Publications in the Year: 2007

Conference Paper

Silva, {LB}, Baptista P, Raniero L, c}alo Dória G{\c, Franco R, de Martins {RFP}, Fortunato {EMC}. 2007. Novel optoelectronic platform using an amorphous/nanocrystalline silicon biosensor for the specific identification of unamplified nucleic acid sequences based on gold nanoparticle probes, jan. Solid-State Sensors, Actuators and Microsystems Conference, 2007. :935–938. Abstract

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Journal Article

Baptista, {PMRV}, Franco R. 2007. Nanodiagnostics: fast colorimetric method for single nucleotide polymorphism/mutation detection, jan. Iet Nanobiotechnology. 1:53–57., Number 4: INST ENGINEERING TECHNOLOGY-IET Abstract

Advances in nanosciences are having a significant impact in many areas of research. The impact of new nanotechnologies has been particularly large in biodiagnostics, where a number of nanoparticle-based assays have been introduced for biomolecules detection. To date, applications of nanoparticles have largely focused on DNA-functionalised gold nanoparticles used as the target-specific probes. These gold nanoparticle-based systems can be used for the detection of specific sequences of DNA (pathogen detection, characterisation of mutation and/or single nucleotide polymorphisms) or RNA (without prior retro-transcription and amplification). Here a rapid and inexpensive nanoparticle-based method for single-base mismatch detection (single nucleotide polymorphism/mutation) in DNA samples is reported. Gold nanoparticles derivatised with thiol modified oligonucleotides complementary to DNA targets - Au-nanoprobes - are used to distinguish fully complementary from mismatched sequences, with a single-base mismatch. The authors have successfully applied this strategy to detect common mutations within the beta-globin gene.

Baptista, {PMRV}, Franco R. 2007. Imaging gold nanoparticles for DNA sequence recognition in biomedical applications, jan. Ieee Transactions On Nanobioscience. 6:282–288., Number 4: Institute of Electrical and Electronics Engineers (IEEE) Abstract

The hybridization of single-stranded oligonucleotide-derivatized gold nanoparticles (An nanoprobes) with double stranded complementary DNA was directly observed by atomic force microscopy (AFM). This specific interaction is the basis for an An nanoprobe-based homogeneous assay for specific DNA sequence detection, based on salt-induced particle aggregation that is prevented when a complementary target is present. For long DNA targets (linearized plasmid DNA) complicated hybridized target DNA-Au-nanoprobes structures were formed, that were interpreted as the basis for stability of the An nanoprobes against salt-induced aggregation. For shorter DNA targets (PCR amplified fragments) hybridization with the An nanoprobes occurred, in the majority of cases, in the expected location of the DNA target fragment containing the specific sequence. The formation of the observed DNA hybridized structures provides evidence at the molecular level for specific hybridization to the target sequence as the method of binding of the An nanoprobes.

de Martins, {RFP}, Baptista P, Raniero L, c}alo Doria G{\c, Silva {LB }, Franco R, Fortunato {EMC}. 2007. Amorphous/nanocrystalline silicon biosensor for the specific identification of unamplified nucleic acid sequences using gold nanoparticle probes, jan. Applied Physics Letters. 90:n/d., Number 2: AIP - American Institute of Physics Abstract

Amorphous/nanocrystalline silicon pi'ii'n devices fabricated on micromachined glass substrates are integrated with oligonucleotide-derivatized gold nanoparticles for a colorimetric detection method. The method enables the specific detection and quantification of unamplified nucleic acid sequences (DNA and RNA) without the need to functionalize the glass surface, allowing for resolution of single nucleotide differences between DNA and RNA sequences-single nucleotide polymorphism and mutation detection. The detector's substrate is glass and the sample is directly applied on the back side of the biosensor, ensuring a direct optical coupling of the assays with a concomitant maximum photon capture and the possibility to reuse the sensor. (c) 2007 American Institute of Physics.

Gaspar, {JF}, Baptista {PV}, Rueff J. 2007. Gold nanoparticle based systems in genetics, mar. Current Pharmacogenomics. 5:39–47., Number 1: Bentham Science Publishers Abstract

Advances in nanoscience are having a significant impact on many scientific fields, boosting the development of a variety of important technologies. The impact of these new technologies is particularly large in biodiagnostics, where a number of nanoparticle-based assays have been introduced for biomolecular detection. The physicochemical malleability and high surface areas of nanoparticle surfaces make them ideal candidates for developing biomarker platforms. Given the variety of strategies afforded through nanoparticle technologies, a significant goal is to tailor nanoparticle surfaces to selectively bind a subset of biomarkers, either for direct detection and characterization or to sequester the target molecules for later study using other available techniques. To date, applications of nanoparticles have largely focused on DNA- or protein-functionalized gold nanoparticles used as the target-specific probes. These unique biophysical properties displayed by gold nanoparticles have huge advantages over conventional detection methods (e.g., molecular fluorophores, microarray technologies). These gold-nanoparticle based systems can then be used for the detection of specific sequences of DNA (pathogen detection, characterization of mutation and/or SNPs) or RNA (without previous retro-transcription and amplification.