Advanced Optical Sensing Techniques for Applications in Biomedicine

A special issue of Biosensors (ISSN 2079-6374). This special issue belongs to the section "Optical and Photonic Biosensors".

Deadline for manuscript submissions: closed (30 June 2023) | Viewed by 38236

Special Issue Editor

CNR-IOM, National Research Council of Italy, Materials Foundry, The Microfabrication Microsensing and Mechanobiology (3M) laboratory, Trieste, Italy
Interests: optical microscopy and manipulation; biophysics; cell signaling; cell mechanics

Special Issue Information

Dear Colleagues,

Due to technological advances and a continuously increasing demand in biomedicine, the optical techniques for medical imaging and diagnostics have been rapidly developed and optimized in the last decade. This has led to better sensitivity and resolution, faster and reliable detection, sensor miniaturization, new biomarkers, and multimodal sensing techniques for a wider range of applications.

This Special Issue invites original contributions on the development of advanced optical techniques and their implementation for biomedical applications. Contributions on topics, including, but not limited to, multimodal imaging and spectroscopy, super resolution, optical manipulation, lab-on-chip miniaturized solutions, cost-effective optical sensors, optical nanomaterials, optical manipulation, and optical fibre sensing, are highly expected. New applications of recognized optical methods and experimental results of novel optical techniques in the field of biomedicine are also very welcome. 

Dr. Dan Cojoc
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

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Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • multimodal imaging and spectroscopy
  • superresolution in biomedicine
  • optical manipulation
  • cost effective optical sensors
  • optical nanomaterials
  • optical fibers
  • optical coherence tomography
  • photoacoustic imaging
  • microraman spectroscopy and SERS

Published Papers (14 papers)

