Química Inorgánica
https://hdl.handle.net/11441/10918
2024-03-19T11:42:20ZBiodegradable particles for protein delivery: estimation of the release kinetics inside cells
https://hdl.handle.net/11441/155236
Biodegradable particles for protein delivery: estimation of the release kinetics inside cells
A methodology to quantify the efficiency of the protein loading and in-vitro delivery for biodegradable capsules
with different architectures based on polyelectrolytes (dextran sulfate, poly-L-arginine and polyethylenimine)
and SiO2 was developed. The capsules were loaded with model proteins such as ovalbumin and green fluorescent
protein (GFP), and the protein release profile inside cells (either macrophages or HeLa cells) after endocytosis
was analysed. Both, protein loading and release kinetics were evaluated by analysing confocal laser scanning
microscopy images using MatLab and CellProfiler software. Our results indicate that silica capsules showed the
most efficient release of proteins as cargo molecules within 48 h, as compared to their polymeric counterparts.
This developed method for the analysis of the intracellular cargo release kinetics from carrier structures could be
used in the future for a better control of drug release profiles.
2022-08-01T00:00:00ZLarge-Scale Synthesis of Hybrid Conductive Polymer-Gold Nanoparticles Using "sacrificial" Weakly Binding Ligands for Printing Electronics
https://hdl.handle.net/11441/154514
Large-Scale Synthesis of Hybrid Conductive Polymer-Gold Nanoparticles Using "sacrificial" Weakly Binding Ligands for Printing Electronics
We describe the gram-scale synthesis of hybrid gold nanoparticles with a shell of conductive polymers. A large-scale synthesis of hexadecyltrimethylammonium bromide (CTAB)-capped gold nanoparticles (AuNP@CTAB) was followed by ligand exchange with conductive polymers based on thiophene in a 10 L reactor equipped with a jacket to ensure a constant temperature of 40 °C and a mechanical stirrer. Slow and controlled reduction of the gold precursors and the presence of small amounts of silver nitrate are revealed to be the critical synthesis variables to obtain particles with a sufficiently narrow size distribution. Batches of approximately 10 g of faceted AuNP@CTAB with tunable average particle sizes from 54 to 85 nm were obtained per batch. Ligand exchange with poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) in the same reactor then yielded hybrid Au@PEDOT:PSS nanoparticles. They were used to formulate sinter-free inks for the inkjet printing of conductive structures without the need for a sintering step.
2021-11-15T00:00:00ZBiodegradation of Bi-Labeled Polymer-Coated Rare-Earth Nanoparticles in Adherent Cell Cultures
https://hdl.handle.net/11441/154513
Biodegradation of Bi-Labeled Polymer-Coated Rare-Earth Nanoparticles in Adherent Cell Cultures
The fate of polymer-coated Eu-and Bi-doped GdVO4 nanoparticles (NPs) of cubic shape upon cellular internalization was investigated. After having been endocytosed by cells, the cubic Eu-and Bi-doped GdVO4 NP cores were partly dissolved and reshaped to rounded structures, which in control experiments could be ascribed to the acidic conditions present in endosomes/lysosomes. With progress of time, there was a significant reduction in the amount of internalized NPs per cell due to proliferation. This was of higher extent than NP exocytosis. Data of the study are compatible with the scenario that endosomal/lysosomal enzymes may partly digest the polymer shell around the NP cores, with enhanced exocytosis of the polymer fragments as compared to the NP cores.
2020-01-14T00:00:00ZConfining Iron Oxide Nanocubes inside Submicrometric Cavities as a Key Strategy to Preserve Magnetic Heat Losses in an Intracellular Environment
https://hdl.handle.net/11441/154512
Confining Iron Oxide Nanocubes inside Submicrometric Cavities as a Key Strategy to Preserve Magnetic Heat Losses in an Intracellular Environment
The design of magnetic nanostructures whose magnetic heating efficiency remains unaffected at the tumor site is a fundamental requirement to further advance magnetic hyperthermia in the clinic. This work demonstrates that the confinement of magnetic nanoparticles (NPs) into a sub-micrometer cavity is a key strategy to enable a certain degree of nanoparticle motion and minimize aggregation effects, consequently preserving the magnetic heat loss of iron oxide nanocubes (IONCs) under different conditions, including intracellular environments. We fabricated magnetic layer-by-layer (LbL) self-assembled polyelectrolyte sub-micrometer capsules using three different approaches, and we studied their heating efficiency as obtained in aqueous dispersions and after internalization by tumor cells. First, IONCs were added to the hollow cavities of LbL submicrocapsules, allowing the IONCs to move to a certain extent in the capsule cavities. Second, IONCs were coencapsulated into solid calcium carbonate cores coated with LbL polymer shells. Third, IONCs were incorporated within the polymer layers of the LbL capsule walls. In aqueous solution, higher specific absorption rate (SAR) values were related to those of free IONCs, while lower SAR values were recorded for capsule/core assemblies. However, after uptake by cancer cell lines (SKOV-3 cells), the SAR values of the free IONCs were significantly lower than those observed for capsule/core assemblies, especially after prolonged incubation periods (24 and 48 h). These results show that IONCs packed into submicrocavities preserve the magnetic losses, as the SAR values remained almost invariable. Conversely, free IONCs without the protective capsule shell agglomerated and their magnetic losses were strongly reduced. Indeed, IONC-loaded capsules and free IONCs reside inside endosomal and lysosomal compartments after cellular uptake and show strongly reduced magnetic losses due to the immobilization and aggregation in centrosymmetrical structures in the intracellular vesicles. The confinement of IONCs into sub-micrometer cavities is a key strategy to provide a sustained and predictable heating dose inside biological matrices.
2019-11-19T00:00:00Z