Search results for "CARRIERS"
showing 10 items of 391 documents
Could the recent zika epidemic have been predicted?
2017
AbstractGiven knowledge at the time, the recent 2015-2016 zika virus (ZIKV) epidemic probably could not have been predicted. Without the prior knowledge of ZIKV being already present in South America, and given the lack of understanding of key epidemiologic processes and long-term records of ZIKV cases in the continent, the best related prediction was for potential risk of an Aedes-borne disease epidemic. Here we use a recently published two-vector capacity model to assess the predictability of the conditions conducive to epidemics of diseases like zika, chikungunya or dengue, transmitted by the independent or concurrent presence of Aedes aegypti and Aedes albopictus. We compare the potenti…
EMPLOYMENT OF CATIONIC SOLID-LIPID NANOPARTICLES AS RNA CARRIERS
2007
Gene transfer represents an important advance in the treatment of both genetic and acquired diseases. In this article, the suitability of cationically modified solid-lipid nanoparticles (SLN) as a nonviral vector for gene delivery was investigated, in order to obtain stable materials able to condense RNA. Cationic SLN were produced by microemulsion using Compritol ATO 888 as matrix lipid, Pluronic F68 as tenside, and dimethyldioctadecylammonium bromide (DDAB) as cationic lipid. The resulting particles were approximately 100 nm in size and showed a highly positive surface charge (+41 mV) in water. Size and shape were further characterized by scanning electron microscopy (SEM) measurements. M…
Polymeric prodrug for release of an antitumoral agent by specific enzymes.
2001
The clinical usefulness of antitumor chemotherapy has been strongly limited by the lack of specificity of most anticancer drugs, which act also against healthy cells. The aim of this work was to design, synthesize, and evaluate a macromolecular prodrug of Cytarabine, a known antitumor drug, which is a specific substrate for plasmin enzyme whose concentration is high in various kinds of tumor mass as a result of plasminogen activator secretion. alpha,beta-Poly(N-hydroxyethyl)-DL-aspartamide (PHEA), a known synthetic and biocompatible polyamino acid, was used as a drug carrier, and Cytarabine was linked to PHEA by D-Val-Leu-Lys spacer synthesized beginning from Cbz-D-Val-LeuOH dipeptide and N…
Self-assembly of janus dendrimers into uniform dendrimersomes and other complex architectures
2010
Janus Drug Delivery Vehicle Efficient drug delivery vehicles need to be produced in a limited size range and with uniform size distribution. The self-assembly of traditional small-molecule and polymeric amphiphiles has led to the production of micelles, liposomes, polymeric micelles, and polymersomes for use in drug delivery applications. Now, Percec et al. (p. 1009 ) describe the self-assembly of Janus-type (i.e., two-headed) dendrimers to produce monodisperse supramolecular constructs, termed “dendrimersomes,” and other complex architectures. The structures, which showed long-term stability as well as very narrow size distributions, were easily produced by the injection of an ethanolic so…
Controlled release using mesoporous materials containing gate-like scaffoldings.
2009
The use of gated mesoporous silica solids as suitable systems for controlled-release protocols is reviewed. These materials are based on mesoporous silica supports that can be prepared with tailor-made pores of around 2 - 10 nm and that show a very large specific surface area (up to 1200 m(2)/g), thus having a large load capacity. The solids can be additionally functionalised in the external surface with gate-like systems that can be opened on command to allow cargo release. Light, redox reactions, pH, temperature, polarity and enzyme-driven protocols are shown. The possible application in drug delivery protocols is discussed.
Finely Tuned Temperature-Controlled Cargo Release Using Paraffin-Capped Mesoporous Silica Nanoparticles
2011
[EN] Trapped: Mesoporous silica nanoparticles were loaded with a fluorescent guest and functionalized with octadecyltrimethoxysilane. The alkyl chains interact with paraffins, which build a hydrophobic layer around the particle (see picture). Upon melting of the paraffin, the guest molecule is released, as demonstrated in cells for the guest doxorubicin. The release temperature can be tuned by choosing an appropriate paraffin. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Cationic Nanohydrogel Particles as Potential siRNA Carriers for Cellular Delivery
2012
Oligonucleotides such as short, double-stranded RNA (siRNA) or plasmid DNA (pDNA) promise high potential in gene therapy. For pharmaceutical application, however, adequate drug carriers are required. Among various concepts progressing in the market or final development, nanosized hydrogel particles may serve as novel transport media especially for siRNA. In this work, a new concept of synthesizing polymeric cationic nanohydrogels was developed, which offers a promising strategy to complex and transport siRNA into cells. For this purpose, amphiphilic reactive ester block copolymers were synthesized by RAFT polymerization of pentafluorophenyl methacrylate as reactive ester monomer together wi…
Nanoparticulate Systems for Drug Delivery and Targeting to the Central Nervous System
2010
Brain delivery is one of the major challenges for the neuropharmaceutical industry since an alarming increase in brain disease incidence is going on. Despite major advances in neuroscience, many potential therapeutic agents are denied access to the central nervous system (CNS) because of the existence of a physiological low permeable barrier, the blood-brain barrier (BBB). To obtain an improvement of drug CNS performance, sophisticated approaches such as nanoparticulate systems are rapidly developing. Many recent data demonstrate that drugs could be transported successfully into the brain using colloidal systems after i.v. injection by several mechanisms such as endocytosis or P-glycoprotei…
Dexamethasone dipropionate loaded nanoparticles of α-elastin-g-PLGA for potential treatment of restenosis.
2013
A graft copolymer of α-elastin with poly(lactic-co-glycolic) acid (PLGA) has been synthesized and successfully employed to produce nanoparticles. Exploiting the known biological activity of α-elastin to promote the maintenance of smooth muscle cells (SMCs) contractile phenotype and the antiproliferative effect of glucocorticoids, the aim of this research was to produce drug-loaded nanoparticles suitable for potential treatment of restenosis. In particular, nanoparticles of α-elastin-g-PLGA with a mean size of 200 nm have been produced and loaded with dexamethasone dipropionate (10% w/w), chosen as a model drug that inhibits proliferation of vascular SMCs. These nanoparticles are able to pro…
Zebrafish Embryos Allow Prediction of Nanoparticle Circulation Times in Mice and Facilitate Quantification of Nanoparticle–Cell Interactions
2020
The zebrafish embryo is a vertebrate well suited for visualizing nanoparticles at high resolution in live animals. Its optical transparency and genetic versatility allow noninvasive, real-time observations of vascular flow of nanoparticles and their interactions with cells throughout the body. As a consequence, this system enables the acquisition of quantitative data that are difficult to obtain in rodents. Until now, a few studies using the zebrafish model have only described semiquantitative results on key nanoparticle parameters. Here, a MACRO dedicated to automated quantitative methods is described for analyzing important parameters of nanoparticle behavior, such as circulation time and…