RESUMO
The structural integrity of living plant cells heavily relies on the plant cell wall containing a nanofibrous cellulose skeleton. Hence, if synthetic plant cells consist of such a cell wall, they would allow for manipulation into more complex synthetic plant structures. Herein, we have overcome the fundamental difficulties associated with assembling lipid vesicles with cellulosic nanofibers (CNFs). We prepare plantosomes with an outer shell of CNF and pectin, and beneath this, a thin layer of lipids (oleic acid and phospholipids) that surrounds a water core. By exploiting the phase behavior of the lipids, regulated by pH and Mg2+ ions, we form vesicle-crowded interiors that change the outer dimension of the plantosomes, mimicking the expansion in real plant cells during, e.g., growth. The internal pressure enables growth of lipid tubules through the plantosome cell wall, which paves the way to the development of hierarchical plant structures and advanced synthetic plant cell mimics.
Assuntos
Células Artificiais/metabolismo , Materiais Biomiméticos/metabolismo , Parede Celular/metabolismo , Células Vegetais/metabolismo , Células Artificiais/citologia , Materiais Biomiméticos/química , Cápsulas/química , Cápsulas/metabolismo , Parede Celular/química , Parede Celular/ultraestrutura , Celulose/química , Microfluídica , Nanofibras/química , Ácido Oleico/química , Pectinas/químicaRESUMO
A newly developed high-pressure rheometer for in situ X-ray scattering experiments is described. A commercial rheometer was modified in such a way that X-ray scattering experiments can be performed under different pressures and shear. First experiments were carried out on hyaluronan, a ubiquitous biopolymer that is important for different functions in the body such as articular joint lubrication. The data hint at a decreased electrostatic interaction at higher pressure, presumably due to the increase of the dielectric constant of water by 3% and the decrease of the free volume at 300â bar.
RESUMO
The development of a dedicated small-angle X-ray scattering setup for the investigation of complex fluids at different controlled shear conditions is reported. The setup utilizes a microfluidics chip with a narrowing channel. As a consequence, a shear gradient is generated within the channel and the effect of shear rate on structure and interactions is mapped spatially. In a first experiment small-angle X-ray scattering is utilized to investigate highly concentrated protein solutions up to a shear rate of 300000â s(-1). These data demonstrate that equilibrium clusters of lysozyme are destabilized at high shear rates.
