@article{DoeringGrigorievTapioetal.2022, author = {Doering, Ulrike and Grigoriev, Dmitry and Tapio, Kosti and Bald, Ilko and B{\"o}ker, Alexander}, title = {Synthesis of nanostructured protein-mineral-microcapsules by sonication}, series = {Soft matter}, volume = {18}, journal = {Soft matter}, number = {13}, publisher = {Royal Society of Chemistry}, address = {London}, issn = {1744-6848}, doi = {10.1039/d1sm01638e}, pages = {2558 -- 2568}, year = {2022}, abstract = {We propose a simple and eco-friendly method for the formation of composite protein-mineral-microcapsules induced by ultrasound treatment. Protein- and nanoparticle-stabilized oil-in-water (O/W) emulsions loaded with different oils are prepared using high-intensity ultrasound. The formation of thin composite mineral proteinaceous shells is realized with various types of nanoparticles, which are pre-modified with Bovine Serum Albumin (BSA) and subsequently characterized by EDX, TGA, zeta potential measurements and Raman spectroscopy. Cryo-SEM and EDX mapping visualizations show the homogeneous distribution of the densely packed nanoparticles in the capsule shell. In contrast to the results reported in our previous paper,(1) the shell of those nanostructured composite microcapsules is not cross-linked by the intermolecular disulfide bonds between BSA molecules. Instead, a Pickering-Emulsion formation takes place because of the amphiphilicity-driven spontaneous attachment of the BSA-modified nanoparticles at the oil/water interface. Using colloidal particles for the formation of the shell of the microcapsules, in our case silica, hydroxyapatite and calcium carbonate nanoparticles, is promising for the creation of new functional materials. The nanoparticulate building blocks of the composite shell with different chemical, physical or morphological properties can contribute to additional, sometimes even multiple, features of the resulting capsules. Microcapsules with shells of densely packed nanoparticles could find interesting applications in pharmaceutical science, cosmetics or in food technology.}, language = {en} } @article{MehrGrigorievHeatonetal.2020, author = {Mehr, Fatemeh Naderi and Grigoriev, Dmitry and Heaton, Rebecca and Baptiste, Joshua and Stace, Anthony J. and Puretskiy, Nikolay and Besley, Elena and B{\"o}ker, Alexander}, title = {Self-assembly behavior of oppositely charged inverse bipatchy microcolloids}, series = {Small : nano micro}, volume = {16}, journal = {Small : nano micro}, number = {14}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1613-6810}, doi = {10.1002/smll.202000442}, pages = {9}, year = {2020}, abstract = {A directed attractive interaction between predefined "patchy" sites on the surfaces of anisotropic microcolloids can provide them with the ability to self-assemble in a controlled manner to build target structures of increased complexity. An important step toward the controlled formation of a desired superstructure is to identify reversible electrostatic interactions between patches which allow them to align with one another. The formation of bipatchy particles with two oppositely charged patches fabricated using sandwich microcontact printing is reported. These particles spontaneously self-aggregate in solution, where a diversity of short and long chains of bipatchy particles with different shapes, such as branched, bent, and linear, are formed. Calculations show that chain formation is driven by a combination of attractive electrostatic interactions between oppositely charged patches and the charge-induced polarization of interacting particles.}, language = {en} } @misc{ZimmermannStompsSchulteOsseilietal.2020, author = {Zimmermann, Marc and Stomps, Benjamin Ren{\´e} Harald and Schulte-Osseili, Christine and Grigoriev, Dmitry and Ewen, Dirk and Morgan, Andrew and B{\"o}ker, Alexander}, title = {Organic dye anchor peptide conjugates as an advanced coloring agent for polypropylene yarn}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {1-2}, issn = {1866-8372}, doi = {10.25932/publishup-54891}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-548913}, pages = {14}, year = {2020}, abstract = {Polypropylene as one of the world's top commodity polymers is also widely used in the textile industry. However, its non-polar nature and partially crystalline structure significantly complicate the process of industrial coloring of polypropylene. Currently, textiles made of polypropylene or with a significant