convert 2-phospho-L-ascorbic acid to ascorbic acid in the presence of the target IgG. Ascorbic acid reduced Ag to Ag, which formed Ag shells on the surface of SiO@Au and enhanced the absorbance of the SiO@Au@Ag solution. Plasmonic immunoassay showed a significant linear relationship between absorbance and the logarithm of IgG concentration in the range of ca. 7 × 10 M to 7 × 10 M. The detection limit was at 1.4 ...
Journal of the Korean Chemical Society, 2006
In this study we analyzed and improved an experiment measuring chemical reaction rates introduced... more In this study we analyzed and improved an experiment measuring chemical reaction rates introduced in the high school science textbooks through an understanding of the phenomena observed in canying out the experiment. For this purpose, the contents of textbooks related to the experiment were analyzed, and the problems observed in car rying out the experiment were addressed through experimental analysis. When the experiment was carried out by the method of aquatic transposition presented in textbooks, the observed volume change of H2 gas was delayed and chemical reaction rate was increased in the early stage of reaction period. To resolve these problems, an improved method for mea suring the reaction rates was suggested. In the improved experiment the reaction rate was measured to be constant on time, which was interpreted in ternis of the concentration of H+ and the surface area of magnesium.
Nanotechnology, 2014
Carbon nanotubes (CNTs) have great potential in the development of high-power electron beam sourc... more Carbon nanotubes (CNTs) have great potential in the development of high-power electron beam sources. However, for such a high-performance electronic device, the electric and thermal contact problem between the metal and CNTs must be improved. Here, we report graphene as an interfacial layer between the metal and CNTs to improve the interfacial contact. The interfacial graphene layer results in a dramatic decrease of the electrical contact resistance by an order of 2 and an increase of the interfacial thermal conductivity by 16%. Such a high improvement in the electrical and thermal interface leads to superior field emission performance with a very low turn-on field of 1.49 V μm −1 at 10 μA cm −2 and a threshold field of 2.00 V μm −1 at 10 mA cm −2 , as well as the maximum current of 16 mA (current density of 2300 A cm −2).
The Journal of Chemical Physics, 2003
Femtosecond coherence spectroscopic study on porphyrin molecules has demonstrated that the oscill... more Femtosecond coherence spectroscopic study on porphyrin molecules has demonstrated that the oscillatory features residing at the transient absorption and fluorescence decay profiles are strongly correlated with the lifetimes of the excited states and the displacements of the minima of the potential energy surfaces that are involved in the pump and probe laser pulses. We have attained a greater degree of control in the wave packet dynamics in the transient absorption by controlling the chirp of the ultrashort optical pulses. This feature provides a clue to the excited potential energy surface such as its curvature and displacement. For two representative porphyrin monomers, ZnII tetraphenylporphyrin and ZnII octaethylporphyrin, we were able to obtain detailed information on the excited state dynamics and subsequent structural changes based on the comparison between the frequency spectra retrieved from the oscillatory features in the transient absorption and fluorescence temporal profi...
ACS Applied Materials & Interfaces, 2013
Journal of the Korean Association for Research in Science Education, 2018
One of the important competencies in knowledge and information society is the competency of Knowl... more One of the important competencies in knowledge and information society is the competency of Knowledge information processing. This is closely related to science education and described as one of the core competencies in the 2015 national curriculum revision. Even with a general agreement of the educational necessity of this competency, its practice in class depends mostly on teachers' will. Therefore, we surveyed science teachers' perceptions and classroom condition about the competency of Knowledge information processing, and we analyzed the questionnaires of 64 middle and high school teachers in Seoul and interviewed three teachers. As a result, all teachers shared the importance of Knowledge information processing competency and explained it in terms of social paradigm and goal of the subject. However, there were not many cases of actual practice in class. The teachers answered that time for Knowledge information processing competency is not enough in class and they also lack of PCK on this competency. About half of the teachers had experiences in teacher training about Knowledge information processing competency but most of their experiences are related to information utilization literacy. The importance of Knowledge information processing competency was very high in three factors (collection, analyzation, and utilization), among which information analysis was the highest. Middle school teachers showed higher scores in most questions even though the differences were not significant, and high school teachers showed higher scores in the importance of information sources at a significant level. In order to cultivate competencies, it is necessary to expand the meaning of science inquiry so as to cover this competency and to consider ways of linking with other subjects and develop methods of teaching and learning.
