Miller Toledo Solano, H. H. Cerecedo-Núñez, Martha Alicia Palomino Ovando, Jocelyn Faubert, K. Misaghian, J. E. Lugo
Due to their unique properties, porous silicon nanostructures have garnered much attention in photonics. For example, these structures can exhibit photoluminescence and are highly efficient in trapping light, making them ideal for applications such as biosensors, optical communication, and solar cells. The production of electromagnetic forces by light is a well-established concept, and the mechanism behind it is well-understood. In the past, we have used these forces to induce mechanical oscillations in a photonic structure based on porous silicon. Usually, to detect the oscillations, a high-precision vibrometer is utilized. However, we report a novel approach to visualizing photonic structure oscillations here. The traditional method of using a vibrometer as an indirect measurement tool has been replaced by one that involves directly observing the changes using a camera, digital movement amplification, a theoretical approximation, and FDTE simulations. This original technique provides researchers with a less expensive means of studying photonic structure movements. This proposal could be extended to other microscopic movements or for dynamical interferometric fringe analysis.
{"title":"A Method for Directly Observing Mechanical Oscillations in Photonic Structures Based on Porous Silicon Nanostructures","authors":"Miller Toledo Solano, H. H. Cerecedo-Núñez, Martha Alicia Palomino Ovando, Jocelyn Faubert, K. Misaghian, J. E. Lugo","doi":"10.3390/micro4010006","DOIUrl":"https://doi.org/10.3390/micro4010006","url":null,"abstract":"Due to their unique properties, porous silicon nanostructures have garnered much attention in photonics. For example, these structures can exhibit photoluminescence and are highly efficient in trapping light, making them ideal for applications such as biosensors, optical communication, and solar cells. The production of electromagnetic forces by light is a well-established concept, and the mechanism behind it is well-understood. In the past, we have used these forces to induce mechanical oscillations in a photonic structure based on porous silicon. Usually, to detect the oscillations, a high-precision vibrometer is utilized. However, we report a novel approach to visualizing photonic structure oscillations here. The traditional method of using a vibrometer as an indirect measurement tool has been replaced by one that involves directly observing the changes using a camera, digital movement amplification, a theoretical approximation, and FDTE simulations. This original technique provides researchers with a less expensive means of studying photonic structure movements. This proposal could be extended to other microscopic movements or for dynamical interferometric fringe analysis.","PeriodicalId":18535,"journal":{"name":"Micro","volume":"24 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139891084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Christina Gioti, K. Vasilopoulos, M. Baikousi, C. Salmas, Angelos Ntaflos, A. Paipetis, Z. Viskadourakis, R. Ikram, Simeon Agathopoulos, G. Kenanakis, M. Karakassides
This work presents the development of novel gypsum board composites for advanced thermal energy storage (TES) and electromagnetic interference (EMI) shielding applications. Activated carbon (AC) derived from spent coffee with a high surface area (SBET = 1372 m2/g) was used as a shape stabilizer, while the commercial paraffin, RT18HC, was used as organic encapsulant phase change material (PCM). The AC showed a remarkable encapsulation efficiency as a shape stabilizer for PCM, with ~120.9 wt% (RT18HC), while the melting enthalpy (ΔHm) of the shape-stabilized PCM was 117.3 J/g. The performance of this PCM/carbon nanocomposite as a thermal energy storage material was examined by incorporating it into building components, such as gypsum wallboards. The microstructure of these advanced panels, their density, and their dispersion of additives were examined using X-ray microtomography. Their thermal-regulated performance was measured through a self-designed room model with a similar homemade environmental chamber that was able to create a uniform temperature environment, surrounding the test room during heating and cooling. The measurements showed that the advanced panels reduce temperature fluctuations and the indoor temperature of the room model, in comparison with normal gypsum panels, by a range of 2–5%. The investigated gypsum board composite samples showed efficient electromagnetic shielding performance in a frequency range of 3.5–7.0 GHz, reaching an EMI value of ~12.5 dB, which is adequate and required for commercial applications, when filled with PCMs.
