By Type: Conference Paper

Detec{\c c}ão de MDRTB por gold-nanoprobes – uma nova abordagem tecnológica desenvolvida em Portugal, Pedrosa, Pedro, Veigas Bruno, Machado Diana, Perdigão João, Portugal Isabel, Couto Isabel, Viveiros Miguel, and Baptista {Pedro V. } , (2013) Abstract
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Alloy metal nanoparticles for multicolor cancer diagnostics, Baptista, {Pedro V. }, c}alo Doria Gon{\c, and Conde João , Colloidal Quantum Dots/Nanocrystals for Biomedical Applications VI, (2011) Abstract

Cancer is a multigenic complex disease where multiple gene loci contribute to the phenotype. The ability to simultaneously monitor differential expression originating from each locus results in a more accurate indicator of degree of cancerous activity than either locus alone. Metal nanoparticles have been thoroughly used as labels for in vitro identification and quantification of target sequences. We have synthesized nanoparticles with assorted noble metal compositions in an alloy format and functionalized them with thiol-modified ssDNA (nanoprobes). These nanoprobes were then used for the simultaneous specific identification of several mRNA targets involved in cancer development - one pot multicolor detection of cancer expression. The different metal composition in the alloy yield different {"}colors{"} that can be used as tags for identification of a given target. Following a non-cross-linking hybridization procedure previously developed in our group for gold nanoprobes, these multicolor nanoprobes were used for the molecular recognition of several different targets including differently spliced variants of relevant genes (e.g. gene products involved in chronic myeloid leukemia BCR, ABL, BCR-ABL fusion product). Based on the spectral signature of mixtures, before and after induced aggregation of metal nanoparticles, the correct identification could be made. Further application to differentially quantify expression of each locus in relation to another will be presented. The differences in nanoparticle stability and labeling efficiency for each metal combination composing the colloids, as well as detection capability for each nanoprobe will be discussed. Additional studies will be conducted towards allele specific expression studies.

AuAg-alloy-nanoprobes for specific nucleic acid detection, Doria, G., Dias {J. T. }, Larguinho M., Pereira E., Franco R., and Baptista P. , Nanotechnology 2010: Bio Sensors, Instruments, Medical, Environment and Energy - Technical Proceedings of the 2010 NSTI Nanotechnology Conference and Expo, NSTI-Nanotech 2010, jan, Volume 3, p.62–65, (2010) Abstract

The derivatization of gold-silver alloy nanoparticles with thiol-ssDNA oligonucleotides (AuAg-alloy-nanoprobes) and their use in nucleic acid detection is presented. A non-cross-linking method has been previously developed by our group using gold nanoparticles, which is based on the colorimetric comparison of solutions before and after salt-induced nanoprobe aggregation. Only the presence of a complementary target stabilizes the nanoprobe, preventing aggregation and colorimetric change after salt addition. Through this approach, the AuAg-alloy-nanoprobes allowed to specifically detect a sequence derived from the RNA polymerase β-subunit gene of Mycobacterium tuberculosis, the etiologic agent of human tuberculosis, with a 2.5-fold enhanced sensitivity (0.3 μg of total DNA) when compared to their gold counterparts.

Novel optoelectronic platform using an amorphous/nanocrystalline silicon biosensor for the specific identification of unamplified nucleic acid sequences based on gold nanoparticle probes, Silva, {Leonardo Bione}, Baptista Pedro, Raniero Leandro, c}alo Dória Gon{\c, Franco Ricardo, de Martins {Rodrigo Ferrão Paiva}, and Fortunato {Elvira Maria Correia} , Solid-State Sensors, Actuators and Microsystems Conference, 2007, jan, p.935–938, (2007) Abstract
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