Quantitative imaging of the complexity in liquid bubbles' evolution reveals the dynamics of film retraction

The dynamics and stability of thin liquid films have fascinated scientists over many decades. Thin film flows are central to numerous areas of engineering, geophysics, and biophysics and occur over a wide range of length, velocity, and liquid properties scales. In spite of many significant developments in this area, we still lack appropriate quantitative experimental tools with the spatial and temporal resolution necessary for a comprehensive study of film evolution. We propose tackling this problem with a holographic technique that combines quantitative phase imaging with a custom setup designed to form and manipulate bubbles. The results, gathered on a model aqueous polymeric solution, provide an unparalleled insight into bubble dynamics through the combination of full-field thickness estimation, three-dimensional imaging, and fast acquisition time. The unprecedented level of detail offered by the proposed methodology will promote a deeper understanding of the underlying physics of thin film dynamics

Quantitative imaging of the complexity in liquid bubbles’ evolution reveals the dynamics of film retraction

Thin liquid films: Seeing bubbles in a better light A procedure for imaging the complex fluid dynamics in bubbles could greatly assist efforts to understand and exploit thin liquid films in applications ranging through medicine, industrial chemistry and engineering. Thin liquid films are ubiquitous in nature, found in such varied systems as soap bubbles, biological membranes, detergents, oils, insulation, foods and geological magma. Researchers in Italy led by Biagio Mandracchia at the Institute of Applied Science and Intelligent Systems in Naples, devised a novel holographic phase imaging technique to watch bubbles as they form, develop, burst and retract. The researchers built customized apparatus to create and manipulate the bubbles. The unprecedented level of detail being revealed offers deeper understanding of the physics underlying thin film behavior. Insights into the complex fluid dynamics within bubbles could advance thin film technology for many applications

Optimal sparsity allows reliable system-aware restoration of fluorescence microscopy images

Incluye: artículo, material suplementario, videos y software.Fluorescence microscopy is one of the most indispensable and informative driving forces for biological research, but the extent of observable biological phenomena is essentially determined by the content and quality of the acquired images. To address the different noise sources that can degrade these images, we introduce an algorithm for multiscale image restoration through optimally sparse representation (MIRO). MIRO is a deterministic framework that models the acquisition process and uses pixelwise noise correction to improve image quality. Our study demonstrates that this approach yields a remarkable restoration of the fluorescence signal for a wide range of microscopy systems, regardless of the detector used (e.g., electron-multiplying charge-coupled device, scientific complementary metal-oxide semiconductor, or photomultiplier tube). MIRO improves current imaging capabilities, enabling fast, low-light optical microscopy, accurate image analysis, and robust machine intelligence when integrated with deep neural networks. This expands the range of biological knowledge that can be obtained from fluorescence microscopy.We acknowledge the support of the National Institutes of Health grants R35GM124846 (to S.J.) and R01AA028527 (to C.X.), the National Science Foundation grants BIO2145235 and EFMA1830941 (to S.J.), and Marvin H. and Nita S. Floyd Research Fund (to S.J.). This research project was supported, in part, by the Emory University Integrated Cellular Imaging Microscopy Core and by PHS Grant UL1TR000454 from the Clinical and Translational Science Award Program, National Institutes of Health, and National Center for Advancing Translational Sciences.S

Metabolic and mitochondria alterations induced by SARS-CoV-2 accessory proteins ORF3a, ORF9b, ORF9c and ORF10

