scholarly journals Information-rich localization microscopy through machine learning

2018 ◽  
Author(s):  
Taehwan Kim ◽  
Seonah Moon ◽  
Ke Xu
Keyword(s):  
Single Molecule ◽  
Data Driven ◽  
Direct Link ◽  
Localization Microscopy ◽  
Point Spread ◽  
Spread Function ◽  
Data Driven Approach ◽  
Multidimensional Information ◽  
Specific Alteration ◽  
Single Molecule Localization Microscopy

While current single-molecule localization microscopy (SMLM) methods often rely on the target-specific alteration of the point spread function (PSF) to encode the multidimensional contents of single fluorophores, we argue that the details of the PSF in an unmodified microscope already contain rich, multidimensional information. We introduce a data-driven approach in which artificial neural networks (ANNs) are trained to make a direct link between an experimental PSF image and its underlying parameters. To demonstrate this concept in real systems, we decipher in fixed cells both the colors and the axial positions of single molecules in regular SMLM data.

scholarly journals Photon count estimation in single-molecule localization microscopy

2018 ◽  
Author(s):  
Rasmus Ø. Thorsen ◽  
Christiaan N. Hulleman ◽  
Mathias Hammer ◽  
David Grünwald ◽  
Sjoerd Stallinga ◽  
...  
Keyword(s):  
Single Molecule ◽  
Axial Position ◽  
Optical Aberrations ◽  
Intensity Estimation ◽  
Localization Microscopy ◽  
Photon Count ◽  
Point Spread ◽  
Spread Function ◽  
Gaussian Point ◽  
Single Molecule Localization Microscopy

Recently, Franke, Sauer and van de Linde1 introduced a way to estimate the axial position of single-molecules (TRABI). To this end, they compared the detected photon count from a temporal radial-aperture-based intensity estimation to the estimated count from Gaussian point-spread function (PSF) fitting to the data. Empirically they found this photometric ratio to be around 0.7-0.8 close to focus and decreasing away from it. Here, we explain this reported but unexplained discrepancy and furthermore show that the photometric ratio as indicator for axial position is susceptible even to typical optical aberrations.

scholarly journals Analyzing engineered point spread functions using phasor-based single-molecule localization microscopy

2020 ◽  
Author(s):  
Koen J.A. Martens ◽  
Abbas Jabermoradi ◽  
Suyeon Yang ◽  
Johannes Hohlbein
Keyword(s):  
Saddle Point ◽  
Single Molecule ◽  
Software Package ◽  
Double Helix ◽  
Three Dimensional ◽  
Fourier Plane ◽  
Point Spread Functions ◽  
Localization Microscopy ◽  
Point Spread ◽  
Single Molecule Localization Microscopy

The point spread function (PSF) of single molecule emitters can be engineered in the Fourier plane to encode three-dimensional localization information, creating double-helix, saddle-point or tetra-pod PSFs. Here, we describe and assess adaptations of the phasor-based single-molecule localization microscopy (pSMLM) algorithm to localize single molecules using these PSFs with sub-pixel accuracy. For double-helix, pSMLM identifies the two individual lobes and uses their relative rotation for obtaining z-resolved localizations, while for saddle-point or tetra-pod, a novel phasor-based deconvolution approach is used. The pSMLM software package delivers similar precision and recall rates to the best-in-class software package (SMAP) at signal-to-noise ratios typical for organic fluorophores. pSMLM substantially improves the localization rate by a factor of 2 - 4x on a standard CPU, with 1-1.5·104 (double-helix) or 2.5·105 (saddle-point/tetra-pod) localizations/second.

scholarly journals Simultaneous orientation and 3D localization microscopy with a Vortex point spread function

2020 ◽  
Author(s):  
Christiaan N. Hulleman ◽  
Rasmus Ø. Thorsen ◽  
Sjoerd Stallinga ◽  
Bernd Rieger
Keyword(s):  
Single Molecule ◽  
Point Spread Function ◽  
Polar Angle ◽  
Phase Mask ◽  
Simultaneous Estimation ◽  
Dipole Orientation ◽  
Localization Microscopy ◽  
Point Spread ◽  
Spread Function ◽  
Microscopy Techniques

