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1.
Nanomedicine (Lond) ; 11(21): 2769-2779, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27739928

RESUMO

AIM: Tunable size ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles from 3 to 9 nm coated with polyethylene glycol phosphonate moieties have been designed for neovascularization MRI. MATERIALS & METHODS: USPIO were synthesized using a nonaqueous sol-gel method. An ischemia-reperfusion rat model has been chosen for neo-angiogenesis and scanned on MRI after injection of different sized USPIO. Histological studies have been performed for USPIO localization within the tissue. RESULTS: The magnetic properties and consequently their MRI relaxivities are drastically dependent on the crystalline core size. In vivo MRI spots were observed specifically in the ischemic area. The best MRI contrast within neovascularization is generated by 6 nm nanoparticles proving that compromise between T2 relaxivity and physico-chemical properties is essential for the design of effective MRI contrast agent.

2.
Eur J Med Chem ; 93: 360-72, 2015 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-25721024

RESUMO

In silico optimisation, synthesis and binding evaluation of αvß3 integrin's affinity for precursors of a new RGD peptidomimetics family are presented. The 2-pyrrolidinone building block was obtained by condensation of l-lysine with dimethoxydihydrofuran followed by reduction. The ring was functionalized with a carboxylic acid and a guanidinium appendage. On the pyrrolidinone heterocycle, the effects on affinity of position, length and relative geometry of the two acid or basic functionalized side chains introduced on the pyrrolidinone ring have been previously evaluated by docking studies. Peptidomimetics have finally been evaluated by competition binding assays for αvß3 integrin's affinity using radio-ligands.


Assuntos
Simulação por Computador , Oligopeptídeos/química , Peptidomiméticos/síntese química , Peptidomiméticos/metabolismo , Pirrolidinonas/síntese química , Pirrolidinonas/metabolismo , Ligação Competitiva , Técnicas de Química Sintética , Humanos , Integrina alfaVbeta3/química , Integrina alfaVbeta3/metabolismo , Simulação de Acoplamento Molecular , Peptidomiméticos/química , Ligação Proteica , Conformação Proteica , Pirrolidinonas/química
3.
Langmuir ; 29(47): 14639-47, 2013 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-24171381

RESUMO

Superparamagnetic fluorescent nanoparticles targeting αvß3 integrins were elaborated using two methodologies: carbodiimide coupling and click chemistries (CuACC and thiol-yne). The nanoparticles are first functionalized with hydroxymethylenebisphonates (HMBP) bearing carboxylic acid or alkyne functions. Then, a large number of these reactives functions were used for the covalent coupling of dyes, poly(ethylene glycol) (PEG), and cyclic RGD. Several methods were used to characterize the nanoparticle surface functionalization, and the magnetic properties of these contrast agents were studied using a 1.5 T clinical MRI. The affinity toward integrins was evidenced by solid-phase receptor-binding assay. In addition to their chemoselective natures, click reactions were shown to be far more efficient than the carbodiimide coupling. The grafting increase was shown to enhance targeting affinity to integrin without imparing MRI and fluorescent properties.


Assuntos
Carbodi-Imidas/química , Integrina alfaVbeta3/química , Nanopartículas de Magnetita/química , Nanopartículas/química , Química Click , Meios de Contraste/química , Fluorescência , Concentração de Íons de Hidrogênio , Imageamento por Ressonância Magnética , Tamanho da Partícula , Espectrometria de Fluorescência , Propriedades de Superfície
4.
Nanoscale ; 5(23): 11478-89, 2013 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-24154564

RESUMO

Magnetic Resonance Imaging (MRI) using contrast agents is a very powerful technique for diagnosis in clinical medicine and biomedical research. The synthesis of ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles targeting αvß3 integrins and acting as new MRI contrast agents seems to be a promising way for cancer diagnosis. Indeed, it is well established that αvß3 integrin plays a key role in tumor angiogenesis acting like a receptor for the extracellular matrix proteins like vitronectin, fibronectin through the arginine-glycine-aspartic acid (RGD) sequence. Up-regulation of αvß3 has been found to be associated with a wide range of cancers, making it a broad-spectrum tumor-marker. In this study, USPIO nanocrystals were synthesized and surface passivated with caffeic acid. The large number of the carboxylic acid functions at the outer surface of the nanoplatforms was used for the covalent coupling of Rhodamine123, polyethylene glycol (PEG) and cyclic RGD. Soluble carbodiimide (EDC) and N-hydroxysuccinimide (NHS) were used to crosslink carboxylic acid with the amino group of the ligands. We examined the design of the nanoplatforms with each individual entity and then the combination of two and three of them. Several methods were used to characterize the nanoparticle surface functionalization and the magnetic properties of these contrast agents were studied using a 1.5 T clinical MRI scanner. The affinity towards integrins was evidenced by surface plasmon resonance and solid-phase receptor-binding assay.


Assuntos
Compostos Férricos/química , Integrina alfaVbeta3/metabolismo , Nanopartículas Metálicas/química , Ácidos Cafeicos/química , Carbodi-Imidas/química , Meios de Contraste/química , Meios de Contraste/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Integrina alfaVbeta3/química , Imageamento por Ressonância Magnética , Magnetismo , Oligopeptídeos/química , Oligopeptídeos/metabolismo , Polietilenoglicóis/química , Ligação Proteica , Rodamina 123/química , Ressonância de Plasmônio de Superfície , Propriedades de Superfície
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