104,985 research outputs found
Dataset supporting the publication "Optical Mie scattering by DNA-assembled three-dimensional gold nanoparticle superlattice crystals".
No full textThis dataset containing spectra and maps of gold-DNA superlattices, numerical simulation results presented in publication:
H J Singh, D Misatziou, C Wheeler, Á Buendía, V Giannini, J A. Sánchez-Gil, M H. V. Werts, T Brown, A H. El-Sagheer, A G. Kanaras, and O L. Muskens;
TITLE: Optical Mie Scattering by DNA-Assembled Three-Dimensional Gold Nanoparticle Superlattice Crystals, published in ACS Appl. Opt. Mater. http://doi.org/10.1021/acsaom.2c00008
This dataset contains:
FigureData_v1.xlsx Excel spreadsheet containing separate worksheets labelled with corresponding figure number.
Each worksheet contains columns of data with Wavelength (nm), and corresponding spectral data (normalized for 1 for 100% transmission / scattering).
Spectral data columns are labelled corresponding to the different parts of the figure.
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miniMie
No full textminiMie is a small scientific Python module for calculating optical cross sections (extinction, scattering, absorption) of spherical (nano)particles in a medium using Mie theory. It is essentially the script that we used and published in: J. R. G. Navarro and M. H. V. Werts, "Resonant light scattering spectroscopy of gold, silver and gold-silver alloy nanoparticles and optical detection in microfluidic channels", Analyst 2013, 138, 583-592. This code is used regularly in our work with plasmonic nanoparticles in solution, e.g., to calculate extinction coefficients, scattering efficiencies, etc.</p
MasonWeaver-analytic: Numerical evaluation of analytic solutions of the Mason-Weaver equation
No full textMasonWeaver-analytic: Numerical evaluation of analytic solutions of the Mason-Weaver equation L. Barthe and M. H. V. Werts, 2022 ENS Rennes / CNRS The Mason-Weaver equation (MWE) is a partial differential equation that describes the sedimentation of small particles in a fluid with the particles being subject to Brownian motion.[1] Understanding the evolution of the vertical concentration profile of an initially homogeneous solution of nanoparticles undergoing sedimentation requires solving the MWE. Previously, we used a numerical finite-difference scheme to find concentration profiles obeying the Mason-Weaver equation.[2][3] We have now developed Python code that evaluates directly the analytic solutions given in the original publication by Mason and Weaver.[1] The task of numerically evaluating the analytic expressions was not as straight-forward as initially expected (as described in the accompanying technical note [4]), but we have finally arrived at an efficient and robust program for obtaining sedimentation concentration profiles from the analytic solutions of the Mason-Weaver equation. [1] Mason, M.; Weaver, W. "The Settling of Small Particles in a Fluid". Phys. Rev. 1924, 23, 412. doi:10.1103/PhysRev.23.412 [2] Midelet, J.; El-Sagheer, A. H.; Brown, T.; Kanaras, A. G.; Werts, M. H. V. "The Sedimentation of Colloidal Nanoparticles in Solution and Its Study Using Quantitative Digital Photography". Part. & Part. Syst. Charact. 2017, 34, 1700095. doi:10.1002/ppsc.201700095 [3] MasonWeaver-finite-diff [4] Barthe, L.; Werts, M. H. V. "Sedimentation of colloidal nanoparticles in fluids: efficient and robust numerical evaluation of analytic solutions of the Mason-Weaver equation". ChemRXiv 2022. doi:10.26434/chemrxiv-2022-91vrq v1.0 Initial release. Calculations are done in the module masonweaver_analytic.py which has been tested in a variety of situations and parameter settings. Accurate, physically sound results are obtained for the time-evolution of the concentration profiles of Brownian particles subject to sedimentation. </p
Quenched fluorescence and enhanced resonant light scattering in molecular plasmonic assemblies
No full textInternational audienceIsolated gold nanoparticles in liquid suspension can effectively quench the fluorescence of molecules that are nearby (< 10 nm), e.g. fluorophores attached to the particles via molecular linkers. Using fluorescence correlation spectroscopy, which analyses the fluorescence from individual objects in a small probe volume, we have been able to demonstrate unambiguously the quenching of ligated chromophores, and to identify spontaneously desorbed ligands that display fluorescence [1,2]. Enhancement of molecular spectroscopic responses may occur at 'hot spots' in aggregates of plasmonic nanoparticles. Moreover, such aggregates display an intense, and specific, resonant light scattering, which in itself provides a useful signal for optical detection at low concentrations in small volumes [3]. We are currently investigating the reversible