Two‐photon microscopy is the tool of choice for fluorescence imaging of deep tissues with high resolution, but can be limited in three‐dimensional acquisition speed and penetration depth. In this work, these issues are addressed by using an acoustic optofluidic lens capable of ultrafast beam shaping on a pixel basis. Driving the lens with different phase profiles enables high‐speed volumetric imaging, or enhanced signal‐to‐background for deeper penetration. Further details can be found in the article by Simonluca Piazza et al. ( e201700050 )
Based on multicolor quantum dots (QDs) labeling, the joint tagging assisted super‐resolution radial fluctuation (JT‐SRRF) nanoscopy achieves high‐fidelity super‐resolution imaging of subcellular microtubules and fast live‐cell parallel tracking of cholera toxin subunit B (CTB) induced lipid clusters spatially distributed below the optical diffraction limit. This method paves the way for fast high‐density parallel tracking, which is especially beneficial for the investigation of the intensive dynamics in live‐cell applications. Further details can be found in the article by Zhiping Zeng, Jing Ma, Peng Xi, and Canhua Xu ( e201800020 ).
We disclose a theranostic device for performing image‐guided riboflavin/UV‐A corneal cross‐linking. The device determines treatment efficacy by real time monitoring of riboflavin concentration in the corneal stroma. The study shows efficacy of the device in eye bank human donor tissues. Further details can be found in the article by Giuseppe Lombardo et al. ( e201800028 )
Tissue autofluorescence provides fluorescence lifetime contrast between acellular tissue and that containing newly seeded cells. Fiber‐based fluorescence lifetime imaging (FLIm) can be used for tracking recellularization of engineered vascular grafts and potential matrix remodeling at large scale, without compromising sample integrity. FLIm cellular contrast was verified in a subset of samples seeded with eGFP‐labelled cells. Results suggests fiberbased FLIm is a suitable tool for monitoring recellularization of engineered tissue nondestructively. Further details can be found in the article by Alba Alfonso‐Garcia, Jeny Shklover, Benjamin E. Sherlock, et al. ( e201700391 ).
Full‐field functional optical hemocytometer (FFOH), based on the absorption intensity fluctuation modulation (AIFM) effect, is in vivo label‐free image method for capillaries of near‐transparent live biological specimens. FFOH can provide a flow video, flow velocity measurement and RBC count, simultaneously. The zebrafish experimental result shows the potential to study the physiological mechanisms of the blood circulation systems. Further details can be found in the article by Fuli Zhang et al. ( e201700039 )
We present a hybrid dual‐wavelength optoacoustic and ultrasound bio‐microscope capable of rapid transcranial visualization of morphology and oxygenation status of large‐scale cerebral vascular networks. Imaging of entire cortical vasculature in mice is achieved with single capillary resolution and complemented by simultaneously acquired pulse‐echo ultrasound microscopy scans of the mouse skull. The new approach holds potential to facilitate studies into neurological and vascular abnormalities of the brain. Further details can be found in the article by Johannes Rebling, Héctor Estrada, Sven Gottschalk, et al. ( e201800057 ).
This study provides a simple method to detect human distal radius bone density based on near infrared (NIR) imaging. The information of bone mineral density can be measured by transluminational optical bone densitometric system. Compared to dual‐energy x‐ray absorptiometry (DXA) results in clinical trial, NIR images show a strong correlation to DXA. Further details can be found in the article by Chun Chung, Yu‐Pin Chen, Tsai‐Hsueh Leu, and Chia‐Wei Sun ( e201700342 ).
One of the main challenges for laser‐scanning microscopy of biological tissues with refractive heterogeneities is the degradation in spatial resolution that occurs as a result of beam steering and distortion. This challenge is particularly significant for dual‐axis confocal (DAC) microscopy, which achieves improved spatial‐filtering and optical‐sectioning performance over traditional confocal microscopy through off‐axis illumination and collection of light with low‐numerical aperture (NA) beams that must intersect precisely at their foci within tissues. DAC microscope image quality is sensitive to positional changes and distortions of these illumination‐ and collection‐beam foci. Previous studies have shown that Bessel beams display improved positional stability and beam quality than Gaussian beams when propagating through tissues with refractive heterogeneities, which suggests that Bessel‐beam illumination may enhance DAC microscopy of such tissues. Here, we utilize both Gaussian and Bessel illumination in a point‐scanned DAC microscope and quantify the resultant degradation in resolution when imaging within heterogeneous optical phantoms and fresh tissues. Results indicate that DAC microscopy with Bessel illumination exhibits reduced resolution degradation from microscopic tissue heterogeneities compared to DAC microscopy with conventional Gaussian illumination.