Rapid Communication in Photoscience, 2013
Journal of the Korean Chemical Society, 2009
The purpose of this study is to identify secondary chemistry teachers' abilities to carry-out exp... more The purpose of this study is to identify secondary chemistry teachers' abilities to carry-out experiment lesson successfully. As far as the research method is concerned, literature reviews, analyses of abilities to carry-out experimentation from science textbooks, and a survey of science teachers' perceptions of experimental ability were employed along with the progressive discussions among the authors. In order to identify secondary chemistry teachers' abilities to carry-out experimentation, we divided the experiment lesson into three stages of preparation, conduct and arrangement, and management of lab, and added the stage of safety. Each stage is classified into sub-areas, and the sub-area consists of subordinate elements. The safety stage was included separately to emphasize the importance of the safety issue in lab and experimental activities. The secondary chemistry teachers' abilities to carry-out experimentation are the abilities to perform 766 박현주-정대홍 • 노석구 • 임희준-한재영 • 박종윤 experiments in person, presupposing the instruction of experiment, and can be featured with the use of reagent and measuring instruments, the preparation of sample, designing experiment, correct experimental habit and skillfulness, data processing, analysis and reasoning, and management of lab and safety.
Phys. Chem. Chem. Phys., 2013
Nanomedicine: Nanotechnology, Biology and Medicine, 2007
The antimicrobial effects of silver (Ag) ion or salts are well known, but the effects of Ag nanop... more The antimicrobial effects of silver (Ag) ion or salts are well known, but the effects of Ag nanoparticles on microorganisms and antimicrobial mechanism have not been revealed clearly. Stable Ag nanoparticles were prepared and their shape and size distribution characterized by particle characterizer and transmission electron microscopic study. The antimicrobial activity of Ag nanoparticles was investigated against yeast, Escherichia coli, and Staphylococcus aureus. In these tests, Muller Hinton agar plates were used and Ag nanoparticles of various concentrations were supplemented in liquid systems. As results, yeast and E. coli were inhibited at the low concentration of Ag nanoparticles, whereas the growth-inhibitory effects on S. aureus were mild. The free-radical generation effect of Ag nanoparticles on microbial growth inhibition was investigated by electron spin resonance spectroscopy. These results suggest that Ag nanoparticles can be used as effective growth inhibitors in various microorganisms, making them applicable to diverse medical devices and antimicrobial control systems.
Advanced Functional Materials, 2013
Journal of the Korean Chemical Society, 2006
In this study, we analyzed the effects of science inquiry learning that applies open-ended hypoth... more In this study, we analyzed the effects of science inquiry learning that applies open-ended hypothesis-test ing learning model in a high school chemistry class of grade 11 in respect of science process skills, science-related atti tude, and appreciation towards science class by cognitive level. Open-ended science inquiry learning activities on 'Metals and their applications' unit in Chemistry I were developed and applied to the treatment groups while the conventional science activities were applied to the control groups. Four classes of 92 students in a high school located in Seoul were assigned into the treatment and control groups, respectively. According to the results in the test of science process skills, the students treated with the alternative experiments emphasizing open-ended hypothesis-testing obtained higher scores in 'experimental design\ 'data conversion and description\ and 'hypothesis test' than those with conventional exper iments but not in 'problem cognition and definition' and 'hypothesis fixing'. There was negative effect on science-related attitude due to increased roles and tasks in the open-ended science inquiry learning activities.
