Effect of nanoparticle size on the near-surface pH-distribution in aqueous and carbonate buffered solutions

Stepan, Thomas; Tété, Lisa; Laundry-Mottiar, Lila; Romanovskaia, Elena; Hedberg, Yolanda; Danninger, Herbert; Auinger, Michael

doi:10.1016/j.electacta.2022.139923

Cited by 10 publications

(5 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…3a), Cu was predicted to be entirely or primarily solid (CuO at pe 5 and Cu 2 O at pe 3.4). When the pH decreased to pH 6.5 and 5, as expected for the surface pH of the electrode during anodic polarization, 41 the relative concentration of aqueous Cu-chloride species increased. There were no solid species predicted at pH 5.…”

Section: Resultsmentioning

confidence: 58%

“…Other input values were 1 mM of the respective amino acid, 9 g l −1 NaCl, pH values of 5, 6.5 and 7.4, a temperature of 25 °C, and a pressure of 1 atm. The lower pH values simulate oxidative conditions present under anodic polarization, 41 and the temperature was chosen to benefit from the best availability of literature data. Solids were allowed to form and precipitate.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Effect of Amino Acids on the Corrosion and Metal Release from Copper and Stainless Steel

Zee

Laundry-Mottiar

Nikpour

et al. 2023

J. Electrochem. Soc.

Self Cite

View full text Add to dashboard Cite

Copper (Cu) and stainless steel 316L are widely used for biomedical applications, such as intrauterine devices and orthopedic/dental implants. Amino acids are abundantly present in biological environments. We investigated the influence of select amino acids on the corrosion of Cu under naturally aerated and deaerated conditions using a phosphate-free buffer. Amino acids increased the corrosion of Cu under both aeration conditions at pH 7.4. Cu release was also significantly (up to 18-fold) increased in the presence of amino acids, investigated at pH 7.4 and 37°C for 24 h under naturally aerated conditions. Speciation modelling predicted a generally increased solubility of Cu in the presence of amino acids at pH 7.4. 316L, investigated for metal release under similar conditions for comparison, released about 1000-fold lower amounts of metals than did Cu and remained passive with no change in surface oxide composition or thickness. However, amino acids also increased the chromium release (up to 52-fold), significantly for lysine, and the iron release for cysteine, while nickel and molybdenum release remained unaffected. This was not predicted by solution speciation modelling. The surface analysis confirmed the adsorption of amino acids on 316L and, to a lower extent, Cu coupons.

show abstract

Section: Resultsmentioning

confidence: 58%

Section: Methodsmentioning

confidence: 99%

Effect of Amino Acids on the Corrosion and Metal Release from Copper and Stainless Steel

Zee

Laundry-Mottiar

Nikpour

et al. 2023

J. Electrochem. Soc.

Self Cite

View full text Add to dashboard Cite

show abstract

“…

where the index i denotes the chemical species (H + , OH − and the buffer ions), c the concentration, D the diffusion coefficient, r the radial distance from the centre, z the electric charge, e 0 Coulomb’s constant, k B Boltzmann’s constant and ϕ the electrical potential. Due to the short diffusion pathways of only a few µm, the set of partial differential equations can be solved for steady-state conditions, as further described in [ 23 ] for the case of flat surfaces and NP geometries [ 24 ]. Given the high I c of the solution, the gradient of the electric potential is small, and the migration term in Equation (1) can be simplified to the case of diffusion only.…”

