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Methods and Protocols Jun 2019We describe an advanced DIVER (Deep Imaging Via Emission Recovery) detection system for two-photon fluorescence microscopy that allows imaging in multiple scattering... (Review)
Review
We describe an advanced DIVER (Deep Imaging Via Emission Recovery) detection system for two-photon fluorescence microscopy that allows imaging in multiple scattering media, including biological tissues, up to a depth of a few mm with micron resolution. This detection system is more sensitive to low level light signals than conventional epi-detection used in two-photon fluorescence microscopes. The DIVER detector efficiently collects scattered emission photons from a wide area of turbid samples at almost any entrance angle in a 2π spherical angle. Using an epi-detection scheme only photons coming from a relatively small area of a sample and at narrow acceptance angle can be detected. The transmission geometry of the DIVER imaging system makes it exceptionally suitable for Second and Third Harmonic Generation (SHG, THG) signal detection. It also has in-depth fluorescence lifetime imaging (FLIM) capability. Using special optical filters with sin-cos spectral response, hyperspectral analysis of images acquired in-depth in scattering media can be performed. The system was successfully employed in imaging of various biological tissues. The DIVER detector can be plugged into a standard microscope stage and used as an external detector with upright commercial two-photon microscopes.
PubMed: 31234383
DOI: 10.3390/mps2020053 -
IScience Jun 2020Optical microscope is one of the most widely used imaging tools for its great flexibility, reliable design, and low cost. Optical microsphere nanoscope (OMN) is invented... (Review)
Review
Optical microscope is one of the most widely used imaging tools for its great flexibility, reliable design, and low cost. Optical microsphere nanoscope (OMN) is invented as a method that can greatly enhance the observation power of conventional optical microscopes. In this perspective, the promising outlook for this approach is briefly discussed. There exists a great freedom to apply this method in various applications. OMN has been successfully commercialized. Our past experience and strategies are summarized in this perspective, which serves as a good reference for the future technology entrepreneurs. Based on our story and model, the factors for success are listed. It can be used to evaluate other commercialization projects and find out the directions that require further improvement.
PubMed: 32534443
DOI: 10.1016/j.isci.2020.101211 -
Medicine and Pharmacy Reports Jul 2023An increased number of clinicians are using magnification to facilitate their vision when carrying out dental examinations and treatments. The best instrument for this... (Review)
Review
An increased number of clinicians are using magnification to facilitate their vision when carrying out dental examinations and treatments. The best instrument for this purpose is the microscope, which has proven to enhance quality, longevity and outcome of clinical work. Its use in some dental specialties (such as endodontics) is now well established, but there is also a role for this equipment in other branches of dentistry. To anticipate the contribution of magnification to dentistry in general, recent research and experimental data on the importance of magnification devices will be considered, from the perspectives of optical issues, diagnosing methods and treatment options. It will be shown that, while the microscope is vital to certain specialties (such as endodontics, periodontics, restorative dentistry and prosthodontics), it has little effect on others (orthodontics, for example). This synthesis of current researchattempts to shed light on the optimal magnification used in certain clinical situations, the distinctive benefits of loupes and microscopes for each dental branch, as well as their drawbacks.
PubMed: 37577013
DOI: 10.15386/mpr-2556 -
Microscopy Research and Technique Oct 2022This article presents a review after an exhaustive search that yielded 23 works carried out in the last decade for the availability of optical microscopes with open... (Review)
Review
This article presents a review after an exhaustive search that yielded 23 works carried out in the last decade for the availability of optical microscopes with open hardware as a low-cost alternative to commercial systems. These works were developed with the aim of covering needs within several areas such as: Bio Sciences research in institutions with limited resources, diagnosis of diseases and health screenings in large populations in developing countries, and training in educational contexts with a need for high availability of equipment and low replacement cost. The analysis of the selected works allows us to classify the analyzed solutions into two main categories, for which their essential characteristics are enumerated: portable field microscopes and multipurpose automated microscopes. Moreover, this work includes a discussion on the degree of maturity of the solutions in terms of the adoption of practices aligned with the development of Open Science. RESEARCH HIGHLIGHTS: Concise review on low-cost microscopes for developing Open Science, exposing the role of smartphone-based microscopy. The work classifies microscopes in two main categories: (1) portable field microscopes, and (2) multipurpose automated microscopes.