The biomaterial distribution and its molecular mechanism of embryonic development in Japanese medaka fish were visualized without staining using high‐speed near‐infrared imaging. It was a remarkable achievement to visualize the structures of eyes, lipid bilayer membranes, micelles, and water structural variations at the interface of different substances. Furthermore, insights on lipid metabolism and membrane functions were obtained from the biased distribution of lipoproteins and the presence of unsaturated fatty acids in the egg membrane. Further details can be found in the article by Mika Ishigaki ( e201700115 )
The concentration difference of major elements in melanocytic skin with respect to pigmentation level is analysed by laser‐induced breakdown spectroscopy (LIBS) to investigate the applicability of LIBS as an in situ feedback tool for selective and complete laser removal of melanocytic skin tissue like nevus. The skin of black silkie chicken which had a characteristic darkly pigmented perifollicular skin surrounded by lightly pigmented extrafollicular skin was used as the sample. The results showed higher LIBS signal intensities of Ca2+ and Mg2+ but lower intensities of Na+, Cl– and K+ in the perifollicular skin than in the extrafollicular skin, which demonstrated the feasibility to use LIBS as a reliable method to distinguish skin tissues with difference in pigmentation level.
Plasma emission of biochemical elements generated with a laser irradiation on melanocytic skin lesion. 相似文献
Gold nanoparticles serve as imaging contrast agents useful for two‐photon nonlinear microscopy of biological cells and tissues. In this study, 100‐nm‐sized gold particles with a multitude of nanopores embedded inside have been physically synthesized and investigated for the plasmonic enhancement in two‐photon luminescence. Exhibiting remarkable potential for two‐photon imaging, the porous gold nanoparticles boost near‐infrared light absorption substantially and allow emission signals 20 times brighter than gold nanorods being currently used as typical imaging agents. Further details can be found in the article by Joo H. Park et al. ( e201700174 )
This paper presents a novel compact fiberoptic based singlet oxygen near‐infrared luminescence probe coupled to an InGaAs/InP single photon avalanche diode (SPAD) detector. Patterned time gating of the single‐photon detector is used to limit unwanted dark counts and eliminate the strong photosensitizer luminescence background. Singlet oxygen luminescence detection at 1270 nm is confirmed through spectral filtering and lifetime fitting for Rose Bengal in water, and Photofrin in methanol as model photosensitizers. The overall performance, measured by the signal‐to‐noise ratio, improves by a factor of 50 over a previous system that used a fiberoptic‐coupled superconducting nanowire single‐photon detector. The effect of adding light scattering to the photosensitizer is also examined as a first step towards applications in tissue in vivo.
Quantitative laser‐induced breakdown spectroscopy (LIBS) is successfully used for in‐vitro analysis of early stage calcification in aortic valvular interstitial cells (VICs). LIBS results indicate 5‐fold improvement in the detection limit of calcium deposition in VICs over cell histology techniques involving staining and colorimetric calcium assays. These results can establish LIBS at the forefront of early detection of calcification in VICs for pathological studies on Calcific Aortic Valve Disease (CAVD). Further details can be found in the article by Seyyed Ali Davari et al. ( e201600288 ).
Label‐free optical nano‐imaging of dendritic structures and intracellular granules in biological cells is demonstrated using a bright and homogeneous nanometric light source. The optical nanometric light source is excited using a focused electron beam. A zinc oxide (ZnO) luminescent thin film was fabricated by atomic layer deposition (ALD) to produce the nanoscale light source. The ZnO film formed by ALD emitted the bright, homogeneous light, unlike that deposited by another method. The dendritic structures of label‐free macrophage receptor with collagenous structure‐expressing CHO cells were clearly visualized below the diffraction limit. The inner fiber structure was observed with 120 nm spatial resolution. Because the bright homogeneous emission from the ZnO film suppresses the background noise, the signal‐to‐noise ratio (SNR) for the imaging results was greater than 10. The ALD method helps achieve an electron beam excitation assisted microscope with high spatial resolution and high SNR.
