• Adaptive fluctuation imaging captures rapid subcellular dynamics 

      Opstad, Ida Sundvor; Ströhl, Florian; Birgisdottir, Åsa birna; Acuña Maldonado, Sebastian Andres; Kalstad, Trine; Myrmel, Truls; Agarwal, Krishna; Ahluwalia, Balpreet Singh (Journal article; Tidsskriftartikkel, 2019-07-22)
      In this work we have explored the live-cell friendly nanoscopy method Multiple Signal Classification Algorithm (MUSICAL) for multi-colour imaging of various organelles and sub-cellular structures in the cardiomyoblast cell line H2c9. We have tested MUSICAL for fast (up to 230Hz), multi-colour time-lapse sequences of various sub-cellular structures (mitochondria, endoplasmic reticulum, microtubules, ...
    • Adaptive fluctuation imaging captures rapid subcellular dynamics 

      Opstad, Ida Sundvor; Ströhl, Florian; Birgisdottir, Åsa birna; Maldonado, Sebastián Andrés Acuña; Kalstad, Trine; Myrmel, Truls; Agarwal, Krishna; Ahluwalia, Balpreet Singh (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-07-22)
      In this work we have explored the live-cell friendly nanoscopy method Multiple Signal Classification Algorithm (MUSICAL) for multi-colour imaging of various organelles and sub-cellular structures in the cardiomyoblast cell line H2c9. We have tested MUSICAL for fast (up to 230Hz), multi-colour time-lapse sequences of various sub-cellular structures (mitochondria, endoplasmic reticulum, microtubules, ...
    • Artefact removal in ground truth deficient fluctuations-based nanoscopy images using deep learning 

      Jadhav, Suyog; Acuña Maldonado, Sebastian Andres; Opstad, Ida Sundvor; Ahluwalia, Balpreet Singh; Agarwal, Krishna; Prasad, Dilip K. (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-12-08)
      Image denoising or artefact removal using deep learning is possible in the availability of supervised training dataset acquired in real experiments or synthesized using known noise models. Neither of the conditions can be fulfilled for nanoscopy (super-resolution optical microscopy) images that are generated from microscopy videos through statistical analysis techniques. Due to several physical ...
    • Bringing optical nanoscopy to life - Super-resolution microscopy of living cells 

      Opstad, Ida Sundvor (Doctoral thesis; Doktorgradsavhandling, 2021-01-29)
      Microscopy is possibly the best tool we have to peer into the microscopic world to enhance our understanding of the usually invisible, but highly complex and vital events every moment taking place inside living cells. Microscopy is brilliant, but also has its physical constraints and technical limitations. Technical advances have in the last decade pushed optical microscopy past physical limits ...
    • Fluorescence fluctuation-based super-resolution microscopy using multimodal waveguided illumination 

      Opstad, Ida Sundvor; Hansen, Daniel Henry; Acuña Maldonado, Sebastian Andres; Ströhl, Florian; Priyadarshi, Anish; Tinguely, Jean-Claude; Dullo, Firehun Tsige; Dalmo, Roy Ambli; Seternes, Tore; Ahluwalia, Balpreet Singh; Agarwal, Krishna (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-07-19)
      Photonic chip-based total internal reflection fluorescence microscopy (c-TIRFM) is an emerging technology enabling a large TIRF excitation area decoupled from the detection objective. Additionally, due to the inherent multimodal nature of wide waveguides, it is a convenient platform for introducing temporal fluctuations in the illumination pattern. The fluorescence fluctuation-based nanoscopy technique ...
    • High-resolution visualization and assessment of basal and OXPHOS-induced mitophagy in H9c2 cardiomyoblasts 

      Godtliebsen, Gustav; Larsen, Kenneth Bowitz; Bhujabal, Zambarlal Babanrao; Opstad, Ida Sundvor; Nager Grifo, Mireia; Punnakkal, Abhinanda Ranjit; Kalstad, Trine; Olsen, Randi; Lund, trine; Prasad, Dilip K.; Agarwal, Krishna; Myrmel, Truls; Birgisdottir, Åsa birna (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-07-05)
      Mitochondria are susceptible to damage resulting from their activity as energy providers. Damaged mitochondria can cause harm to the cell and thus mitochondria are subjected to elaborate quality-control mechanisms including elimination via lysosomal degradation in a process termed mitophagy. Basal mitophagy is a house-keeping mechanism fine-tuning the number of mitochondria according to the metabolic ...
    • Label-free nanoscopy enabled by coherent imaging with photonic waveguides 

