Sensors

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12 pages, 4066 KiB

Open AccessCommunication

Simultaneous Recognition and Detection of Adenosine Phosphates by Machine Learning Analysis for Surface-Enhanced Raman Scattering Spectral Data

by Ryosuke Nishitsuji, Tomoharu Nakashima, Hideaki Hisamoto and Tatsuro Endo

Sensors 2024, 24(20), 6648; https://doi.org/10.3390/s24206648 - 15 Oct 2024

Viewed by 613

Abstract

Adenosine phosphates (adenosine 5′-monophosphate (AMP), adenosine 5′-diphosphate (ADP), and adenosine 5′-triphosphate (ATP)) play important roles in energy storage and signal transduction in the human body. Thus, a measurement method that simultaneously recognizes and detects adenosine phosphates is necessary to gain insight into complex [...] Read more.

Adenosine phosphates (adenosine 5′-monophosphate (AMP), adenosine 5′-diphosphate (ADP), and adenosine 5′-triphosphate (ATP)) play important roles in energy storage and signal transduction in the human body. Thus, a measurement method that simultaneously recognizes and detects adenosine phosphates is necessary to gain insight into complex energy-relevant biological processes. Surface-enhanced Raman scattering (SERS) is a powerful technique for this purpose. However, the similarities in size, charge, and structure of adenosine phosphates (APs) make their simultaneous recognition and detection difficult. Although approaches that combine SERS and machine learning have been studied, they require massive quantities of training data. In this study, limited AP spectral data were obtained using fabricated gold nanostructures for SERS measurements. The training data were created by feature selection and data augmentation after preprocessing the small amount of acquired spectral data. The performances of several machine learning models trained on these generated training data were compared. Multilayer perceptron model successfully detected the presence of AMP, ADP, and ATP with an accuracy of 0.914. Consequently, this study establishes a new measurement system that enables the highly accurate recognition and detection of adenosine phosphates from limited SERS spectral data. Full article

(This article belongs to the Special Issue Micro/Nano-Devices for Biosensing: From Single Molecule Sensing to Device Applications)

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14 pages, 2133 KiB

Open AccessArticle

An Electrochemical Nucleic Acid Biosensor for Triple-Negative Breast Cancer Biomarker Detection

by Lexi Hansen, Sanket Naresh Nagdeve, Baviththira Suganthan and Ramaraja P. Ramasamy

Sensors 2024, 24(17), 5747; https://doi.org/10.3390/s24175747 - 4 Sep 2024

Viewed by 1111

Abstract

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer, affecting younger women and women of minorities. The nomenclature “triple negative” is derived from the absence of the three most common breast cancer biomarkers: progesterone receptor (PR), estrogen receptor (ER), and [...] Read more.

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer, affecting younger women and women of minorities. The nomenclature “triple negative” is derived from the absence of the three most common breast cancer biomarkers: progesterone receptor (PR), estrogen receptor (ER), and human epidermal growth factor receptor 2 (HER2). It derives its name from testing negative for these three most common breast cancer biomarkers. Currently, TNBC is diagnosed at advanced stages, necessitating the need for a diagnostic tool or method to identify this malignancy at an early stage prior to metastasis. In this study, a novel electrochemical biosensor was developed, optimized, and evaluated for the detection of microRNA-10b (miRNA-10b), marking the first use of this biomarker for the early diagnosis of TNBC. The biosensor demonstrated the ability to detect concentrations as low as 10 pM. Furthermore, the biosensor was specific toward the target biomarker, distinguishing non-target miRNAs of similar size. The efficacy of the biosensor for TNBC early diagnosis was further validated using human serum samples. Full article

(This article belongs to the Special Issue Micro/Nano-Devices for Biosensing: From Single Molecule Sensing to Device Applications)

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8 pages, 1979 KiB

Open AccessCommunication

Nanoimprinted Plasmonic Crystals for Cost-Effective SERS Identification of Methylated DNAs

by Daiki Kawasaki, Ryosuke Nishitsuji and Tatsuro Endo

Sensors 2024, 24(14), 4599; https://doi.org/10.3390/s24144599 - 16 Jul 2024

Viewed by 812

Abstract

The development of a cost-effective and rapid assay technique for the identification of DNA methylation is one of the most crucial issues in the field of biomedical diagnosis because DNA methylation plays key roles in human health. The plasmonic crystal-based surface-enhanced Raman spectroscopy [...] Read more.

