scholarly journals The Recent Advances in Raman Microscopy and Imaging Techniques for Biosensors

Biosensors ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 25 ◽  
Author(s):  
Alexander Rzhevskii

Raman microspectroscopy is now well established as one of the most powerful analytical techniques for a diverse range of applications in physical (material) and biological sciences. Consequently, the technique provides exceptional analytical opportunities to the science and technology of biosensing due to its capability to analyze both parts of a biosensor system—biologically sensitive components, and a variety of materials and systems used in physicochemical transducers. Recent technological developments in Raman spectral imaging have brought additional possibilities in two- and three-dimensional (2D and 3D) characterization of the biosensor’s constituents and their changes on a submicrometer scale in a label-free, real-time nondestructive method of detection. In this report, the essential components and features of a modern confocal Raman microscope are reviewed using the instance of Thermo Scientific DXRxi Raman imaging microscope, and examples of the potential applications of Raman microscopy and imaging for constituents of biosensors are presented.

2019 ◽  
Author(s):  
Jeonghun Oh ◽  
Jea Sung Ryu ◽  
Moosung Lee ◽  
Jaehwang Jung ◽  
Seung yun Han ◽  
...  

AbstractMeasuring alterations in bacteria upon antibiotic application is important for basic studies in microbiology, drug discovery, and clinical diagnosis, and disease treatment. However, imaging and 3D time-lapse response analysis of individual bacteria upon antibiotic application remain largely unexplored mainly due to limitations in imaging techniques. Here, we present a method to systematically investigate the alterations in individual bacteria in 3D and quantitatively analyze the effects of antibiotics. Using optical diffraction tomography, in-situ responses of Escherichia coli and Bacillus subtilis to various concentrations of ampicillin were investigated in a label-free and quantitative manner. The presented method reconstructs the dynamic changes in the 3D refractive-index distributions of living bacteria in response to antibiotics at sub-micrometer spatial resolution.


eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Moosung Lee ◽  
Young-Ho Lee ◽  
Jinyeop Song ◽  
Geon Kim ◽  
YoungJu Jo ◽  
...  

The immunological synapse (IS) is a cell-cell junction between a T cell and a professional antigen-presenting cell. Since the IS formation is a critical step for the initiation of an antigen-specific immune response, various live-cell imaging techniques, most of which rely on fluorescence microscopy, have been used to study the dynamics of IS. However, the inherent limitations associated with the fluorescence-based imaging, such as photo-bleaching and photo-toxicity, prevent the long-term assessment of dynamic changes of IS with high frequency. Here, we propose and experimentally validate a label-free, volumetric, and automated assessment method for IS dynamics using a combinational approach of optical diffraction tomography and deep learning-based segmentation. The proposed method enables an automatic and quantitative spatiotemporal analysis of IS kinetics of morphological and biochemical parameters associated with IS dynamics, providing a new option for immunological research.


PLoS ONE ◽  
2019 ◽  
Vol 14 (5) ◽  
pp. e0216811 ◽  
Author(s):  
Maria Antonietta Ferrara ◽  
Angela Filograna ◽  
Rajeev Ranjan ◽  
Daniela Corda ◽  
Carmen Valente ◽  
...  

2021 ◽  
Vol 22 (10) ◽  
pp. 5068
Author(s):  
Igor Buzalewicz ◽  
Agnieszka Ulatowska-Jarża ◽  
Aleksandra Kaczorowska ◽  
Marlena Gąsior-Głogowska ◽  
Halina Podbielska ◽  
...  

Quantifying changes in bacteria cells in the presence of antibacterial treatment is one of the main challenges facing contemporary medicine; it is a challenge that is relevant for tackling issues pertaining to bacterial biofilm formation that substantially decreases susceptibility to biocidal agents. Three-dimensional label-free imaging and quantitative analysis of bacteria–photosensitizer interactions, crucial for antimicrobial photodynamic therapy, is still limited due to the use of conventional imaging techniques. We present a new method for investigating the alterations in living cells and quantitatively analyzing the process of bacteria photodynamic inactivation. Digital holographic tomography (DHT) was used for in situ examination of the response of Escherichia coli and Staphylococcus aureus to the accumulation of the photosensitizers immobilized in the copolymer revealed by the changes in the 3D refractive index distributions of single cells. Obtained results were confirmed by confocal microscopy and statistical analysis. We demonstrated that DHT enables real-time characterization of the subcellular structures, the biophysical processes, and the induced local changes of the intracellular density in a label-free manner and at sub-micrometer spatial resolution.


Science ◽  
2008 ◽  
Vol 322 (5909) ◽  
pp. 1857-1861 ◽  
Author(s):  
Christian W. Freudiger ◽  
Wei Min ◽  
Brian G. Saar ◽  
Sijia Lu ◽  
Gary R. Holtom ◽  
...  

Label-free chemical contrast is highly desirable in biomedical imaging. Spontaneous Raman microscopy provides specific vibrational signatures of chemical bonds, but is often hindered by low sensitivity. Here we report a three-dimensional multiphoton vibrational imaging technique based on stimulated Raman scattering (SRS). The sensitivity of SRS imaging is significantly greater than that of spontaneous Raman microscopy, which is achieved by implementing high-frequency (megahertz) phase-sensitive detection. SRS microscopy has a major advantage over previous coherent Raman techniques in that it offers background-free and readily interpretable chemical contrast. We show a variety of biomedical applications, such as differentiating distributions of omega-3 fatty acids and saturated lipids in living cells, imaging of brain and skin tissues based on intrinsic lipid contrast, and monitoring drug delivery through the epidermis.