      Ströhl, Florian; Opstad, Ida Sundvor; Tinguely, Jean-Claude; Dullo, Firehun Tsige; Kaminski, Clemens F.; Ahluwalia, Balpreet Singh (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-07-29)
      In this project it was found that Fourier ptychographic microscopy can be improved far beyond its conventional limits via waveguide-based optical systems. Extensive in silico studies showed that images obtained on highrefractive index material waveguide chips in conjunction with hyperspectral illumination light and finely designed waveguide geometries can be combined via a modified phase-retrieval ...
    • Label-free superior contrast with c-band ultra-violet extinction microscopy 

      Wolfson, Deanna; Opstad, Ida Sundvor; Hansen, Daniel Henry; Mao, Hong; Ahluwalia, Balpreet Singh; Ströhl, Florian (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-03-03)
      In 1934, Frits Zernike demonstrated that it is possible to exploit the sample’s refractive index to obtain superior contrast images of biological cells. The refractive index contrast of a cell surrounded by media yields a change in the phase and intensity of the transmitted light wave. This change can be due to either scattering or absorption caused by the sample. Most cells are transparent at visible ...
    • Learning Nanoscale Motion Patterns of Vesicles in Living Cells 

      Sekh, Arif Ahmed; Opstad, Ida Sundvor; Birgisdottir, Åsa B.; Myrmel, Truls; Ahluwalia, Balpreet Singh; Agarwal, Krishna; Prasad, Dilip K. (Conference object; Konferansebidrag, 2020-08-05)
      Detecting and analyzing nanoscale motion patterns of vesicles, smaller than the microscope resolution (~250 nm), inside living biological cells is a challenging problem. State-of-the-art CV approaches based on detection, tracking, optical flow or deep learning perform poorly for this problem. We propose an integrative approach, built upon physics based simulations, nanoscopy algorithms, and shallow ...
    • Learning nanoscale motion patterns of vesicles in living cells 

      Sekh, Arif Ahmed; Opstad, Ida Sundvor; Birgisdottir, Åsa Birna; Myrmel, Truls; Ahluwalia, Balpreet Singh; Agarwal, Krishna; Prasad, Dilip K. (Chapter; Bokkapittel, 2020)
      Detecting and analyzing nanoscale motion patterns of vesicles, smaller than the microscope resolution (~250 nm), inside living biological cells is a challenging problem. State-of-the-art CV approaches based on detection, tracking, optical flow or deep learning perform poorly for this problem. We propose an integrative approach, built upon physics based simulations, nanoscopy algorithms, and shallow ...
    • Live-cell imaging of human spermatozoa using structured illumination microscopy 

      Opstad, Ida Sundvor; Popova, Daria; Acharya, Ganesh; Basnet, Purusotam; Ahluwalia, Balpreet Singh (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-11-05)
      Structural details of spermatozoa are interesting from the perspectives of fundamental biology and growing reproductive health problems. Studies of nanostructural details of these extremely motile cells have been limited to fixed cells, largely using electron microscopy. Here we provide the protocols for and demonstrate live-cell multi-color super-resolution imaging of human spermatozoa using ...
    • Multi-color imaging of sub-mitochondrial structures in living cells using structured illumination microscopy 

      Opstad, Ida Sundvor; Wolfson, Deanna; Øie, Cristina Ionica; Ahluwalia, Balpreet Singh (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-05-18)
      The dimensions of mitochondria are close to the diffraction limit of conventional light microscopy techniques, making the complex internal structures of mitochondria unresolvable. In recent years, new fluorescence-based optical imaging techniques have emerged, which allow for optical imaging below the conventional limit, enabling super-resolution (SR). Possibly the most promising SR and diffraction-limited ...
    • Multidisciplinary biophotonics, open science, and. . . plug & pray deep learning? 