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Research

Jump to: Review

22 pages, 2019 KiB  
Article
High-Accuracy Renal Cell Carcinoma Discrimination through Label-Free SERS of Blood Serum and Multivariate Analysis
by Bogdan Adrian Buhas, Valentin Toma, Nicolae Crisan, Guillaume Ploussard, Teodor Andrei Maghiar, Rareș-Ionuț Știufiuc and Constantin Mihai Lucaciu
Biosensors 2023, 13(8), 813; https://doi.org/10.3390/bios13080813 - 13 Aug 2023
Cited by 1 | Viewed by 1468
Abstract
Renal cell carcinoma (RCC) represents the sixth most frequently diagnosed cancer in men and is asymptomatic, being detected mostly incidentally. The apparition of symptoms correlates with advanced disease, aggressive histology, and poor outcomes. The development of the Surface-Enhanced Raman Scattering (SERS) technique opened [...] Read more.
Renal cell carcinoma (RCC) represents the sixth most frequently diagnosed cancer in men and is asymptomatic, being detected mostly incidentally. The apparition of symptoms correlates with advanced disease, aggressive histology, and poor outcomes. The development of the Surface-Enhanced Raman Scattering (SERS) technique opened the way for investigating and detecting small molecules, especially in biological liquids such as serum or blood plasma, urine, saliva, and tears, and was proposed as a simple technique for the diagnosis of various diseases, including cancer. In this study, we investigated the use of serum label-free SERS combined with two multivariate analysis tests: Principal Component Analysis combined with Linear Discriminate Analysis (PCA-LDA) and Supported Vector Machine (SVM) for the discrimination of 50 RCC cancer patients from 45 apparently healthy donors. In the case of LDA-PCA, we obtained a discrimination accuracy of 100% using 12 principal components and a quadratic discrimination function. The accuracy of discrimination between RCC stages was 88%. In the case of the SVM approach, we obtained a training accuracy of 100%, a validation accuracy of 92% for the discrimination between RCC and controls, and an accuracy of 81% for the discrimination between stages. We also performed standard statistical tests aimed at improving the assignment of the SERS vibration bands, which, according to our data, are mainly due to purinic metabolites (uric acid and hypoxanthine). Moreover, our results using these assignments and Student’s t-test suggest that the main differences in the SERS spectra of RCC patients are due to an increase in the uric acid concentration (a conclusion in agreement with recent literature), while the hypoxanthine concentration is not statistically different between the two groups. Our results demonstrate that label-free SERS combined with chemometrics holds great promise for non-invasive and early detection of RCC. However, more studies are needed to validate this approach, especially when combined with other urological diseases. Full article
(This article belongs to the Special Issue Advanced Optical Sensing Techniques for Applications in Biomedicine)
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11 pages, 2525 KiB  
Article
Label-Free Analysis of Urine Samples with In-Flow Digital Holographic Microscopy
by Lucia Gigli, Nicoletta Braidotti, Maria Augusta do R. B. F. Lima, Catalin Dacian Ciubotaru and Dan Cojoc
Biosensors 2023, 13(8), 789; https://doi.org/10.3390/bios13080789 - 04 Aug 2023
Viewed by 825
Abstract
Urinary tract infections are among the most frequent infectious diseases and require screening a great amount of urine samples from patients. However, a high percentage of samples result as negative after urine culture plate tests (CPTs), demanding a simple and fast preliminary technique [...] Read more.
Urinary tract infections are among the most frequent infectious diseases and require screening a great amount of urine samples from patients. However, a high percentage of samples result as negative after urine culture plate tests (CPTs), demanding a simple and fast preliminary technique to screen out the negative samples. We propose a digital holographic microscopy (DHM) method to inspect fresh urine samples flowing in a glass capillary for 3 min, recording holograms at 2 frames per second. After digital reconstruction, bacteria, white and red blood cells, epithelial cells and crystals were identified and counted, and the samples were classified as negative or positive according to clinical cutoff values. Taking the CPT as reference, we processed 180 urine samples and compared the results with those of urine flow cytometry (UFC). Using standard evaluation metrics for our screening test, we found a similar performance for DHM and UFC, indicating DHM as a suitable and fast screening technique retaining several advantages. As a benefit of DHM, the technique is label-free and does not require sample preparation. Moreover, the phase and amplitude images of the cells and other particles present in urine are digitally recorded and can serve for further investigation afterwards. Full article