{"title":"Enhanced Gypsum Boards with Activated Carbon Composites and Phase Change Materials for Advanced Thermal Energy Storage and Electromagnetic Interference Shielding Properties","authors":"Christina Gioti, K. Vasilopoulos, M. Baikousi, C. Salmas, Angelos Ntaflos, A. Paipetis, Z. Viskadourakis, R. Ikram, Simeon Agathopoulos, G. Kenanakis, M. Karakassides","doi":"10.3390/micro4010005","DOIUrl":"https://doi.org/10.3390/micro4010005","url":null,"abstract":"This work presents the development of novel gypsum board composites for advanced thermal energy storage (TES) and electromagnetic interference (EMI) shielding applications. Activated carbon (AC) derived from spent coffee with a high surface area (SBET = 1372 m2/g) was used as a shape stabilizer, while the commercial paraffin, RT18HC, was used as organic encapsulant phase change material (PCM). The AC showed a remarkable encapsulation efficiency as a shape stabilizer for PCM, with ~120.9 wt% (RT18HC), while the melting enthalpy (ΔHm) of the shape-stabilized PCM was 117.3 J/g. The performance of this PCM/carbon nanocomposite as a thermal energy storage material was examined by incorporating it into building components, such as gypsum wallboards. The microstructure of these advanced panels, their density, and their dispersion of additives were examined using X-ray microtomography. Their thermal-regulated performance was measured through a self-designed room model with a similar homemade environmental chamber that was able to create a uniform temperature environment, surrounding the test room during heating and cooling. The measurements showed that the advanced panels reduce temperature fluctuations and the indoor temperature of the room model, in comparison with normal gypsum panels, by a range of 2–5%. The investigated gypsum board composite samples showed efficient electromagnetic shielding performance in a frequency range of 3.5–7.0 GHz, reaching an EMI value of ~12.5 dB, which is adequate and required for commercial applications, when filled with PCMs.","PeriodicalId":18535,"journal":{"name":"Micro","volume":"60 31","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139600778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Amer Dawoud, Rashid Mia, J. Motchaalangaram, Wujian Miao, Karl J Wallace
A miniaturized electrochemical sensor was developed for the remote detection of chemical warfare agent (CWA) simulants. To facilitate drone-based remote sensing, this present study focuses on advancing the miniaturized and compact electrochemical sensor for monitoring two CWA simulants, diisopropyl fluorophosphate (DFP) and O,S-diethylmethylphosphonothioate (O,S-DEMPT). The differential pulse voltammetry (DPV) signal was processed, and the DPV signature features were extracted on the basis of the redox properties associated with the absence and the presence of DFP and O,S-DEMPT. Upon the addition of 0.10 equivalence of DFP or O,S-DEMPT, a shift in potential (E) of ~0.13 V was recorded. The limit of detection (LOD) was calculated to be 0.25 µM (0.046 ppm) and 0.10 µM (0.017 ppm) for DFP and O,S-DEMPT, respectively. These results were validated using a portable Palmsens Emstat HR potentiostat, which corroborated the results obtained using a lab benchtop potentiostat. Additionally, Boolean logic (“AND” operation) was implemented for future drone technology deployment. This advancement enables the fabrication of a networked device capable of autonomously executing tasks without constant oversight.