Asia-Pacific Science Education
The suitability and characteristics of middle school inquiry activities in the 2015 National Curr... more The suitability and characteristics of middle school inquiry activities in the 2015 National Curriculum of Science in Korea were studied from the perspective of eight science teachers with rich experience in teaching science inquiry activities. In-depth interviews revealed problems teachers experienced while conducting inquiry classes. Problems were classified into five categories: inquiry level, method, tool, inquiry result, difficulty in guidance, and safety. Based on this analysis, strategies for an inquiry improvement plan are suggested, including that quantitative inquiry requiring numerical interpretation of data obtained from the process of inquiry should be emphasized. Concrete guidance of inquiries should be provided for non-major science teachers to help them instruct inquiries more easily. Institutional improvement is needed to develop curriculum activities and the improvement of science lab and classroom environments are necessary for conducting inquiry activities utiliz...
Advances in Experimental Medicine and Biology, 2021
Silica consists of one silicon atom and two oxygen atoms (SiO 2) and is commonly used in various ... more Silica consists of one silicon atom and two oxygen atoms (SiO 2) and is commonly used in various aspects of daily life. For example, it has been used as glass, insulator, and so on. Nowadays, silica is used as core reagents for fabricating and encapsulating nanoparticles (NPs). In this chapter, the usage of silica in nanotechnology is described. Synthesis and surface modification of silica nanoparticles (SiNPs), including via the Stöber method, reverse microemulsion method, and modified sol-gel method, are illustrated. Then, various NPs with silica encapsulation are explained. At last, the biological applications of those mentioned NPs are described.
Advances in Experimental Medicine and Biology, 2021
This review presents the main characteristics of metal nanoparticles (NPs), especially consisting... more This review presents the main characteristics of metal nanoparticles (NPs), especially consisting of noble metal such as Au and Ag, and brief information on their synthesis methods. The physical and chemical properties of the metal NPs are described, with a particular focus on the optically variable properties (surface plasmon resonance based properties) and surface-enhanced Raman scattering of plasmonic materials. In addition, this chapter covers ways to achieve advances by utilizing their properties in the biological studies and medical fields (such as imaging, diagnostics, and therapeutics). These descriptions will help researchers new to nanomaterials for biomedical diagnosis to understand easily the related knowledge and also will help researchers involved in the biomedical field to learn about the latest research trends.
Sensors, 2021
Prostate-specific antigen (PSA) is the best-known biomarker for early diagnosis of prostate cance... more Prostate-specific antigen (PSA) is the best-known biomarker for early diagnosis of prostate cancer. For prostate cancer in particular, the threshold level of PSA <4.0 ng/mL in clinical samples is an important indicator. Quick and easy visual detection of the PSA level greatly helps in early detection and treatment of prostate cancer and reducing mortality. In this study, we developed optimized silica-coated silver-assembled silica nanoparticles (SiO2@Ag@SiO2 NPs) that were applied to a visual lateral flow immunoassay (LFIA) platform for PSA detection. During synthesis, the ratio of silica NPs to silver nitrate changed, and as the synthesized NPs exhibited distinct UV spectra and colors, most optimized SiO2@Ag@SiO2 NPs showed the potential for early prostate cancer diagnosis. The PSA detection limit of our LFIA platform was 1.1 ng/mL. By applying each SiO2@Ag@SiO2 NP to the visual LFIA platform, optimized SiO2@Ag@SiO2 NPs were selected in the test strip, and clinical samples from ...
Journal of the Korean Chemical Society, Jun 20, 2009
In this study we investigated and tried to understand problems monitored in an experiment on reac... more In this study we investigated and tried to understand problems monitored in an experiment on reactivity of metals in chemistry I. Three problems were discussed. First, the reason that aluminium plate does not react with other metal ions such as zinc, iron and copper was studied and the way to overcome this problem was suggested. Second, the reason that the bubbles were generated when FeSO4(aq) and Zn(s) react was discussed. Third, the precipitates which appeared in the reaction of FeSO4(aq) and Zn(s) were identified. Through reference study and experimental investigation, we could reach the following results. First, aluminium could not react with other metal ions due to the surface oxide layer that is formed very fast and prevents aluminium from reacting with metal ions in solution. This problem could be overcome by allowing a competing reaction of acid and aluminium during the reaction of aluminium and metal ions. Second, the observed bubbles were identified to be hydrogen gas, produced by the reaction between metals and hydronium ion in the solution. Third, black precipitates that were produced on the surface of zinc plate and exhibited magnetic property were characterized to be Fe3O4(s), and brown precipitates that were produced in the solution phase were to be Fe2O3(s) by the analysis of X-ray photoelectron spectra.