Topics: Microscopy; Smartphone
PubMed: 35879870
DOI: 10.1002/jemt.24200 -
Biomedical Optics Express Jan 2022Confocal microscopy is a standard approach for obtaining volumetric images of a sample with high axial and lateral resolution, especially when dealing with scattering...
Confocal microscopy is a standard approach for obtaining volumetric images of a sample with high axial and lateral resolution, especially when dealing with scattering samples. Unfortunately, a confocal microscope is quite expensive compared to traditional microscopes. In addition, the point scanning in confocal microscopy leads to slow imaging speed and photobleaching due to the high dose of laser energy. In this paper, we demonstrate how the advances in machine learning can be exploited to "teach" a traditional wide-field microscope, one that's available in every lab, into producing 3D volumetric images like a confocal microscope. The key idea is to obtain multiple images with different focus settings using a wide-field microscope and use a 3D generative adversarial network (GAN) based neural network to learn the mapping between the blurry low-contrast image stacks obtained using a wide-field microscope and the sharp, high-contrast image stacks obtained using a confocal microscope. After training the network with widefield-confocal stack pairs, the network can reliably and accurately reconstruct 3D volumetric images that rival confocal images in terms of its lateral resolution, z-sectioning and image contrast. Our experimental results demonstrate generalization ability to handle unseen data, stability in the reconstruction results, high spatial resolution even when imaging thick (∼40 microns) highly-scattering samples. We believe that such learning-based microscopes have the potential to bring confocal imaging quality to every lab that has a wide-field microscope.
PubMed: 35154871
DOI: 10.1364/BOE.444488 -
Scientific Reports Jul 2019An optical microscope enables image-based findings and diagnosis on microscopic targets, which is indispensable in many scientific, industrial and medical settings. A...
An optical microscope enables image-based findings and diagnosis on microscopic targets, which is indispensable in many scientific, industrial and medical settings. A standard benchtop microscope platform, equipped with e.g., bright-field and phase-contrast modes, is of importance and convenience for various users because the wide-field and label-free properties allow for morphological imaging without the need for specific sample preparation. However, these microscopes never have capability of acquiring molecular contrast in a label-free manner. Here, we develop a simple add-on optical unit, comprising of an amplitude-modulated mid-infrared semiconductor laser, that is attached to a standard microscope platform to deliver the additional molecular contrast of the specimen on top of its conventional microscopic image, based on the principle of photothermal effect. We attach this unit, termed molecular-contrast unit, to a standard phase-contrast microscope, and demonstrate high-speed label-free molecular-contrast phase-contrast imaging of silica-polystyrene microbeads mixture and molecular-vibrational spectroscopic imaging of HeLa cells. Our simple molecular-contrast unit can empower existing standard microscopes and deliver a convenient accessibility to the molecular world.
Topics: HeLa Cells; Humans; Lasers, Semiconductor; Light; Microscopy, Phase-Contrast; Microspheres; Molecular Imaging; Polystyrenes; Silicon Dioxide; Spectrophotometry, Infrared
PubMed: 31316091
DOI: 10.1038/s41598-019-46383-6 -
Biomedical Optics Express May 2020Optical microscopes are an essential tool for both the detection of disease in clinics, and for scientific analysis. However, in much of the world access to...
Optical microscopes are an essential tool for both the detection of disease in clinics, and for scientific analysis. However, in much of the world access to high-performance microscopy is limited by both the upfront cost and maintenance cost of the equipment. Here we present an open-source, 3D-printed, and fully-automated laboratory microscope, with motorised sample positioning and focus control. The microscope is highly customisable, with a number of options readily available including trans- and epi- illumination, polarisation contrast imaging, and epi-florescence imaging. The OpenFlexure microscope has been designed to enable low-volume manufacturing and maintenance by local personnel, vastly increasing accessibility. We have produced over 100 microscopes in Tanzania and Kenya for educational, scientific, and clinical applications, demonstrating that local manufacturing can be a viable alternative to international supply chains that can often be costly, slow, and unreliable.
