The role of charge on the diffusion of solutes and nanoparticles (silicon nanocrystals, nTiO2, nAu) in a biofilm

2013 ◽  
Vol 10 (1) ◽  
pp. 34 ◽  
Author(s):  
Mahmood Golmohamadi ◽  
Rhett J. Clark ◽  
Jonathan G. C. Veinot ◽  
Kevin J. Wilkinson
Keyword(s):  
Carboxylic Acid ◽  
Diffusion Coefficients ◽  
Electrostatic Interactions ◽  
Emerging Contaminants ◽  
Correlation Spectroscopy ◽  
Fluorescence Correlation ◽  
Self Diffusion ◽  
Wide Range ◽  
Tetramethylrhodamine Methyl Ester

Environmental context The mobility and bioavailability of both contaminants and nutrients in the environment depends, to a large extent, on their diffusion. Because the majority of microorganisms in the environment are embedded in biofilms, it is essential to quantify diffusion in biofilms in order to evaluate the risk of emerging contaminants, including nanomaterials and charged solutes. This study quantifies diffusion, in a model environmental biofilm, for a number of model contaminants of variable size and charge. Abstract The effect of solute and biofilm charge on self-diffusion (Brownian motion) in biofilms is examined. Diffusion coefficients (D) of several model (fluorescent) solutes (rhodamine B; tetramethylrhodamine, methyl ester; Oregon Green 488 carboxylic acid, succinimidyl ester and Oregon Green 488 carboxylic acid) and nanoparticles (functionalised silicon, gold and titanium) were determined using fluorescence correlation spectroscopy (FCS). Somewhat surprisingly, little effect due to charge was observed on the diffusion measurements in the biofilms. Furthermore, the ratio of the diffusion coefficient in the biofilm with respect to that in water (Db/Dw) remained virtually constant across a wide range of ionic strengths (0.1–100mM) for both negatively and positively charged probes. In contrast, the self-diffusion coefficients of nanoparticles with sizes >10nm greatly decreased in the biofilms with respect to those in water. Furthermore, much larger nanoparticles (>66nm) appeared to be completely excluded from the biofilms. The results indicated that for many oligotrophic biofilms in the environment, the diffusion of solutes and nanoparticles will be primarily controlled by obstruction rather than electrostatic interactions. The results also imply that most nanomaterials will become significantly less mobile and less bioavailable (to non-planktonic organisms) as they increase in size beyond ~10nm.

scholarly journals Quantifying Diffusion in a Biofilm ofStreptococcus mutans

2010 ◽  
Vol 55 (3) ◽  
pp. 1075-1081 ◽  
Author(s):  
Zeshi Zhang ◽  
Elena Nadezhina ◽  
Kevin J. Wilkinson
Keyword(s):  
Ionic Strength ◽  
Fluorescent Probes ◽  
Diffusion Coefficients ◽  
Correlation Spectroscopy ◽  
Fluorescence Correlation ◽  
Self Diffusion ◽  
Probe Size ◽  
Order Of Magnitude ◽  
Biofilm Heterogeneity ◽  
Insight Into

ABSTRACTIn biofilms, diffusion may limit the chemical activity of nutrients, toxic compounds, and medicines. This study provides direct, noninvasive insight into the factors that will most effectively limit the transport of antibiotics and biocides in biofilms. Self-diffusion coefficients have been determined for a number of fluorescent probes in biofilms ofStreptococcus mutansusing fluorescence correlation spectroscopy. The effects of probe size and charge and the roles of biofilm pH, ionic strength, and heterogeneity were studied systematically. The relative diffusion coefficients (Din the biofilm divided by that in water) decreased with increasing probe size (3,000-molecular-weight [3K], 10K, 40K, 70K, and 2,000K dextrans). Studies using variably charged substrates (tetramethylrhodamine, Oregon Green, rhodamine B, and rhodamine 6G) showed that the self-diffusion coefficients decreased with an increasing negative charge of the fluorescent probes. No significant effect was observed for changes to the ionic strength (10−4to 10−1M) or pH (4 to 9) of the biofilm. Biofilm heterogeneity was responsible for variations of ca. one order of magnitude in the diffusion coefficients.