2019 ◽  
Author(s):  
Jake W. Willows ◽  
Magdalena Blaszkiewicz ◽  
Amy Lamore ◽  
Samuel Borer ◽  
Amanda L. Dubois ◽  
...  

AbstractAdipose tissue requires neural innervation in order to regulate important metabolic functions. Though seminal work on adipose denervation has underscored the importance of adipose-nerve interactions in both white (energy storing) and brown (energy expending) adipose tissues, much remains a mystery. This is due, in part, to the inability to effectively visualize the various nerve subtypes residing within these tissues and to gain a comprehensive quantitation of neurite density in an entire depot. With the recent surge of advanced imaging techniques such as light sheet microscopy and optical clearing procedures, adipose tissue imaging has been reinvigorated with a focus on three-dimensional analysis of tissue innervation. However, clearing techniques are time consuming, often require solvents caustic to objective lenses, alter tissue morphology, and greatly reduce fluorophore lifespan. Not only are current methods of imaging wholemount adipose tissues inconvenient, but often attempts to quantify neurite density across physiological or pathophysiological conditions have been limited to representative section sampling. We have developed a new method of adipose tissue neurite imaging and quantitation that is faster than current clearing-based methods, does not require caustic chemicals, and leaves the tissue fully intact. Maintenance of a fully intact depot allowed for tiling z-stacks and producing maximum intensity projections of the entire adipose depot, which were then used to quantify neurite density across the tissue. With this processing method we were able to characterize the nerves, nerve-subtypes, and neurovascular interactions within the inguinal subcutaneous white adipose tissue in mice using up to five fluorescent channels at high resolution. We also utilized second harmonic generation, which provides label-free imaging, to investigate collagen fiber abundance in adipose of obese mice.


Author(s):  
Jerome J. Paulin

Within the past decade it has become apparent that HVEM offers the biologist a means to explore the three-dimensional structure of cells and/or organelles. Stereo-imaging of thick sections (e.g. 0.25-10 μm) not only reveals anatomical features of cellular components, but also reduces errors of interpretation associated with overlap of structures seen in thick sections. Concomitant with stereo-imaging techniques conventional serial Sectioning methods developed with thin sections have been adopted to serial thick sections (≥ 0.25 μm). Three-dimensional reconstructions of the chondriome of several species of trypanosomatid flagellates have been made from tracings of mitochondrial profiles on cellulose acetate sheets. The sheets are flooded with acetone, gluing them together, and the model sawed from the composite and redrawn.The extensive mitochondrial reticulum can be seen in consecutive thick sections of (0.25 μm thick) Crithidia fasciculata (Figs. 1-2). Profiles of the mitochondrion are distinguishable from the anterior apex of the cell (small arrow, Fig. 1) to the posterior pole (small arrow, Fig. 2).


Author(s):  
Karen F. Han

The primary focus in our laboratory is the study of higher order chromatin structure using three dimensional electron microscope tomography. Three dimensional tomography involves the deconstruction of an object by combining multiple projection views of the object at different tilt angles, image intensities are not always accurate representations of the projected object mass density, due to the effects of electron-specimen interactions and microscope lens aberrations. Therefore, an understanding of the mechanism of image formation is important for interpreting the images. The image formation for thick biological specimens has been analyzed by using both energy filtering and Ewald sphere constructions. Surprisingly, there is a significant amount of coherent transfer for our thick specimens. The relative amount of coherent transfer is correlated with the relative proportion of elastically scattered electrons using electron energy loss spectoscopy and imaging techniques.Electron-specimen interactions include single and multiple, elastic and inelastic scattering. Multiple and inelastic scattering events give rise to nonlinear imaging effects which complicates the interpretation of collected images.


Author(s):  
Nora Rat ◽  
Iolanda Muntean ◽  
Diana Opincariu ◽  
Liliana Gozar ◽  
Rodica Togănel ◽  
...  

Development of interventional methods has revolutionized the treatment of structural cardiac diseases. Given the complexity of structural interventions and the anatomical variability of various structural defects, novel imaging techniques have been implemented in the current clinical practice for guiding the interventional procedure and for selection of the device to be used. Three– dimensional echocardiography is the most used imaging method that has improved the threedimensional assessment of cardiac structures, and it has considerably reduced the cost of complications derived from malalignment of interventional devices. Assessment of cardiac structures with the use of angiography holds the advantage of providing images in real time, but it does not allow an anatomical description. Transesophageal Echocardiography (TEE) and intracardiac ultrasonography play major roles in guiding Atrial Septal Defect (ASD) or Patent Foramen Ovale (PFO) closure and device follow-up, while TEE is the procedure of choice to assess the flow in the Left Atrial Appendage (LAA) and the embolic risk associated with a decreased flow. On the other hand, contrast CT and MRI have high specificity for providing a detailed description of structure, but cannot assess the flow through the shunt or the valvular mobility. This review aims to present the role of modern imaging techniques in pre-procedural assessment and intraprocedural guiding of structural percutaneous interventions performed to close an ASD, a PFO, an LAA or a patent ductus arteriosus.


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