{"title":"Toward Remote Detection of Chemical Warfare Simulants Using a Miniature Potentiostat","authors":"Amer Dawoud, Rashid Mia, J. Motchaalangaram, Wujian Miao, Karl J Wallace","doi":"10.3390/micro4010004","DOIUrl":"https://doi.org/10.3390/micro4010004","url":null,"abstract":"A miniaturized electrochemical sensor was developed for the remote detection of chemical warfare agent (CWA) simulants. To facilitate drone-based remote sensing, this present study focuses on advancing the miniaturized and compact electrochemical sensor for monitoring two CWA simulants, diisopropyl fluorophosphate (DFP) and O,S-diethylmethylphosphonothioate (O,S-DEMPT). The differential pulse voltammetry (DPV) signal was processed, and the DPV signature features were extracted on the basis of the redox properties associated with the absence and the presence of DFP and O,S-DEMPT. Upon the addition of 0.10 equivalence of DFP or O,S-DEMPT, a shift in potential (E) of ~0.13 V was recorded. The limit of detection (LOD) was calculated to be 0.25 µM (0.046 ppm) and 0.10 µM (0.017 ppm) for DFP and O,S-DEMPT, respectively. These results were validated using a portable Palmsens Emstat HR potentiostat, which corroborated the results obtained using a lab benchtop potentiostat. Additionally, Boolean logic (“AND” operation) was implemented for future drone technology deployment. This advancement enables the fabrication of a networked device capable of autonomously executing tasks without constant oversight.","PeriodicalId":18535,"journal":{"name":"Micro","volume":"34 43","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139607414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sanja Mahović Poljaček, Maja Strižić Jakovljević, T. Tomašegović
Photochromism refers to a reversible colour change induced by the irradiation of photochromic materials with ultraviolet (UV) or visible light that reverts to the original colour after the light source is removed. This effect arises from chemical transformations between two isomers with different absorption spectra, involving processes like proton transfer, chemical-bond formation, and isomerisation. These photochromic inks, appearing as crystalline powders with micro-sized particles, require dissolution in a suitable matrix to achieve the colour change. Photochromic inks are used in security, as functional coatings for paper and packaging, in the fabric industry, and in other ways. This study examines the influence of varying concentrations of micro-sized photochromic pigments and different ink-coating thicknesses on the photochromic effect on sustainable paperboard substrates. Artificial ageing was performed to assess the photochromic response and lightfastness in relation to pigment concentration, ink-coating thickness, and the influence of the paperboard substrates. The results of this research could contribute to enhancing knowledge on employing photochromic inks for diverse packaging applications.
{"title":"Photochromic Responses and Stability of Functional Inks Applied on Sustainable Packaging Materials","authors":"Sanja Mahović Poljaček, Maja Strižić Jakovljević, T. Tomašegović","doi":"10.3390/micro4010003","DOIUrl":"https://doi.org/10.3390/micro4010003","url":null,"abstract":"Photochromism refers to a reversible colour change induced by the irradiation of photochromic materials with ultraviolet (UV) or visible light that reverts to the original colour after the light source is removed. This effect arises from chemical transformations between two isomers with different absorption spectra, involving processes like proton transfer, chemical-bond formation, and isomerisation. These photochromic inks, appearing as crystalline powders with micro-sized particles, require dissolution in a suitable matrix to achieve the colour change. Photochromic inks are used in security, as functional coatings for paper and packaging, in the fabric industry, and in other ways. This study examines the influence of varying concentrations of micro-sized photochromic pigments and different ink-coating thicknesses on the photochromic effect on sustainable paperboard substrates. Artificial ageing was performed to assess the photochromic response and lightfastness in relation to pigment concentration, ink-coating thickness, and the influence of the paperboard substrates. The results of this research could contribute to enhancing knowledge on employing photochromic inks for diverse packaging applications.","PeriodicalId":18535,"journal":{"name":"Micro","volume":"155 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139622409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Haobo Wang, S. Sakthinathan, Arjunan Karthi Keyan, Chung-Lun Yu, Satoshi Kameoka, T. Chiu, Karuppiah Nagaraj
Metal–organic frame (MOF) materials may have the advantages of a regular pore structure, large porosity, and large specific surface area, which could provide better catalytic activity, but they have some disadvantages in electrocatalysis. In contrast, carbon nanofibers (CNFs) prepared by electrospinning methods have good conductivity and stability. Therefore, this research aimed to generate MOF/CNFs composite materials to improve the electrochemical properties of MOF materials and apply them to the field of electrochemical sensing. This experiment was based on the preparation of straight unidirectional CNFs by an electrospinning method at 2000 RPM. The original method of preparing zeolitic imidazolate frameworks (ZIF-8) was improved and ZIF-8 was uniformly dispersed on the surface of CNFs to form a ZIF-8/CNF composite with a fiber diameter of about 0.10 to 0.35 µm. The specific surface area of the CNFs was about 42.28 m2/g, while that of the ZIF-8/CNF composite was about 999.82 m2/g. The specific surface area of the ZIF-8/CNF composite was significantly larger than that of CNFs. The GCE/ZIF-8/CNF electrode had an excellent electrochemical reaction, with an oxidation peak at about 216 μA, which proved that the ZIF-8/CNF composite material would have good catalytic activity and excellent electrochemical properties for the detection of nitrofurazone compared to other modified electrodes.