Section: Methodsmentioning

confidence: 99%

“…This, in turn, affects cellular interactions, transport mechanisms, accumulation and/or excretion of the therapeutic potential of NPs [ 21 , 22 ]. In addition, local pH shifts caused by chemical reactions on the particle surface must be considered, as these might have a strong impact on the local environment [ 23 ] due to stronger pH gradients around smaller NPs [ 24 ]. However, steep pH gradients between the dispersant and the particle surface would further acidify the NP environment, which could be exploited in wound healing.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Influence of Wound-Treatment-Relevant Buffer Systems on the Colloidal and Optical Properties of Gold Nanoparticles

et al. 2023

Self Cite

View full text Add to dashboard Cite

Biocompatible gold nanoparticles (AuNPs) are used in wound healing due to their radical scavenging activity. They shorten wound healing time by, for example, improving re-epithelialization and promoting the formation of new connective tissue. Another approach that promotes wound healing through cell proliferation while inhibiting bacterial growth is an acidic microenvironment, which can be achieved with acid-forming buffers. Accordingly, a combination of these two approaches appears promising and is the focus of the present study. Here, 18 nm and 56 nm gold NP (Au) were prepared with Turkevich reduction synthesis using design-of-experiments methodology, and the influence of pH and ionic strength on their behaviour was investigated. The citrate buffer had a pronounced effect on the stability of AuNPs due to the more complex intermolecular interactions, which was also confirmed by the changes in optical properties. In contrast, AuNPs dispersed in lactate and phosphate buffer were stable at therapeutically relevant ionic strength, regardless of their size. Simulation of the local pH distribution near the particle surface also showed a steep pH gradient for particles smaller than 100 nm. This suggests that the healing potential is further enhanced by a more acidic environment at the particle surface, making this strategy a promising approach.

show abstract

“…Some of the authors of this study have shown in simulations that the pH-gradients are steeper (and closer to the NP surface) for smaller nanoparticles. 23 These differences to planar surfaces become significant for nanoparticle sizes <10 nm. Second, time-of-flight secondary ion mass spectrometry measurements performed on the 5 and 50 nm Au NPs of this study showed a strong interaction between the 5 nm Au NPs and cysteine, 9 forming an Au thiolate complex.…”

Section: Cyclic Voltammetry Of Differently Sized Au Nps Immobilized Onmentioning

confidence: 99%

Electrochemical Estimations of the Gold Nanoparticle Size Effect on Cysteine-Gold Oxidation

Romanovskaia

Slovenský

Kalantarian

et al. 2022

J. Electrochem. Soc.

Self Cite

View full text Add to dashboard Cite

Gold nanoparticles are interesting for nanobiomedical applications, such as for drug delivery and as diagnostic imaging contrast agents. However, their stability and reactivity in-vivo are influenced by their surface properties and size. Here, we investigate the electrochemical oxidation of differently sized citrate-coated gold nanoparticles in the presence and absence of L-cysteine, a thiol-containing amino acid with high binding affinity to gold. We found that smaller sized (5, 10 nm) gold nanoparticles were significantly more susceptible to electrochemical L-cysteine interactions and/or L-cysteine-facilitated gold oxidation than larger (20, 50 nm) sized gold nanoparticles, both for the same mass and nominal surface area, under the conditions investigated (pH 7.4, room temperature, stagnant solutions, and scan rates of 0.5 to 450 mV/s). The electrochemical measurements of drop-casted gold nanoparticle suspensions on paraffin-impregnated graphite electrodes were susceptible to the quality of the electrode. Increased cycling resulted in irreversible oxidation and detachment/oxidation of gold into solution. Our results suggest that L-cysteine-gold interactions are stronger for smaller nanoparticles.

show abstract

Effect of nanoparticle size on the near-surface pH-distribution in aqueous and carbonate buffered solutions

Cited by 10 publications

References 42 publications

Effect of Amino Acids on the Corrosion and Metal Release from Copper and Stainless Steel

Effect of Amino Acids on the Corrosion and Metal Release from Copper and Stainless Steel

Investigation of the Influence of Wound-Treatment-Relevant Buffer Systems on the Colloidal and Optical Properties of Gold Nanoparticles

Electrochemical Estimations of the Gold Nanoparticle Size Effect on Cysteine-Gold Oxidation

Contact Info

Product

Resources

About