Antiviral signaling, immune response and cell metabolism in human body are dysregulated by SARS-CoV-2, the causative agent of the COVID-19. Here, we show that SARS-CoV-2 accessory proteins ORF3a, ORF9b, ORF9c and ORF10 induce a significant mitochondrial and metabolic reprogramming in A549 lung epithelial cells. While all four ORFs caused mitochondrial fragmentation and altered mitochondrial function, only ORF3a and ORF9c induced a marked structural alteration in mitochondrial cristae. ORF9b, ORF9c and ORF10 induced largely overlapping transcriptomes. In contrast, ORF3a induced a distinct transcriptome, including the downregulation of numerous genes for proteins with critical mitochondrial functions and morphology. Genome-Scale Metabolic Models predicted common and private metabolic flux reprogramming, notably a depressed amino acid metabolism, and an enhanced metabolism of specific lipids distinctly induced by ORF3a. These findings reveal metabolic dependencies and vulnerabilities prompted by SARS-CoV-2 accessory proteins that may be exploited to identify new targets for intervention.This research work was funded by the European Commission – NextGenerationEU (Regulation EU 2020/2094), through CSIC's Global Health Platform (PTI+ Salud Global) (COVID-19-117 and SGL2103015), Junta de Andalucía (CV20-20089), Spanish Ministry of Science project (PID2021-123399OB-I00), the Agency for Management of University and Research Grants from Generalitat de Catalunya-AGAUR (2020PANDE00048 and 2021SGR00350) and ICREA foundation (ICREA-Academia-2021 to MC) of Generalitat de Catalunya, and an AESi grant of the Instituto de Salud Carlos III (PI20CIII-00014). TGG is recipient of a Ramón y Cajal contract funded by MCIN/AEU/10.13039/501100011033 and NextGeneration EU/PRTR.N

Looking at the interface: Novel Microscopy Techniques for Quantitative Phase Imaging in Total Internal Reflection

Looking at the interfaces is very important for many biological and chemical applications: from the imaging of thin polymeric films to the study of cell/substrate interactions. Total Internal Reflection (TIR) microscopy and Surface Plasmon Resonance imaging (SPRi) are usually the preferred techniques when high sensitivity of measurement is required. They use super critical illumination to create evanescent waves at the sample/substrate boundary. The very short range of penetration of these evanescent waves allows to retrieve information about few hundreds of nanometers from the contact surface. Evanescent wave microscopy has proven itself as a good tool for the characterization of thin films, cellular focal adhesions and biomolecular binding events. However, despite the high sensitivities achieved so far, each technique alone has a limited detection range with optimal sensitivity. The main goal of this work is to show how these techniques can benefit from the exploitation of the phase response of the evanescent waves, both in terms of sensitivity and reliability. In this thesis we show the versatility of Digital Holography Microscopy for the development of innovative and compact systems for quantitative phase imaging and, in particular, the implementation of through-the-objective configurations for Holographic TIR microscopy and SPRi. Advantages, issues, and applications are discussed throughout the work. At the same time, possible implementations and future perspectives are also presented with the aim to show the potential and raise interest for the development of new techniques for label-free imaging of interfaces

Fast and Accurate Thickness Mapping of Thin Liquid Films

The thickness of thin liquid films is of great interest to industrial processes and life science. However, there are not appropriate quantitative experimental tools for an adequate study of film evolution in case of not-ideal conditions. Here, we show the application of a holographic system for the evaluation of the 3D topography and thickness of evolving protein films. We use a custom holographic microscope that combines quantitative phase imaging with materials engineering. This technique offers an unprecedented level of details and we anticipate that it will promote a deeper understanding of the underlying physics of thin film dynamics

Holographic microscope slide in a spatio-temporal imaging modality for reliable 3D cell counting

In the current trend of miniaturization and simplification of imaging flow cytometry, Lab-on-a-Chip (LoC) microfluidic devices represent an innovative and cost-effective solution. In this framework, we propose for the first time a novel platform based on the compactness of a holographic microscope slide (HMS) in combination with the new computational features of space-time digital holography (STDH) that uses a 1D linear sensor array (LSA) instead of 2D CCD or CMOS cameras to respond to real diagnostic needs. In this LoC platform, computational methods, holography, and microfluidics are intertwined in order to provide an imaging system with a reduced amount of optical components and capability to achieve reliable cell counting even in the absence of very accurate flow control. STDH exploits the sample motion into the microfluidic channel to obtain an unlimited field-of-view along the flow direction, independent of the magnification factor. Furthermore, numerical refocusing typical of a holographic modality allows imaging and visualization of the entire volume of the channel, thus avoiding loss of information due to the limited depth of focus of standard microscopes. Consequently, we believe that this platform could open new perspectives for enhancing the throughput by 3D volumetric imaging