PubMed: 32499936
DOI: 10.1364/BOE.385729 -
Biomedical Optics Express Aug 2023Traditional miniaturized fluorescence microscopes are critical tools for modern biology. Invariably, they struggle to simultaneously image with a high spatial resolution...
Traditional miniaturized fluorescence microscopes are critical tools for modern biology. Invariably, they struggle to simultaneously image with a high spatial resolution and a large field of view (FOV). Lensless microscopes offer a solution to this limitation. However, real-time visualization of samples is not possible with lensless imaging, as image reconstruction can take minutes to complete. This poses a challenge for usability, as real-time visualization is a crucial feature that assists users in identifying and locating the imaging target. The issue is particularly pronounced in lensless microscopes that operate at close imaging distances. Imaging at close distances requires shift-varying deconvolution to account for the variation of the point spread function (PSF) across the FOV. Here, we present a lensless microscope that achieves real-time image reconstruction by eliminating the use of an iterative reconstruction algorithm. The neural network-based reconstruction method we show here, achieves more than 10000 times increase in reconstruction speed compared to iterative reconstruction. The increased reconstruction speed allows us to visualize the results of our lensless microscope at more than 25 frames per second (fps), while achieving better than 7 µm resolution over a FOV of 10 mm. This ability to reconstruct and visualize samples in real-time empowers a more user-friendly interaction with lensless microscopes. The users are able to use these microscopes much like they currently do with conventional microscopes.
PubMed: 37799697
DOI: 10.1364/BOE.490199 -
Journal of Oral and Maxillofacial... 2022Pathologists come across various structures in the microscopic sections that are unrelated to the tissues. Artifacts can occur in the tissue from the time the area is...
BACKGROUND
Pathologists come across various structures in the microscopic sections that are unrelated to the tissues. Artifacts can occur in the tissue from the time the area is prepared for biopsy, during fixation, grossing, processing, sectioning and staining of the specimen. Food substances may get entrapped into the oral tissues and can lead to misdiagnosis. The aim of this study was to observe the microscopic appearances of commonly implanted food particles.
METHODS
Fourteen food samples were procured from a local market in Chennai, India. This included guava, chilli, chickpeas, channa dal (split chickpeas), cucumber, brinjal, carrot, capsicum, cabbage and urad dal and brown chickpea. The food samples were fixed in 10% formalin for 24 h and were subsequently processed. Hematoxylin and eosin staining was performed, and the sections were observed under the microscope.
RESULTS
Each specimen revealed unique, distinct histology of each food type. Channa dal microscopically in hematoxylin- and eosin-stained sections revealed round-to-oval structures with central pale eosinophilic lobulation. Capsicum showed round-to-polygonal structures of different shapes and sizes with clear central areas. Urad dal microscopically showed cluster of 5-6 eosinophilic structures separated by regular partitions.
CONCLUSION
It is important to study the microscopic appearances of commonly implanted food particles to prevent any diagnostic dilemmas. Further studies are required involving various other food particles and their microscopic appearances.
PubMed: 36588857
DOI: 10.4103/jomfp.jomfp_117_21 -
Frontiers in Chemistry 2022As a typical microscopic imaging technology, the emergence of the microscope has accelerated the pace of human exploration of the micro world. With the development of... (Review)
Review
As a typical microscopic imaging technology, the emergence of the microscope has accelerated the pace of human exploration of the micro world. With the development of science and technology, microscopes have developed from the optical microscopes at the time of their invention to electron microscopes and even atomic force microscopes. The resolution has steadily improved, allowing humans to expand the field of research from the initial animal and plant tissues to microorganisms such as bacteria, and even down to the nanolevel. The microscope is now widely used in life science, material science, geological research, and other fields. It can be said that the development of microscopes also promotes the development of micro- and nanotechnology. It is foreseeable that microscopes will play a significant part in the exploration of the microworld for a long time to come. The development of microscope technology is the focus of this study, which summarized the properties of numerous microscopes and discussed their applications in micro and nanotechnology. At the same time, the application of microscopic imaging technology in micro- and nanofields was investigated based on the properties of various microscopes.
PubMed: 35864864
DOI: 10.3389/fchem.2022.931169