SÃntese e caracterizaÃÃo de nanocristais luminescentes baseados em semicondutores II-VI para fins de aplicaÃÃo como biomarcadores

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

In this work we present synthetic procedures in aqueous medium for the obtention of luminescent II-VI (CdS/Cd(OH)2 and CdTe/CdS) semiconductor nanocrystals. These methodologies, based on colloidal chemistry, resulted in particles with a size average of 8,5 nm for the CdS/Cd(OH)2 system and 3,8 nm for the CdTe/CdS system. The optical properties of these materials were characterized using electronic absoprion, emission and excitation spectrocopies while the structural properties were characterized by transmission electronic microscopy and X-ray powder diffraction. The CdS/Cd(OH)2 nanocrystals were chemically modified (by using either one of the following functionalizers: glutaraldehyde, glutaraldehyde/Anti-A or glutaraldehyde/Concanavalin-A) for their application in biolabelling. These systems were characterized by electronic absorption, emission and excitation spectroscopy and by transmission electronic microscopy. Finally, we describe the experimental procedures used to conjugate the modified CdS/Cd(OH)2 nanocrystals in three different biological systems: (i) A+ and O+ type red blood cells, (ii) Leishmania amazonensis parasites in the promastigote form and (iii) histologycal sections of human mammary healthy tissues and Fibroadenoma tissues (a benign type of tumor). We discuss the different marking patterns observed for the biological samples in terms of different possible processes of luminescence

ASSUNTO(S)

fluorescent labels nanoparticles quantum dots nanocristais funcionalizaÃÃo confinamento quÃntico semiconductors nanocrystals semicondutores quantum confinement biolabels nanopartÃculas biomarcadores functionalization quimica pontos quÃnticos marcadores fluorescentes

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