The development of a cost-effective and rapid assay technique for the identification of DNA methylation is one of the most crucial issues in the field of biomedical diagnosis because DNA methylation plays key roles in human health. The plasmonic crystal-based surface-enhanced Raman spectroscopy (SERS) technique is promising for the realization of such an assay method owing to its capability of generating uniformly enhanced electric fields to achieve high reproducibility and accuracy in SERS assays. However, the time and technical costs of fabricating plasmonic crystals are high, owing to the need for nanofabrication equipment. In this study, we developed nanoimprinted plasmonic crystals for cost-effective and rapid DNA methylation assays. Our plasmonic crystals identified methylated DNA with the 40-base pair adenomatous polyposis coli (APC) gene sequence, which is correlated with cell growth and cancer cells. Full article

(This article belongs to the Special Issue Micro/Nano-Devices for Biosensing: From Single Molecule Sensing to Device Applications)

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10 pages, 2803 KiB

Open AccessArticle

In Vivo Multimodal Imaging of Stem Cells Using Nanohybrid Particles Incorporating Quantum Dots and Magnetic Nanoparticles

by Shota Yamada, Hiroshi Yukawa, Kaori Yamada, Yuki Murata, Jun-ichiro Jo, Masaya Yamamoto, Ayae Sugawara-Narutaki, Yasuhiko Tabata and Yoshinobu Baba

Sensors 2022, 22(15), 5705; https://doi.org/10.3390/s22155705 - 30 Jul 2022

Cited by 2 | Viewed by 2923

Abstract

The diagnosis of the dynamics, accumulation, and engraftment of transplanted stem cells in vivo is essential for ensuring the safety and the maximum therapeutic effect of regenerative medicine. However, in vivo imaging technologies for detecting transplanted stem cells are not sufficient at present. [...] Read more.

The diagnosis of the dynamics, accumulation, and engraftment of transplanted stem cells in vivo is essential for ensuring the safety and the maximum therapeutic effect of regenerative medicine. However, in vivo imaging technologies for detecting transplanted stem cells are not sufficient at present. We developed nanohybrid particles composed of dendron-baring lipids having two unsaturated bonds (DLU2) molecules, quantum dots (QDs), and magnetic nanoparticles in order to diagnose the dynamics, accumulation, and engraftment of transplanted stem cells, and then addressed the labeling and in vivo fluorescence and magnetic resonance (MR) imaging of stem cells using the nanohybrid particles (DLU2-NPs). Five kinds of DLU2-NPs (DLU2-NPs-1-5) composed of different concentrations of DLU2 molecules, QDs525, QDs605, QDs705, and ATDM were prepared. Adipose tissue-derived stem cells (ASCs) were labeled with DLU2-NPs for 4 h incubation, no cytotoxicity or marked effect on the proliferation ability was observed in ASCs labeled with DLU2-NPs (640- or 320-fold diluted). ASCs labeled with DLU2-NPs (640-fold diluted) were transplanted subcutaneously onto the backs of mice, and the labeled ASCs could be imaged with good contrast using in vivo fluorescence and an MR imaging system. DLU2-NPs may be useful for in vivo multimodal imaging of transplanted stem cells. Full article

(This article belongs to the Special Issue Micro/Nano-Devices for Biosensing: From Single Molecule Sensing to Device Applications)

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12 pages, 9319 KiB

Open AccessArticle

Material-Specific Determination Based on Microscopic Observation of Single Microplastic Particles Stained with Fluorescent Dyes

by Hiroshi Aoki

Sensors 2022, 22(9), 3390; https://doi.org/10.3390/s22093390 - 28 Apr 2022

Cited by 5 | Viewed by 3530

Abstract

Microplastics are increasingly suspected of having serious negative effects on ecological systems and living organisms. These effects are different based on the materials of the microplastics, leading to the importance of the determination of the materials. For material determination, spectral fingerprints based on [...] Read more.