proportion of polypropylene are dyed under quite harsh conditions, including the use of high pressures and temperatures, which makes this process energy intensive. This research presents a three-step synthesis of coloring agents, capable of adhering onto synthetic polypropylene yarns without harsh energy-consuming conditions. This is possible by encapsulation of organic pigments using trimethoxyphenylsilane, introduction of surface double bonds via modification of the silica shell with trimethoxysilylpropylmethacrylate and final attachment of highly adhesive anchor peptides using thiol-ene chemistry. We demonstrate the applicability of this approach by dyeing polypropylene yarns in a simple process under ambient conditions after giving a step-by-step guide for the synthesis of these new dyeing agents. Finally, the successful dyeing of the yarns is visualized, and its practicability is discussed.}, language = {en} } @article{ZimmermannStompsSchulteOsseilietal.2020, author = {Zimmermann, Marc and Stomps, Benjamin Ren{\´e} Harald and Schulte-Osseili, Christine and Grigoriev, Dmitry and Ewen, Dirk and Morgan, Andrew and B{\"o}ker, Alexander}, title = {Organic dye anchor peptide conjugates as an advanced coloring agent for polypropylene yarn}, series = {Textile Research Journal}, volume = {91}, journal = {Textile Research Journal}, number = {1-2}, publisher = {Sage Publ.}, address = {London}, issn = {0040-5175}, doi = {10.1177/0040517520932231}, pages = {28 -- 39}, year = {2020}, abstract = {Polypropylene as one of the world's top commodity polymers is also widely used in the textile industry. However, its non-polar nature and partially crystalline structure significantly complicate the process of industrial coloring of polypropylene. Currently, textiles made of polypropylene or with a significant proportion of polypropylene are dyed under quite harsh conditions, including the use of high pressures and temperatures, which makes this process energy intensive. This research presents a three-step synthesis of coloring agents, capable of adhering onto synthetic polypropylene yarns without harsh energy-consuming conditions. This is possible by encapsulation of organic pigments using trimethoxyphenylsilane, introduction of surface double bonds via modification of the silica shell with trimethoxysilylpropylmethacrylate and final attachment of highly adhesive anchor peptides using thiol-ene chemistry. We demonstrate the applicability of this approach by dyeing polypropylene yarns in a simple process under ambient conditions after giving a step-by-step guide for the synthesis of these new dyeing agents. Finally, the successful dyeing of the yarns is visualized, and its practicability is discussed.}, language = {en} } @article{HaaseGrigorievMoehwaldetal.2011, author = {Haase, Martin F. and Grigoriev, Dmitry and Moehwald, Helmuth and Tiersch, Brigitte and Shchukin, Dmitry G.}, title = {Nanoparticle modification by weak polyelectrolytes for pH-sensitive pickering emulsions}, series = {Langmuir}, volume = {27}, journal = {Langmuir}, number = {1}, publisher = {American Chemical Society}, address = {Washington}, issn = {0743-7463}, doi = {10.1021/la1027724}, pages = {74 -- 82}, year = {2011}, abstract = {The affinity of weak polyelectrolyte coated oxide particles to the oil-water interface can be controlled by the degree of dissociation and the thickness of the weak polyelectrolyte layer. Thereby the oil in water (o/w) emulsification ability of the particles can be enabled. We selected the weak polyacid poly(methacrylic acid sodium salt) and the weak polybase poly(allylamine hydrochloride) for the surface modification of oppositely charged alumina and silica colloids, respectively. The isoelectric point and the pH range of colloidal stability of both particle-polyelectrolyte composites depend on the thickness of the weak polyelectrolyte layer. The pH-dependent wettability of a weak polyelectrolyte-coated oxide surface is characterized by contact angle measurements. The o/w emulsification properties of both particles for the nonpolar oil dodecane and the more polar oil diethylphthalate are investigated by measurements of the droplet size distributions. Highly stable emulsions can be obtained when the degree of dissociation of the weak polyelectrolyte is below 80\%. Here the average droplet size depends on the degree of dissociation, and a minimum can be found when 15 to 45\% of the monomer units are dissociated. The thickness of the adsorbed polyelectrolyte layer strongly influences the droplet size of dodecane/water emulsion droplets but has a less pronounced impact on the diethylphthalate/water droplets. We explain the dependency of the droplet size on the emulsion pH value and the polyelectrolyte coating thickness with arguments based on the particle-wetting properties, the particle aggregation state, and the oil phase polarity. Cryo-SEM visualization shows that the regularity of the densely packed particles on the oil-water interface correlates with the degree of dissociation of the corresponding polyelectrolyte.