RESUMO
Molecular imaging comprises non-invasive monitoring of functional and spatiotemporal processes at molecular and cellular levels in living systems. Advanced imaging techniques can monitor such processes. Peptide receptors over-expressed in tumours can be targeted by peptides conjugated to radionuclides, near-infrared fluorochromes, metallic nanoparticles or quantum dots for target-specific cancer imaging.
Assuntos
Imagem Molecular/métodos , Neoplasias/diagnóstico , Oligopeptídeos , Animais , Corantes Fluorescentes/química , Produtos do Gene tat/química , Produtos do Gene tat/metabolismo , Humanos , Imageamento por Ressonância Magnética/métodos , Imageamento por Ressonância Magnética/tendências , Imagem Molecular/tendências , Nanopartículas/química , Neoplasias/diagnóstico por imagem , Neoplasias/metabolismo , Oligopeptídeos/síntese química , Oligopeptídeos/química , Oligopeptídeos/metabolismo , Peptídeos/química , Peptídeos/metabolismo , Tomografia por Emissão de Pósitrons/métodos , Tomografia por Emissão de Pósitrons/tendências , Pontos Quânticos , Receptores de Peptídeos/metabolismo , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Tomografia Computadorizada de Emissão de Fóton Único/tendênciasRESUMO
A multifunctional system of gold nanoparticles (AuNP) capped by the [Tyr(3)]Octreotide (TOC) peptide was prepared and characterized by transmission electron microscopy (TEM) and UV-Vis, infrared and fluorescence spectroscopy. AuNP and AuNP-TOC fluorescence emission spectra were obtained both in solution and in murine AR42J-tumor tissues. Results suggest that AuNP were functionalized with TOC through interactions with the N-terminal amine of the phenylalanine, the amide groups and possibly with the indole group of the tryptophan residue. The fluorescence analyses in tissue revealed a recognition of the AuNP-TOC conjugate for the neuroendocrine tumor because of the lower energy position of the fluorescence resonance (692 nm) with respect to that of the AuNP in the same tumoral tissue (684 nm). The emission band observed in the near-infrared region (692 nm) opens the possibility for AuNP-TOC use in bioimaging.