{"title":"Preparation of Zeolitic Imidazolate Framework and Carbon Nanofiber Composites for Nitrofurazone Detection","authors":"Haobo Wang, S. Sakthinathan, Arjunan Karthi Keyan, Chung-Lun Yu, Satoshi Kameoka, T. Chiu, Karuppiah Nagaraj","doi":"10.3390/micro4010002","DOIUrl":"https://doi.org/10.3390/micro4010002","url":null,"abstract":"Metal–organic frame (MOF) materials may have the advantages of a regular pore structure, large porosity, and large specific surface area, which could provide better catalytic activity, but they have some disadvantages in electrocatalysis. In contrast, carbon nanofibers (CNFs) prepared by electrospinning methods have good conductivity and stability. Therefore, this research aimed to generate MOF/CNFs composite materials to improve the electrochemical properties of MOF materials and apply them to the field of electrochemical sensing. This experiment was based on the preparation of straight unidirectional CNFs by an electrospinning method at 2000 RPM. The original method of preparing zeolitic imidazolate frameworks (ZIF-8) was improved and ZIF-8 was uniformly dispersed on the surface of CNFs to form a ZIF-8/CNF composite with a fiber diameter of about 0.10 to 0.35 µm. The specific surface area of the CNFs was about 42.28 m2/g, while that of the ZIF-8/CNF composite was about 999.82 m2/g. The specific surface area of the ZIF-8/CNF composite was significantly larger than that of CNFs. The GCE/ZIF-8/CNF electrode had an excellent electrochemical reaction, with an oxidation peak at about 216 μA, which proved that the ZIF-8/CNF composite material would have good catalytic activity and excellent electrochemical properties for the detection of nitrofurazone compared to other modified electrodes.","PeriodicalId":18535,"journal":{"name":"Micro","volume":"19 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139444371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Micromechanical switches are of significant interest for advanced radio frequency and microwave systems, but their practical implementation is limited by low reliability. Electrodes of a microscopic size develop weak contact force that leads to high and unstable contact resistance. The force is typically increased by using a sophisticated switch design with extended lateral dimensions, although a simple and compact cantilever is more preferable. The paper describes for the first time a comprehensive approach to enhance the force of an electrostatically actuated switch. The strategy is applied to a miniature device based on a 50 µm long cantilever. The contact force is increased from 10 to 112 µN, making the switch strong enough to achieve low and stable contact resistance. The restoring force is also enhanced in order to ensure reliable de-actuation. The growth of forces is accompanied by a reduction in the pull-in voltage. Connecting several cantilevers in parallel and manipulating the number and position of contact bumps additionally improves the force and mechanical stability of the switch. An optimal design contains a triple cantilever with two bumps. It provides 50% higher force per contact compared to the single-cantilever switch at the same pull-in voltage and keeps the advantages of a miniature device. The proposed design strategy may be used for building reliable MEMS switches.