We have developed an engineered Point Spread Function (PSF) to enable the simultaneous estimation of dipole orientation, 3D position and degree of rotational constraint of single-molecule emitters from a single 2D focal plane. Besides giving access to orientation information, the Vortex PSF along with the vectorial PSF fitter avoids localization bias common in localization microscopy for fixed dipole emitters. We demonstrate this technique on reorienting single-molecules and using binding-activated localization microscopy on DNA intercalators, corroborating perpendicular azimuthal angles to the DNA axis for in-plane emitters but find a non-uniform distribution as a function of the polar angle. The Vortex PSF is realized by an affordable glass phase mask and has a compact footprint that can easily be combined with localization microscopy techniques on rotationally constrained emitters.

scholarly journals Depth-dependent PSF calibration and aberration correction for 3D single-molecule localization

2019 ◽  
Author(s):  
Yiming Li ◽  
Yu-Le Wu ◽  
Philipp Hoess ◽  
Markus Mund ◽  
Jonas Ries
Keyword(s):  
Single Molecule ◽  
Open Source Software ◽  
Software Tool ◽  
Calibration Procedure ◽  
Experimental Calibration ◽  
Point Spread ◽  
Processing Step ◽  
Spread Function ◽  
The Individual ◽  
Single Molecule Localization Microscopy

Abstract3D Single molecule localization microscopy relies on fitting of the individual molecules with a point spread function (PSF) model. The reconstructed images often show local squeezing or expansion in z. A common cause are depth-induced aberrations in conjunction with an imperfect PSF model calibrated from beads on a coverslip, resulting in a mismatch between measured PSF and real PSF. Here, we developed a strategy for accurate z-localization in which we use the imperfect PSF model for fitting, determine the fitting errors and correct for them in a post-processing step. We present an open-source software tool and a simple experimental calibration procedure that allow retrieving accurate z-positions in any PSF engineering approach or fitting modality, even at large imaging depths.

scholarly journals Simultaneous orientation and 3D localization microscopy with a Vortex point spread function

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Christiaan N. Hulleman ◽  
Rasmus Ø. Thorsen ◽  
Eugene Kim ◽  
Cees Dekker ◽  
Sjoerd Stallinga ◽  
...  
Keyword(s):  
Single Molecule ◽  
Point Spread Function ◽  
Position Estimation ◽  
Phase Plate ◽  
Light Path ◽  
Excitation Light ◽  
Localization Microscopy ◽  
Point Spread ◽  
Spread Function ◽  
Polarization Splitting

AbstractEstimating the orientation and 3D position of rotationally constrained emitters with localization microscopy typically requires polarization splitting or a large engineered Point Spread Function (PSF). Here we utilize a compact modified PSF for single molecule emitter imaging to estimate simultaneously the 3D position, dipole orientation, and degree of rotational constraint from a single 2D image. We use an affordable and commonly available phase plate, normally used for STED microscopy in the excitation light path, to alter the PSF in the emission light path. This resulting Vortex PSF does not require polarization splitting and has a compact PSF size, making it easy to implement and combine with localization microscopy techniques. In addition to a vectorial PSF fitting routine we calibrate for field-dependent aberrations which enables orientation and position estimation within 30% of the Cramér-Rao bound limit over a 66 μm field of view. We demonstrate this technique on reorienting single molecules adhered to the cover slip, λ-DNA with DNA intercalators using binding-activated localization microscopy, and we reveal periodicity on intertwined structures on supercoiled DNA.

Single-Molecule Imaging of Active Mitochondrial Nitroreductases using a Photo-Crosslinking Fluorescent Sensor

2019 ◽  
Author(s):  
Zacharias Thiel ◽  
Pablo Rivera-Fuentes
Keyword(s):  
Subcellular Localization ◽  
Fluorescent Probe ◽  
Single Molecule ◽  
Mammalian Cells ◽  
Fluorescent Sensor ◽  
Biological Functions ◽  
Localization Microscopy ◽  
Drug Activation ◽  
Nitroreductase Activity ◽  
Single Molecule Localization Microscopy

Many biomacromolecules are known to cluster in microdomains with specific subcellular localization. In the case of enzymes, this clustering greatly defines their biological functions. Nitroreductases are enzymes capable of reducing nitro groups to amines and play a role in detoxification and pro-drug activation. Although nitroreductase activity has been detected in mammalian cells, the subcellular localization of this activity remains incompletely characterized. Here, we report a fluorescent probe that enables super-resolved imaging of pools of nitroreductase activity within mitochondria. This probe is activated sequentially by nitroreductases and light to give a photo-crosslinked adduct of active enzymes. In combination with a general photoactivatable marker of mitochondria, we performed two-color, threedimensional, single-molecule localization microscopy. These experiments allowed us to image the sub-mitochondrial organization of microdomains of nitroreductase activity.<br>

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