Fluorescence correlation spectroscopy: The technique and its applications in soft matter

2018 ◽  
Vol 4 (4) ◽  
Author(s):  
Anjali Gupta ◽  
Jagadish Sankaran ◽  
Thorsten Wohland
Keyword(s):  
Single Molecule ◽  
Fluorescence Correlation Spectroscopy ◽  
Soft Matter ◽  
Photophysical Properties ◽  
Spatiotemporal Analysis ◽  
Correlation Spectroscopy ◽  
Basic Principles ◽  
Chemical Reaction Kinetics ◽  
Fluorescence Correlation ◽  
Wide Range

Abstract Fluorescence correlation spectroscopy (FCS) is a well-established single-molecule method used for the quantitative spatiotemporal analysis of dynamic processes in a wide range of samples. It possesses single-molecule sensitivity but provides ensemble averaged molecular parameters such as mobility, concentration, chemical reaction kinetics, photophysical properties and interaction properties. These parameters have been utilized to characterize a variety of soft matter systems. This review provides an overview of the basic principles of various FCS modalities, their instrumentation, data analysis, and the applications of FCS to soft matter systems.

c , T-Dependence of the Self Diffusion in Concentrated Aqueous Sucrose Solutions

1994 ◽  
Vol 49 (3-4) ◽  
pp. 258-264 ◽  
Author(s):  
D. Girlich ◽  
H.-D. Lüdemann ◽  
C. Buttersack ◽  
K. Buchholz
Keyword(s):  
Field Gradient ◽  
Concentration Dependence ◽  
Diffusion Coefficients ◽  
The Self ◽  
Water Molecules ◽  
Pulsed Field Gradient Nmr ◽  
Pulsed Field ◽  
Self Diffusion ◽  
Sucrose Solutions ◽  
Wide Range

The self diffusion coefficients D of the water molecules and of sucrose have been determined by the pulsed field gradient NMR technique over a wide range of temperatures and concentrations (cmax: 70% w/w suc.). All temperature dependencies can be fitted to a Vogel- Tammann-Fulcher equation. The isothermic concentration dependence of D for the sucrose is given by a simple exponential concentration dependence

Monte Carlo simulation of fluorescence correlation spectroscopy data

2011 ◽  
Vol 76 (3) ◽  
pp. 207-222 ◽  
Author(s):  
Peter Košovan ◽  
Filip Uhlík ◽  
Jitka Kuldová ◽  
Miroslav Štěpánek ◽  
Zuzana Limpouchová ◽  
...  
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Diffusion Coefficients ◽  
Fluorescence Correlation Spectroscopy ◽  
Rotational Diffusion ◽  
Correlation Spectroscopy ◽  
Analytical Models ◽  
Spherical Particles ◽  
Fluorescence Signal ◽  
Fluorescence Correlation

We employed the Monte Carlo simulation methodology to emulate the diffusion of fluorescently labeled particles and understand the source of differences between values of diffusion coefficients (and consequently hydrodynamic radii) of fluorescently labeled nanoparticles measured by fluorescence correlation spectroscopy (FCS) and dynamic light scattering (DLS). We used the simulation program developed in our laboratory and studied the diffusion of spherical particles of different sizes, which are labeled on their surface. In this study, we focused on two complicating effects: (i) multiple labeling and (ii) rotational diffusion which affect the fluorescence signal from large particles and hinder the analysis of autocorrelation functions according to simple analytical models. We have shown that the fluorescence fluctuations can be well fitted using the analytical model for small point-like particles, but the obtained parameters deviate in some cases significantly from the real ones. It means that the current data treatment yields apparent values of diffusion coefficients and other parameters only and the interpretation of experimental results for systems of particles with sizes comparable to the size of the active illuminated volume requires great care and precaution.