(This article belongs to the Special Issue Advanced Optical Sensing Techniques for Applications in Biomedicine)
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16 pages, 1431 KiB  
Article
Fluholoscopy—Compact and Simple Platform Combining Fluorescence and Holographic Microscopy
by David Alonso, Javier Garcia and Vicente Micó
Biosensors 2023, 13(2), 253; https://doi.org/10.3390/bios13020253 - 10 Feb 2023
Cited by 1 | Viewed by 2278
Abstract
The combination of different imaging modalities into single imaging platforms has a strong potential in biomedical sciences as it permits the analysis of complementary properties of the target sample. Here, we report on an extremely simple, cost-effective, and compact microscope platform for achieving [...] Read more.
The combination of different imaging modalities into single imaging platforms has a strong potential in biomedical sciences as it permits the analysis of complementary properties of the target sample. Here, we report on an extremely simple, cost-effective, and compact microscope platform for achieving simultaneous fluorescence and quantitative phase imaging modes with the capability of working in a single snapshot. It is based on the use of a single illumination wavelength to both excite the sample’s fluorescence and provide coherent illumination for phase imaging. After passing the microscope layout, the two imaging paths are separated using a bandpass filter, and the two imaging modes are simultaneously obtained using two digital cameras. We first present calibration and analysis of both fluorescence and phase imaging modalities working independently and, later on, experimental validation for the proposed common-path dual-mode imaging platform considering static (resolution test targets, fluorescent micro-beads, and water-suspended lab-made cultures) as well as dynamic (flowing fluorescent beads, human sperm cells, and live specimens from lab-made cultures) samples. Full article
(This article belongs to the Special Issue Advanced Optical Sensing Techniques for Applications in Biomedicine)
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19 pages, 5171 KiB  
Article
Ultrasensitive Optical Fingerprinting of Biorelevant Molecules by Means of SERS-Mapping on Nanostructured Metasurfaces
by Elizaveta Kozhina, Sergey Bedin, Alexander Martynov, Stepan Andreev, Alexey Piryazev, Yuri Grigoriev, Yulia Gorbunova and Andrey Naumov
Biosensors 2023, 13(1), 46; https://doi.org/10.3390/bios13010046 - 28 Dec 2022
Cited by 3 | Viewed by 1947
Abstract
The most relevant technique for portable (on-chip) sensors is Surface Enhanced Raman Scattering (SERS). This strategy crashes in the case of large (biorelevant) molecules and nano-objects, whose SERS spectra are irreproducible for “homeopathic” concentrations. We suggested solving this problem by SERS-mapping. We analyzed [...] Read more.
The most relevant technique for portable (on-chip) sensors is Surface Enhanced Raman Scattering (SERS). This strategy crashes in the case of large (biorelevant) molecules and nano-objects, whose SERS spectra are irreproducible for “homeopathic” concentrations. We suggested solving this problem by SERS-mapping. We analyzed the distributions of SERS parameters for relatively “small” (malachite green (MG)) and “large” (phthalocyanine, H2Pc*) molecules. While fluctuations of spectra for “small” MG were negligible, noticeable distribution of spectra was observed for “large” H2Pc*. We show that the latter is due to a random arrangement of molecules with respect to “hot spot” areas, which have limited sizes, thus amplifying the lines corresponding to vibrations of different molecule parts. We have developed a method for engineering low-cost SERS substrates optimized for the best enhancement efficiency and a measurement protocol to obtain a reliable Raman spectrum, even for a countable number of large molecules randomly distributed over the substrate. Full article
