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Monitoring Molecular Properties of a Fluorescence Light-Up Aptamer Using Fluorescence Cross-Correlation Spectroscopy. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12042002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Fluorescence light-up aptamers (FLAPs) are tools for RNA imaging, wherein the RNA of interest is appended with a FLAP sequence that can bind to a corresponding small-molecule fluorogen and enhance its fluorescence. The fluorescence properties of FLAPs have mostly been analyzed in bulk and described as the average of a large number of RNA–fluorogen complexes. In this study, we evaluated the feasibility of fluorescence correlation spectroscopy (FCS)- and fluorescence cross-correlation spectroscopy (FCCS)-based quantifications of FLAPs in a solution using Broccoli, a common FLAP, and its corresponding fluorogen, DFHBI-1T. We investigated the folding efficiency, photostability, and photophysical properties of the Broccoli–DFHBI-1T complex using their FCS/FCCS characteristics. With FCS, we observed that the fluorescence was affected by the affinity between Broccoli and DFHBI-1T and the folding (maturation) state of Broccoli RNA. Moreover, the FCCS measurement of ATTO647N-labeled Broccoli and its complex with DFHBI-1T revealed the proportion of the mature Broccoli–DFHBI-1T complex. The current FCS/FCCS-based study of Broccoli–DFHBI-1T provides a model for analyzing FLAPs and their fluorogen pairs at the single-molecule level.
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Wang W, Ma Y, Bonaccorsi S, Cong VT, Pandžić E, Yang Z, Goyette J, Lisi F, Tilley RD, Gaus K, Gooding JJ. Investigating Spatial Heterogeneity of Nanoparticles Movement in Live Cells with Pair-Correlation Microscopy and Phasor Analysis. Anal Chem 2021; 93:3803-3812. [PMID: 33590750 DOI: 10.1021/acs.analchem.0c04285] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
How nanoparticles distribute in living cells and overcome cellular barriers are important criteria in the design of drug carriers. Pair-correlation microscopy is a correlation analysis of fluctuation in the fluorescence intensity obtained by a confocal line scan that can quantify the dynamic properties of nanoparticle diffusion including the number of mobile nanoparticles, diffusion coefficient, and transit time across a spatial distance. Due to the potential heterogeneities in nanoparticle properties and the complexity within the cellular environment, quantification of averaged auto- and pair-correlation profiles may obscure important insights into the ability of nanoparticles to deliver drugs. To overcome this issue, we used phasor analysis to develop a data standardizing method, which can segment the scanned line into several subregions according to diffusion and address the spatial heterogeneity of nanoparticles moving inside cells. The phasor analysis is a fit-free method that represents autocorrelation profiles for each pixel relative to free diffusion on the so-called phasor plots. Phasor plots can then be used to select subpopulations for which the auto- and pair-correlation analysis can be performed separately. We demonstrate the phasor analysis for pair-correlation microscopy for investigating 16 nm, Cy5-labeled silica nanoparticles diffusing across the plasma membrane and green fluorescent proteins (GFP) diffusing across nuclear envelope in MCF-7 cells.
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Affiliation(s)
- Wenqian Wang
- School of Chemistry, University of New South Wales, Sydney 2052, Australia.,Australian Centre for NanoMedicine, University of New South Wales, Sydney 2052, Australia.,ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of New South Wales, Sydney 2052, Australia
| | - Yuanqing Ma
- School of Medical Science, University of New South Wales, Sydney 2052, Australia.,EMBL Australia Node in Single Molecule Science, University of New South Wales, Sydney 2052, Australia.,ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Sydney 2052, Australia
| | - Simone Bonaccorsi
- School of Chemistry, University of New South Wales, Sydney 2052, Australia.,Australian Centre for NanoMedicine, University of New South Wales, Sydney 2052, Australia.,ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of New South Wales, Sydney 2052, Australia
| | - Vu Thanh Cong
- School of Chemistry, University of New South Wales, Sydney 2052, Australia.,Australian Centre for NanoMedicine, University of New South Wales, Sydney 2052, Australia.,ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of New South Wales, Sydney 2052, Australia
| | - Elvis Pandžić
- Biomedical Imaging Facility, Mark Wainwright Analytical Centre, University of New South Wales, Sydney 2052, Australia
| | - Zhengmin Yang
- School of Medical Science, University of New South Wales, Sydney 2052, Australia.,EMBL Australia Node in Single Molecule Science, University of New South Wales, Sydney 2052, Australia.,ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Sydney 2052, Australia
| | - Jesse Goyette
- School of Medical Science, University of New South Wales, Sydney 2052, Australia.,EMBL Australia Node in Single Molecule Science, University of New South Wales, Sydney 2052, Australia.,ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Sydney 2052, Australia
| | - Fabio Lisi
- School of Chemistry, University of New South Wales, Sydney 2052, Australia.,Australian Centre for NanoMedicine, University of New South Wales, Sydney 2052, Australia.,ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of New South Wales, Sydney 2052, Australia
| | - Richard D Tilley
- School of Chemistry, University of New South Wales, Sydney 2052, Australia.,Australian Centre for NanoMedicine, University of New South Wales, Sydney 2052, Australia.,Electron Microscope Unit, Mark Wainwright Analytical Centre, University of New South Wales, Sydney 2052, Australia
| | - Katharina Gaus
- School of Medical Science, University of New South Wales, Sydney 2052, Australia.,EMBL Australia Node in Single Molecule Science, University of New South Wales, Sydney 2052, Australia.,ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Sydney 2052, Australia
| | - J Justin Gooding
- School of Chemistry, University of New South Wales, Sydney 2052, Australia.,Australian Centre for NanoMedicine, University of New South Wales, Sydney 2052, Australia.,ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of New South Wales, Sydney 2052, Australia
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