@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{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} }