Nanomaterials, 2021
Prostate cancer can be detected early by testing the presence of prostate-specific antigen (PSA) ... more Prostate cancer can be detected early by testing the presence of prostate-specific antigen (PSA) in the blood. Lateral flow immunoassay (LFIA) has been used because it is cost effective and easy to use and also has a rapid sample-to-answer process. Quantum dots (QDs) with very bright fluorescence have been previously used to improve the detection sensitivity of LFIAs. In the current study, a highly sensitive LFIA kit was devised using QD-embedded silica nanoparticles. In the present study, only a smartphone and a computer software program, ImageJ, were used, because the developed system had high sensitivity by using very bright nanoprobes. The limit of PSA detection of the developed LFIA system was 0.138 ng/mL. The area under the curve of this system was calculated as 0.852. The system did not show any false-negative result when 47 human serum samples were analyzed; it only detected PSA and did not detect alpha-fetoprotein and newborn calf serum in the samples. Additionally, fluores...
Journal of Nanobiotechnology, 2021
Background Blood prostate-specific antigen (PSA) levels are widely used as diagnostic biomarkers ... more Background Blood prostate-specific antigen (PSA) levels are widely used as diagnostic biomarkers for prostate cancer. Lateral-flow immunoassay (LFIA)-based PSA detection can overcome the limitations associated with other methods. LFIAbased PSA detection in clinical samples enables prognosis and early diagnosis owing to the use of high-performance signal reporters. Results Here, a semiquantitative LFIA platform for PSA detection in blood was developed using Au–Ag nanoparticles (NPs) assembled on silica NPs (SiO2@Au–Ag NPs) that served as signal reporters. Synthesized SiO2@Au–Ag NPs exhibited a high absorbance at a wide wavelength range (400–800 nm), with a high scattering on nitrocellulose membrane test strips. In LFIA, the color intensity of the test line on the test strip differed depending on the PSA concentration (0.30–10.00 ng/mL), and bands for the test line on the test strip could be used as a standard. When clinical samples were assessed using this LFIA, a visual test line wi...
Physical Chemistry Chemical Physics, 2019
Gold nanocubes modified to form roughened structures with very strong and uniform single-particle... more Gold nanocubes modified to form roughened structures with very strong and uniform single-particle surface-enhanced Raman scattering intensity were developed.
Scientific reports, Jan 19, 2018
We have developed a sensitive colorimetric immunoassay with broad dynamic range using enzyme-cata... more We have developed a sensitive colorimetric immunoassay with broad dynamic range using enzyme-catalyzed Ag growth on gold nanoparticle (NP)-assembled silica (SiO@Au@Ag). To reduce Ag ion content and promote Ag growth on the assembled Au NPs, alkaline phosphatase (AP)-based enzymatic amplification was incorporated, which considerably increased the colorimetric read-out. As a model study, sandwich enzyme-linked immunosorbent assay (ELISA) was used to quantify target IgG. The immune complexes capture the Ab-IgG-AP-labeled detection Ab and trigger the enzyme-catalyzed reaction to convert 2-phospho-L-ascorbic acid to ascorbic acid in the presence of the target IgG. Ascorbic acid reduced Ag to Ag, which formed Ag shells on the surface of SiO@Au and enhanced the absorbance of the SiO@Au@Ag solution. Plasmonic immunoassay showed a significant linear relationship between absorbance and the logarithm of IgG concentration in the range of ca. 7 × 10 M to 7 × 10 M. The detection limit was at 1.4 ...