{"title":"Design Guideline for a Cantilever-Type MEMS Switch with High Contact Force","authors":"I. Uvarov, Igor A. Belozerov","doi":"10.3390/micro4010001","DOIUrl":"https://doi.org/10.3390/micro4010001","url":null,"abstract":"Micromechanical switches are of significant interest for advanced radio frequency and microwave systems, but their practical implementation is limited by low reliability. Electrodes of a microscopic size develop weak contact force that leads to high and unstable contact resistance. The force is typically increased by using a sophisticated switch design with extended lateral dimensions, although a simple and compact cantilever is more preferable. The paper describes for the first time a comprehensive approach to enhance the force of an electrostatically actuated switch. The strategy is applied to a miniature device based on a 50 µm long cantilever. The contact force is increased from 10 to 112 µN, making the switch strong enough to achieve low and stable contact resistance. The restoring force is also enhanced in order to ensure reliable de-actuation. The growth of forces is accompanied by a reduction in the pull-in voltage. Connecting several cantilevers in parallel and manipulating the number and position of contact bumps additionally improves the force and mechanical stability of the switch. An optimal design contains a triple cantilever with two bumps. It provides 50% higher force per contact compared to the single-cantilever switch at the same pull-in voltage and keeps the advantages of a miniature device. The proposed design strategy may be used for building reliable MEMS switches.","PeriodicalId":18535,"journal":{"name":"Micro","volume":"32 14","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138956428","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. von Gratowski, Z. Kosakovskaya, V. Koledov, V. Shavrov, A. Smolovich, A. P. Orlov, R. N. Denisjuk, Cong Wang, Junge Liang
The structure and phenomena arising from charge transfer in cold field emission mode in a single closed carbon nanotube (CNT) under cold field emission conditions are studied. Inhomogeneities of the structure of CNT in the form of two types of superlattices are found by studying microphotographs obtained by AFM, SEM, and TEM. The features of charge transfer in a quasi-one-dimensional carbon nanotube emitter with a small gap between the anode and cathode are studied under conditions of low-voltage field emission. It is established that the I-V characteristics reveal voltage thresholds and resonant peaks, which are associated with the opening of conduction channels in the region of van Hove singularities. In the region of peaks in the I-V characteristics, the emission current exceeds the one calculated using the Fowler–Nordheim (F-N) function by one to three orders of magnitude. The I-V characteristic is not that the curve straightens in F-N coordinates. It is found that the peaks in the I-V characteristics have distinct regions of negative differential conductivity.
{"title":"Structural Inhomogeneities and Nonlinear Phenomena in Charge Transfer under Cold Field Emission in Individual Closed Carbon Nanotubes","authors":"S. von Gratowski, Z. Kosakovskaya, V. Koledov, V. Shavrov, A. Smolovich, A. P. Orlov, R. N. Denisjuk, Cong Wang, Junge Liang","doi":"10.3390/micro3040064","DOIUrl":"https://doi.org/10.3390/micro3040064","url":null,"abstract":"The structure and phenomena arising from charge transfer in cold field emission mode in a single closed carbon nanotube (CNT) under cold field emission conditions are studied. Inhomogeneities of the structure of CNT in the form of two types of superlattices are found by studying microphotographs obtained by AFM, SEM, and TEM. The features of charge transfer in a quasi-one-dimensional carbon nanotube emitter with a small gap between the anode and cathode are studied under conditions of low-voltage field emission. It is established that the I-V characteristics reveal voltage thresholds and resonant peaks, which are associated with the opening of conduction channels in the region of van Hove singularities. In the region of peaks in the I-V characteristics, the emission current exceeds the one calculated using the Fowler–Nordheim (F-N) function by one to three orders of magnitude. The I-V characteristic is not that the curve straightens in F-N coordinates. It is found that the peaks in the I-V characteristics have distinct regions of negative differential conductivity.","PeriodicalId":18535,"journal":{"name":"Micro","volume":"88 14","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138600295","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Vijayaraj, K. Altaff, M. Jayaprakashvel, R. Muthezhilan, B. Saran, P. Kurinjinathan, Selvakumari Jeyaperumal, Venkatesan Perumal, R. M. S. Kumar, Lakshmanan Govindan
In this research article we report the potentials of chitin-based silver nanoparticles (chitin AgNPs) derived from Indian mimic goatfish (Mulloidichthys ayliffe) scales as an effective food preservation agent. The study comprehensively presents the multifaceted attributes of chitin AgNPs, including their synthesis, characterization, and antimicrobial properties. Chitin yield from M. ayliffe scales and three-spot swimming crab (P. sanguinolentus) exoskeleton was determined, with the insoluble content quantified. FTIR analysis unveiled distinct absorption peaks for chitin, and scanning electron microscopy revealed the ultrastructure of chitin from both the sources. Using UV–visible spectroscopy, the biosynthesis of AgNPs was accomplished and characterized, with the color shift of the solution serving as proof of a successful synthesis. UV–vis spectra provided insights into nanoparticle size and shape. SEM micrographs exhibited spherical particle morphology, while FTIR spectra indicated amino group interactions contributing to AgNP stabilization. The antimicrobial potential of chitin AgNPs was assessed against the food pathogen, Vibrio spp. Chitin films displayed significant antimicrobial activity, particularly AgNP-synthesized chitin from M. ayliffe scales, demonstrated the highest Vibrio spp. inhibition activity. Furthermore, chitin AgNPs were incorporated into the common chili, Capsicum annuum and the tomato, Solanum lycopersicum to extend their shelf life at room temperature. This study reveals the efficacy of chitin AgNPs from M. ayliffe scales as potent agents for food preservation, offering insights into their physical, mechanical, and antimicrobial attributes. The application of chitin AgNPs to perishable food items highlights their potential in enhancing shelf life and quality, opening innovative avenues for sustainable food preservation.