(This article belongs to the Special Issue Advanced Optical Sensing Techniques for Applications in Biomedicine)
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12 pages, 3968 KiB  
Article
Correlative Raman–Electron–Light (CREL) Microscopy Analysis of Lipid Droplets in Melanoma Cancer Stem Cells
by Francesca Pagliari, Elisa Sogne, Davide Panella, Gerardo Perozziello, Carlo Liberale, Gobind Das, Alice Turdo, Simone Di Franco, Joao Seco, Andrea Falqui, Santo Gratteri, Arturo Pujia, Enzo Di Fabrizio, Patrizio Candeloro and Luca Tirinato
Biosensors 2022, 12(12), 1102; https://doi.org/10.3390/bios12121102 - 01 Dec 2022
Cited by 1 | Viewed by 1655
Abstract
Among all neoplasms, melanoma is characterized by a very high percentage of cancer stem cells (CSCs). Several markers have been proposed for their identification, and lipid droplets (LDs) are among them. Different techniques are used for their characterization such as mass spectrometry, imaging [...] Read more.
Among all neoplasms, melanoma is characterized by a very high percentage of cancer stem cells (CSCs). Several markers have been proposed for their identification, and lipid droplets (LDs) are among them. Different techniques are used for their characterization such as mass spectrometry, imaging techniques, and vibrational spectroscopies. Some emerging experimental approaches for the study of LDs are represented by correlative light–electron microscopy and by correlative Raman imaging–scanning electron microscopy (SEM). Based on these scientific approaches, we developed a novel methodology (CREL) by combining Raman micro-spectroscopy, confocal fluorescence microscopy, and SEM coupled with an energy-dispersive X-ray spectroscopy module. This procedure correlated cellular morphology, chemical properties, and spatial distribution from the same region of interest, and in this work, we presented the application of CREL for the analysis of LDs within patient-derived melanoma CSCs (MCSCs). Full article
(This article belongs to the Special Issue Advanced Optical Sensing Techniques for Applications in Biomedicine)
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10 pages, 1556 KiB  
Article
A Novel Methodology for Detecting Variations in Cell Surface Antigens Using Cell-Tearing by Optical Tweezers
by Chih-Lang Lin, Shyang-Guang Wang, Meng-Tsung Tien, Chung-Han Chiang, Yi-Chieh Lee, Patrice L. Baldeck and Chow-Shing Shin
Biosensors 2022, 12(8), 656; https://doi.org/10.3390/bios12080656 - 19 Aug 2022
Viewed by 1505
Abstract
The quantitative analysis of cell surface antigens has attracted increasing attention due to the antigenic variation recognition that can facilitate early diagnoses. This paper presents a novel methodology based on the optical “cell-tearing” and the especially proposed “dilution regulations” to detect variations in [...] Read more.
The quantitative analysis of cell surface antigens has attracted increasing attention due to the antigenic variation recognition that can facilitate early diagnoses. This paper presents a novel methodology based on the optical “cell-tearing” and the especially proposed “dilution regulations” to detect variations in cell surface antigens. The cell attaches to the corresponding antibody-coated slide surface. Then, the cell-binding firmness between a single cell and the functionalized surface is assayed by optically tearing using gradually reduced laser powers incorporated with serial antibody dilutions. Groups B and B3 of red blood cells (RBCs) were selected as the experiment subject. The results indicate that a higher dilution called for lower power to tear off the cell binding. According to the proposed relative-quantitative analysis theory, antigenic variation can be intuitively estimated by comparing the maximum allowable dilution folds. The estimation result shows good consistency with the finding in the literature. This study suggests a novel methodology for examining the variation in cell surface antigens, expected to be widely capable with potential sensor applications not only in biochemistry and biophysics, but also in the micro-/nano- engineering field. Full article
(This article belongs to the Special Issue Advanced Optical Sensing Techniques for Applications in Biomedicine)
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12 pages, 3541 KiB  
Article
Design of a Lab-On-Chip for Cancer Cell Detection through Impedance and Photoelectrochemical Response Analysis
by Yu-Ping Hsiao, Arvind Mukundan, Wei-Chung Chen, Ming-Tsang Wu, Shang-Chin Hsieh and Hsiang-Chen Wang
