Exploration of Neutral Versus Polyelectrolyte Behavior of Poly(ethylene glycol)s in Alkali Ion Solutions using Single-Nanopore Recording

Discala, Françoise; Bacri, Laurent; Foster, D. P.; Pelta, Juan; Oukhaled, Abdelghani

doi:10.1021/jz400938q

Cited by 54 publications

(82 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, we may be at the limit of the model used to extrapolate the energy barrier for the translocation, being entry and transport processes, of proteins into the pore. We demonstrated that at low electrical driving force these unfolded proteins translocated through the aerolysin nanopore in a non-extended conformation, as previously observed for a neutral polymer, 71 according to the Daoud and de Gennes “blob” model. 76 …”

Section: Discussionsupporting

confidence: 80%

“…70,71 Because the covalent dimer is twice the length of pertactin, we were able to extract experimentally the entropic barrier contribution for the entry of the proteins inside the pore:

Δ U_{dimer \to monomer} = k_{B} T l n true(\frac{Π_{dimer}}{Π_{monomer}} true)

The partition coefficient Π reads Π = (1/ N A v pore )( Pr ), where N A is the Avogadro constant, v pore represents the pore volume, and the residence probability Pr = τ occup /( τ tot c ), where τ occup is the time occupied per protein inside the pore, τ tot is the total acquisition time and c is the protein concentration. 72 Thus, ΔU dimer → monomer = U entropic = k B T ln ( Pr dimer / Pr monomer ) = 0.73 ± 0.04 k B T , which is the estimated entropic contribution.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Dynamics and Energy Contributions for Transport of Unfolded Pertactin through a Protein Nanopore

et al. 2015

Self Cite

View full text Add to dashboard Cite

To evaluate the physical parameters governing translocation of an unfolded protein across a lipid bilayer, we studied protein transport through aerolysin, a passive protein channel, at the single molecule level. The protein model used was the passenger domain of pertactin, an autotransporter virulence protein. Transport of pertactin through the aerolysin nanopore was detected as transient partial current blockades as the unfolded protein partially occluded the aerolysin channel. We compared the dynamics of entry and transport for unfolded pertactin and a covalent end-to-end dimer of the same protein. For both the monomer and the dimer, the event frequency of current blockades increased exponentially with the applied voltage, while the duration of each event decreased exponentially as a function of the electrical potential. The blockade time was twice as long for the dimer as for the monomer. The calculated activation free energy includes a main enthalpic component that we attribute to electrostatic interactions between pertactin and the aerolysin nanopore (despite the low Debye length), plus an entropic component due to confinement of the unfolded chain within the narrow pore. Comparing our experimental results to previous studies and theory suggests that unfolded proteins cross the membrane by passing through the nanopore in a somewhat compact conformation according to the “blob” model of Daoud and de Gennes.

show abstract

Section: Discussionsupporting

confidence: 80%

“…70,71 Because the covalent dimer is twice the length of pertactin, we were able to extract experimentally the entropic barrier contribution for the entry of the proteins inside the pore:

Δ U_{dimer \to monomer} = k_{B} T l n true(\frac{Π_{dimer}}{Π_{monomer}} true)

Section: Resultsmentioning

confidence: 99%

Dynamics and Energy Contributions for Transport of Unfolded Pertactin through a Protein Nanopore

et al. 2015

Self Cite

View full text Add to dashboard Cite

show abstract

“…One of the main features of the α -hemolysin nanopore is its stability over a wide range of experimental conditions, including aqueous solution of different salts2829 at widely different concentrations1630, denaturing agents3132, the variation of pH3334 or of temperature3536. In particular, single-channel currents through α -hemolysin have previously been recorded at temperature varying between 2 °C35 and 93 °C36.…”

Section: Resultsmentioning

confidence: 99%

High Temperature Extends the Range of Size Discrimination of Nonionic Polymers by a Biological Nanopore

Piguet¹,

Ouldali²,

Discala³

et al. 2016

Sci Rep

Self Cite

View full text Add to dashboard Cite

We explore the effect of temperature on the interaction of polydisperse mixtures of nonionic poly(ethylene glycol) (PEG) polymers of different average molar masses with the biological nanopore α-hemolysin. In contrast with what has been previously observed with various nanopores and analytes, we find that, for PEGs larger than a threshold molar mass (2000 g/mol, PEG 2000), increasing temperature increases the duration of the PEG/nanopore interaction. In the case of PEG 3400 the duration increases by up to a factor of 100 when the temperature increases from 5 °C to 45 °C. Importantly, we find that increasing temperature extends the polymer size range of application of nanopore-based single-molecule mass spectrometry (Np-SMMS)-type size discrimination. Indeed, in the case of PEG 3400, discrimination of individual molecular species of different monomer number is impossible at room temperature but is achieved when the temperature is raised to 45 °C. We interpret our observations as the consequence of a decrease of PEG solubility and a collapse of PEG molecules with higher temperatures. In addition to expanding the range of application of Np-SMMS to larger nonionic polymers, our findings highlight the crucial role of the polymer solubility for the nanopore detection.

show abstract

“…GNPs prior to PEGylation are generally negatively charged, due to the use of citrate as stabilizing agent during synthesis, which is negatively charged (E. C. Cho et al 2009a). PEG, in contrast, is generally neutral (Breton et al 2013). Coating of GNPs with PEG has an insulating effect that lowers the zeta potential magnitude.…”

Section: Discussionmentioning

confidence: 99%

Gold Nanoparticle Toxicity in Mice and Rats: Species Differences

et al. 2018

View full text Add to dashboard Cite

Nanotoxicity studies are greatly needed to advance nanomedical technologies into clinical practice. We assessed the toxic effects of a single intravenous exposure to commercially available gold nanoparticles (GNPs) in mice and rats. Fifteen-nm GNPs were purchased and independently characterized. Animals were exposed to either 1,000 mg GNPs/kg body weight (GNP group) or phosphate-buffered saline. Subsets of animals were euthanized and samples collected at 1, 7, 14, 21, and 28 days postexposure. Independent characterization demonstrated that the physicochemical properties of the purchased GNPs were in good agreement with the information provided by the supplier. Mice exposed to GNPs developed granulomas in the liver and transiently increased serum levels of the pro-inflammatory cytokine interleukin-18. No such alterations were found in rats. While there was no fatality in mice post-GNP exposure, a number of the rats died within hours of GNP administration. Differences in GNP biodistribution and excretion were also detected between the two species, with rats having a higher relative accumulation of GNPs in spleen and greater fecal excretion. In conclusion, GNPs have the ability to incite a robust macrophage response in mice, and there are important species-specific differences in their biodistribution, excretion, and potential for toxicity.

show abstract

Exploration of Neutral Versus Polyelectrolyte Behavior of Poly(ethylene glycol)s in Alkali Ion Solutions using Single-Nanopore Recording

Cited by 54 publications

References 48 publications

Dynamics and Energy Contributions for Transport of Unfolded Pertactin through a Protein Nanopore

Dynamics and Energy Contributions for Transport of Unfolded Pertactin through a Protein Nanopore

High Temperature Extends the Range of Size Discrimination of Nonionic Polymers by a Biological Nanopore

Gold Nanoparticle Toxicity in Mice and Rats: Species Differences

Contact Info

Product

Resources

About