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1.  Protein phosphorylation detection using dual-mode field-effect devices and nanoplasmonic sensors 
Scientific Reports  2015;5:8687.
Phosphorylation by kinases is an important post-translational modification of proteins. It is a critical control for the regulation of vital cellular activities, and its dysregulation is implicated in several diseases. A common drug discovery approach involves, therefore, time-consuming screenings of large libraries of candidate compounds to identify novel inhibitors of protein kinases. In this work, we propose a novel method that combines localized surface plasmon resonance (LSPR) and electrolyte insulator semiconductor (EIS)-based proton detection for the rapid identification of novel protein kinase inhibitors. In particular, the selective detection of thiophosphorylated proteins by LSPR is achieved by changing their resonance properties via a pre-binding with gold nanoparticles. In parallel, the EIS field-effect structure allows the real-time electrochemical monitoring of the protein phosphorylation by detecting the release of protons associated with the kinases activity. This innovative combination of both field-effect and nanoplasmonic sensing makes the detection of protein phosphorylation more reliable and effective. As a result, the screening of protein kinase inhibitors becomes more rapid, sensitive, robust and cost-effective.
PMCID: PMC4346972  PMID: 25732235
2.  Localized Surface Plasmon Resonance as a Biosensing Platform for Developing Countries 
Biosensors  2014;4(2):172-188.
The discovery of the phenomena known as localized surface plasmon resonance (LSPR) has provided the basis for many research areas, ranging from materials science to biosensing. LSPR has since been viewed as a transduction platform that could yield affordable, portable devices for a multitude of applications. This review aims to outline the potential applications within developing countries and the challenges that are likely to be faced before the technology can be effectively employed.
PMCID: PMC4264378  PMID: 25587417
localized surface plasmon resonance; low-cost biosensors; medical diagnostics; environmental monitoring
3.  DNA Barcoding of Sigmodontine Rodents: Identifying Wildlife Reservoirs of Zoonoses  
PLoS ONE  2013;8(11):e80282.
Species identification through DNA barcoding is a tool to be added to taxonomic procedures, once it has been validated. Applying barcoding techniques in public health would aid in the identification and correct delimitation of the distribution of rodents from the subfamily Sigmodontinae. These rodents are reservoirs of etiological agents of zoonoses including arenaviruses, hantaviruses, Chagas disease and leishmaniasis. In this study we compared distance-based and probabilistic phylogenetic inference methods to evaluate the performance of cytochrome c oxidase subunit I (COI) in sigmodontine identification. A total of 130 sequences from 21 field-trapped species (13 genera), mainly from southern Brazil, were generated and analyzed, together with 58 GenBank sequences (24 species; 10 genera). Preliminary analysis revealed a 9.5% rate of misidentifications in the field, mainly of juveniles, which were reclassified after examination of external morphological characters and chromosome numbers. Distance and model-based methods of tree reconstruction retrieved similar topologies and monophyly for most species. Kernel density estimation of the distance distribution showed a clear barcoding gap with overlapping of intraspecific and interspecific densities < 1% and 21 species with mean intraspecific distance < 2%. Five species that are reservoirs of hantaviruses could be identified through DNA barcodes. Additionally, we provide information for the description of a putative new species, as well as the first COI sequence of the recently described genus Drymoreomys. The data also indicated an expansion of the distribution of Calomys tener. We emphasize that DNA barcoding should be used in combination with other taxonomic and systematic procedures in an integrative framework and based on properly identified museum collections, to improve identification procedures, especially in epidemiological surveillance and ecological assessments.
PMCID: PMC3823626  PMID: 24244670
4.  Phylogenetic relationship of the Brazilian isolates of the rat lungworm Angiostrongylus cantonensis (Nematoda: Metastrongylidae) employing mitochondrial COI gene sequence data 
Parasites & Vectors  2012;5:248.
