Elucidating chromatin structure in vitro requires resolution below 10 nm to visualize the mononucleosome has been an ongoing challenge. In this work, we achieve sub-10-nm imaging of nucleic acids via spectroscopic intrinsic-contrast photon-localization optical nanoscopy (SICLON) without the use of external labels. SICLON leverages two key innovations: using endogenous nucleotides as the emission source and a custom-made imaging system that can simultaneously record the position and optical spectra of emitting molecules. With a novel spectral regression algorithm that identifies the spectroscopic fingerprints of neighboring molecules that were previously indistinguishable, we demonstrate the utility of SICLON by visualizing unlabeled poly-nucleotides and linear single-stranded DNA fibers with a resolution of 6.2 nm.
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http://dx.doi.org/10.1364/OL.43.005817 | DOI Listing |
We demonstrate PaCMAN, a ptychography algorithm that can reconstruct high quality images with broadband illumination sources while being robust to shot, detector, and parasitic noise. We extend prior monochromatization work to improve accuracy, especially for discrete spectra, and also demonstrate how PaCMAN can be converted into Ms. PaCMAN, a multi-spectral variant that outperforms multi-spectral ePIE.
View Article and Find Full Text PDFHigh-resolution X-ray imaging of noncrystalline objects is often achieved through the approach of scanning coherent diffractive imaging known as ptychography. The imaging resolution is usually limited by the scattering properties of the sample, where weak diffraction signals at the highest scattering angles compete with parasitic scattering. Here, we demonstrate that X-ray multilayer Laue lenses with a high numerical aperture (NA) can be used to create a strong reference beam that holographically boosts weak scattering from the sample over a large range of scattering angles, enabling high-resolution imaging that is tolerant of such background.
View Article and Find Full Text PDFNano Lett
November 2024
Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200438, China.
Dye sensitization enhances the luminescence of lanthanide nanoparticles by improving light-harvesting. Typically, Yb serves as an energy bridge but absorbs at a single transition, limiting dyes' options (λ > 700 nm) due to the spectral overlap requirement. In contrast, the emitter Er spans energy levels from UV to NIR, making it ideal for multicolor excitation.
View Article and Find Full Text PDFJ Biomed Opt
June 2024
Northwestern University, Department of Biomedical Engineering, Evanston, Illinois, United States.
Significance: Spectroscopic single-molecule localization microscopy (sSMLM) takes advantage of nanoscopy and spectroscopy, enabling sub-10 nm resolution as well as simultaneous multicolor imaging of multi-labeled samples. Reconstruction of raw sSMLM data using deep learning is a promising approach for visualizing the subcellular structures at the nanoscale.
Aim: Develop a novel computational approach leveraging deep learning to reconstruct both label-free and fluorescence-labeled sSMLM imaging data.
Analyst
May 2024
Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas 72701, USA.
Single-molecule localization microscopy (SMLM), a type of super-resolution fluorescence microscopy, has become a strong technique in the toolbox of chemists, biologists, physicists, and engineers in recent years for its unique ability to resolve characteristic features at the nanoscopic level. It drastically improves the resolution of optical microscopes beyond the diffraction limit, with which previously unresolvable structures can now be studied. Spectrally resolved super-resolution fluorescence microscopy multiplexing of different fluorophores is one of the greatest advancements among SMLM techniques.
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