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13 pages, 6217 KiB

Open AccessArticle

High-Performance Refractive Index and Temperature Sensing Based on Toroidal Dipole in All-Dielectric Metasurface

by Jingjing Zhao, Xinye Fan, Wenjing Fang, Wenxing Xiao, Fangxin Sun, Chuanchuan Li, Xin Wei, Jifang Tao, Yanling Wang and Santosh Kumar

Sensors 2024, 24(12), 3943; https://doi.org/10.3390/s24123943 - 18 Jun 2024

Cited by 2 | Viewed by 1134

Abstract

This article shows an all-dielectric metasurface consisting of “H”-shaped silicon disks with tilted splitting gaps, which can detect the temperature and refractive index (RI). By introducing asymmetry parameters that excite the quasi-BIC, there are three distinct Fano resonances with nearly 100% modulation depth, [...] Read more.

This article shows an all-dielectric metasurface consisting of “H”-shaped silicon disks with tilted splitting gaps, which can detect the temperature and refractive index (RI). By introducing asymmetry parameters that excite the quasi-BIC, there are three distinct Fano resonances with nearly 100% modulation depth, and the maximal quality factor (Q-factor) is over 10⁴. The predominant roles of different electromagnetic excitations in three distinct modes are demonstrated through near-field analysis and multipole decomposition. A numerical analysis of resonance response based on different refractive indices reveals a RI sensitivity of 262 nm/RIU and figure of merit (FOM) of 2183 RIU⁻¹. This sensor can detect temperature fluctuations with a temperature sensitivity of 59.5 pm/k. The proposed metasurface provides a novel method to induce powerful TD resonances and offers possibilities for the design of high-performance sensors. Full article

(This article belongs to the Special Issue Novel Optical Biosensing Technology)

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11 pages, 2444 KiB

Open AccessArticle

Construction of Chitosan-Modified Naphthalimide Fluorescence Probe for Selective Detection of Cu²⁺

by Chunwei Yu, Jin Huang, Mei Yang and Jun Zhang

Sensors 2024, 24(11), 3425; https://doi.org/10.3390/s24113425 - 26 May 2024

Viewed by 729

Abstract

A chitosan-based Cu²⁺ fluorescent probe was designed and synthesized independently using the C-2-amino group of chitosan with 1, 8-naphthalimide derivatives. A series of experiments were conducted to characterize the optical properties of the grafted probe. The fluorescence quenching effect was investigated based [...] Read more.

A chitosan-based Cu²⁺ fluorescent probe was designed and synthesized independently using the C-2-amino group of chitosan with 1, 8-naphthalimide derivatives. A series of experiments were conducted to characterize the optical properties of the grafted probe. The fluorescence quenching effect was investigated based on the interactions between the probe and common metals. It was found that the proposed probe displayed selective interaction with Cu²⁺ over other metal ions and anions, reaching equilibrium within 5 min. Full article

(This article belongs to the Special Issue Novel Optical Biosensing Technology)

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19 pages, 4328 KiB

Open AccessArticle

Can a Small Change in the Heterocyclic Substituent Significantly Impact the Physicochemical and Biological Properties of (Z)-2-(5-Benzylidene-4-oxo-2-thioxothiazolidin-3-yl)acetic Acid Derivatives?

by Agata Szlapa-Kula, Slawomir Kula, Łukasz Kaźmierski, Anna Biernasiuk and Przemysław Krawczyk

Sensors 2024, 24(5), 1524; https://doi.org/10.3390/s24051524 - 27 Feb 2024

Cited by 1 | Viewed by 899

Abstract

Rhodanine-3-acetic acid derivatives are attractive compounds with versatile effects. What is very important is that compounds of this type have many biological properties. They are tested, among others, as fluorescent probes for bioimaging and aldose reductase inhibitors. Rhodanine-3-acetic acid derivatives also have antibacterial, [...] Read more.

Rhodanine-3-acetic acid derivatives are attractive compounds with versatile effects. What is very important is that compounds of this type have many biological properties. They are tested, among others, as fluorescent probes for bioimaging and aldose reductase inhibitors. Rhodanine-3-acetic acid derivatives also have antibacterial, antifungal and anticancer activity. The presented work demonstrates that a slight change in the five-membered heterocyclic substituent significantly affects the properties of the compounds under consideration. Three rhodanine-3-acetic acid derivatives (A-1–A-3) were obtained in the Knoevenagel condensation reaction with good yields, ranging from 54% to 71%. High thermal stability of the tested compounds was also demonstrated above 240 °C. The absorption and emission maxima in polar and non-polar solvents were determined. Then, the possibility of using the considered derivatives for fluorescence bioimaging was checked. Compounds A-1 and A-2 were successfully used as fluorescent dyes of fixed cells of mammalian origin. In addition, biological activity tests against bacteria and fungi were carried out. Our results showed that A-1 and A-2 showed the most excellent antimicrobial activity among the newly synthesized compounds, especially against Gram-positive bacteria. Full article

