Search results for "carrier"
showing 10 items of 1256 documents
Influence of functionalization on interaction and drug release from α,β-polyaspartylhydrazide derivatives to a biomembrane model: evaluation by diffe…
2004
Abstract A comparative study on the ability of various polymers to interact with a biomembrane model was carried out by differential scanning calorimetry (DSC). The investigated samples were a water soluble polymer, the α,β-polyaspartylhydrazide (PAHy) and its derivatives containing polyethylene glycol (PEG2000) (sample PAHy–PEG2000), or hexadecylamine (C16) (sample PAHy–C16) or both compounds (sample PAHy–PEG2000–C16). Some samples are able to arrange themselves as micellar structures and to interact potentially with the membrane surface so as to favor the release of the drug near the target membrane and consequently to improve drug adsorption processes. First, the interaction of all polym…
PHEA‐PLLA: A New Polymer Blend For Tissue Engineering Applications
2011
One of most important features that a material should have in order to be utilized for tissue engineering applications is its biocompatibility and its chemical surface. These properties are required for a high degree of cell adhesion on the scaffold. Poly‐L‐lactid acid (PLLA) is a biocompatible synthetic polymer approved by the Food and Drug Administration for human clinical applications. It has been largely employed, in the last years, as a constituent of surgical and implantable devices. PHEA is a biocompatible water‐soluble synthetic polymer, with a protein‐like structure, whose use as a drug carrier and as starting material for many other biomedical and pharmaceutical applications has b…
Persistent photovoltage in methylammonium lead iodide perovskite solar cells
2014
Open circuit voltage decay measurements are performed on methylammonium lead iodide (CH3NH3PbI3) perovskite solar cells to investigate the charge carrier recombination dynamics. The measurements are compared to the two reference polymer-fullerene bulk heterojunction solar cells based on P3HT:PC60BM and PTB7:PC70BM blends. In the perovskite devices, two very different time domains of the voltage decay are found, with a first drop on a short time scale that is similar to the organic solar cells. However, two major differences are also observed. 65-70% of the maximum photovoltage persists on much longer timescales, and the recombination dynamics are dependent on the illumination intensity.
Carbohydrate nanocarriers in biomedical applications: functionalization and construction
2015
The specific targeting of either tumor cells or immune cells in vivo by carefully designed and appropriately surface-functionalized nanocarriers may become an effective therapeutic treatment for a variety of diseases. Carbohydrates, which are prominent biomolecules, have shown their outstanding ability in balancing the biocompatibility, stability, biodegradability, and functionality of nanocarriers. The recent applications of sugar (mono/oligosaccharides and/or polysaccharides) for the development of nanomedicines are summarized in this review, including the application of carbohydrates for the surface-functionalization of various nanocarriers and for the construction of the nanocarrier its…
Total Synthesis of a Partial Structure from Arabinogalactan and Its Application for Allergy Prevention
2020
Abstract Arabinogalactan, a microheterogeneous polysaccharide occurring in plants, is known for its allergy‐protective activity, which could potentially be used for preventive allergy treatment. New treatment options are highly desirable, especially in a preventive manner, due to the constant rise of atopic diseases worldwide. The structural origin of the allergy‐protective activity of arabinogalactan is, however, still unclear and isolation of the polysaccharide is not feasible for pharmaceutical applications due to a variation of the activity of the natural product and contaminations with endotoxins. Therefore, a pentasaccharide partial structure was selected for total synthesis and subse…
Expression, regulation and function of carrier proteins for cationic amino acids.
2001
Different carrier proteins exhibiting distinct transport properties participate in cationic amino acid transport. There are sodium-independent systems, such as b+, y+, y+L and b0,+, and a sodium-dependent system B0,+, most of which have now been identified at the molecular level. In most non-epithelial cells, members of the cationic amino acid transporter (CAT) family mediating system y+ activity seem to be the major entry pathway for cationic amino acids. CAT proteins underlie complex regulation at the transcriptional, post-transcriptional and activity levels. Recent evidence indicates that individual CAT isoforms are necessary for providing the substrate for nitric oxide synthesis, for ex…
Interactions between proteins and poly(ethylene-glycol) investigated using molecular dynamics simulations
2017
Poly(ethylene-glycol) (PEG) is a polymer used to coat therapeutic preparations, like drugs or drug nanocarriers, and improve their efficacy. This effect is probably due to a reduction of the interactions of the coated species with the host organism. Nevertheless, experiments show that PEGylated materials do interact with the surrounding biological milieu, and in particular with blood proteins. Here, we use atomistic molecular dynamics simulations to characterize the interactions between the polymer and several blood proteins. In these simulations, the proteins are immersed in a mixture of PEG and water molecules. We observe how PEG distributes around the protein surface and measure PEG-prot…
Polymeric Micelles and Liposomes as Potential Drug Carriers
1986
In the past, a whole aray of polymeric carriers for biologically active substances have been reported. In this field the main interest has focused on the use of randomly solubilized polymers. Naturally occuring amphiphilic transport proteins can be modelled by synthetic micellar solubilized polymers. Poly(ethylene oxide)-polypeptide block copolymers with hydrophobic and cyclophosphamide-containing side groups are described. These micellar systems are able to transport different hydrophobic drugs.
Engineered Multifunctional Nanotools for Biological Applications
2011
Smart multifunctional magnetic nanoparticles are popular candidates for several biological applications owing to their intrinsic magnetic property and diverse applications that range from rare protein separation and biomedical utilization to cancer therapy and diagnostics. A universal protocol, for the development of such nanocarriers, is highly desirable for scientists with different backgrounds so that custom-made multifunctional nanoparticles can be developed to address their needs, among which are the superparamagnetic iron oxide and manganese oxide nanoparticles that are synthesized through high temperature decomposition reactions. However, an interface is needed to present these inorg…
In situ gel forming graft copolymers of a polyaspartamide and polylactic acid: Preparation and characterization
2008
Abstract In situ gel forming systems have been prepared by linking polylactic acid (PLA) to a water soluble and polyfunctional polymer, such as α,β-poly( N -2-hydroxyethyl)- d , l -aspartamide (PHEA). Three graft copolymers PHEA–PLA with a different derivatization degree in PLA, have been synthesized and characterized. PHEA–PLA graft copolymer with the highest amount in PLA has been used to prepare solutions in organic solvents able to give rise to gel-like matrices when injected into phosphate buffered saline solution. The chemical degradation of these gels has been evaluated and in vitro tests have been performed to evaluate the cell compatibility of the hydrolysis products. The possibili…