scholarly journals Characterizing anomalous diffusion in crowded polymer solutions and gels over five decades in time with variable-lengthscale fluorescence correlation spectroscopy

Soft Matter ◽  
2016 ◽  
Vol 12 (18) ◽  
pp. 4190-4203 ◽  
Author(s):  
Daniel S. Banks ◽  
Charmaine Tressler ◽  
Robert D. Peters ◽  
Felix Höfling ◽  
Cécile Fradin
Keyword(s):  
Anomalous Diffusion ◽  
Fluorescence Correlation Spectroscopy ◽  
Polymer Solutions ◽  
Tracer Diffusion ◽  
Correlation Spectroscopy ◽  
Fluorescence Correlation ◽  
Wide Range

FCS with a wide range of beam waists was used to measure tracer diffusion in crowded media over five decades in time, thus providing a strong test for different models of anomalous diffusion.

Accurate Diffusion Coefficients of Organosoluble Reference Dyes in Organic Media Measured by Dual-Focus Fluorescence Correlation Spectroscopy

ACS Nano ◽  
2015 ◽  
Vol 9 (7) ◽  
pp. 7360-7373 ◽  
Author(s):  
Karel Goossens ◽  
Mira Prior ◽  
Victor Pacheco ◽  
Dieter Willbold ◽  
Klaus Müllen ◽  
...  
Keyword(s):  
Diffusion Coefficients ◽  
Fluorescence Correlation Spectroscopy ◽  
Correlation Spectroscopy ◽  
Organic Media ◽  
Fluorescence Correlation

scholarly journals The deformation rate, atomic mobility and mechanical properties of metals

2021 ◽  
Vol 97 (1) ◽  
pp. 28-37
Author(s):  
D.S. Gertsriken ◽  
◽  
A.M. Husak ◽  
V.F. Mazanko ◽  
S. Ye. Bogdanov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Diffusion Coefficients ◽  
Mechanical Characteristics ◽  
Radioactive Isotopes ◽  
Diffusion Welding ◽  
Magnetic Pulse ◽  
Layer By Layer ◽  
Self Diffusion ◽  
Wide Range ◽  
The Difference

The dependences of diffusion coefficients in metals with different crystal lattice (b.c.c., f.c.c., h.c.p., b.c.t.), subjected to pulse effects by different types of processing in a wide range of strain rates (10-2 - 106 s-1) without heating and at T < 0,5 Tpl. studied by m ethods based on the use of radioactive indicators 55Fe, 95Nb, 60Co, 65Zn, 63Ni, 26Al, 44Ti (layer-by-layer radiometric analysis of residual integral activity, macro- and microautoradiography). Used such types of processing as ultrasonic shock treatment, diffusion welding, shock load, magnetic pulse processing, etc. On the same materials subjected to the same types of processing, mechanical characteristics (impact strength, microhardness, tensile strength, etc.) were determined. In addition, literature data related to the determination of some mechanical characteristics in the deformation of metals at different speeds were used. It turned out that with increasing the rate of plastic deformation there is not only an increase in the mobility of atoms, but also a decrease in differences in the values of the diffusion coefficients of intrinsic atoms and other diffusers in different metals. Despite the large difference in melting temperatures, in particular zinc and niobium, their self-diffusion coefficients in the migration of atoms without heating at a rate of 106 s-1 differ only 1.5 times, while at 1 s-1 the difference in the mobility of atoms is 4 orders of magnitude. It is shown that the velocity dependences of diffusion and mechanical characteristics can be rectilinear, have extremum or inflection, but they will be approximately the same for diffusion coefficients and parameters that characterize the mechanical properties of metals under impulse loads. Establishing the type of velocity dependences for diffusion and mechanical characteristics makes it possible to determine intermediate and extrapolated values for both characteristics, as well as on the schedule of one dependence to predict the shape of the other with a certain accuracy. Keywords: radioactive isotopes, self- and heterodiffusion, pulse loads, strain rate, mechanical characteristic.

Sign in / Sign up

Export Citation Format

Share Document