Search results for "Nanoparticles"
showing 10 items of 1286 documents
A top-down synthesis route to ultrasmall multifunctional Gd-based Silica nanoparticles for theranostic applications
2013
International audience; New, ultrasmall nanoparticles with sizes below 5 nm have been obtained. These small rigid platforms (SRP) are composed of a polysiloxane matrix with DOTAGA (1,4,7,10-tetraazacyclododecane-1-glutaric anhydride-4,7,10-triacetic acid)-Gd3+ chelates on their surface. They have been synthesised by an original top-down process: 1) formation of a gadolinium oxide Gd2O3 core, 2) encapsulation in a polysiloxane shell grafted with DOTAGA ligands, 3) dissolution of the gadolinium oxide core due to chelation of Gd3+ by DOTAGA ligands and 4) polysiloxane fragmentation. These nanoparticles have been fully characterised using photon correlation spectroscopy (PCS), transmission elec…
Stimuli-responsive hybrid materials: breathing in magnetic layered double hydroxides induced by a thermoresponsive molecule
2014
[EN] A hybrid magnetic multilayer material of micrometric size, with highly crystalline hexagonal crystals consisting of CoAl-LDH ferromagnetic layers intercalated with thermoresponsive 4-(4-anilinophenylazo)benzenesulfonate (AO5) molecules diluted (ratio 9 : 1) with a flexible sodium dodecylsulphate (SDS) surfactant has been obtained. The resulting material exhibits thermochromism attributable to the isomerization between the azo (prevalent at room temperature) and the hydrazone (favoured at higher temperatures) tautomers, leading to a thermomechanical response. In fact, these crystals exhibited thermally induced motion triggering remarkable changes in the crystal morphology and volume. In…
Magnetic Soft Matter: Book of Abstracts, 79th Scientific Conference of the University of Latvia, February 11, 2021
2021
Seminar chair is Professor Andrejs Cēbers. Seminar organizing committee includes Dārta Antāne, Ivars Driķis and Guntars Kitenbergs.
Magnetic Nanoparticles as Many-Spin Systems
2005
We have demonstrated by different analytical and numerical methods the importance of accounting for the magnetization inhomogeneities in magnetic nanoparticles, especially in the presence of surface anisotropy. The latter makes the magnetization inhomogeneous even at T = 0 and in general modifies the relation between the intrinsic and induced magnetizations. It also changes the magnetization switching mechanism, since for strong surface anisotropy the particle’s spins switch cluster-wise. For weak surface anisotropy we have been able to calculate the spin canting in the particle analytically and to obtain a novel second-order contribution to the particle’s overall anisotropy. It remains to …
Systemic RNA delivery to dendritic cells exploits antiviral defence for cancer immunotherapy
2016
Lymphoid organs, in which antigen presenting cells (APCs) are in close proximity to T cells, are the ideal microenvironment for efficient priming and amplification of T-cell responses. However, the systemic delivery of vaccine antigens into dendritic cells (DCs) is hampered by various technical challenges. Here we show that DCs can be targeted precisely and effectively in vivo using intravenously administered RNA-lipoplexes (RNA-LPX) based on well-known lipid carriers by optimally adjusting net charge, without the need for functionalization of particles with molecular ligands. The LPX protects RNA from extracellular ribonucleases and mediates its efficient uptake and expression of the encod…
An in vitro and in vivo study of peptide-functionalized nanoparticles for brain targeting: The importance of selective blood-brain barrier uptake
2017
Targeted delivery of drugs across endothelial barriers remains a formidable challenge, especially in the case of the brain, where the blood-brain barrier severely limits entry of drugs into the central nervous system. Nanoparticle-mediated transport of peptide/protein-based drugs across endothelial barriers shows great potential as a therapeutic strategy in a wide variety of diseases. Functionalizing nanoparticles with peptides allows for more efficient targeting to specific organs. We have evaluated the hemocompatibilty, cytotoxicity, endothelial uptake, efficacy of delivery and safety of liposome, hyperbranched polyester, poly(glycidol) and acrylamide-based nanoparticles functionalized wi…
Studying Closed Hydrodynamic Models of "In Vivo" DNA Perfusion in Pig Liver for Gene Therapy Translation to Humans.
2016
17 páginas, 6 figuras. En la versión online contiene 3 figuras y 1 tabla en información suplemetaria
Smart copolymer coated SPIONs for colon cancer chemotherapy
2019
Human colon cancer is one of the higher aggressive solid tumors, whose high mortality, much like many other solid tumors, results from metastasis formation. To reduce this high mortality, more effective chemotherapy, allowing a specific tumor accumulation and an efficient early-stage medical imaging as well, are still needed. At this regard, stimuli-responsive nanocarriers for anticancer drug delivery are promising strategy in cancer therapy. For this purpose, a dual targeted redox-responsive drug delivery system, prepared by coating superparamagnetic nanoparticles (SPIONs) with the amphiphilic copolymer INU-LA-PEG-FA and loading doxorubicin (DOXO-SPIONs) was investigated as tool for solid …
Apolipoprotein-mediated transport of nanoparticle-bound drugs across the blood-brain barrier.
2002
Recent studies have shown that drugs that are normally unable to cross the blood-brain barrier (BBB) following intravenous injection can be transported across this barrier by binding to poly(butyl cyanoacrylate) nanoparticles and coating with polysorbate 80. However, the mechanism of this transport so far was not known. In the present paper, the possible involvement of apolipoproteins in the transport of nanoparticle-bound drugs into the brain is investigated. Poly(butyl cyanoacrylate) nanoparticles loaded with the hexapeptide dalargin were coated with the apolipoproteins AII, B, CII, E, or J without or after precoating with polysorbate 80. In addition, loperamide-loaded nanoparticles were …
Application of nano-hydroxyapatite/chitosan scaffolds on rat calvarial critical-sized defects: A pilot study
2018
Background The purpose of this pilot study was to evaluate for the first time the effect of 75/25 w/w nano-Hydroxyapatite/Chitosan (nHAp/CS) scaffolds on Guided Bone Regeneration (GBR) in rat calvarial critical-sized defects (CSDs). Material and Methods Six adult Sprague Dawley rats, 3 males and 3 females, were used. Two CSDs, full thickness and 5mm in diameter, were trephined in both sides of the parietal bone. The right CSD was filled with nHAp/CS scaffold, while the left CSD remained empty, as the control group. The wound was sutured in layers. Rats were euthanized with diethyl ether inhalation at 2, 4 and 8 weeks after surgical procedure. Histological and histomorphometric analysis was …