scholarly journals Label‐free bioanalysis of Leishmania infantum using refractive index tomography with partially coherent illumination

2019 ◽  
Vol 12 (9) ◽  
Author(s):  
Juan M. Soto ◽  
Alicia Mas ◽  
José A. Rodrigo ◽  
Tatiana Alieva ◽  
Gustavo Domínguez‐Bernal
Keyword(s):  
Refractive Index ◽  
Leishmania Infantum ◽  
Label Free ◽  
Partially Coherent ◽  
Coherent Illumination

scholarly journals Optimization analysis of partially coherent illumination for refractive index tomographic microscopy

2021 ◽  
Vol 143 ◽  
pp. 106624
Author(s):  
Jiaji Li ◽  
Ning Zhou ◽  
Zhidong Bai ◽  
Shun Zhou ◽  
Qian Chen ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optimization Analysis ◽  
Partially Coherent ◽  
Coherent Illumination

Partially coherent illumination engineering for enhanced refractive index tomography

2018 ◽  
Vol 43 (19) ◽  
pp. 4699 ◽  
Author(s):  
Juan M. Soto ◽  
José A. Rodrigo ◽  
Tatiana Alieva
Keyword(s):  
Refractive Index ◽  
Partially Coherent ◽  
Illumination Engineering ◽  
Coherent Illumination

Optimizing design of partially coherent illumination for refractive index tomographic microscopy

2021 ◽  
Author(s):  
Jiaji Li ◽  
Ning Zhou ◽  
Zhidong Bai ◽  
Shun Zhou ◽  
Qian Chen ◽  
...  
Keyword(s):  
Refractive Index ◽  
Partially Coherent ◽  
Optimizing Design ◽  
Coherent Illumination

scholarly journals Partially Coherent Illumination Based Point-Diffraction Digital Holographic Microscopy Study Dynamics of Live Cells

2021 ◽  
Vol 9 ◽  
Author(s):  
Kequn Zhuo ◽  
Yu Wang ◽  
Yang Wang ◽  
Kai Wen ◽  
Min Liu ◽  
...  
Keyword(s):  
Speckle Noise ◽  
Microscopy Study ◽  
Digital Holographic Microscopy ◽  
Live Cells ◽  
Dynamic Processes ◽  
Label Free ◽  
Fringe Contrast ◽  
Partially Coherent ◽  
Holographic Microscopy ◽  
Coherent Illumination

This paper presents a partially coherent point-diffraction digital holographic microscopy (PC-pDHM) prototype and demonstrates its application in label-free imaging of the dynamic processes of live cells. In PC-pDHM, the light scattered by a rotating diffuser is coupled into a multi-mode fiber, and the output light is used as the partially coherent illumination (PCI), which reduces the speckle noise significantly in PC-pDHM. A polarization-grating is used to remold the object and the reference waves, and the fringe contrast of the generated hologram can be adjusted by changing the polarization of the illumination wave. Using the PC-pDHM prototype, transparent samples and notably the dynamic processes of live cells were imaged with high contrast and in a label-free manner, discovering the pathological mechanisms of biology in the cellular and sub-cellular levels.

scholarly journals Critical angle reflection imaging for quantification of molecular interactions on glass surface

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Guangzhong Ma ◽  
Runli Liang ◽  
Zijian Wan ◽  
Shaopeng Wang
Keyword(s):  
Refractive Index ◽  
Small Molecule ◽  
Molecular Interactions ◽  
Glass Surface ◽  
Critical Angle ◽  
Dynamic Range ◽  
Refractive Index Change ◽  
Label Free ◽  
Index Change ◽  
Sensing Range

AbstractQuantification of molecular interactions on a surface is typically achieved via label-free techniques such as surface plasmon resonance (SPR). The sensitivity of SPR originates from the characteristic that the SPR angle is sensitive to the surface refractive index change. Analogously, in another interfacial optical phenomenon, total internal reflection, the critical angle is also refractive index dependent. Therefore, surface refractive index change can also be quantified by measuring the reflectivity near the critical angle. Based on this concept, we develop a method called critical angle reflection (CAR) imaging to quantify molecular interactions on glass surface. CAR imaging can be performed on SPR imaging setups. Through a side-by-side comparison, we show that CAR is capable of most molecular interaction measurements that SPR performs, including proteins, nucleic acids and cell-based detections. In addition, we show that CAR can detect small molecule bindings and intracellular signals beyond SPR sensing range. CAR exhibits several distinct characteristics, including tunable sensitivity and dynamic range, deeper vertical sensing range, fluorescence compatibility, broader wavelength and polarization of light selection, and glass surface chemistry. We anticipate CAR can expand SPR′s capability in small molecule detection, whole cell-based detection, simultaneous fluorescence imaging, and broader conjugation chemistry.

