TY  - JOUR
A1  - Doering, Ulrike
A1  - Grigoriev, Dmitry
A1  - Tapio, Kosti
A1  - Bald, Ilko
A1  - Böker, Alexander
T1  - Synthesis of nanostructured protein-mineral-microcapsules by sonication
JF  - Soft matter
N2  - 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.
Y1  - 2022
U6  - https://doi.org/10.1039/d1sm01638e
SN  - 1744-6848
VL  - 18
IS  - 13
SP  - 2558
EP  - 2568
PB  - Royal Society of Chemistry
CY  - London
ER  - 
TY  - JOUR
A1  - Reifarth, Martin
A1  - Bekir, Marek
A1  - Bapolisi, Alain M.
A1  - Titov, Evgenii
A1  - Nusshardt, Fabian
A1  - Nowaczyk, Julius
A1  - Grigoriev, Dmitry
A1  - Sharma, Anjali
A1  - Saalfrank, Peter
A1  - Santer, Svetlana
A1  - Hartlieb, Matthias
A1  - Böker, Alexander
T1  - A dual pH- and light-responsive spiropyrane-based surfactant
BT  - investigations on Its switching behavior and remote control over emulsion stability
JF  - Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker ; International edition
N2  - 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.
KW  - Dual-Responsiveness
KW  - Manipulation of Emulsion Stability
KW  - Spiropyrane
KW  - Surfactant
KW  - Switchable Surfactants
KW  - pH-Dependent Photoresponsivity
Y1  - 2022
U6  - https://doi.org/10.1002/anie.202114687
SN  - 1433-7851
SN  - 1521-3773
VL  - 61
IS  - 21
PB  - Wiley-VCH
CY  - Weinheim
ER  -