(This article belongs to the Special Issue Novel Optical Biosensing Technology)

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15 pages, 5656 KiB

Open AccessArticle

The Loss-Function of KNL1 Causes Oligospermia and Asthenospermia in Mice by Affecting the Assembly and Separation of the Spindle through Flow Cytometry and Immunofluorescence

by Yuwei Zhao, Jingmin Yang, Daru Lu, Yijian Zhu, Kai Liao, Yafei Tian and Rui Yin

Sensors 2023, 23(5), 2571; https://doi.org/10.3390/s23052571 - 25 Feb 2023

Cited by 1 | Viewed by 2273

Abstract

KNL1 (kinetochore scaffold 1) has attracted much attention as one of the assembly elements of the outer kinetochore, and the functions of its different domains have been gradually revealed, most of which are associated with cancers, but few links have been made between [...] Read more.

KNL1 (kinetochore scaffold 1) has attracted much attention as one of the assembly elements of the outer kinetochore, and the functions of its different domains have been gradually revealed, most of which are associated with cancers, but few links have been made between KNL1 and male fertility. Here, we first linked KNL1 to male reproductive health and the loss-function of KNL1 resulted in oligospermia and asthenospermia in mice (an 86.5% decrease in total sperm number and an 82.4% increase in static sperm number, respectively) through CASA (computer-aided sperm analysis). Moreover, we introduced an ingenious method to pinpoint the abnormal stage in the spermatogenic cycle using flow cytometry combined with immunofluorescence. Results showed that 49.5% haploid sperm was reduced and 53.2% diploid sperm was increased after the function of KNL1 was lost. Spermatocytes arrest was identified at the meiotic prophase I of spermatogenesis, which was induced by the abnormal assembly and separation of the spindle. In conclusion, we established an association between KNL1 and male fertility, providing a guide for future genetic counseling regarding oligospermia and asthenospermia, and a powerful method for further exploring spermatogenic dysfunction by utilizing flow cytometry and immunofluorescence. Full article

(This article belongs to the Special Issue Novel Optical Biosensing Technology)

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10 pages, 1694 KiB

Open AccessArticle

A Novel Fluorescent Sensor Based on Aptamer and qPCR for Determination of Glyphosate in Tap Water

by Yong Shao, Run Tian, Jiaqi Duan, Miao Wang, Jing Cao, Zhen Cao, Guangyue Li, Fen Jin, A. M. Abd El-Aty and Yongxin She

Sensors 2023, 23(2), 649; https://doi.org/10.3390/s23020649 - 6 Jan 2023

Cited by 2 | Viewed by 2547

Abstract

Glyphosate (GLYP) is a broad-spectrum, nonselective, organic phosphine postemergence herbicide registered for many food and nonfood fields. Herein, we developed a biosensor (Mbs@dsDNA) based on carboxylated modified magnetic beads incubated with NH₂-polyA and then hybridized with polyT-glyphosate aptamer and complementary DNA. [...] Read more.

Glyphosate (GLYP) is a broad-spectrum, nonselective, organic phosphine postemergence herbicide registered for many food and nonfood fields. Herein, we developed a biosensor (Mbs@dsDNA) based on carboxylated modified magnetic beads incubated with NH₂-polyA and then hybridized with polyT-glyphosate aptamer and complementary DNA. Afterwards, a quantitative detection method based on qPCR was established. When the glyphosate aptamer on Mbs@dsDNA specifically recognizes glyphosate, complementary DNA is released and then enters the qPCR signal amplification process. The linear range of the method was 0.6 μmol/L–30 mmol/L and the detection limit was set at 0.6 μmol/L. The recoveries in tap water ranged from 103.4 to 104.9% and the relative standard deviations (RSDs) were <1%. The aptamer proposed in this study has good potential for recognizing glyphosate. The detection method combined with qPCR might have good application prospects in detecting and supervising other pesticide residues. Full article

(This article belongs to the Special Issue Novel Optical Biosensing Technology)

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12 pages, 4782 KiB

Open AccessCommunication

Plasmonic Refractive Index and Temperature Sensor Based on Graphene and LiNbO₃

by Muhammad Irfan, Yousuf Khan, Atiq Ur Rehman, Muhammad A. Butt, Svetlana N. Khonina and Nikolay L. Kazanskiy

Sensors 2022, 22(20), 7790; https://doi.org/10.3390/s22207790 - 14 Oct 2022

Cited by 17 | Viewed by 2561

Abstract

A high-efficiency dual-purpose plasmonic perfect absorber sensor based on LiNbO₃ and graphene layers was investigated in this paper for the refractive index and thermal sensing. The sensor design was kept simple for easy fabrication, comprising a LiNbO₃ substrate with a quartz [...] Read more.