The rat lungworm Angiostrongylus cantonensis can cause eosinophilic meningoencephalitis in humans. This nematode’s main definitive hosts are rodents and its intermediate hosts are snails. This parasite was first described in China and currently is dispersed across several Pacific islands, Asia, Australia, Africa, some Caribbean islands and most recently in the Americas. Here, we report the genetic variability among A. cantonensis isolates from different geographical locations in Brazil using mitochondrial cytochrome c oxidase subunit I (COI) gene sequences.
The isolates of A. cantonensis were obtained from distinct geographical locations of Brazil. Genomic DNAs were extracted, amplified by polymerase reaction, purified and sequenced. A partial sequence of COI gene was determined to assess their phylogenetic relationship.
The sequences of A. cantonensis were monophyletic. We identified a distinct clade that included all isolates of A. cantonensis from Brazil and Asia based on eight distinct haplotypes (ac1, ac2, ac3, ac4, ac5, ac6, ac7 and ac8) from a previous study. Interestingly, the Brazilian haplotype ac5 is clustered with isolates from Japan, and the Brazilian haplotype ac8 from Rio de Janeiro, São Paulo, Pará and Pernambuco states formed a distinct clade. There is a divergent Brazilian haplotype, which we named ac9, closely related to Chinese haplotype ac6 and Japanese haplotype ac7.
The genetic variation observed among Brazilian isolates supports the hypothesis that the appearance of A. cantonensis in Brazil is likely a result of multiple introductions of parasite-carrying rats, transported on ships due to active commerce with Africa and Asia during the European colonization period. The rapid spread of the intermediate host, Achatina fulica, also seems to have contributed to the dispersion of this parasite and the infection of the definitive host in different Brazilian regions.
PMCID: PMC3514143  PMID: 23130987
Rattus norvegicus; Achatina fulica; Eosinophilic meningoencephalitis; Molecular phylogeny; Cytochrome c oxidase subunit I; Brazil
5.  Carbon Nanostructure-Based Field-Effect Transistors for Label-Free Chemical/Biological Sensors 
Sensors (Basel, Switzerland)  2010;10(5):5133-5159.
Over the past decade, electrical detection of chemical and biological species using novel nanostructure-based devices has attracted significant attention for chemical, genomics, biomedical diagnostics, and drug discovery applications. The use of nanostructured devices in chemical/biological sensors in place of conventional sensing technologies has advantages of high sensitivity, low decreased energy consumption and potentially highly miniaturized integration. Owing to their particular structure, excellent electrical properties and high chemical stability, carbon nanotube and graphene based electrical devices have been widely developed for high performance label-free chemical/biological sensors. Here, we review the latest developments of carbon nanostructure-based transistor sensors in ultrasensitive detection of chemical/biological entities, such as poisonous gases, nucleic acids, proteins and cells.
PMCID: PMC3292167  PMID: 22399927
chemical and biological sensors; carbon nanotubes; grapheme
6.  Polycrystalline Silicon ISFETs on Glass Substrate 
Sensors (Basel, Switzerland)  2005;5(4):293-301.
The Ion Sensitive Field Effect Transistor (ISFET) operation based on polycrystalline silicon thin film transistors is reported. These devices can be fabricated on inexpensive disposable substrates such as glass or plastics and are, therefore, promising candidates for low cost single-use intelligent multisensors. In this work we have developed an extended gate structure with PE-CVD Si3N4 deposited on top of a conductor, which also provides the electrical connection to the remote TFT gate. Nearly ideal pH sensitivity (54 mV/pH) and stable operation have been achieved. Temperature effects have also been characterized. A penicillin sensor has been fabricated by functionalizing the sensing area with penicillinase. The shift increases almost linearly upon the increase of penicillin concentration until saturation is reached for ∼ 7 mM. Poly-Si TFT structures with a gold sensing area have been also successfully applied to field-effect detection of DNA.
PMCID: PMC3933903
polycrystalline silicon thin film transistor; Ion Sensitive Field Effect Transistor; pH sensor; penicillin; DNA; silicon nitride

Results 1-6 (6)