Label-free characterization of ultra violet-radiation-induced changes in skin fibroblasts with Raman spectroscopy and quantitative phase microscopy

Minimizing morbidities and mortalities associated with skin cancers requires sustained research with the goal of obtaining fresh insights into disease onset and progression under specific stimuli, particularly the influence of ultraviolet rays. In the present study, label-free profiling of skin fibroblasts exposed to time-bound ultra-violet radiation has been performed using quantitative phase imaging and Raman spectroscopy. Statistically significant differences in quantifiable biophysical parameters, such as matter density and cell dry mass, were observed with phase imaging. Accurate estimation of changes in the biochemical constituents, notably nucleic acids and proteins, was demonstrated through a combination of Raman spectroscopy and multivariate analysis of spectral patterns. Overall, the findings of this study demonstrate the promise of these non-perturbative optical modalities in accurately identifying cellular phenotypes and responses to external stimuli by combining molecular and biophysical information.National Institutes of Health (U.S.) (Grant P41-EB015871-30)National Institutes of Health (U.S.) (Grant U01-NS090438-03)National Institutes of Health (U.S.) (Grant R21-NS091982-01)National Institutes of Health (U.S.) (Grant R01-HL121386-03

Reflection phase microscopy using spatio-temporal coherence of light

Many disease states are associated with cellular biomechanical changes as markers. Label-free phase microscopes are used to quantify thermally driven interface fluctuations, which allow the deduction of important cellular rheological properties. Here, the spatio-temporal coherence of light was used to implement a high-speed reflection phase microscope with superior depth selectivity and higher phase sensitivity. Nanometric scale motion of cytoplasmic structures can be visualized with fine details and three-dimensional resolution. Specifically, the spontaneous fluctuation occurring on the nuclear membrane of a living cell was observed at video rate. By converting the reflection phase into displacement, the sensitivity in quantifying nuclear membrane fluctuation was found to be about one nanometer. A reflection phase microscope can potentially elucidate biomechanical mechanisms of pathological and physiological processes.Korea Health Industry Development Institute. Korea Health Technology R&D Project (H114C3477)National Research Foundation of Korea (1R01HL121386-01A1)National Research Foundation of Korea (4R44EB012415)National Research Foundation of Korea (5R01NS051320)National Research Foundation of Korea (9P41EB015871-26A1)National Science Foundation (U.S.) (CBET-0939511)Hamamatsu CorporationSingapore-MIT Alliance. BioSystems and Micromechanics (BioSyM) Inter-Disciplinary Research GroupKorea University (Future Research Grant

SNP@Domain: a web resource of single nucleotide polymorphisms (SNPs) within protein domain structures and sequences.

The single nucleotide polymorphisms (SNPs) in conserved protein regions have been thought to be strong candidates that alter protein functions. Thus, we have developed SNP@Domain, a web resource, to identify SNPs within human protein domains. We annotated SNPs from dbSNP with protein structure-based as well as sequence-based domains: (i) structure-based using SCOP and (ii) sequence-based using Pfam to avoid conflicts from two domain assignment methodologies. Users can investigate SNPs within protein domains with 2D and 3D maps. We expect this visual annotation of SNPs within protein domains will help scientists select and interpret SNPs associated with diseases. A web interface for the SNP@Domain is freely available at http://snpnavigator.net/ and from http://bioportal.net/.This project was supported by the Korean Ministry of Science and Technology (MOST) under grant number M10508040002-05N0804-00210 and M10407010001-05N0701-00100. Y.B.C. is supported by Biogreen21 program (20050401-034-791-006-03-00 and 20050301-034-481-006-02-00). Funding to pay the Open Access publication charges for this article was provided by M10407010001-05N0701-00100 grant of MOST

Optical imaging featuring both long working distance and high spatial resolution by correcting the aberration of a large aperture lens

