Search results for " nanoparticles"
showing 10 items of 794 documents
Exploring Strategies for Labeling Viruses with Gold Nanoclusters through Non-equilibrium Molecular Dynamics Simulations.
2017
Biocompatible gold nanoclusters can be utilized as contrast agents in virus imaging. The labeling of viruses can be achieved noncovalently but site-specifically by linking the cluster to the hydrophobic pocket of a virus via a lipid-like pocket factor. We have estimated the binding affinities of three different pocket factors of echovirus 1 (EV1) in molecular dynamics simulations combined with non-equilibrium free-energy calculations. We have also studied the effects on binding affinities with a pocket factor linked to the Au102pMBA44 nanocluster in different protonation states. Although the absolute binding affinities are over-estimated for all the systems, the trend is in agreement with r…
Additives for vaccine storage to improve thermal stability of adenoviruses from hours to months
2016
Up to 80% of the cost of vaccination programmes is due to the cold chain problem (that is, keeping vaccines cold). Inexpensive, biocompatible additives to slow down the degradation of virus particles would address the problem. Here we propose and characterize additives that, already at very low concentrations, improve the storage time of adenovirus type 5. Anionic gold nanoparticles (10−8–10−6 M) or polyethylene glycol (PEG, molecular weight ∼8,000 Da, 10−7–10−4 M) increase the half-life of a green fluorescent protein expressing adenovirus from ∼48 h to 21 days at 37 °C (from 7 to >30 days at room temperature). They replicate the known stabilizing effect of sucrose, but at several orders of…
Impact of polymer-modified gold nanoparticles on brain endothelial cells: exclusion of endoplasmic reticulum stress as a potential risk factor
2016
A library of polymer-coated gold nanoparticles (AuNPs) differing in size and surface modifications was examined for uptake and induction of cellular stress responses in the endoplasmic reticulum (ER stress) in human brain endothelial cells (hCMEC/D3). ER stress is known to affect the physiology of endothelial cells (ECs) and may lead to inflammation or apoptosis. Thus, even if applied at non-cytotoxic concentrations ER stress caused by nanoparticles should be prevented to reduce the risk of vascular diseases and negative effects on the integrity of barriers (e.g. blood-brain barrier). We exposed hCMEC/D3 to twelve different AuNPs (three sizes: 18, 35, and 65 nm, each with four surface-modif…
Photocatalytic Activity of Polymer Nanoparticles Modulates Intracellular Calcium Dynamics and Reactive Oxygen Species in HEK-293 Cells
2018
Optical modulation of living cells activity by light-absorbing exogenous materials is gaining increasing interest, due to the possibility both to achieve high spatial and temporal resolution with a minimally invasive and reversible technique and to avoid the need of viral transfection with light-sensitive proteins. In this context, conjugated polymers represent ideal candidates for photo-transduction, due to their excellent optoelectronic and biocompatibility properties. In this work, we demonstrate that organic polymer nanoparticles, based on poly(3-hexylthiophene) conjugated polymer, establish a functional interaction with an in vitro cell model (Human Embryonic Kidney cells, HEK-293). Th…
mRNA-Based Vaccines
2021
Increases in the world’s population and population density promote the spread of emerging pathogens. Vaccines are the most cost-effective means of preventing this spread. Traditional methods used to identify and produce new vaccines are not adequate, in most instances, to ensure global protection. New technologies are urgently needed to expedite large scale vaccine development. mRNA-based vaccines promise to meet this need. mRNA-based vaccines exhibit a number of potential advantages relative to conventional vaccines, namely they (1) involve neither infectious elements nor a risk of stable integration into the host cell genome; (2) generate humoral and cell-mediated immunity; (3) are well-t…
Magnetite Nanoparticles Prepared By Spark Erosion
2016
Abstract In the present research, we study a possibility of using the electric spark erosion method as an alternative to the method of chemical co-precipitation for preparation of magnetic nanoparticles. Initiation of high frequency electric discharge between coarse iron particles under a layer of distilled water allows obtaining pure magnetite nanoparticles.
Ligand density on nanoparticles: A parameter with critical impact on nanomedicine
2019
Nanoparticles modified with ligands for specific targeting towards receptors expressed on the surface of target cells are discussed in literature towards improved delivery strategies. In such concepts the ligand density on the surface of the nanoparticles plays an important role. How many ligands per nanoparticle are best for the most efficient delivery? Importantly, this number may be different for in vitro and in vivo scenarios. In this review first viruses as "biological" nanoparticles are analyzed towards their ligand density, which is then compared to the ligand density of engineered nanoparticles. Then, experiments are reviewed in which in vitro and in vivo nanoparticle delivery has b…
Coupling tumor necrosis factor‐related apoptosis‐inducing ligand to iron oxide nanoparticles increases its apoptotic activity on HCT116 and HepG2 mal…
2019
International audience; Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has been considered as a potential anticancer agent owing to its selectivity for malignant cells. However, its clinical use remains limited because of its poor efficacy. Attempts to increase its antitumor activity include, among others, its functionalization by nanoparticles (NPs). In the present study, TRAIL was grafted onto magnetic spinel iron oxide NPs of defined core size, 10 and 100 nm on average, to see whether the size of the resulting nanovectors, NV10 and NV100, respectively, might affect TRAIL efficacy and selectivity. Apoptosis induced by NV10 and NV100 was higher than by TRAIL alone in both …
Angular Trapping of Anisometric Nano-Objects in a Fluid
2012
We demonstrate the ability to trap, levitate, and orient single anisometric nanoscale objects with high angular precision in a fluid. An electrostatic fluidic trap confines a spherical object at a spatial location defined by the minimum of the electrostatic system free energy. For an anisometric object and a potential well lacking angular symmetry, the system free energy can further strongly depend on the object's orientation in the trap. Engineering the morphology of the trap thus enables precise spatial and angular confinement of a single levitating nano-object, and the process can be massively parallelized. Since the physics of the trap depends strongly on the surface charge of the objec…
Gold nanostar–polymer hybrids for siRNA delivery: Polymer design towards colloidal stability and in vitro studies on breast cancer cells
2017
To overcome the low bioavailability of siRNA (small interfering RNA) and to improve their transfection efficiency, the use of non-viral delivery carriers is today a feasible approach to transform the discovery of these incredibly potent and versatile drugs into clinical practice. Polymer-modified gold nanoconstructs (AuNCs) are currently viewed as efficient and safe intracellular delivery carriers for siRNA, as they have the possibility to conjugate the ability to stably entrap and deliver siRNAs inside cells with the advantages of gold nanoparticles, which can act as theranostic agents and radiotherapy enhancers through laser-induced hyperthermia. In this study, AuNCs were prepared by coat…