}, language = {en} } @article{MehrGrigorievPuretskiyetal.2019, author = {Mehr, Fatemeh Naderi and Grigoriev, Dmitry and Puretskiy, Nikolay and B{\"o}ker, Alexander}, title = {Mono-patchy zwitterionic microcolloids as building blocks for pH-controlled self-assembly}, series = {Soft matter}, volume = {15}, journal = {Soft matter}, number = {11}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1744-683X}, doi = {10.1039/c8sm02151a}, pages = {2430 -- 2438}, year = {2019}, abstract = {A directional molecular interaction between microcolloids can be achieved through pre-defined sites on their surface, patches, which might make them follow each other in a controlled way and assemble into target structures of more complexity. In this article, we report the successful generation and characterization of mono-patchy melamine-formaldehyde microparticles with oppositely charged patches made of poly(methyl vinyl ether-alt-maleic acid) or polyethyleneimine via microcontact printing. The study of their self-aggregation behavior in solution shows that by change of pH, particle dimers are formed via attractive electrostatic force between the patchy and non-patchy surface of the particles, which reaches its optimum at a specific pH.}, language = {en} } @article{ZimmermannJohnGrigorievetal.2018, author = {Zimmermann, Marc and John, Daniela and Grigoriev, Dmitry and Puretskiy, Nikolay and B{\"o}ker, Alexander}, title = {From 2D to 3D patches on multifunctional particles}, series = {Soft matter}, volume = {14}, journal = {Soft matter}, number = {12}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1744-683X}, doi = {10.1039/c8sm00163d}, pages = {2301 -- 2309}, year = {2018}, abstract = {A straightforward approach for the precise multifunctional surface modification of particles with three-dimensional patches using microcontact printing is presented. By comparison to previous works it was possible to not only control the diameter, but also to finely tune the thickness of the deposited layer, opening up the way for three-dimensional structures and orthogonal multifunctionality. The use of PEI as polymeric ink, PDMS stamps for microcontact printing on silica particles and the influence of different solvents during particle release on the creation of functional particles with three-dimensional patches are described. Finally, by introducing fluorescent properties by incorporation of quantum dots into patches and by particle self-assembly via avidin-biotin coupling, the versatility of this novel modification method is demonstrated.}, language = {en} } @article{HaaseGrigorievMoehwaldetal.2010, author = {Haase, Martin F. and Grigoriev, Dmitry and Moehwald, Helmuth and Tiersch, Brigitte and Shchukin, Dmitry G.}, title = {Encapsulation of amphoteric substances in a pH-sensitive pickering emulsion}, issn = {1932-7447}, doi = {10.1021/Jp104052s}, year = {2010}, abstract = {Oil-in-water (o/w) Pickering emulsions stabilized with silica nanoparticles were prepared. Droplets of diethyl phthalate (oil phase) act as reservoirs for 8-hydroxyquinoline (8-HQ), which is used as (a) the hydrophobizing agent for the silica particles and (b) an encapsulated corrosion inhibitor for application in active feedback coatings. The hydrophobization of silica nanoparticles with 8-HQ is determined by the amount of this agent adsorbed on the nanoparticle surface. The latter is governed by the 8-HQ concentration in the aqueous phase, which in turn depends on the degree of protonation and fir ally on the pH. We observe three ranges of 8-HQ adsorption value with respect to nanoparticle hydophobization: (I) insufficient, (2) sufficient, and (3) excessive adsorption by the formation of an 8-HQ bilayer, where only case 2 leads to the necessary nanoparticle hydrophobization. Hence emulsions stable in a narrow pH window between pH 5.5 and 4.4 follow. Here functional molecules are sufficiently charged to compensate for the charges on silica nanoparticles to make them interfacially active and thus able to stabilize an emulsion but they are still to a large extent uncharged and thereby remain in the oil phase. The emulsification is reversible upon changing the pH to a value beyond the stability region.