aggregation of various functionalised gold nanoparticles, using microfluidic systems [4] as a platform for precise control of the aggregation as well as for the development of new (molecular plasmonic) biosensing schemes. Funding by ERANet-NanoSci (MOLIMEN) and ANR (JCJC 2010, COMONSENS) is gratefully acknowledged. [1] M. Loumaigne, R. Praho, D. Nutarelli, M. H. V Werts and A. Débarre, Phys. Chem. Chem. Phys. 12 (2010) 11004-11014 [2] J. R. G. Navarro, M. Plugge, M. Loumaigne, A. Sanchez-Gonzalez, B. Mennucci, A. Débarre, A. M. Brouwer, M. H. V Werts, Photochem. Photobiol. Sci. 9 (2010) 1042-1054 [3] J. R. G. Navarro and M. H. V Werts. Analyst 138 (2013) 583-592 [4] M. H. V. Werts, V. Raimbault, R. Texier-Picard, R. Poizat, O. Français, L. Griscom and J. R. G. Navarro, Lab on a Chip 12 (2012) 808-82
Quenched fluorescence and enhanced resonant light scattering in molecular plasmonic assemblies
No full textInternational audienceIsolated gold nanoparticles in liquid suspension can effectively quench the fluorescence of molecules that are nearby (< 10 nm), e.g. fluorophores attached to the particles via molecular linkers. Using fluorescence correlation spectroscopy, which analyses the fluorescence from individual objects in a small probe volume, we have been able to demonstrate unambiguously the quenching of ligated chromophores, and to identify spontaneously desorbed ligands that display fluorescence [1,2]. Enhancement of molecular spectroscopic responses may occur at 'hot spots' in aggregates of plasmonic nanoparticles. Moreover, such aggregates display an intense, and specific, resonant light scattering, which in itself provides a useful signal for optical detection at low concentrations in small volumes [3]. We are currently investigating the reversible aggregation of various functionalised gold nanoparticles, using microfluidic systems [4] as a platform for precise control of the aggregation as well as for the development of new (molecular plasmonic) biosensing schemes. Funding by ERANet-NanoSci (MOLIMEN) and ANR (JCJC 2010, COMONSENS) is gratefully acknowledged. [1] M. Loumaigne, R. Praho, D. Nutarelli, M. H. V Werts and A. Débarre, Phys. Chem. Chem. Phys. 12 (2010) 11004-11014 [2] J. R. G. Navarro, M. Plugge, M. Loumaigne, A. Sanchez-Gonzalez, B. Mennucci, A. Débarre, A. M. Brouwer, M. H. V Werts, Photochem. Photobiol. Sci. 9 (2010) 1042-1054 [3] J. R. G. Navarro and M. H. V Werts. Analyst 138 (2013) 583-592 [4] M. H. V. Werts, V. Raimbault, R. Texier-Picard, R. Poizat, O. Français, L. Griscom and J. R. G. Navarro, Lab on a Chip 12 (2012) 808-82
Quenched fluorescence and enhanced resonant light scattering in molecular plasmonic assemblies
No full textInternational audienceIsolated gold nanoparticles in liquid suspension can effectively quench the fluorescence of molecules that are nearby (< 10 nm), e.g. fluorophores attached to the particles via molecular linkers. Using fluorescence correlation spectroscopy, which analyses the fluorescence from individual objects in a small probe volume, we have been able to demonstrate unambiguously the quenching of ligated chromophores, and to identify spontaneously desorbed ligands that display fluorescence [1,2]. Enhancement of molecular spectroscopic responses may occur at 'hot spots' in aggregates of plasmonic nanoparticles. Moreover, such aggregates display an intense, and specific, resonant light scattering, which in itself provides a useful signal for optical detection at low concentrations in small volumes [3]. We are currently investigating the reversible aggregation of various functionalised gold nanoparticles, using microfluidic systems [4] as a platform for precise control of the aggregation as well as for the development of new (molecular plasmonic) biosensing schemes. Funding by ERANet-NanoSci (MOLIMEN) and ANR (JCJC 2010, COMONSENS) is gratefully acknowledged. [1] M. Loumaigne, R. Praho, D. Nutarelli, M. H. V Werts and A. Débarre, Phys. Chem. Chem. Phys. 12 (2010) 11004-11014 [2] J. R. G. Navarro, M. Plugge, M. Loumaigne, A. Sanchez-Gonzalez, B. Mennucci, A. Débarre, A. M. Brouwer, M. H. V Werts, Photochem. Photobiol. Sci. 9 (2010) 1042-1054 [3] J. R. G. Navarro and M. H. V Werts. Analyst 138 (2013) 583-592 [4] M. H. V. Werts, V. Raimbault, R. Texier-Picard, R. Poizat, O. Français, L. Griscom and J. R. G. Navarro, Lab on a Chip 12 (2012) 808-82
Quenched fluorescence and enhanced resonant light scattering in molecular plasmonic assemblies
