scholarly journals Physicochemical Evaluation of Insulin Complexes with QPDMAEMA-b-PLMA-b-POEGMA Cationic Amphiphlic Triblock Terpolymer Micelles

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 309 ◽  
Author(s):  
Athanasios Skandalis ◽  
Anastasiia Murmiliuk ◽  
Miroslav Štěpánek ◽  
Stergios Pispas
Keyword(s):  
Ionic Strength ◽  
Surface Charge ◽  
Electrostatic Interactions ◽  
Protein Complexes ◽  
Force Microscopy ◽  
Atomic Force ◽  
Cationic Micelles ◽  
Micellar Aggregates ◽  
Physicochemical Evaluation ◽  
Triblock Terpolymers

Herein, poly[quaternized 2-(dimethylamino)ethyl methacrylate-b-lauryl methacrylate-b-(oligo ethylene glycol)methacrylate] (QPDMAEMA-b-PLMA-b-POEGMA) cationic amphiphilic triblock terpolymers were used as vehicles for the complexation/encapsulation of insulin (INS). The terpolymers self-assemble in spherical micelles with PLMA cores and mixed QPDMAEMA/POEGMA coronas in aqueous solutions. The cationic micelles were complexed via electrostatic interactions with INS, which contains anionic charges at pH 7. The solutions were colloidally stable in all INS ratios used. Light-scattering techniques were used for investigation of the complexation ability and the size and surface charge of the terpolymer/INS complexes. The results showed that the size of the complexes increases as INS ratio increases, while at the same time the surface charge remains positive, indicating the formation of clusters of micelles/INS complexes in the solution. Fluorescence spectroscopy measurements revealed that the conformation of the protein is not affected after the complexation with the terpolymer micellar aggregates. It was observed that as the solution ionic strength increases, the size of the QPDMAEMA-b-PLMA-b-POEGMA/INS complexes initially decreases and then remains practically constant at higher ionic strength, indicating further aggregation of the complexes. atomic force microscopy (AFM) measurements showed the existence of both clusters and isolated nanoparticulate terpolymer/protein complexes.

scholarly journals Visualization and identification of hepatitis c viral particles by atomic force microscopy combined with ms/ms analysis

2010 ◽  
Vol 56 (1) ◽  
pp. 26-39 ◽  
Author(s):  
A.L. Kaysheva ◽  
Yu.D. Ivanov ◽  
V.G. Zgoda ◽  
P.A. Frantsuzov ◽  
T.O. Pleshakova ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Hepatitis C ◽  
Protein Complexes ◽  
Mass Spectrometric ◽  
Force Microscopy ◽  
Atomic Force ◽  
Spectrometric Identification ◽  
Detection And Identification ◽  
Viral Particles ◽  
Mass Spectrometric Identification

Possibility of detection and identification of hepatitis C viral particles with mass spectrometry (MS) in combination with atomic force microscopy (AFM) had been investigated. AFM/MS approach is based on two technologies: 1. AFM-biospecific fishing that allows to detect, concentrate from solution and to count protein complexes on a surface of AFM-nanochip; 2. mass spectrometric identification of these complexes. AFM-biospecific fishing of HCVcoreAg from solution was carried onto surface of AFM-nanochips with immobilized anti-HCVcoreAg. It was shown that HCVcoreAg/anti-HCVcoreim complexes were formed onto AFM-nanochips in quantity sufficient for mass spectrometric identification. Thus, AFM/MS approach allows to identify fragments of hepatitis C virus fished onto a surface of AFM-nanochip from serum.

scholarly journals Anomalous Interfacial Structuring of a Non-Halogenated Ionic Liquid: Effect of Substrate and Temperature

2018 ◽  
Vol 2 (4) ◽  
pp. 60 ◽  
Author(s):  
Milad Radiom ◽  
Patricia Pedraz ◽  
Georgia Pilkington ◽  
Patrick Rohlmann ◽  
Sergei Glavatskih ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Surface Charge ◽  
Force Measurement ◽  
Surface Force ◽  
Solid Surfaces ◽  
Effect Of Temperature ◽  
Decay Length ◽  
Force Microscopy ◽  
Large Size ◽  
Atomic Force