Biosensors 2022, 12(6), 405; https://doi.org/10.3390/bios12060405 - 13 Jun 2022
Cited by 24 | Viewed by 3813
Abstract
In this study, a biochip was fabricated using a light-absorbing layer of a silicon solar element combined with serrated, interdigitated electrodes and used to identify four different types of cancer cells: CE81T esophageal cancer, OE21 esophageal cancer, A549 lung adenocarcinoma, and TSGH-8301 bladder [...] Read more.
In this study, a biochip was fabricated using a light-absorbing layer of a silicon solar element combined with serrated, interdigitated electrodes and used to identify four different types of cancer cells: CE81T esophageal cancer, OE21 esophageal cancer, A549 lung adenocarcinoma, and TSGH-8301 bladder cancer cells. A string of pearls was formed from dielectrophoretic aggregated cancer cells because of the serrated interdigitated electrodes. Thus, cancer cells were identified in different parts, and electron–hole pairs were separated by photo-excited carriers through the light-absorbing layer of the solar element. The concentration catalysis mechanism of GSH and GSSG was used to conduct photocurrent response and identification, which provides the fast, label-free measurement of cancer cells. The total time taken for this analysis was 13 min. Changes in the impedance value and photocurrent response of each cancer cell were linearly related to the number of cells, and the slope of the admittance value was used to distinguish the location of the cancerous lesion, the slope of the photocurrent response, and the severity of the cancerous lesion. The results show that the number of cancerous cells was directly proportional to the admittance value and the photocurrent response for all four different types of cancer cells. Additionally, different types of cancer cells could easily be differentiated using the slope value of the photocurrent response and the admittance value. Full article
(This article belongs to the Special Issue Advanced Optical Sensing Techniques for Applications in Biomedicine)
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11 pages, 1710 KiB  
Article
Label-Free miRNA-21 Analysis Based on Strand Displacement and Terminal Deoxynucleotidyl Transferase-Assisted Amplification Strategy
by Ying Yan, Han Zhao, Yukang Fang, Changbei Ma and Junxiang Chen
Biosensors 2022, 12(5), 328; https://doi.org/10.3390/bios12050328 - 12 May 2022
Cited by 2 | Viewed by 2006
Abstract
MicroRNAs (miRNAs) are regarded as a rising star in the biomedical industry. By monitoring slight increases in miRNA-21 levels, the possibilities of multi-type malignancy can be evaluated more precisely and earlier. However, the inconvenience and insensitivity of traditional methods for detecting miRNA-21 levels [...] Read more.
MicroRNAs (miRNAs) are regarded as a rising star in the biomedical industry. By monitoring slight increases in miRNA-21 levels, the possibilities of multi-type malignancy can be evaluated more precisely and earlier. However, the inconvenience and insensitivity of traditional methods for detecting miRNA-21 levels remains challenging. In this study, a partially complementary cDNA probe was designed to detect miRNA-21 with target-triggered dual amplification based on strand displacement amplification (SDA) and terminal deoxynucleotidyl transferase (TdT)-assisted amplification. In this system, the presence of miRNA-21 can hybridize with template DNA to initiate SDA, generating a large number of trigger molecules. With the assistance of TdT and dGTP, the released trigger DNA with 3′-OH terminal can be elongated to a superlong poly(guanine) sequence, and a notable fluorescence signal was observed in the presence of thioflavin T. By means of dual amplification strategy, the sensing platform showed a good response tomiRNA-21 with a detection limit of 1.7 pM (S/N = 3). Moreover, the specificity of this method was verified using a set of miRNA with sequence homologous to miRNA-21. In order to further explore its practical application capabilities, the expression of miRNA in different cell lines was quantitatively analyzed and compared with the qRT-PCR. The considerable results of this study suggest great potential for the application of the proposed approach in clinical diagnosis. Full article
(This article belongs to the Special Issue Advanced Optical Sensing Techniques for Applications in Biomedicine)
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Review