No full textInternational audienceIsolated gold nanoparticles in liquid suspension can effectively quench the fluorescence of molecules that are nearby (< 10 nm), e.g. fluorophores attached to the particles via molecular linkers. Using fluorescence correlation spectroscopy, which analyses the fluorescence from individual objects in a small probe volume, we have been able to demonstrate unambiguously the quenching of ligated chromophores, and to identify spontaneously desorbed ligands that display fluorescence [1,2]. Enhancement of molecular spectroscopic responses may occur at 'hot spots' in aggregates of plasmonic nanoparticles. Moreover, such aggregates display an intense, and specific, resonant light scattering, which in itself provides a useful signal for optical detection at low concentrations in small volumes [3]. We are currently investigating the reversible aggregation of various functionalised gold nanoparticles, using microfluidic systems [4] as a platform for precise control of the aggregation as well as for the development of new (molecular plasmonic) biosensing schemes. Funding by ERANet-NanoSci (MOLIMEN) and ANR (JCJC 2010, COMONSENS) is gratefully acknowledged. [1] M. Loumaigne, R. Praho, D. Nutarelli, M. H. V Werts and A. Débarre, Phys. Chem. Chem. Phys. 12 (2010) 11004-11014 [2] J. R. G. Navarro, M. Plugge, M. Loumaigne, A. Sanchez-Gonzalez, B. Mennucci, A. Débarre, A. M. Brouwer, M. H. V Werts, Photochem. Photobiol. Sci. 9 (2010) 1042-1054 [3] J. R. G. Navarro and M. H. V Werts. Analyst 138 (2013) 583-592 [4] M. H. V. Werts, V. Raimbault, R. Texier-Picard, R. Poizat, O. Français, L. Griscom and J. R. G. Navarro, Lab on a Chip 12 (2012) 808-82
Linear and non-linear optical spectroscopy of 'well-behaved' colloidal suspensions of nanocrystal assemblies
No full textInternational audienceThe directed self-assembly of nanocrystals in the liquid phase can yield new materials with interesting optical properties for potential applications in medical diagnostics, phototherapy, photoenergy, and the guiding of light. Development of self-assembly strategies for such materials require clear relations between the generated structures and their optical properties. It is therefore useful to study the spectroscopy of nanocrystal assemblies in their native colloidal suspension.If a suspension of nanoparticles obeys established models of how colloidal suspensions behave in terms of diffusion[1], sedimentation and dependence of aggregation state on liquid phase composition, spectroscopic parameters of the suspended nanoparticles can be determined quantitatively in real-time, giving access to their dynamic behaviour and information during their functional performance. In this presentation we will show the spectroscopic methods that we utilise for the characterisation of colloidal plasmonic nanoparticle suspensions. These consist of steady-state methods (such as resonant light scattering[2]), as well as time-correlated spectroscopies[3] that work at the single-particle level, and even allow for recording of spectra of single particles diffusing in suspension[4,5]. We will present our latest developments concerning the measurement of extinction and scattering cross sections of plasmonic nano-objects, the diffusion and sedimentation behaviour of plasmonic colloids, and the intrinsic photoluminescence of various advanced gold nanoparticle assemblies (such as DNA-linked gold nanoparticles[6]). This plasmon-mediated luminescence is observed under both monophotonic or multiphoton excitation.[1] M. H. V. Werts, V. Raimbault, R. Texier-Picard, R. Poizat, O. Français, L. Griscom, J. R. G. Navarro. Lab Chip 2012, 12, 808.[2] J. R. G. Navarro, M. H. V. Werts, Analyst 2013, 138, 583. [3] M. Loumaigne, R. Praho, D. Nutarelli, M. H. V. Werts, A. Débarre. Phys. Chem. Chem. Phys. 2010, 12, 11004.[4] M. Loumaigne, P. Vasanthakumar, A. Richard, A. Débarre. ACS Nano 2012, 6, 10512.[5] M. Loumaigne, J. R. G. Navarro, S. Parola, M. H. V. Werts, A. Débarre, Nanoscale 2015, 7, 9013.[6] P. K. Harimech, S. R. Gerrard, A. H. El-Sagheer, T. Brown, A. G. Kanaras, J. Am. Chem. Soc. 2015, 137, 9242
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
The sedimentation of colloidal nanoparticles in solution and its study using quantitative digital photography
No full textSedimentation and diffusion are important aspects of the behavior of colloidalnanoparticles in solution, and merit attention during the synthesis, characterization, and application of nanoparticles. Here, the sedimentation of nanoparticles is studied quantitatively using digital photography and a simple model based on the Mason–Weaver equation. Good agreement between experimental time-lapse photography and numerical solutions of the model is found for a series of gold nanoparticles. The new method is extended to study for the first time the gravitational sedimentation of DNA-linked gold nanoparticle dimers as a model system of a higher complexity structure. Additionally, simple formulas are derived for estimating suitableparameters for the preparative centrifugation of nanoparticle solutions
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