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Dawid Lupa

Bio: Dawid Lupa is an academic researcher from Polish Academy of Sciences. The author has contributed to research in topics: Nanoparticle & Chemistry. The author has an hindex of 3, co-authored 9 publications receiving 56 citations.

Papers
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Journal ArticleDOI
01 May 2016
TL;DR: It was shown that the theoretical model adequately reflects the main features of the experimental results, especially the significant increase in the dissolution rate for lower pH, and the presence of two kinetic regimes was quantitatively explained in terms of the decrease in the coverage of the fast dissolving oxide layer.
Abstract: A general model of an oxidative dissolution of silver particle suspensions was developed that rigorously considers the bulk and surface solute transport. A two-step surface reaction scheme was proposed that comprises the formation of the silver oxide phase by direct oxidation and the acidic dissolution of this phase leading to silver ion release. By considering this, a complete set of equations is formulated describing oxygen and silver ion transport to and from particles' surfaces. These equations are solved in some limiting cases of nanoparticle dissolution in dilute suspensions. The obtained kinetic equations were used for the interpretation of experimental data pertinent to the dissolution kinetics of citrate-stabilized silver nanoparticles. In these kinetic measurements the role of pH and bulk suspension concentration was quantitatively evaluated by using the atomic absorption spectrometry (AAS). It was shown that the theoretical model adequately reflects the main features of the experimental results, especially the significant increase in the dissolution rate for lower pH. Also the presence of two kinetic regimes was quantitatively explained in terms of the decrease in the coverage of the fast dissolving oxide layer. The overall silver dissolution rate constants characterizing these two regimes were determined.

46 citations

Journal ArticleDOI
25 Jun 2018-Langmuir
TL;DR: New data acquired in this work confirm the feasibility of preparing gold nanoparticle layers on polymer microparticles characterized by a controlled structure, coverage, and electrokinetic properties.
Abstract: Formation of positively charged gold nanoparticle layers on polystyrene microparticles (PSMs600) was studied using the electrokinetic and the concentration depletion methods based on atomic force microscopy (AFM) and scanning electron microscopy (SEM) imaging. Primarily, the dependence of electrophoretic mobility of microparticles on the gold nanoparticle concentration in the suspension was measured. These results were quantitatively interpreted in terms of the three-dimensional electrokinetic model. This allowed to derive a formula for calculating the coverage of nanoparticles under in situ conditions whose validity was confirmed by direct SEM imaging of deposited gold nanoparticles (AuNPs). Additionally, the maximum coverage of gold nanoparticles for various ionic strengths was determined using a concentration depletion method based on AFM imaging of residual particles deposited on the silica substrate. The maximum coverage increased with ionic strength attaining a value of 0.35 for the ionic strength o...

18 citations

Journal ArticleDOI
TL;DR: In this paper, an alternative route is developed consisting in a deposition of positively charged gold nanoparticles on silica carrier microparticles in an electrostatic interaction driven colloidal self-assembly process.

14 citations

Journal ArticleDOI
TL;DR: In this article , the authors discuss the structural complexity of lipid membranes, as well as the importance to simplify studied systems in order to understand phenomena occurring in natural, complex membranes, such systems require a model interface to be analyzed.

7 citations

Journal ArticleDOI
TL;DR: In this paper, the authors acknowledge partial financial support from the National Science Centre Poland under the OPUS grant number UMO-2016/21/B/ST4/03798.
Abstract: The authors acknowledge partial financial support from the National Science Centre Poland under the OPUS grant number UMO-2016/21/B/ST4/03798. M.G and P.W. acknowledge the fellowship with project no. POWR. 03.02.00-00-I013/16. This research was supported in part by PLGrid (CYFRONET) Infrastructure, by the Spanish Ministerio de Ciencia e Innovacion (grant PGC2018-094852-B-C21 and PID2019-107098RJ-I00), the Generalitat Valenciana (grant AICO/2019/195 and SEJI/2020/007) and Universitat Jaume I (grant UJI·B2020-031 and UJI-A2019-04). We acknowledge the joint consortium “Interdisciplinary Centre of Physical, Chemical and Biological Sciences” of ICSC PAS and INP PAS for providing access to the Agilent 1290 Infinity System with an automatic autosampler and an M.S. Agilent 6460 Triple Quad Detector.

