Experimentální biofotonika
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- ItemTomographic microscope for low-coherent quantitative phase imaging(SPIE, 2025-02-17) Špaček, Matěj; Dvořák, Vladislav; Pachl, Přemysl; Buček, Jozef; Neumanová, Anna; Dostál, ZbyněkA novel tomographic microscope setup utilizing the principle of Holographic Incoherent-light-source Quantitative Phase Imaging is introduced. This setup combines the advantages of achromatic off-axis holography with the ultrafast operation of a digital micromirror device-based tomographic illuminator. The imaging theory is explained, and the optical design of the microscope is described. The functionality of the microscope modules is demonstrated experimentally using a light source of limited spatial coherence.
- ItemNeurovascular Network Explorer 2.0: A Database of 2-Photon Single Vessel Diameter Measurements from Mouse SI Cortexin Response To Optogenetic Stimulation(Frontiers, 2017-02-01) Uhlířová, Hana; Peifang, Tiam; Kilic, Kivilcim; Thunemann, Martin; Sridhar, Vishnu B.; Bartsch, Hauke; Dale, Anders M.; Devor, Anna; Saisan, Payam A.Here, we present a novel database containing 2-photon data from our recently published experimental study (Uhlirova et al., 2016a) and a second generation of our GUI-based software engine that we call NNE 2.0. The data, GUI, and source code are freely available for download from our academic website (http://nil.ucsd.edu/data/NNE/NNE2_HDbase_v1.0/). The database contains 2-photon measurements of arteriolar diameter changes in response to selective optogenetic (OG) activation of cortical inhibitory neurons (INs).
- ItemMultimodal Holographic Microscopy: Distinction between Apoptosis and Oncosis(PLOS, 2015-03-24) Balvan, Jan; Křížová, Aneta; Gumulec, Jaromír; Raudenská, Martina; Sládek, Zbyšek; Sedláčková, Miroslava; Babula, Petr; Svobodová, Markéta; Kizek, René; Chmelík, Radim; Masařík, MichalIdentification of specific cell death is of a great value for many scientists. Predominant types of cell death can be detected by flow-cytometry (FCM). Nevertheless, the absence of cellular morphology analysis leads to the misclassification of cell death type due to underestimated oncosis. However, the definition of the oncosis is important because of its potential reversibility. Therefore, FCM analysis of cell death using annexin V/propidium iodide assay was compared with holographic microscopy coupled with fluorescence detection Multimodal holographic microscopy (MHM). The aim was to highlight FCM limitations and to point out MHM advantages. It was shown that the annexin V+/PI phenotype is not specific of early apoptotic cells, as previously believed, and that morphological criteria have to be necessarily combined with annexin V/PI for the cell death type to be ascertained precisely. MHM makes it possible to distinguish oncosis clearly from apoptosis and to stratify the progression of oncosis.
- ItemOn quantitativeness of diffraction-limited quantitative phase imaging(AIP Publishing, 2024-12-01) Bouchal, Zdeněk; Bouchal, Petr; Chmelíková, Tereza; Fiurásek, JaromírQuantitative phase imaging (QPI) has advanced by accurately quantifying phase shifts caused by weakly absorbing biological and artificial structures. Despite extensive research, the diffraction limits of QPI have not been established and examined. Hence, it remains unclear whether diffraction-affected QPI provides reliable quantification or merely visualizes phase objects, similar to phase contrast methods. Here, we develop a general diffraction phase imaging theory and show that it is intrinsically connected with Rayleigh's resolution theory. Our approach reveals the entanglement of phases under restoration, imposing diffraction bounds on spatial phase resolution and, unexpectedly, on phase accuracy. We prove that the phase accuracy depends on the size, shape, and absorption of objects forming the sample and significantly declines if the object size approaches the Rayleigh limit (a relative phase error of -16% for an Airy disk-sized object with low phase shift). We show that the phase accuracy limits can be enhanced at the cost of deteriorated phase resolution by attenuating the sample background light. The QPI diffraction limits are thoroughly examined in experiments with certified phase targets and biological cells. The study's relevance is underscored by results showing that the phase accuracy of some structures is lost (a relative phase error of -40%) even though they are spatially resolved (a phase visibility of 0.5). A reliable procedure is used to estimate phase errors in given experimental conditions, opening the way to mitigate errors' impact through data post-processing. Finally, the phase accuracy enhancement in super-resolution QPI is discovered, which has not been previously reported.
- ItemMigrastatics-Anti-metastatic and Anti-invasion Drugs: Promises and Challenges(Elsevier, 2017-06-01) Gandalovičová, Aneta; Rösel, Daniel; Fernandes, Michael; Veselý, Pavel; Henenberg, Petr; Čermák, Vladimír; Petruželka, Luboš; Kumar, Sunil; Sanz-Moreno, Victoria; Brábek, JanIn solid cancers, invasion and metastasis account for more than 90% of mortality. However, in the current armory of anticancer therapies, a specific category of anti-invasion and antimetastatic drugs is missing. Here, we coin the term ‘migrastatics’ for drugs interfering with all modes of cancer cell invasion and metastasis, to distinguish this class from conventional cytostatic drugs, which are mainly directed against cell proliferation. We define actin polymerization and contractility as target mechanisms for migrastatics, and review candidate migrastatic drugs. Critical assessment of these antimetastatic agents is warranted, because they may define new options for the treatment of solid cancers.