Biomedical subjects

Gillian Barratt

Publications and source records attributed to Gillian Barratt.

4 recordsLinked to original sources

PubMed2003

Methodology for assaying recombinant interleukin-2 associated with liposomes by combined gel exclusion chromatography and fluorescence.

A simple methodology based on fluorescence and gel exclusion chromatography (GEC) has been developed to assay recombinant Interleukin-2 (rIL-2) associated with vesicles. A Sephadex G75 column was used to separate the liposomes from non-entrapped rIL-2. The elution of the rIL-2 liposomes was monitored by coupling fluorescent and light scattering detection. The solubilisation of the vesicles with octylglucoside (OG) before the assay was necessary to avoid interference from light scattering. This methodology can be automated to yield an on-line system that can separate, solubilise and quantify rIL-2 in liposome samples. It can be extended to any protein associated with vesicles provided that the former can be detected by fluorescence.

Chromatography, Gel↗

PubMed2003

Surface-engineered nanoparticles for multiple ligand coupling.

The design of surface-engineered nanoparticles for targeting to specific sites is a major challenge. To our knowledge, no study in the literature deals with ligand functionalization of biodegradable nanoparticles through biotin-avidin interactions. With the aim of conceiving small-sized nanoparticles which can be easily functionalized with a variety of ligands or mixtures thereof, biotinylated and PEGylated biotin-poly(ethylene glycol)-poly(epsilon-caprolactone) (B-PEG-PCL) copolymers were synthesized and used to prepare nanoparticles of around 100 nm. Avidin, followed by biotinylated wheat germ agglutinin as a model lectin, were coupled to their surface by taking advantage of the strong biotin-avidin complex formation. The cytotoxicity of the nanospheres towards Caco-2 cells in culture was negligible (more than 82% cell survival for nanoparticle concentrations up to 300 microg/well). The amount of radiolabeled poly(lactic acid) (PLA) or PEG-PLA nanoparticles associated with Caco-2 cells was only 0.7% and 1.5% of the amount added, respectively. This value was increased to 8.5% when a sufficient amount of lectin was bound to the PEG-PLA copolymer. After further studies, the biotin-PEG-coated nanoparticles could be helpful tools for studying the interaction between cells and functionalized nanoparticles with various surface characteristics (PEG layer density and thickness, ligand type and density).

Binding Sites↗

PubMed2003

Polyester-poly(ethylene glycol) nanoparticles loaded with the pure antiestrogen RU 58668: physicochemical and opsonization properties.

PURPOSE: The pure antiestrogen RU58668 (RU) was encapsulated within nanospheres (NS) and nanocapsules (NC) prepared from different polyester copolymers with poly(ethylene glycol) (PEG) chains. The influence of their physicochemical properties on drug release in vitro and their susceptibility to opsonization were evaluated. METHODS: RU-loaded PEG-bearing nanoparticles (NP) prepared by interfacial deposition of preformed polymer were characterized (size, zeta potential, percentage encapsulation and loading). In vitro release kinetics were studied in the presence of 10% fetal calf serum (FCS). Their opsonization in mouse serum was evaluated by silver staining of SDS-PAGE and Western blotting of desorbed proteins. RESULTS: The NS were smaller than NC and had a zeta potential close to zero and a higher percentage of loading. RU release from NS in vitro was reduced as compared with the dissolution profile of free RU in a serum-containing medium. Decreased opsonin adsorption at the surface of pegylated NS was observed. CONCLUSION: Small nanoparticulate systems containing a high load of pure antiestrogen, showing reduced drug release, have been developed. Among the six nanosphere preparations containing RU, two show a size below 200 nm, and two others undergo reduced protein adsorption in the presence of serum, compatible with increased persistence in the blood.

Animals↗

PubMed2002

Nanocapsule technology: a review.

Nanocapsules are submicroscopic colloidal drug carrier systems composed of an oily or an aqueous core surrounded by a thin polymer membrane. Two technologies can be used to obtain such nanocapsules: the interfacial polymerization of a monomer or the interfacial nanodeposition of a preformed polymer. This article is an extended review of these nanocapsule technologies and their applications for the treatment of various diseases (including cancer and infections).

Animals↗