6 citations


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02 Oct 2014
TL;DR: This review discusses the major transformation processes of Ag-NPs in various aqueous environments, particularly transformations of the metallic Ag cores caused by reactions with (in)organic ligands, and the effects of such transformations on physical and chemical stability and toxicity.
Abstract: Silver nanoparticles (Ag-NPs) readily transform in the environment, which modifies their properties and alters their transport, fate, and toxicity. It is essential to consider such transformations when assessing the potential environmental impact of Ag-NPs. This review discusses the major transformation processes of Ag-NPs in various aqueous environments, particularly transformations of the metallic Ag cores caused by reactions with (in)organic ligands, and the effects of such transformations on physical and chemical stability and toxicity. Thermodynamic arguments are used to predict what forms of oxidized silver will predominate in various environmental scenarios. Silver binds strongly to sulfur (both organic and inorganic) in natural systems (fresh and sea waters) as well as in wastewater treatment plants, where most Ag-NPs are expected to be concentrated and then released. Sulfidation of Ag-NPs results in a significant decrease in their toxicity due to the lower solubility of silver sulfide, potentiall...

145 citations

Journal ArticleDOI
TL;DR: The mechanisms behind the confrontation of bacteria against various drugs and the effect of physico-chemical properties of silver species on their bactericidal action are discussed as well as the available reports on bacterial transcriptomic and proteomic profiles upon the exposure of various silver species are critically evaluated.

133 citations

Journal ArticleDOI
TL;DR: In this paper, the authors quantify the kinetics, pH, and size dependency of silver ion (Ag+) release from AgNPs and explain their results in a consistent manner with a mechanistic view.
Abstract: Oxidative dissolution has large implications for the environmental fate and toxicity of silver nanoparticles (AgNPs). In this study, we quantify the kinetics, pH, and size dependency of silver ion (Ag+) release from AgNPs and explain our results in a consistent manner with a mechanistic view. Pristine AgNPs are covered by partially oxidized silver present in a single layer of subvalent Ag3OH groups that will be released by oxidative dissolution via two different pathways. Undersaturation of a solution, created by acidification, will initiate a fast oxidative dissolution process in which a pristine surface can be opened at particular points that grow laterally until a full layer of Ag is stripped off. At the newly exposed surface, Ag3OH is reformed. The opening of new spots stops due to increasing Ag+ concentrations. Via another pathway, the initial Ag3OH can be released by oxidative dissolution while simultaneously a new stable surface state is built with subvalent silver in two layers. This process is initiated by dilution and is visible around neutral pH values and may release a maximum of 30 ± 1 μmol Ag+ m−2. Its equilibration can be well described with a formulated thermodynamic model. The equilibrium constant (log K) is linearly related to the specific surface area of the AgNPs used, but can be shifted by the type of capping agent. The particle size dependency of the log K can be attributed to a surface Gibbs free energy contribution of 0.7 ± 0.1 J m−2. Ag+ release by stripping is relatively fast (∼1 day) in contrast to the process that leads to equilibration of two types of surface species that differ in the amount of subvalent silver. For this process, a kinetic Langmuir model has been developed in which the rate of Ag+ release is governed by adsorbed molecular oxygen that can be activated via a proton, while adsorption of molecular oxygen by itself can become rate limiting in the initial stage of dissolution with high rates of release. In our study with data of different kinds, the overall release and equilibration by AgNPs has been interpreted successfully with a coherent, overarching mechanistic view.

92 citations

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TL;DR: The main focus of this review is recent advances in the preparation of bio-based nanostructures as mentioned in this paper, which can be presented in various shapes, including spheres, boxes, tubes, nanorods and nanohorns.

66 citations

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TL;DR: Antibacterial properties of nanoAg were addressed by determining their minimal bactericidal concentrations in deionised water to minimise the influence of silver speciation on its bioavailability and were the interplay of NP size, solubility and surface coating.

59 citations