Change search
Link to record
Permanent link

Direct link
BETA
Chaudhary, Himanshu
Publications (4 of 4) Show all publications
Chaudhary, H., Ferreira Fernandes, R. M., Gowda, V., Claessens, M. M. A., Furo, I. & Lendel, C. (2019). Intrinsically disordered protein as carbon nanotube dispersant: How dynamic interactions lead to excellent colloidal stability. Journal of Colloid and Interface Science, 556, 172-179
Open this publication in new window or tab >>Intrinsically disordered protein as carbon nanotube dispersant: How dynamic interactions lead to excellent colloidal stability
Show others...
2019 (English)In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 556, p. 172-179Article in journal (Refereed) Published
Abstract [en]

The rich pool of protein conformations combined with the dimensions and properties of carbon nanotubes create new possibilities in functional materials and nanomedicine. Here, the intrinsically disordered protein α-synuclein is explored as a dispersant of single-walled carbon nanotubes (SWNTs) in water. We use a range of spectroscopic methods to quantify the amount of dispersed SWNT and to elucidate the binding mode of α-synuclein to SWNT. The dispersion ability of α-synuclein is good even with mild sonication and the obtained dispersion is very stable over time. The whole polypeptide chain is involved in the interaction accompanied by a fraction of the chain changing into a helical structure upon binding. Similar to other dispersants, we observe that only a small fraction (15–20%) of α-synuclein is adsorbed on the SWNT surface with an average residence time below 10 ms

Place, publisher, year, edition, pages
Academic Press, 2019
National Category
Physical Chemistry
Identifiers
urn:nbn:se:kth:diva-258234 (URN)10.1016/j.jcis.2019.08.050 (DOI)2-s2.0-85070901886 (Scopus ID)
Note

QC 20191014

Available from: 2019-09-10 Created: 2019-09-10 Last updated: 2019-10-15Bibliographically approved
Atapour, M., Wei, Z., Chaudhary, H., Lendel, C., Odnevall Wallinder, I. & Hedberg, Y. (2019). Metal release from stainless steel 316L in whey protein - And simulated milk solutions under static and stirring conditions. Food Control, 101, 163-172
Open this publication in new window or tab >>Metal release from stainless steel 316L in whey protein - And simulated milk solutions under static and stirring conditions
Show others...
2019 (English)In: Food Control, ISSN 0956-7135, E-ISSN 1873-7129, Vol. 101, p. 163-172Article in journal (Refereed) Published
Abstract [en]

Stainless steel is an important transport and processing contact material for bovine milk and dairy products. Release (migration) of metals, ions, complexes or wear debris/particles, and metal-induced protein aggregation in such environments are hence important to consider both from a corrosion and food safety perspective. This study aims on investigating the release of iron (Fe), chromium (Cr), and nickel (Ni) from AISI 316L stainless steel in contact with whey protein solutions relevant for protein drinks, and on how the whey proteins are influenced by stirring with a magnetic stir bar and metal release. Mechanistic insight is gained by parallel investigations of metal release from two reference non-protein containing solutions, a metal-complexing (citrate-containing) simulated milk solution (SMS) and a low complexing phosphate buffered saline solution (PBS). All immersion exposures were conducted at pH 6.8 for 0.5, 4, 24 and 48 hat room temperature at static and stirring conditions. All solutions and samples were investigated using different chemical, spectroscopic, microscopic, and electrochemical methods. Significantly higher amounts of Fe, Cr, and Ni were released into the whey protein solution (80 g/L) as compared to SMS and PBS. Strong enrichment of Cr in the surface oxide and reduction of the surface oxide thickness were associated with a higher amount of Ni release in the metal-complexing solutions (SMS and whey protein) compared with PBS. Stirring conditions resulted in higher amounts of metal release, enrichment of Cr in the surface oxide, and clear signs of wear of the 316L surface in all solutions compared to static conditions. The wear mechanism in the whey protein solution was different as compared to corresponding processes in SMS and PBS, involving an etching-like process and larger-sized wear debris. Electrochemical measurements at static conditions confirmed observed differences between the solutions, with the lowest corrosion resistance observed for coupons exposed in the whey protein solution, followed by SMS and PBS. Released metals in solution from the 316L coupons in contact with the whey protein solution resulted in enhanced rates of protein aggregation and precipitation of protein aggregates from solution. Further studies should be made to investigate other relevant test conditions and assess toxicological risks.