在这篇研究文章中，我们报告了从印度拟山羊鱼（Mulloidichthys ayliffe）鳞片中提取的甲壳素银纳米粒子（甲壳素 AgNPs）作为一种有效食品保鲜剂的潜力。该研究全面介绍了甲壳素 AgNPs 的多方面属性，包括其合成、表征和抗菌特性。研究人员测定了 M. ayliffe 鳞片和三点游蟹（P. sanguinolentus）外骨骼中甲壳素的产量，并对其中的不溶物含量进行了量化。傅立叶变换红外光谱分析揭示了甲壳素的不同吸收峰，扫描电子显微镜显示了两种来源的甲壳素的超微结构。利用紫外可见光谱，完成了 AgNPs 的生物合成并对其进行了表征，溶液的颜色变化证明了合成的成功。通过紫外-可见光谱可以了解纳米粒子的大小和形状。扫描电子显微镜（SEM）显微照片显示了颗粒的球形形态，而傅立叶变换红外光谱（FTIR）则表明氨基基团的相互作用有助于 AgNP 的稳定。甲壳素薄膜显示出显著的抗菌活性，尤其是由 M. ayliffe 鳞片合成的 AgNP 甲壳素对弧菌的抑制活性最高。此外，将甲壳素 AgNPs 添加到普通辣椒和番茄中，可延长它们在室温下的保质期。这项研究揭示了来自 M. ayliffe 鳞片的甲壳素 AgNPs 作为食品保鲜剂的功效，并对其物理、机械和抗菌属性进行了深入研究。甲壳素 AgNPs 在易腐食品中的应用凸显了其在提高保质期和质量方面的潜力，为可持续食品保鲜开辟了创新之路。
{"title":"Chitin-Derived Silver Nanoparticles for Enhanced Food Preservation: Synthesis, Characterization, and Antimicrobial Potential","authors":"R. Vijayaraj, K. Altaff, M. Jayaprakashvel, R. Muthezhilan, B. Saran, P. Kurinjinathan, Selvakumari Jeyaperumal, Venkatesan Perumal, R. M. S. Kumar, Lakshmanan Govindan","doi":"10.3390/micro3040062","DOIUrl":"https://doi.org/10.3390/micro3040062","url":null,"abstract":"In this research article we report the potentials of chitin-based silver nanoparticles (chitin AgNPs) derived from Indian mimic goatfish (Mulloidichthys ayliffe) scales as an effective food preservation agent. The study comprehensively presents the multifaceted attributes of chitin AgNPs, including their synthesis, characterization, and antimicrobial properties. Chitin yield from M. ayliffe scales and three-spot swimming crab (P. sanguinolentus) exoskeleton was determined, with the insoluble content quantified. FTIR analysis unveiled distinct absorption peaks for chitin, and scanning electron microscopy revealed the ultrastructure of chitin from both the sources. Using UV–visible spectroscopy, the biosynthesis of AgNPs was accomplished and characterized, with the color shift of the solution serving as proof of a successful synthesis. UV–vis spectra provided insights into nanoparticle size and shape. SEM micrographs exhibited spherical particle morphology, while FTIR spectra indicated amino group interactions contributing to AgNP stabilization. The antimicrobial potential of chitin AgNPs was assessed against the food pathogen, Vibrio spp. Chitin films displayed significant antimicrobial activity, particularly AgNP-synthesized chitin from M. ayliffe scales, demonstrated the highest Vibrio spp. inhibition activity. Furthermore, chitin AgNPs were incorporated into the common chili, Capsicum annuum and the tomato, Solanum lycopersicum to extend their shelf life at room temperature. This study reveals the efficacy of chitin AgNPs from M. ayliffe scales as potent agents for food preservation, offering insights into their physical, mechanical, and antimicrobial attributes. The application of chitin AgNPs to perishable food items highlights their potential in enhancing shelf life and quality, opening innovative avenues for sustainable food preservation.","PeriodicalId":18535,"journal":{"name":"Micro","volume":"173 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139208114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
E. Kavetsou, Ioanna Pitterou, Nikos G. Dimitrioglou, Stefanos Kikionis, E. Kritsi, P. Zoumpoulakis, E. Pontiki, Dimitra Hadjipavlou-Litina, Dimitris T. Hatziavramidis, A. Detsi