Journal of the Korean Chemical Society, 2006
In this study we analyzed and improved an experiment measuring chemical reaction rates introduced... more In this study we analyzed and improved an experiment measuring chemical reaction rates introduced in the high school science textbooks through an understanding of the phenomena observed in canying out the experiment. For this purpose, the contents of textbooks related to the experiment were analyzed, and the problems observed in car rying out the experiment were addressed through experimental analysis. When the experiment was carried out by the method of aquatic transposition presented in textbooks, the observed volume change of H2 gas was delayed and chemical reaction rate was increased in the early stage of reaction period. To resolve these problems, an improved method for mea suring the reaction rates was suggested. In the improved experiment the reaction rate was measured to be constant on time, which was interpreted in ternis of the concentration of H+ and the surface area of magnesium.
Nanotechnology, 2014
Carbon nanotubes (CNTs) have great potential in the development of high-power electron beam sourc... more Carbon nanotubes (CNTs) have great potential in the development of high-power electron beam sources. However, for such a high-performance electronic device, the electric and thermal contact problem between the metal and CNTs must be improved. Here, we report graphene as an interfacial layer between the metal and CNTs to improve the interfacial contact. The interfacial graphene layer results in a dramatic decrease of the electrical contact resistance by an order of 2 and an increase of the interfacial thermal conductivity by 16%. Such a high improvement in the electrical and thermal interface leads to superior field emission performance with a very low turn-on field of 1.49 V μm −1 at 10 μA cm −2 and a threshold field of 2.00 V μm −1 at 10 mA cm −2 , as well as the maximum current of 16 mA (current density of 2300 A cm −2).
The Journal of Chemical Physics, 2003
Femtosecond coherence spectroscopic study on porphyrin molecules has demonstrated that the oscill... more Femtosecond coherence spectroscopic study on porphyrin molecules has demonstrated that the oscillatory features residing at the transient absorption and fluorescence decay profiles are strongly correlated with the lifetimes of the excited states and the displacements of the minima of the potential energy surfaces that are involved in the pump and probe laser pulses. We have attained a greater degree of control in the wave packet dynamics in the transient absorption by controlling the chirp of the ultrashort optical pulses. This feature provides a clue to the excited potential energy surface such as its curvature and displacement. For two representative porphyrin monomers, ZnII tetraphenylporphyrin and ZnII octaethylporphyrin, we were able to obtain detailed information on the excited state dynamics and subsequent structural changes based on the comparison between the frequency spectra retrieved from the oscillatory features in the transient absorption and fluorescence temporal profi...
ACS Applied Materials & Interfaces, 2013
Journal of the Korean Association for Research in Science Education, 2018
One of the important competencies in knowledge and information society is the competency of Knowl... more One of the important competencies in knowledge and information society is the competency of Knowledge information processing. This is closely related to science education and described as one of the core competencies in the 2015 national curriculum revision. Even with a general agreement of the educational necessity of this competency, its practice in class depends mostly on teachers' will. Therefore, we surveyed science teachers' perceptions and classroom condition about the competency of Knowledge information processing, and we analyzed the questionnaires of 64 middle and high school teachers in Seoul and interviewed three teachers. As a result, all teachers shared the importance of Knowledge information processing competency and explained it in terms of social paradigm and goal of the subject. However, there were not many cases of actual practice in class. The teachers answered that time for Knowledge information processing competency is not enough in class and they also lack of PCK on this competency. About half of the teachers had experiences in teacher training about Knowledge information processing competency but most of their experiences are related to information utilization literacy. The importance of Knowledge information processing competency was very high in three factors (collection, analyzation, and utilization), among which information analysis was the highest. Middle school teachers showed higher scores in most questions even though the differences were not significant, and high school teachers showed higher scores in the importance of information sources at a significant level. In order to cultivate competencies, it is necessary to expand the meaning of science inquiry so as to cover this competency and to consider ways of linking with other subjects and develop methods of teaching and learning.