}, language = {en} } @article{ZimmermannGrigorievPuretskiyetal.2018, author = {Zimmermann, Marc and Grigoriev, Dmitry and Puretskiy, Nikolay and B{\"o}ker, Alexander}, title = {Characteristics of microcontact printing with polyelectrolyte ink for the precise preparation of patches on silica particles}, series = {RSC Advances}, volume = {8}, journal = {RSC Advances}, number = {69}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {2046-2069}, doi = {10.1039/c8ra07955b}, pages = {39241 -- 39247}, year = {2018}, abstract = {This publication demonstrates the abilities of a precise and straightforward microcontact printing approach for the preparation of patchy silica particles. In a broad particle size range, it is possible to finely tune the number and parameters of three-dimensional patches like diameter and thickness using only polyethyleneimine ink, poly(dimethoxysilane) as stamp material and a suitable release solvent.}, language = {en} } @article{DoeringGrigorievTapioetal.2021, author = {Doering, Ulrike and Grigoriev, Dmitry and Tapio, Kosti and Rosencrantz, Sophia and Rosencrantz, Ruben R. and Bald, Ilko and B{\"o}ker, Alexander}, title = {About the mechanism of ultrasonically induced protein capsule formation}, series = {RSC Advances : an international journal to further the chemical sciences / Royal Society of Chemistry}, volume = {11}, journal = {RSC Advances : an international journal to further the chemical sciences / Royal Society of Chemistry}, number = {27}, publisher = {RSC Publishing}, address = {London}, issn = {2046-2069}, doi = {10.1039/d0ra08100k}, pages = {16152 -- 16157}, year = {2021}, abstract = {In this paper, we propose a consistent mechanism of protein microcapsule formation upon ultrasound treatment. Aqueous suspensions of bovine serum albumin (BSA) microcapsules filled with toluene are prepared by use of high-intensity ultrasound following a reported method. Stabilization of the oil-in-water emulsion by the adsorption of the protein molecules at the interface of the emulsion droplets is accompanied by the creation of the cross-linked capsule shell due to formation of intermolecular disulfide bonds caused by highly reactive species like superoxide radicals generated sonochemically. The evidence for this mechanism, which until now remained elusive and was not proven properly, is presented based on experimental data from SDS-PAGE, Raman spectroscopy and dynamic light scattering.}, language = {en} } @article{ReifarthBekirBapolisietal.2022, author = {Reifarth, Martin and Bekir, Marek and Bapolisi, Alain M. and Titov, Evgenii and Nusshardt, Fabian and Nowaczyk, Julius and Grigoriev, Dmitry and Sharma, Anjali and Saalfrank, Peter and Santer, Svetlana and Hartlieb, Matthias and B{\"o}ker, Alexander}, title = {A dual pH- and light-responsive spiropyrane-based surfactant}, series = {Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker ; International edition}, volume = {61}, journal = {Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker ; International edition}, number = {21}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1433-7851}, doi = {10.1002/anie.202114687}, pages = {10}, year = {2022}, abstract = {A cationic surfactant containing a spiropyrane unit is prepared exhibiting a dual-responsive adjustability of its surface-active characteristics. The switching mechanism of the system relies on the reversible conversion of the non-ionic spiropyrane (SP) to a zwitterionic merocyanine (MC) and can be controlled by adjusting the pH value and via light, resulting in a pH-dependent photoactivity: While the compound possesses a pronounced difference in surface activity between both forms under acidic conditions, this behavior is suppressed at a neutral pH level. The underlying switching processes are investigated in detail, and a thermodynamic explanation based on a combination of theoretical and experimental results is provided. This complex stimuli-responsive behavior enables remote-control of colloidal systems. To demonstrate its applicability, the surfactant is utilized for the pH-dependent manipulation of oil-in-water emulsions.}, language = {en} }