The present study focuses on the synthesis of the natural product 4-methyl-umbelliferone (4-MU, hymecromone), the preparation, characterization, and biological activity evaluation of 4-MU inclusion complexes with β-cyclodextrin (β-CD), as well as their incorporation into pharmaceutical tablets. The inclusion complexes (ICs) were characterized using DLS, SEM, TGA as well as FT-IR, UV-vis, and NMR spectroscopies. The release profile of 4-MU from the β-CD-4-MU ICs was studied in three different pH: 1.2 (aqueous hydrochloric acid), 7.4, and 6.8 (phosphate-buffered solutions), to simulate the stomach, physiological, and intestine pH, respectively. The ICs were incorporated in pharmaceutical tablets which were prepared by direct compression and were characterized for their mechanical properties. The optimal composition of 4-MU as the active pharmaceutical ingredient (API) and excipients was determined using design of experiment (DoE), and the dissolution studies were performed at pH 1.2 at 37 ± 0.5 °C. The sustained release profile of the pharmaceutical tablets showed a delayed burst release effect at 20 min (20% drug release) compared to that of the ICs at the same time interval (70%). The results indicated that the kinetic model describing the release profile of 4-MU from the ICs and tablets is the Higuchi model, while the release mechanism is swelling and diffusion, as was indicated by the Korsmeyer–Peppas kinetic model. The optimization analysis revealed that the optimum composition contains x1 = 150.95 mg of β-CD-4-MU ICs, x2 = 82.65 mg of microcrystalline cellulose, and x3 = 12.40 mg of calcium phosphate.
{"title":"Formulation of Pharmaceutical Tablets Containing β-Cyclodextrin-4-Methyl-Umbelliferone (Hymecromone) Inclusion Complexes and Study of the Dissolution Kinetics","authors":"E. Kavetsou, Ioanna Pitterou, Nikos G. Dimitrioglou, Stefanos Kikionis, E. Kritsi, P. Zoumpoulakis, E. Pontiki, Dimitra Hadjipavlou-Litina, Dimitris T. Hatziavramidis, A. Detsi","doi":"10.3390/micro3040061","DOIUrl":"https://doi.org/10.3390/micro3040061","url":null,"abstract":"The present study focuses on the synthesis of the natural product 4-methyl-umbelliferone (4-MU, hymecromone), the preparation, characterization, and biological activity evaluation of 4-MU inclusion complexes with β-cyclodextrin (β-CD), as well as their incorporation into pharmaceutical tablets. The inclusion complexes (ICs) were characterized using DLS, SEM, TGA as well as FT-IR, UV-vis, and NMR spectroscopies. The release profile of 4-MU from the β-CD-4-MU ICs was studied in three different pH: 1.2 (aqueous hydrochloric acid), 7.4, and 6.8 (phosphate-buffered solutions), to simulate the stomach, physiological, and intestine pH, respectively. The ICs were incorporated in pharmaceutical tablets which were prepared by direct compression and were characterized for their mechanical properties. The optimal composition of 4-MU as the active pharmaceutical ingredient (API) and excipients was determined using design of experiment (DoE), and the dissolution studies were performed at pH 1.2 at 37 ± 0.5 °C. The sustained release profile of the pharmaceutical tablets showed a delayed burst release effect at 20 min (20% drug release) compared to that of the ICs at the same time interval (70%). The results indicated that the kinetic model describing the release profile of 4-MU from the ICs and tablets is the Higuchi model, while the release mechanism is swelling and diffusion, as was indicated by the Korsmeyer–Peppas kinetic model. The optimization analysis revealed that the optimum composition contains x1 = 150.95 mg of β-CD-4-MU ICs, x2 = 82.65 mg of microcrystalline cellulose, and x3 = 12.40 mg of calcium phosphate.","PeriodicalId":18535,"journal":{"name":"Micro","volume":"101 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139247315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this work, we aimed to analyze the impact of extracts prepared from dried Lavandula angustifolia (lavender) flowers and leaves on the synthesis of silver