We investigate the interfacial properties of the non-halogenated ionic liquid (IL), trihexyl(tetradecyl)phosphonium bis(mandelato)borate, [P6,6,6,14][BMB], in proximity to solid surfaces, by means of surface force measurement. The system consists of sharp atomic force microscopy (AFM) tips interacting with solid surfaces of mica, silica, and gold. We find that the force response has a monotonic form, from which a characteristic steric decay length can be extracted. The decay length is comparable with the size of the ions, suggesting that a layer is formed on the surface, but that it is diffuse. The long alkyl chains of the cation, the large size of the anion, as well as crowding of the cations at the surface of negatively charged mica, are all factors which are likely to oppose the interfacial stratification which has, hitherto, been considered a characteristic of ionic liquids. The variation in the decay length also reveals differences in the layer composition at different surfaces, which can be related to their surface charge. This, in turn, allows the conclusion that silica has a low surface charge in this aprotic ionic liquid. Furthermore, the effect of temperature has been investigated. Elevating the temperature to 40 °C causes negligible changes in the interaction. At 80 °C and 120 °C, we observe a layering artefact which precludes further analysis, and we present the underlying instrumental origin of this rather universal artefact.

scholarly journals Nanohydrogels Based on Self-Assembly of Cationic Pullulan and Anionic Dextran Derivatives for Efficient Delivery of Piroxicam

Pharmaceutics ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 622 ◽  
Author(s):  
Dorota Lachowicz ◽  
Przemyslaw Mielczarek ◽  
Roma Wirecka ◽  
Katarzyna Berent ◽  
Anna Karewicz ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Self Assembly ◽  
Electrostatic Interactions ◽  
Dextran Sulfate ◽  
Force Microscopy ◽  
Grafting Reaction ◽  
Atomic Force ◽  
Transmission Electron ◽  
Efficient Delivery ◽  
Model Drug

A cationic derivative of pullulan was obtained by grafting reaction and used together with dextran sulfate to form polysaccharide-based nanohydrogel cross-linked via electrostatic interactions between polyions. Due to the polycation-polyanion interactions nanohydrogel particles were formed instantly and spontaneously in water. The nanoparticles were colloidally stable and their size and surface charge could be controlled by the polycation/polyanion ratio. The morphology of the obtained particles was visualized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM). The resulting structures were spherical, with hydrodynamic diameters in the range of 100–150 nm. The binding constant (Ka) of a model drug, piroxicam, to the cationic pullulan (C-PUL) was determined by spectrophotometric measurements. The value of Ka was calculated according to the Benesi—Hildebrand equation to be (3.6 ± 0.2) × 103 M−1. After binding to cationic pullulan, piroxicam was effectively entrapped inside the nanohydrogel particles and released in a controlled way. The obtained system was efficiently taken up by cells and was shown to be biocompatible.

Comparison of atomic force microscopy and zeta potential derived surface charge density

2020 ◽  
Vol 130 (3) ◽  
pp. 36001
Author(s):  
M. Herzberg ◽  
S. Dobberschütz ◽  
D. Okhrimenko ◽  
N. E. Bovet ◽  
M. P. Andersson ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Zeta Potential ◽  
Charge Density ◽  
Surface Charge ◽  
Surface Charge Density ◽  
Force Microscopy ◽  
Atomic Force

Atomic Force Microscopy on RNA-Protein Complexes related to RNAi

2005 ◽  
Vol 2005 (Fall) ◽  
Author(s):  
Nils Anspach ◽  
Blagovesta Popova ◽  
Christian Hammann ◽  
Lukasz Jaskiewicz ◽  
Witold Filipowicz ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Protein Complexes ◽  
Force Microscopy ◽  
Atomic Force ◽  
Rna Protein Complexes

scholarly journals Bioadhesion of various proteins on random, diblock and triblock copolymer surfaces and the effect of pH conditions

2010 ◽  
Vol 8 (58) ◽  
pp. 630-640 ◽  
Author(s):  
Manuel L. B. Palacio ◽  
Scott R. Schricker ◽  
Bharat Bhushan
Keyword(s):  
Block Copolymers ◽  
Methyl Methacrylate ◽  
Protein Interactions ◽  
Electrostatic Interactions ◽  
Chemical Compositions ◽  
Poly Methyl Methacrylate ◽  
Force Microscopy ◽  
Atomic Force ◽  
Ph Conditions ◽  
Adhesive Interactions

The adhesive interactions of block copolymers composed of poly(methyl methacrylate) (PMMA)/poly(acrylic acid) (PAA) and poly(methyl methacrylate)/poly(2-hydroxyethyl methacrylate) (PHEMA) with the proteins fibronectin, bovine serum albumin and collagen were studied by atomic force microscopy. Adhesion experiments were performed both at physiological pH and at a slightly more acidic condition (pH 6.2) to model polymer–protein interactions under inflammatory or infectious conditions. The PMMA/PAA block copolymers were found to be more sensitive to the buffer environment than PMMA/PHEMA owing to electrostatic interactions between the ionized acrylate groups and the proteins. It was found that random, diblock and triblock copolymers exhibit distinct adhesion profiles although their chemical compositions are identical. This implies that biomaterial nanomorphology can be used to control protein–polymer interactions and potentially cell adhesion.

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