      Opstad, Ida Sundvor (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-06-06)
      Due to its great creative potential for innovation and scientific discovery, inter- and multidisciplinary collaboration is being increasingly encouraged by institutions and funding agencies. The increased opportunities in the multidisciplinary arena also come with significant challenges like the added experimental, analytical and logistical complexity, blended with a high likelihood of miscommunications. ...
    • MusiJ: an ImageJ plugin for video nanoscopy 

      Acuña Maldonado, Sebastian Andres; Ströhl, Florian; Opstad, Ida Sundvor; Ahluwalia, Balpreet S.; Agarwal, Krishna (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-04-14)
      We present an open-source implementation of the fluctuation-based nanoscopy method MUSICAL for ImageJ. This implementation improves the algorithm’s computational efficiency and takes advantage of multi-threading to provide orders of magnitude faster reconstructions than the original MATLAB implementation. In addition, the plugin is capable of generating super-resolution videos from large stacks of ...
    • Physics-based machine learning for subcellular segmentation in living cells 

      Sekh, Arif Ahmed; Opstad, Ida Sundvor; Godtliebsen, Gustav; Birgisdottir, Åsa Birna; Ahluwalia, Balpreet Singh; Agarwal, Krishna; Prasad, Dilip K. (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-12-15)
      Segmenting subcellular structures in living cells from fluorescence microscope images is a ground truth (GT)-deficient problem. The microscopes’ three-dimensional blurring function, finite optical resolution due to light diffraction, finite pixel resolution and the complex morphological manifestations of the structures all contribute to GT-hardness. Unsupervised segmentation approaches are quite ...
    • Soft thresholding schemes for multiple signal classification algorithm 

      Acuña Maldonado, Sebastian Andres; Opstad, Ida Sundvor; Godtliebsen, Fred; Ahluwalia, Balpreet Singh; Agarwal, Krishna (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-10-28)
      Multiple signal classification algorithm (MUSICAL) exploits temporal fluctuations in fluorescence intensity to perform super-resolution microscopy by computing the value of a super-resolving indicator function across a fine sample grid. A key step in the algorithm is the separation of the measurements into signal and noise subspaces, based on a single user-specified parameter called the threshold. ...
    • Structured Illumination Microscopy of Biological Structures 

      Wolfson, Deanna; Villegas, Luis; Opstad, Ida Sundvor; Birgisdottir, Åsa birna; Øie, Cristina Ionica; Ahluwalia, Balpreet Singh (Conference object; Konferansebidrag, 2018)
      <p>Resolution in optical microscopy has long been limited to the Abbe diffraction limit, i.e. about 250 nm laterally for visible wavelengths on a very good microscope. In the last two decades several techniques have been devised to circumvent this limit: an achievement which was recognized with the 2014 Nobel Prize in Chemistry. Structured Illumination Microscopy (SIM) was the first of these techniques ...
    • Super-condenser enables labelfree nanoscopy 

      Ströhl, Florian; Opstad, Ida Sundvor; Tinguely, Jean-Claude; Dullo, Firehun Tsige; Mela, Ioanna; Osterrieth, Johannes W.M; Ahluwalia, Balpreet Singh; Kaminski, Clemens F. (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-08-22)
      Labelfree nanoscopy encompasses optical imaging with resolution in the 100 nm range using visible wavelengths. Here, we present a labelfree nanoscopy method that combines coherent imaging techniques with waveguide microscopy to realize a <i>super-condenser</i> featuring maximally inclined coherent darkfield illumination with artificially stretched wave vectors due to large refractive indices of the ...
    • Super-condenser enables labelfree nanoscopy 

      Ströhl, Florian; Opstad, Ida Sundvor; Tinguely, Jean-Claude; Dullo, Firehun Tsige; Mela, Ioanna; Osterrieth, Johannes W.M; Ahluwalia, Balpreet Singh; Kaminski, Clemens F. (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-08-22)
      Labelfree nanoscopy encompasses optical imaging with resolution in the 100 nm range using visible wavelengths. Here, we present a labelfree nanoscopy method that combines coherent imaging techniques with waveguide microscopy to realize a <i>super-condenser</i> featuring maximally inclined coherent darkfield illumination with artificially stretched wave vectors due to large refractive indices of the ...
    • Super-Resolution Imaging of Sub-Mitochondrial Structures using Structured Illumination Microscopy 

      Opstad, Ida Sundvor (Master thesis; Mastergradsoppgave, 2016-05-15)
      Modern science is based on observation, and its advances are limited by what is possible to observe. For centuries optical microscopy was limited by the diffraction of light, making structures closer together than half the wavelength of light unresolvable. In recent years, the new field of optical nanoscopy has emerged, enabling diffraction-limited structures to be resolved. As opposed to ...