scholarly journals Perfect Absorption and Refractive-Index Sensing by Metasurfaces Composed of Cross-Shaped Hole Arrays in Metal Substrate

Nanomaterials ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 63
Author(s):  
Zhendong Yan ◽  
Chaojun Tang ◽  
Guohua Wu ◽  
Yumei Tang ◽  
Ping Gu ◽  
...  
Keyword(s):  
Refractive Index ◽  
High Performance ◽  
Narrow Band ◽  
Label Free ◽  
Hybrid Mode ◽  
Perfect Absorption ◽  
Refractive Index Sensing ◽  
Sensing Applications ◽  
Silver Substrate ◽  
Hole Arrays

Achieving perfect electromagnetic wave absorption with a sub-nanometer bandwidth is challenging, which, however, is desired for high-performance refractive-index sensing. In this work, we theoretically study metasurfaces for sensing applications based on an ultra-narrow band perfect absorption in the infrared region, whose full width at half maximum (FWHM) is only 1.74 nm. The studied metasurfaces are composed of a periodic array of cross-shaped holes in a silver substrate. The ultra-narrow band perfect absorption is related to a hybrid mode, whose physical mechanism is revealed by using a coupling model of two oscillators. The hybrid mode results from the strong coupling between the magnetic resonances in individual cross-shaped holes and the surface plasmon polaritons on the top surface of the silver substrate. Two conventional parameters, sensitivity (S) and figure of merit (FOM), are used to estimate the sensing performance, which are 1317 nm/RIU and 756, respectively. Such high-performance parameters suggest great potential for the application of label-free biosensing.

Holography with partially coherent illumination

1969 ◽  
Vol 28 (9) ◽  
pp. 623-624 ◽  
Author(s):  
W. Mirandé ◽  
I. Weingärtner
Keyword(s):  
Partially Coherent ◽  
Coherent Illumination

scholarly journals Label-Free Digital Holo-tomographic Microscopy Reveals Virus-Induced Cytopathic Effects in Live Cells

mSphere ◽  
2018 ◽  
Vol 3 (6) ◽  
Author(s):  
Artur Yakimovich ◽  
Robert Witte ◽  
Vardan Andriasyan ◽  
Fanny Georgi ◽  
Urs F. Greber
Keyword(s):  
Refractive Index ◽  
Vaccinia Virus ◽  
Virus Type ◽  
Live Cells ◽  
Refractive Index Gradient ◽  
Label Free ◽  
Virus Infections ◽  
Cytopathic Effects ◽  
Infected Cells ◽  
Index Gradient

ABSTRACTCytopathic effects (CPEs) are a hallmark of infections. CPEs are difficult to observe due to phototoxicity from classical light microscopy. We report distinct patterns of virus infections in live cells using digital holo-tomographic microscopy (DHTM). DHTM is label-free and records the phase shift of low-energy light passing through the specimen on a transparent surface with minimal perturbation. DHTM measures the refractive index (RI) and computes the refractive index gradient (RIG), unveiling optical heterogeneity in cells. We find that vaccinia virus (VACV), herpes simplex virus (HSV), and rhinovirus (RV) infections progressively and distinctly increased RIG. VACV infection, but not HSV and RV infections, induced oscillations of cell volume, while all three viruses altered cytoplasmic membrane dynamics and induced apoptotic features akin to those caused by the chemical compound staurosporine. In sum, we introduce DHTM for quantitative label-free microscopy in infection research and uncover virus type-specific changes and CPE in living cells with minimal interference.IMPORTANCEThis study introduces label-free digital holo-tomographic microscopy (DHTM) and refractive index gradient (RIG) measurements of live, virus-infected cells. We use DHTM to describe virus type-specific cytopathic effects, including cyclic volume changes of vaccinia virus infections, and cytoplasmic condensations in herpesvirus and rhinovirus infections, distinct from apoptotic cells. This work shows for the first time that DHTM is suitable to observe virus-infected cells and distinguishes virus type-specific signatures under noninvasive conditions. It provides a basis for future studies, where correlative fluorescence microscopy of cell and virus structures annotate distinct RIG values derived from DHTM.

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