nanoparticles (AgNPs) (wherein the shape and size of AgNPs and the efficiency of the process were analyzed) and to prove the possibility of transferring the AgNPs’ properties into a polymer matrix. An ex situ method was used to incorporate AgNPs and prepare polymer matrix composite (PVP-AgNPs) films (via casting) and fibers (via electrospinning). We used UV-vis absorption spectrophotometry, Fourier Transform Infrared Spectroscopy (FTIR), Transmission Electron Microscopy (TEM), and Scanning Electron Microscopy (SEM) to analyze and characterize the AgNPs and prepared composites. The results of FTIR analysis confirmed the presence of phytochemicals that can reduce silver ions from Ag+ to Ag0 in both extracts. The presence of spherical nanoparticles was confirmed via TEM regardless of the type of extract used. However, leaf extract caused the formation of AgNPs with a narrower size interval (an average size of 20 nm), and with higher efficiency, compared to the nanoparticles prepared using the flower extract. The nanoparticles prepared using the leaf extract were then incorporated into the polymer matrix, and thin polymer composite films and fibers were successfully prepared. The anti-biofilm activity of AgNPs colloids and prepared polymer nanocomposites against green algae Chlorella kessleri was studied. The anti-biofilm properties of the AgNPs were proved, along with the efficient transfer of their toxic properties into nontoxic polymer.
{"title":"Impact of Two Lavender Extracts on Silver Nanoparticle Synthesis, and the Study of Nanoparticles’ Antibiofilm Properties and Their Ability to Transfer them into a Nontoxic Polymer","authors":"Lívia Mačák, O. Velgosova, S. Dolinská","doi":"10.3390/micro3040060","DOIUrl":"https://doi.org/10.3390/micro3040060","url":null,"abstract":"In this work, we aimed to analyze the impact of extracts prepared from dried Lavandula angustifolia (lavender) flowers and leaves on the synthesis of silver nanoparticles (AgNPs) (wherein the shape and size of AgNPs and the efficiency of the process were analyzed) and to prove the possibility of transferring the AgNPs’ properties into a polymer matrix. An ex situ method was used to incorporate AgNPs and prepare polymer matrix composite (PVP-AgNPs) films (via casting) and fibers (via electrospinning). We used UV-vis absorption spectrophotometry, Fourier Transform Infrared Spectroscopy (FTIR), Transmission Electron Microscopy (TEM), and Scanning Electron Microscopy (SEM) to analyze and characterize the AgNPs and prepared composites. The results of FTIR analysis confirmed the presence of phytochemicals that can reduce silver ions from Ag+ to Ag0 in both extracts. The presence of spherical nanoparticles was confirmed via TEM regardless of the type of extract used. However, leaf extract caused the formation of AgNPs with a narrower size interval (an average size of 20 nm), and with higher efficiency, compared to the nanoparticles prepared using the flower extract. The nanoparticles prepared using the leaf extract were then incorporated into the polymer matrix, and thin polymer composite films and fibers were successfully prepared. The anti-biofilm activity of AgNPs colloids and prepared polymer nanocomposites against green algae Chlorella kessleri was studied. The anti-biofilm properties of the AgNPs were proved, along with the efficient transfer of their toxic properties into nontoxic polymer.","PeriodicalId":18535,"journal":{"name":"Micro","volume":"53 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139266598","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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