A high-efficiency dual-purpose plasmonic perfect absorber sensor based on LiNbO₃ and graphene layers was investigated in this paper for the refractive index and thermal sensing. The sensor design was kept simple for easy fabrication, comprising a LiNbO₃ substrate with a quartz layer, thin layer of graphene, four gold nanorods, and a nanocavity in each unit cell. The nanocavity is located in the middle of the cell to facilitate the penetration of EM energy to the subsurface layers. The proposed sensor design achieved an output response of 99.9% reflection, which was easy to detect without having any specialized conditions for operability. The performance of the device was numerically investigated for the biomedical refractive index range of 1.33 to 1.40, yielding a sensitivity value of 981 nm/RIU with a figure-of-merit of 61.31 RIU⁻¹. By including an additional polydimethylsiloxane polymer functional layer on the top, the device was also tested as a thermal sensor, which yielded a sensitivity level of −0.23 nm/°C. Full article

(This article belongs to the Special Issue Novel Optical Biosensing Technology)

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19 pages, 999 KiB

Open AccessArticle

Using Extended Technology Acceptance Model to Assess the Adopt Intention of a Proposed IoT-Based Health Management Tool

by Dewen Liu, Qi Li and Shenghao Han

Sensors 2022, 22(16), 6092; https://doi.org/10.3390/s22166092 - 15 Aug 2022

Cited by 13 | Viewed by 3734

Abstract

Advancements in IoT technology contribute to the digital progress of health science. This paper proposes a cloud-centric IoT-based health management framework and develops a system prototype that integrates sensors and digital technology. The IoT-based health management tool can collect real-time health data and [...] Read more.

Advancements in IoT technology contribute to the digital progress of health science. This paper proposes a cloud-centric IoT-based health management framework and develops a system prototype that integrates sensors and digital technology. The IoT-based health management tool can collect real-time health data and transmit it to the cloud, thus transforming the signals of various sensors into shared content that users can understand. This study explores whether individuals in need tend to use the proposed IoT-based technology for health management, which may lead to the new development of digital healthcare in the direction of sensors. The novelty of this research lies in extending the research perspective of sensors from the technical level to the user level and explores how individuals understand and adopt sensors based on innovatively applying the IoT to health management systems. By organically combining TAM with MOA theory, we propose a comprehensive model to explain why individuals develop perceptions of usefulness, ease of use, and risk regarding systems based on factors related to motivation, opportunity, and ability. Structural equation modeling was used to analyze the online survey data collected from respondents. The results showed that perceived usefulness and ease of use positively impacted adoption intention, Perceived ease of use positively affected perceived usefulness. Perceived risk had a negative impact on adoption intention. Readiness was only positively related to perceived usefulness, while external benefits were positively related to perceived ease of use and negatively related to perceived risk. Facilitative conditions were positively correlated with perceived ease of use and negatively correlated with perceived risk. Technical efficacy was positively related to perceived ease of use and perceived usefulness. Overall, the research model revealed the cognitive mechanism that affects the intention of individuals to use the system combining sensors and the IoT and guides the digital transformation of health science. Full article

(This article belongs to the Special Issue Novel Optical Biosensing Technology)

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Review

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27 pages, 3085 KiB

Open AccessReview

Review of Advances in the Measurement of Skin Hydration Based on Sensing of Optical and Electrical Tissue Properties

by Iman M. Gidado, Meha Qassem, Iasonas F. Triantis and Panicos A. Kyriacou

Sensors 2022, 22(19), 7151; https://doi.org/10.3390/s22197151 - 21 Sep 2022

Cited by 19 | Viewed by 9047

Abstract

The presence of water in the skin is crucial for maintaining the properties and functions of the skin, in particular its outermost layer, known as the stratum corneum, which consists of a lipid barrier. External exposures can affect the skin’s hydration levels and [...] Read more.

The presence of water in the skin is crucial for maintaining the properties and functions of the skin, in particular its outermost layer, known as the stratum corneum, which consists of a lipid barrier. External exposures can affect the skin’s hydration levels and in turn, alter its mechanical and physical properties. Monitoring these alterations in the skin’s water content can be applicable in clinical, cosmetic, athletic and personal settings. Many techniques measuring this parameter have been investigated, with electrical-based methods currently being widely used in commercial devices. Furthermore, the exploration of optical techniques to measure hydration is growing due to the outcomes observed through the penetration of light at differing levels. This paper comprehensively reviews such measurement techniques, focusing on recent experimental studies and state-of-the-art devices. Full article

(This article belongs to the Special Issue Novel Optical Biosensing Technology)

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