Jump to: Research

35 pages, 7984 KiB  
Review
Using Biosensors to Study Organoids, Spheroids and Organs-on-a-Chip: A Mechanobiology Perspective
by Muhammad Sulaiman Yousafzai and John A. Hammer
Biosensors 2023, 13(10), 905; https://doi.org/10.3390/bios13100905 - 24 Sep 2023
Viewed by 2144
Abstract
The increasing popularity of 3D cell culture models is being driven by the demand for more in vivo-like conditions with which to study the biochemistry and biomechanics of numerous biological processes in health and disease. Spheroids and organoids are 3D culture platforms that [...] Read more.
The increasing popularity of 3D cell culture models is being driven by the demand for more in vivo-like conditions with which to study the biochemistry and biomechanics of numerous biological processes in health and disease. Spheroids and organoids are 3D culture platforms that self-assemble and regenerate from stem cells, tissue progenitor cells or cell lines, and that show great potential for studying tissue development and regeneration. Organ-on-a-chip approaches can be used to achieve spatiotemporal control over the biochemical and biomechanical signals that promote tissue growth and differentiation. These 3D model systems can be engineered to serve as disease models and used for drug screens. While culture methods have been developed to support these 3D structures, challenges remain to completely recapitulate the cell–cell and cell–matrix biomechanical interactions occurring in vivo. Understanding how forces influence the functions of cells in these 3D systems will require precise tools to measure such forces, as well as a better understanding of the mechanobiology of cell–cell and cell–matrix interactions. Biosensors will prove powerful for measuring forces in both of these contexts, thereby leading to a better understanding of how mechanical forces influence biological systems at the cellular and tissue levels. Here, we discussed how biosensors and mechanobiological research can be coupled to develop accurate, physiologically relevant 3D tissue models to study tissue development, function, malfunction in disease, and avenues for disease intervention. Full article
(This article belongs to the Special Issue Advanced Optical Sensing Techniques for Applications in Biomedicine)
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43 pages, 11260 KiB  
Review
Recent Advances in Metaphotonic Biosensors
by Dang Du Nguyen, Seho Lee and Inki Kim
Biosensors 2023, 13(6), 631; https://doi.org/10.3390/bios13060631 - 07 Jun 2023
Cited by 2 | Viewed by 2787
Abstract
Metaphotonic devices, which enable light manipulation at a subwavelength scale and enhance light–matter interactions, have been emerging as a critical pillar in biosensing. Researchers have been attracted to metaphotonic biosensors, as they solve the limitations of the existing bioanalytical techniques, including the sensitivity, [...] Read more.
Metaphotonic devices, which enable light manipulation at a subwavelength scale and enhance light–matter interactions, have been emerging as a critical pillar in biosensing. Researchers have been attracted to metaphotonic biosensors, as they solve the limitations of the existing bioanalytical techniques, including the sensitivity, selectivity, and detection limit. Here, we briefly introduce types of metasurfaces utilized in various metaphotonic biomolecular sensing domains such as refractometry, surface-enhanced fluorescence, vibrational spectroscopy, and chiral sensing. Further, we list the prevalent working mechanisms of those metaphotonic bio-detection schemes. Furthermore, we summarize the recent progress in chip integration for metaphotonic biosensing to enable innovative point-of-care devices in healthcare. Finally, we discuss the impediments in metaphotonic biosensing, such as its cost effectiveness and treatment for intricate biospecimens, and present a prospect for potential directions for materializing these device strategies, significantly influencing clinical diagnostics in health and safety. Full article
(This article belongs to the Special Issue Advanced Optical Sensing Techniques for Applications in Biomedicine)
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16 pages, 3256 KiB  
Review
Gold Nanoparticle-Based Plasmonic Biosensors
by Enrico Ferrari
Biosensors 2023, 13(3), 411; https://doi.org/10.3390/bios13030411 - 22 Mar 2023
Cited by 22 | Viewed by 3747
Abstract
One of the emerging technologies in molecular diagnostics of the last two decades is the use of gold nanoparticles (AuNPs) for biosensors. AuNPs can be functionalized with various biomolecules, such as nucleic acids or antibodies, to recognize and bind to specific targets. AuNPs [...] Read more.
One of the emerging technologies in molecular diagnostics of the last two decades is the use of gold nanoparticles (AuNPs) for biosensors. AuNPs can be functionalized with various biomolecules, such as nucleic acids or antibodies, to recognize and bind to specific targets. AuNPs present unique optical properties, such as their distinctive plasmonic band, which confers a bright-red color to AuNP solutions, and their extremely high extinction coefficient, which makes AuNPs detectable by the naked eye even at low concentrations. Ingenious molecular mechanisms triggered by the presence of a target analyte can change the colloidal status of AuNPs from dispersed to aggregated, with a subsequent visible change in color of the solution due to the loss of the characteristic plasmonic band. This review describes how the optical properties of AuNPs have been exploited for the design of plasmonic biosensors that only require the simple mixing of reagents combined with a visual readout and focuses on the molecular mechanisms involved. This review illustrates selected examples of AuNP-based plasmonic biosensors and promising approaches for the point-of-care testing of various analytes, spanning from the viral RNA of SARS-CoV-2 to the molecules that give distinctive flavor and color to aged whisky. Full article