Rapid Communication in Photoscience, 2013
Journal of the Korean Chemical Society, 2009
The purpose of this study is to identify secondary chemistry teachers' abilities to carry-out exp... more The purpose of this study is to identify secondary chemistry teachers' abilities to carry-out experiment lesson successfully. As far as the research method is concerned, literature reviews, analyses of abilities to carry-out experimentation from science textbooks, and a survey of science teachers' perceptions of experimental ability were employed along with the progressive discussions among the authors. In order to identify secondary chemistry teachers' abilities to carry-out experimentation, we divided the experiment lesson into three stages of preparation, conduct and arrangement, and management of lab, and added the stage of safety. Each stage is classified into sub-areas, and the sub-area consists of subordinate elements. The safety stage was included separately to emphasize the importance of the safety issue in lab and experimental activities. The secondary chemistry teachers' abilities to carry-out experimentation are the abilities to perform 766 박현주-정대홍 • 노석구 • 임희준-한재영 • 박종윤 experiments in person, presupposing the instruction of experiment, and can be featured with the use of reagent and measuring instruments, the preparation of sample, designing experiment, correct experimental habit and skillfulness, data processing, analysis and reasoning, and management of lab and safety.
Phys. Chem. Chem. Phys., 2013
Nanomedicine: Nanotechnology, Biology and Medicine, 2007
The antimicrobial effects of silver (Ag) ion or salts are well known, but the effects of Ag nanop... more The antimicrobial effects of silver (Ag) ion or salts are well known, but the effects of Ag nanoparticles on microorganisms and antimicrobial mechanism have not been revealed clearly. Stable Ag nanoparticles were prepared and their shape and size distribution characterized by particle characterizer and transmission electron microscopic study. The antimicrobial activity of Ag nanoparticles was investigated against yeast, Escherichia coli, and Staphylococcus aureus. In these tests, Muller Hinton agar plates were used and Ag nanoparticles of various concentrations were supplemented in liquid systems. As results, yeast and E. coli were inhibited at the low concentration of Ag nanoparticles, whereas the growth-inhibitory effects on S. aureus were mild. The free-radical generation effect of Ag nanoparticles on microbial growth inhibition was investigated by electron spin resonance spectroscopy. These results suggest that Ag nanoparticles can be used as effective growth inhibitors in various microorganisms, making them applicable to diverse medical devices and antimicrobial control systems.
Advanced Functional Materials, 2013
Journal of the Korean Chemical Society, 2006
In this study, we analyzed the effects of science inquiry learning that applies open-ended hypoth... more In this study, we analyzed the effects of science inquiry learning that applies open-ended hypothesis-test ing learning model in a high school chemistry class of grade 11 in respect of science process skills, science-related atti tude, and appreciation towards science class by cognitive level. Open-ended science inquiry learning activities on 'Metals and their applications' unit in Chemistry I were developed and applied to the treatment groups while the conventional science activities were applied to the control groups. Four classes of 92 students in a high school located in Seoul were assigned into the treatment and control groups, respectively. According to the results in the test of science process skills, the students treated with the alternative experiments emphasizing open-ended hypothesis-testing obtained higher scores in 'experimental design\ 'data conversion and description\ and 'hypothesis test' than those with conventional exper iments but not in 'problem cognition and definition' and 'hypothesis fixing'. There was negative effect on science-related attitude due to increased roles and tasks in the open-ended science inquiry learning activities.
Asia-Pacific Science Education
The suitability and characteristics of middle school inquiry activities in the 2015 National Curr... more The suitability and characteristics of middle school inquiry activities in the 2015 National Curriculum of Science in Korea were studied from the perspective of eight science teachers with rich experience in teaching science inquiry activities. In-depth interviews revealed problems teachers experienced while conducting inquiry classes. Problems were classified into five categories: inquiry level, method, tool, inquiry result, difficulty in guidance, and safety. Based on this analysis, strategies for an inquiry improvement plan are suggested, including that quantitative inquiry requiring numerical interpretation of data obtained from the process of inquiry should be emphasized. Concrete guidance of inquiries should be provided for non-major science teachers to help them instruct inquiries more easily. Institutional improvement is needed to develop curriculum activities and the improvement of science lab and classroom environments are necessary for conducting inquiry activities utiliz...