High-resolution optical imaging within thick objects has been a challenging task due to the short working distance of conventional high numerical aperture (NA) objective lenses. Lenses with a large physical diameter and thus a large aperture, such as microscope condenser lenses, can feature both a large NA and a long working distance. However, such lenses suffer from strong aberrations. To overcome this problem, we present a method to correct the aberrations of a transmission-mode imaging system that is composed of two condensers. The proposed method separately identifies and corrects aberrations of illumination and collection lenses of up to 1.2 NA by iteratively optimizing the total intensity of the synthetic aperture images in the forward and phase-conjugation processes. At a source wavelength of 785 nm, we demonstrated a spatial resolution of 372 nm at extremely long working distances of up to 1.6 mm, an order of magnitude improvement in comparison to conventional objective lenses. Our method of converting microscope condensers to high-quality objectives may facilitate increases in the imaging depths of super-resolution and expansion microscopes. © The Author(s) 201

Depth-selective imaging of macroscopic objects hidden behind a scattering layer using low-coherence and wide-field interferometry

Imaging systems targeting macroscopic objects tend to have poor depth selectivity. In this Letter, we present a 3D imaging system featuring a depth resolution of 200 μm, depth scanning range of more than 1 m, and view field larger than 70×70 mm2. For depth selectivity, we set up an off-axis digital holographic imaging system using a light source with a coherence length of 400 μm. A prism pair was installed in the reference beam path for long-range depth scanning. We performed imaging macroscopic targets with multiple different layers and also demonstrated imaging targets hidden behind a scattering layer. © 2016 Elsevier B.V. All rights reserved1221sciescopu

In vivo visualization of butterfly scale cell morphogenesis in Vanessa cardui

During metamorphosis, the wings of a butterfly sprout hundreds of thousands of scales with intricate microstructures and nano-structures that determine the wings’ optical appearance, wetting characteristics, thermodynamic properties, and aerodynamic behavior. Although the functional characteristics of scales are well known and prove desirable in various applications, the dynamic processes and temporal coordination required to sculpt the scales’ many structural features remain poorly understood. Current knowledge of scale growth is primarily gained from ex vivo studies of fixed scale cells at discrete time points; to fully understand scale formation, it is critical to characterize the time-dependent morphological changes throughout their development. Here, we report the continuous, in vivo, label-free imaging of growing scale cells of Vanessa cardui using speckle-correlation reflection phase microscopy. By capturing time-resolved volumetric tissue data together with nanoscale surface height information, we establish a morphological timeline of wing scale formation and gain quantitative insights into the underlying processes involved in scale cell patterning and growth. We identify early differences in the patterning of cover and ground scales on the young wing and quantify geometrical parameters of growing scale features, which suggest that surface growth is critical to structure formation. Our quantitative, time-resolved in vivo imaging of butterfly scale development provides the foundation for decoding the processes and biomechanical principles involved in the formation of functional structures in biological materials.NSF (DMREF-1922321)NSF CBET program (Grant 1804241)NIH Grant (P41EB015871)NIH Grant (R21GM140613)NIH Grant (R01HL158102)NIH Grant (R01DA045549)Grant U01CA202177DOE (DE-FOA-0002359

Optical transfer function of time-gated coherent imaging in the presence of a scattering medium

Optical imaging of objects embedded within scattering media such as biological tissues suffers from the loss of resolving power. In our previous work, we proposed an approach called collective accumulation of single scattering (CASS) microscopy that attenuates this detrimental effect of multiple light scattering by combining the time-gated detection and spatial input-output correlation. In the present work, we perform a rigorous theoretical analysis on the effect of multiple light scattering to the optical transfer function of CASS microscopy. In particular, the spatial frequency-dependent signal to noise ratio (SNR) is derived depending on the intensity ratio of the single- and multiple-scattered waves. This allows us to determine the depth-dependent resolving power. We conducted experiments using a Siemens star-like target having various spatial frequency components and supported the theoretical derived SNR spectra. Our study provides a theoretical framework for understanding the effect of multiple light scattering in high-resolution and deep-tissue optical imaging (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement11Nsciescopu