(This article belongs to the Special Issue Advanced Optical Sensing Techniques for Applications in Biomedicine)
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15 pages, 1367 KiB  
Review
Label-Free Long-Term Methods for Live Cell Imaging of Neurons: New Opportunities
by Zrinko Baričević, Zahra Ayar, Samuel M. Leitao, Miranda Mladinic, Georg E. Fantner and Jelena Ban
Biosensors 2023, 13(3), 404; https://doi.org/10.3390/bios13030404 - 20 Mar 2023
Cited by 1 | Viewed by 1868
Abstract
Time-lapse light microscopy combined with in vitro neuronal cultures has provided a significant contribution to the field of Developmental Neuroscience. The establishment of the neuronal polarity, i.e., formation of axons and dendrites, key structures responsible for inter-neuronal signaling, was described in 1988 by [...] Read more.
Time-lapse light microscopy combined with in vitro neuronal cultures has provided a significant contribution to the field of Developmental Neuroscience. The establishment of the neuronal polarity, i.e., formation of axons and dendrites, key structures responsible for inter-neuronal signaling, was described in 1988 by Dotti, Sullivan and Banker in a milestone paper that continues to be cited 30 years later. In the following decades, numerous fluorescently labeled tags and dyes were developed for live cell imaging, providing tremendous advancements in terms of resolution, acquisition speed and the ability to track specific cell structures. However, long-term recordings with fluorescence-based approaches remain challenging because of light-induced phototoxicity and/or interference of tags with cell physiology (e.g., perturbed cytoskeletal dynamics) resulting in compromised cell viability leading to cell death. Therefore, a label-free approach remains the most desirable method in long-term imaging of living neurons. In this paper we will focus on label-free high-resolution methods that can be successfully used over a prolonged period. We propose novel tools such as scanning ion conductance microscopy (SICM) or digital holography microscopy (DHM) that could provide new insights into live cell dynamics during neuronal development and regeneration after injury. Full article
(This article belongs to the Special Issue Advanced Optical Sensing Techniques for Applications in Biomedicine)
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28 pages, 9237 KiB  
Review
Optical Light Sources and Wavelengths within the Visible and Near-Infrared Range Using Photoacoustic Effects for Biomedical Applications
by Unsang Jung, Jaemyung Ryu and Hojong Choi
Biosensors 2022, 12(12), 1154; https://doi.org/10.3390/bios12121154 - 10 Dec 2022
Cited by 3 | Viewed by 1740
Abstract
The photoacoustic (PA) effect occurs when sound waves are generated by light according to the thermodynamic and optical properties of the materials; they are absorption spectroscopic techniques that can be applied to characterize materials that absorb pulse or continuous wave (CW)-modulated electromagnetic radiation. [...] Read more.
The photoacoustic (PA) effect occurs when sound waves are generated by light according to the thermodynamic and optical properties of the materials; they are absorption spectroscopic techniques that can be applied to characterize materials that absorb pulse or continuous wave (CW)-modulated electromagnetic radiation. In addition, the wavelengths and properties of the incident light significantly impact the signal-to-ratio and contrast with photoacoustic signals. In this paper, we reviewed how absorption spectroscopic research results have been used in applying actual photoacoustic effects, focusing on light sources of each wavelength. In addition, the characteristics and compositions of the light sources used for the applications were investigated and organized based on the absorption spectrum of the target materials. Therefore, we expect that this study will help researchers (who desire to study photoacoustic effects) to more efficiently approach the appropriate conditions or environments for selecting the target materials and light sources. Full article
(This article belongs to the Special Issue Advanced Optical Sensing Techniques for Applications in Biomedicine)
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40 pages, 1372 KiB  
Review
The Current State of Optical Sensors in Medical Wearables
by Erik Vavrinsky, Niloofar Ebrahimzadeh Esfahani, Michal Hausner, Anton Kuzma, Vratislav Rezo, Martin Donoval and Helena Kosnacova
Biosensors 2022, 12(4), 217; https://doi.org/10.3390/bios12040217 - 06 Apr 2022
Cited by 34 | Viewed by 8938
Abstract
Optical sensors play an increasingly important role in the development of medical diagnostic devices. They can be very widely used to measure the physiology of the human body. Optical methods include PPG, radiation, biochemical, and optical fiber sensors. Optical sensors offer excellent metrological [...] Read more.
Optical sensors play an increasingly important role in the development of medical diagnostic devices. They can be very widely used to measure the physiology of the human body. Optical methods include PPG, radiation, biochemical, and optical fiber sensors. Optical sensors offer excellent metrological properties, immunity to electromagnetic interference, electrical safety, simple miniaturization, the ability to capture volumes of nanometers, and non-invasive examination. In addition, they are cheap and resistant to water and corrosion. The use of optical sensors can bring better methods of continuous diagnostics in the comfort of the home and the development of telemedicine in the 21st century. This article offers a large overview of optical wearable methods and their modern use with an insight into the future years of technology in this field. Full article
(This article belongs to the Special Issue Advanced Optical Sensing Techniques for Applications in Biomedicine)
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