Microplastics are increasingly suspected of having serious negative effects on ecological systems and living organisms. These effects are different based on the materials of the microplastics, leading to the importance of the determination of the materials. For material determination, spectral fingerprints based on FT-IR and Raman microspectroscopy are previously and commonly used, though they require patience and special skills. In this study, we have developed a novel technique for microscopic observation of single microplastic particles stained with fluorescent dyes to enable fluorescence-based determination of materials of these particles as a first screening of material determination. Commercially available and popular microplastic particles and fluorescent dyes were used. Fluorescence microscopy was carried out to observe the degree of fluorescent intensity for various combinations of microplastics and dyes based on the difference in fluorescent intensity of microplastics before and after staining with the dyes. We have found a dependence of the fluorescent intensity on the combination of the microplastics and the dye. Fluorescein gave the highest increase in intensity for PS (polystyrene), showing a statistically significant difference between fluorescent intensity for PS and that for PP (polypropylene) or PE (polyethylene). The use of Fluorescein thus enables specific detection of PS. On the other hand, Nile Red gave the highest increase in fluorescence for PP, indicating that the combination of Nile Red and PP gives a significantly greater interaction than with other combinations. The use of Nile Red thus enables the specific detection of PP. These results indicate the possibility of the material determination of microplastics by using fluorescent dyes. This is the first demonstration of the differential determination of the materials of single-particle microplastics based on a material-specific increase in fluorescent intensity by staining microplastics with fluorescent dyes. Full article

(This article belongs to the Special Issue Micro/Nano-Devices for Biosensing: From Single Molecule Sensing to Device Applications)

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9 pages, 3021 KiB

Open AccessArticle

Characterization of Extra-Cellular Vesicle Dielectrophoresis and Estimation of Its Electric Properties

by Hao Chen, Tsubasa Yamakawa, Masafumi Inaba, Michihiko Nakano and Junya Suehiro

Sensors 2022, 22(9), 3279; https://doi.org/10.3390/s22093279 - 25 Apr 2022

Cited by 10 | Viewed by 2700

Abstract

Dielectrophoresis (DEP) refers to a type of electrical motion of dielectric particles. Because DEP is caused by particle polarization, it has been utilized to characterize particles. This study investigated the DEP of three types of exosomes, namely bovine milk, human breast milk, and [...] Read more.

Dielectrophoresis (DEP) refers to a type of electrical motion of dielectric particles. Because DEP is caused by particle polarization, it has been utilized to characterize particles. This study investigated the DEP of three types of exosomes, namely bovine milk, human breast milk, and human breast cancer exosomes. Exosomes are kinds of extracellular vesicles. The crossover frequencies of the exosomes were determined by direct observation of their DEPs. Consequently, bovine and human milk exosomes showed similar DEP properties, whereas the cancer exosomes were significantly different from the others. The membrane capacitance and conductivity of the exosomes were estimated using determined values. A significant difference was observed between bovine and human milk exosomes on their membrane capacitance. It was revealed that the membrane capacitances of human breast milk and human breast cancer exosomes were almost identical to those of their host cells and the conductivity of the exosomes were much lower than that of the host cell. Based on these results, DEP separation of the human breast milk and cancer exosomes was demonstrated. These results imply that DEP can be utilized to separate and identify cancer exosomes rapidly. Additionally, our method can be utilized to estimate the electric property of other types of extracellular vesicles. Full article

(This article belongs to the Special Issue Micro/Nano-Devices for Biosensing: From Single Molecule Sensing to Device Applications)

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13 pages, 2298 KiB

Open AccessArticle

Influence of Electroporation Medium on Delivery of Cell-Impermeable Small Molecules by Electrical Short-Circuiting via an Aqueous Droplet in Dielectric Oil: A Comparison of Different Fluorescent Tracers

by Yuki Watanabe, Hirohito Nihonyanagi, Rika Numano, Takayuki Shibata, Kazunori Takashima and Hirofumi Kurita

Sensors 2022, 22(7), 2494; https://doi.org/10.3390/s22072494 - 24 Mar 2022

Cited by 3 | Viewed by 2756

Abstract

Membrane permeabilization stimulated by high-voltage electric pulses has been used to deliver cell-impermeable exogenous molecules. The electric field effect on the cells depends on various experimental parameters, such as electric field strength, the number of electric pulses, and the electroporation medium. In this [...] Read more.

