resumo
This research demonstrates that fluorescent silica nanoparticles containing a lanthanide picolinate complex can be used as optical biolabels by using Candida albicans cells as the model targeting system. As such, new fluorescent biolabels have been prepared by encapsulation of the picolinate terbium(III) complex K-2[Tb-2(pic)(8)]center dot 7H(2)O (Tbpic) in silica particles through a reverse microemulsion process. The surfaces of the ensuing core-shell nanoparticles were functionalized with 3-aminopropyltriethoxysilane and then quaternized with methyl iodide in order to increase their water-stability and promote uptake by the cells. Confocal microscopy experiments demonstrated that in comparison to the non-quaternized analogues, the uptake of the functionalized nanoparticles by Candida albicans was improved. Therefore the methylation of silica surfaces as described here appears to be a more general strategy to improve the uptake of functionalized nano-silica particles by these cells. There is evidence from these studies that in this case the nanoparticles penetrated the cell wall but did not penetrate the nuclear membrane, thus allowing selective cell biolabeling.
palavras-chave
MESOPOROUS SILICA; EUROPIUM NANOPARTICLES; CANDIDA-ALBICANS; LUMINESCENCE; DYE; ENCAPSULATION; PORPHYRINS; SURFACES; CATIONS; SBA-15
categoria
Materials Science
autores
Gomes, MC; Fernandes, R; Cunha, A; Tome, JP; Trindade, T
nossos autores
Maria Clara Gomes
Investigador Júnior
Tito Trindade
Professor Catedráticoagradecimentos
M. C. Gomes thanks FCT for the grant SFRH/BD/88334/2012. Thanks are due to FCT and FEDER, for funding the project PTDC/CTM/101538/2008, QOPNA (Pest-C/QUI/UI0062/2011), CICECO (Pest-C/CTM-LA0011/2011) and CESAM (PEst-C/MAR/LA0017/2011) research units.