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 )
Congenital cardiovascular defects are the leading cause of birth defect related death. It has been hypothesized that fluid mechanical forces of embryonic blood flow affect cardiovascular development and play a role in congenital malformations. Studies in small animal embryos can improve our understanding of congenital malformations and can lead to better treatment. We present a feasibility study in which high‐resolution optical coherence tomography (OCT) and computational fluid dynamics (CFD) are combined to provide quantitative analysis of the embryonic flow mechanics and the associated anatomy in a small animal model.
Optical coherence tomography through an implanted dorsal imaging window allows for prolonged in vivo structural and functional assessment of the mouse oviduct (Fallopian tube), including threedimensional structural imaging, quantitative measurements of the smooth muscle contraction, and mapping of cilia beat frequency. This method brings new opportunities for live studies and longitudinal analyses of mouse reproductive events in the native context. Further details can be found in the article by Shang Wang et al. ( e201700316 ).
The potential use of Gold Nanoparticles (GNPs) as contrast agents for clinical intracoronary frequency domain Optical Coherence Tomography (OCT) is here explored. The OCT contrast enhancement caused by GNPs of different sizes and morphologies has been systematically investigated and correlated with their optical properties. Among the different GNPs commercially available with plasmon resonances close to the operating wavelength of intracoronary OCT (1.3 µm), Gold Nanoshells (GNSs) have provided the best OCT contrast due to their largest scattering cross section at this wavelength. Clinical intracoronary OCT catheters are here demonstrated to be capable of three dimensional visualization and real‐time tracking of individual GNSs. Results here included open an avenue to novel application of intravascular clinical OCT in combination with GNPs, such as real time evaluation of intravascular obstructions or pressure gradients.
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 )
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.
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 ).
In vivo multiphoton imaging was used to map changes in hepatobiliary metabolism in liver fibrosis (left column) and hepatocellular carcinoma (right column). The top row shows the maps of kinetic rate constant of the uptake and esterase processing while the bottom row shows that of bile canalicular excretion of xenobiotics. Further details can be found in the article by Chih‐Ju Lin, Sheng‐Lin Lee, Wei‐Hsiang Wang, et al. ( e201700338 ).
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 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 )
Multiphoton microscopy (MPM) has become increasingly popular and widely used in both basic and clinical liver studies over the past few years. This technology provides insights into deep live tissues with less photobleaching and phototoxicity, which helps us to better understand the cellular morphology, microenvironment, immune responses and spatiotemporal dynamics of drugs and therapeutic cells in the healthy and diseased liver. This review summarizes the principles, opportunities, applications and limitations of MPM in hepatology. A key emphasis is on the use of fluorescence lifetime imaging (FLIM) to add additional quantification and specificity to the detection of endogenous fluorescent species in the liver as well as exogenous molecules and nanoparticles that are applied to the liver in vivo. We anticipate that in the near future MPM‐FLIM will advance our understanding of the cellular and molecular mechanisms of liver diseases, and will be evaluated from bench to bedside, leading to real‐time histology of human liver diseases.
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 ).
A new type of high‐throughput imaging flow cytometer (>20 000 cells s‐1) based upon an all‐optical ultrafast laser‐scanning imaging technique, called free‐space angular‐chirp‐enhanced delay (FACED) is reported. FACED imaging flow cytometers enables high‐throughput visualization of functional morphology of individual cells with subcellular resolution. It critically empowers largescale and deep characterization of single cells and their heterogeneity with high statistical power— an ability to become increasingly critical in single‐cell analysis adopted in a wide range of biomedical and life‐science applications. Further details can be found in the article by Wenwei Yan et al. ( e201700178 )
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 )
An integrated 4‐modality endoscopy system combining white light imaging, autofluorescence imaging, diffuse reflectance spectroscopy and Raman spectroscopy technologies was developed for in vivo endoscopic nasopharyngeal cancer detection. Both high diagnostic sensitivity (98.6%) and high specificity (95.1%) for differentiating cancer from normal tissue sites were achieved using this system combined with multivariate diagnostic algorithm, demonstrating great potential for improving real‐time, in vivo diagnosis of cancer at endoscopy. Further details can be found in the article by Duo Lin et al. ( e201700251 )
The internalization kinetics and intracellular spatial distribution of functionalized diatomite nanoparticles in human lung epidermoid carcinoma cell line have been investigated by confocal fluorescence and Raman microscopy. In this context, Raman imaging due to its non‐destructive, chemically selective and label‐free working principle provides evidence that the nanovectors are internalized and co‐localize with lipid environments, suggesting an endocytic internalisation route. Nanoparticle uptakes and intracellular persistence are observed up to 72 hours, without damage to cell viability or morphology. Further details can be found in the article by Stefano Managò et al. ( e201700207 )
For the first time, spatially resolved quantitative metrics of light scattering recovered with sub‐diffusive spatial frequency domain imaging (sd‐SFDI) are shown to be sensitive to changes in intratumoral morphology and viability by direct comparison to histopathological analysis. Two freshly excised subcutaneous murine tumor cross‐sections were measured with sd‐SFDI, and recovered optical scatter parameter maps were co‐registered to whole mount histology. Unique clustering of the optical scatter parameters vs. γ (i.e. diffuse scattering vs. relative backscattering) evaluated at a single wavelength showed complete separation between regions of viable tumor, aggresive tumor with stromal growth, varying levels of necrotic tumor, and also peritumor muscle. The results suggest that with further technical development, sd‐SFDI may represent a non‐destructive screening tool for analysis of excised tissue or a non‐invasive approach to investigate suspicious lesions without the need for exogenous labels or spectrally resolved imaging.
Raman images were used to study the effect of the contaminant chlorpyriphos‐oxon on zebrafish eye samples. Multivariate Curve Resolution‐Alternating Least Squares (MCR‐ALS) was used to obtain the distribution maps and spectral signatures of biological components present in the images analyzed. The use of MCRALS spectral signatures as starting information for Partial Least Squares‐Discriminant Analysis allowed statistical assessment of the effect of the contaminant at a specific tissue level. Further details can be found in the article by Víctor Olmos et al. ( e201700089 ).
The cover shows the image enhancement of biological tissues provided by the Indices of Polarimetric Purity (IPPs). By measuring the Mueller matrix of a biological sample, using an imaging polarimeter, the IPPs are calculated. They are polarimetric indicators providing further synthetization of depolarizing samples and leading to enhanced image contrast for some biological structures. Once the IPPs are calculated, a pseudo‐colouring technique is applied for higher visualization. Further details can be found in the article by Albert Van Eeckhout et al. ( e201700189 )
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 ).
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