Place, publisher, year, edition, pages
ELSEVIER SCI LTD, 2019
Keywords
Protein, Whey, Stainless steel, Metal release, Food, Milk, Atomic absorption spectroscopy, X-ray photoelectron spectroscopy, Photon cross correlation spectroscopy, UV- visible spectroscopy, Scanning electron microscopy, Polarization resistance, Corrosion
National Category
Corrosion Engineering
Identifiers
urn:nbn:se:kth:diva-251269 (URN)10.1016/j.foodcont.2019.02.031 (DOI)000465049000023 ()2-s2.0-85063112841 (Scopus ID)
Note

QC 20190513

Available from: 2019-05-13 Created: 2019-05-13 Last updated: 2019-05-29Bibliographically approved
Hedberg, Y., Dobryden, I., Chaudhary, H., Wei, Z., Claesson, P. M. & Lendel, C. (2019). Synergistic effects of metal-induced aggregation of human serum albumin. Colloids and Surfaces B: Biointerfaces, 173, 751-758
Open this publication in new window or tab >>Synergistic effects of metal-induced aggregation of human serum albumin
Show others...
2019 (English)In: Colloids and Surfaces B: Biointerfaces, ISSN 0927-7765, E-ISSN 1873-4367, Vol. 173, p. 751-758Article in journal (Refereed) Published
Abstract [en]

Exposure to cobalt (Co), chromium (Cr), and nickel (Ni) occurs often via skin contact and from different dental and orthopedic implants. The metal ions bind to proteins, which may induce structural changes and aggregation, with different medical consequences. We investigated human serum albumin (HSA) aggregation in the presence of Co-II, Cr-III, and/or Ni-II ions and/or their nanoparticle precipitates by using scattering, spectroscopic, and imaging techniques, at simulated physiological conditions (phosphate buffered saline - PBS, pH 7.3) using metal salts that did not affect the pH, and at HSA:metal molar ratios of up to 1:8. Co ions formed some solid nano particles in PBS at the investigated conditions, as determined by nanoparticle tracking analysis, but the Cr-III anions and Ni-II ions remained fully soluble. It was found that all metal ions induced HSA aggregation, and this effect was significantly enhanced when a mixture of all three metal ions was present instead of any single type of ion. Thus, the metal ions induce aggregation synergistically. HSA aggregates formed linear structures on a mica surface in the presence of Cr-III ions. A clear tendency of aggregation and linearly aligned aggregates was seen in the presence of all three metal ions. Spectroscopic investigations indicated that the majority of the HSA molecules maintained their alpha helical secondary structure and conformation. This study highlights the importance of synergistic effects of metal ions and/or their precipitates on protein aggregation, which are highly relevant for implant materials and common exposures to metals.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE BV, 2019
Keywords
Cobalt, Chromium, Nickel, Binding, Albumin, Aggregation
National Category
Physical Chemistry
Identifiers
urn:nbn:se:kth:diva-241193 (URN)10.1016/j.colsurfb.2018.10.061 (DOI)000454377300089 ()30384272 (PubMedID)2-s2.0-85055579350 (Scopus ID)
Note

QC 20190121

Available from: 2019-01-21 Created: 2019-01-21 Last updated: 2019-01-21Bibliographically approved
Tiwari, D., Mercury, L., Dijkstra, M., Chaudhary, H. & Federico Hernandez-Sanchez, J. (2018). Post-pinch-off relaxation of two-dimensional droplets in a Hele-Shaw cell. Physical Review Fluids, 3(12), Article ID 124202.
Open this publication in new window or tab >>Post-pinch-off relaxation of two-dimensional droplets in a Hele-Shaw cell
Show others...
2018 (English)In: Physical Review Fluids, E-ISSN 2469-990X, Vol. 3, no 12, article id 124202Article in journal (Refereed) Published
Abstract [en]

We report on the shape relaxation of two-dimensional (2D) droplets, formed right after the spontaneous pinch-off of a capillary bridge droplet confined within a Hele-Shaw cell. An array of bridge droplets confined within a microchip device first undergoes neck thinning due to the evaporation-driven volume change. Subsequently, an abrupt topological change transforms each bridge droplet into a small central satellite droplet and the twin droplets pinned at the edges of the cell. We monitor the shape relaxation with high-temporal-resolution optical microscopy. Capillary action drives the 2D shape relaxation, while the viscous dissipation in the film retards it. As a result, the tip of the twin droplets exhibits a self-similar parabolic shape evolution. Based on these observations, the lubrication-approximation model accurately predicts the internal pressure evolution and the droplet tip displacement. The geometrical confinement substantially slows down the dynamics, facilitating visualization of the capillary-viscous regime, even for low-viscosity liquids. The characteristic relaxation timescale shows an explicit dependence on the confinement ratio (width/gap) and the capillary velocity of liquid. We verify the broad applicability of the model using different liquids.

Place, publisher, year, edition, pages
AMER PHYSICAL SOC, 2018
Keywords
BREGEAS G, 1995, PHYSICAL REVIEW LETTERS, V75, P3886
National Category
Nano Technology
Identifiers
urn:nbn:se:kth:diva-241205 (URN)10.1103/PhysRevFluids.3.124202 (DOI)000454193900002 ()2-s2.0-85059410813 (Scopus ID)
Note

QC 20190118

Available from: 2019-01-18 Created: 2019-01-18 Last updated: 2019-04-04Bibliographically approved
Organisations

Search in DiVA

Show all publications