Advances in Experimental Medicine and Biology, 2021
Silica consists of one silicon atom and two oxygen atoms (SiO 2) and is commonly used in various ... more Silica consists of one silicon atom and two oxygen atoms (SiO 2) and is commonly used in various aspects of daily life. For example, it has been used as glass, insulator, and so on. Nowadays, silica is used as core reagents for fabricating and encapsulating nanoparticles (NPs). In this chapter, the usage of silica in nanotechnology is described. Synthesis and surface modification of silica nanoparticles (SiNPs), including via the Stöber method, reverse microemulsion method, and modified sol-gel method, are illustrated. Then, various NPs with silica encapsulation are explained. At last, the biological applications of those mentioned NPs are described.
Advances in Experimental Medicine and Biology, 2021
This review presents the main characteristics of metal nanoparticles (NPs), especially consisting... more This review presents the main characteristics of metal nanoparticles (NPs), especially consisting of noble metal such as Au and Ag, and brief information on their synthesis methods. The physical and chemical properties of the metal NPs are described, with a particular focus on the optically variable properties (surface plasmon resonance based properties) and surface-enhanced Raman scattering of plasmonic materials. In addition, this chapter covers ways to achieve advances by utilizing their properties in the biological studies and medical fields (such as imaging, diagnostics, and therapeutics). These descriptions will help researchers new to nanomaterials for biomedical diagnosis to understand easily the related knowledge and also will help researchers involved in the biomedical field to learn about the latest research trends.
Sensors, 2021
Prostate-specific antigen (PSA) is the best-known biomarker for early diagnosis of prostate cance... more Prostate-specific antigen (PSA) is the best-known biomarker for early diagnosis of prostate cancer. For prostate cancer in particular, the threshold level of PSA <4.0 ng/mL in clinical samples is an important indicator. Quick and easy visual detection of the PSA level greatly helps in early detection and treatment of prostate cancer and reducing mortality. In this study, we developed optimized silica-coated silver-assembled silica nanoparticles (SiO2@Ag@SiO2 NPs) that were applied to a visual lateral flow immunoassay (LFIA) platform for PSA detection. During synthesis, the ratio of silica NPs to silver nitrate changed, and as the synthesized NPs exhibited distinct UV spectra and colors, most optimized SiO2@Ag@SiO2 NPs showed the potential for early prostate cancer diagnosis. The PSA detection limit of our LFIA platform was 1.1 ng/mL. By applying each SiO2@Ag@SiO2 NP to the visual LFIA platform, optimized SiO2@Ag@SiO2 NPs were selected in the test strip, and clinical samples from ...
Journal of the Korean Chemical Society, Jun 20, 2009
In this study we investigated and tried to understand problems monitored in an experiment on reac... more In this study we investigated and tried to understand problems monitored in an experiment on reactivity of metals in chemistry I. Three problems were discussed. First, the reason that aluminium plate does not react with other metal ions such as zinc, iron and copper was studied and the way to overcome this problem was suggested. Second, the reason that the bubbles were generated when FeSO4(aq) and Zn(s) react was discussed. Third, the precipitates which appeared in the reaction of FeSO4(aq) and Zn(s) were identified. Through reference study and experimental investigation, we could reach the following results. First, aluminium could not react with other metal ions due to the surface oxide layer that is formed very fast and prevents aluminium from reacting with metal ions in solution. This problem could be overcome by allowing a competing reaction of acid and aluminium during the reaction of aluminium and metal ions. Second, the observed bubbles were identified to be hydrogen gas, produced by the reaction between metals and hydronium ion in the solution. Third, black precipitates that were produced on the surface of zinc plate and exhibited magnetic property were characterized to be Fe3O4(s), and brown precipitates that were produced in the solution phase were to be Fe2O3(s) by the analysis of X-ray photoelectron spectra.