Membrane permeabilization stimulated by high-voltage electric pulses has been used to deliver cell-impermeable exogenous molecules. The electric field effect on the cells depends on various experimental parameters, such as electric field strength, the number of electric pulses, and the electroporation medium. In this study, we show the influence of the electroporation medium on membrane permeabilization stimulated by electrical short-circuiting via an aqueous droplet in dielectric oil, a novel methodology developed by our previous investigations. We investigated the membrane permeabilization by three methods, influx of calcium ions, uptake of nucleic acid-binding fluorophores (YO-PRO-1), and calcein leakage. We demonstrated that the external medium conductivity had a significant impact on the cells in all described experiments. The short-circuiting using a low-conductivity electroporation medium enhanced the formation of both transient and irreversible membrane pores. We also found that clathrin-mediated endocytosis contributed to YO-PRO-1 uptake when a cell culture medium was used as an electroporation medium. Full article

(This article belongs to the Special Issue Micro/Nano-Devices for Biosensing: From Single Molecule Sensing to Device Applications)

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11 pages, 3585 KiB

Open AccessArticle

Rapid DNA Sequencing Technology Based on the Sanger Method for Bacterial Identification

by Shunsuke Furutani, Nozomi Furutani, Yasuyuki Kawai, Akifumi Nakayama and Hidenori Nagai

Sensors 2022, 22(6), 2130; https://doi.org/10.3390/s22062130 - 9 Mar 2022

Cited by 5 | Viewed by 6159

Abstract

Antimicrobial resistance, a global health concern, has been increasing due to inappropriate use of antibacterial agents. To facilitate early treatment of sepsis, rapid bacterial identification is imperative to determine appropriate antibacterial agent for better therapeutic outcomes. In this study, we developed a rapid [...] Read more.

Antimicrobial resistance, a global health concern, has been increasing due to inappropriate use of antibacterial agents. To facilitate early treatment of sepsis, rapid bacterial identification is imperative to determine appropriate antibacterial agent for better therapeutic outcomes. In this study, we developed a rapid PCR method, rapid cycle sequencing, and microchip electrophoresis, which are the three elemental technologies for DNA sequencing based on the Sanger sequencing method, for bacterial identification. We achieved PCR amplification within 13 min and cycle sequencing within 14 min using a rapid thermal cycle system applying microfluidic technology. Furthermore, DNA analysis was completed in 14 min by constructing an algorithm for analyzing and performing microchip electrophoresis. Thus, the three elemental Sanger-based DNA sequencing steps were accomplished within 41 min. Development of a rapid purification process subsequent to PCR and cycle sequence using a microchip would help realize the identification of causative bacterial agents within one hour, and facilitate early treatment of sepsis. Full article

(This article belongs to the Special Issue Micro/Nano-Devices for Biosensing: From Single Molecule Sensing to Device Applications)

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9 pages, 1461 KiB

Open AccessCommunication

AC-Electroosmosis-Assisted Surface Plasmon Resonance Sensing for Enhancing Protein Signals with a Simple Kretschmann Configuration

by Kyohei Terao and Shohei Kondo

Sensors 2022, 22(3), 854; https://doi.org/10.3390/s22030854 - 23 Jan 2022

Cited by 3 | Viewed by 2616

Abstract

A surface plasmon resonance (SPR) sensor chip fabricated with a comb-shaped microelectrode array to supply alternating current (AC) voltage is reported. The chip induces circulating flow near the surface (i.e., AC electroosmosis). The circulating flow provides a mixing effect, which enhances the binding [...] Read more.

A surface plasmon resonance (SPR) sensor chip fabricated with a comb-shaped microelectrode array to supply alternating current (AC) voltage is reported. The chip induces circulating flow near the surface (i.e., AC electroosmosis). The circulating flow provides a mixing effect, which enhances the binding of the analyte molecules. We evaluated the SPR characteristics of the chip and demonstrated an improvement in protein binding to the chip surface. SPR sensor chips with comb-shaped microelectrodes were fabricated using standard UV lithography. Sensing experiments were conducted using a standard Kretschmann-type SPR measurement system. To demonstrate the mixing effect of AC electroosmosis, we evaluated the binding of immunoglobulin G molecules onto the sensor surface where anti-immunoglobulin G antibodies were covalently immobilized. The result indicates that the amount of binding increases by a factor of 1.7 above that achieved by using a conventional chip, suggesting enhancement of the protein signal. Full article

(This article belongs to the Special Issue Micro/Nano-Devices for Biosensing: From Single Molecule Sensing to Device Applications)

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