Germanium vs Silicon: All‐dielectric nanoparticles provides the heat resistance for proteins under light‐induced heating. Further details can be found in the article by Andrei A. Krasilin et al. ( e201700322 )
Cell death plays a critical role in health and homeostasis as well as in the pathogenesis and treatment of a broad spectrum of diseases and can be broadly divided into two main categories: apoptosis, or programmed cell death, and necrosis, or acute cell death. While these processes have been characterized extensively in vitro, label‐free detection of apoptosis and necrosis at the cellular level in vivo has yet to be shown. In this study, for the first time, fluorescence lifetime imaging microscopy (FLIM) of intracellular reduced nicotinamide adenine dinucleotide (NADH) was utilized to assess the metabolic response of in vivo mouse epidermal keratinocytes following induction of apoptosis and necrosis. Results show significantly elevated levels of both the mean lifetime of NADH and the intracellular ratio of protein bound‐to‐free NADH in the apoptotic compared to the necrotic tissue. In addition, the longitudinal profiles of these two cell death processes show remarkable differences. By identifying and extracting these temporal metabolic signatures, apoptosis in single cells can be studied in native tissue environments within the living organism.
Protein secondary structural alteration in the serum sample as induced by colitis has been demonstrated via the spectral fitting. Using DSS mouse models of acute colitis and IL10‐/‐ for chronic colitis, a significant difference in the integral ratio of Gaussian energy bands representing α‐helix and β‐pleated sheet structures were obtained. Further details can be found in the article by Jitto Titus et al. ( e201700057 ).
In this study, we introduce two key improvements that overcome limitations of existing polygon scanning microscopes while maintaining high spatial and temporal imaging resolution over large field of view (FOV). First, we proposed a simple and straightforward means to control the scanning angle of the polygon mirror to carry out photomanipulation without resorting to high speed optical modulators. Second, we devised a flexible data sampling method directly leading to higher image contrast by over 2‐fold and digital images with 100 megapixels (10 240 × 10 240) per frame at 0.25 Hz. This generates sub‐diffraction limited pixels (60 nm per pixels over the FOV of 512 μm) which increases the degrees of freedom to extract signals computationally. The unique combined optical and digital control recorded fine fluorescence recovery after localized photobleaching (r ~10 μm) within fluorescent giant unilamellar vesicles and micro‐vascular dynamics after laser‐induced injury during thrombus formation in vivo. These new improvements expand the quantitative biological‐imaging capacity of any polygon scanning microscope system.
Semiconductor nanocomposites provide advantages beyond the capability of typical fluorescent materials for cancer detection. In this work, nanowire‐based probes with dual color channels are employed to demonstrate the capacity of cancer cell detection. Purple emitting ZnO/antibody probes are applied to detect cancer cells and meanwhile TiO2/antibody probes with green light emission are applied to identify normal fibroblast cells. A series of quantitative analyses are conducted to verify the correlation between the concentrations of ZnO and TiO2 probes, cell numbers, and peak intensities of the PL spectra. The results provide a quantitative reference for developing nanowire‐based cancel cell probes.
Peripheral arterial disease (PAD) can further cause lower limb ischemia. Quantitative evaluation of the vascular perfusion in the ischemic limb contributes to diagnosis of PAD and preclinical development of new drug. In vivo time‐series indocyanine green (ICG) fluorescence imaging can noninvasively monitor blood flow and has a deep tissue penetration. The perfusion rate estimated from the time‐series ICG images is not enough for the evaluation of hindlimb ischemia. The information relevant to the vascular density is also important, because angiogenesis is an essential mechanism for post‐ischemic recovery. In this paper, a multiparametric evaluation method is proposed for simultaneous estimation of multiple vascular perfusion parameters, including not only the perfusion rate but also the vascular perfusion density and the time‐varying ICG concentration in veins. The target method is based on a mathematical model of ICG pharmacokinetics in the mouse hindlimb. The regression analysis performed on the time‐series ICG images obtained from a dynamic reflectance fluorescence imaging system. The results demonstrate that the estimated multiple parameters are effective to quantitatively evaluate the vascular perfusion and distinguish hypo‐perfused tissues from well‐perfused tissues in the mouse hindlimb. The proposed multiparametric evaluation method could be useful for PAD diagnosis.
The estimated perfusion rate and vascular perfusion density maps (left) and the time‐varying ICG concentration in veins of the ankle region (right) of the normal and ischemic hindlimbs. 相似文献
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