Polymer brush modified electrode with switchable selectivity triggered by pH changes enhanced by gold nanoparticles

In this work, a sensor was built up with smart material based on polymer brush and gold nanoparticles. The modified electrode functionalized with polyacrylic acid (PAA) tethered to indium tin oxide (ITO) and covered with gold nanoparticle (ITO/PAA/Au) demonstrated switchable interfacial properties discriminating different pHs. The switchable electrochemical and plasmonic process was characterized by cyclic voltammetry (CV), electrochemistry impedance spectroscopy (EIS), and localized surface plasmon resonance (LSPR).Neste trabalho foi desenvolvido um sensor com propriedades inteligentes, baseado em polímeros escova (poli-ácido acrílico) modificado com nanopartículas de ouro. Este novo material demonstrou propriedades comutáveis que podem discriminar diferentes pHs. O eletrodo foi caracterizado por voltametria cíclica (CV), espectroscopia de impedância eletroquímica (EIS) e ressonância plasmônica de superfície localizada (LSPR)

Plasmonic Nanobiosensor with Chain Reaction Amplification Mechanism

Herein we demonstrate a plasmonic nanobiosensor that explores chain reaction amplification mechanisms to transduce chemical signals released in biocatalytic reactions, turning optical signals into a visual spectral range. The sensor has a very simple design: gold nanoparticles resting in the surface of a grafted P2VP film. Changes in the gold nanoparticles' position causes changes in the plasmon coupling mode. This is detected by means of a maximum absorbance shift.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Glucose biosensor based on multisegment nanowires exhibiting reversible magnetic control

We describe the amperometric detection of glucose using oriented nanowires with magnetic switching of the bioelectrochemical process. The fabrication process of the nanowires was prepared through controlled nucleation and growth during a stepwise electrochemical deposition, and it was characterized using scanning electron microscopy. Cyclic voltammetry and amperometry were used to study the magnetoswitchable property; this control was accomplished by changing the surface orientation of nanowires. Under the optimal condition, the amperometric response was also linear up to a glucose concentration of 0.1-16.0 mmol L-1 with a sensitivity of 81 mu A. mM(-1). The detection limit was estimated for 4.8 x 10(-8) mol L-1, defined from a signal/noise ratio of 3. It also exhibits good reproducibility and high selectivity with insignificant interference from ascorbic acid, acetoaminophen, and uric acid. The resulting biosensor was applied to detect the blood sugar in human serum samples without any pretreatment, and the results were comparatively in agreement with the clinical assay. (C) 2014 Elsevier B.V. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Molecular and Morphological Evidence Reveals a New Species in the <i>Phyllomedusa hypochondrialis</i> Group (Hylidae, Phyllomedusinae) from the Atlantic Forest of the Highlands of Southern Brazil

<div><p>The taxonomic status of a disjunctive population of <i>Phyllomedusa</i> from southern Brazil was diagnosed using molecular, chromosomal, and morphological approaches, which resulted in the recognition of a new species of the <i>P. hypochondrialis</i> group. Here, we describe <i>P. rustica</i> sp. n. from the Atlantic Forest biome, found in natural highland grassland formations on a plateau in the south of Brazil. Phylogenetic inferences placed <i>P. rustica</i> sp. n. in a subclade that includes <i>P. rhodei</i> + all the highland species of the clade. Chromosomal morphology is conservative, supporting the inference of homologies among the karyotypes of the species of this genus. <i>Phyllomedusa rustica</i> is apparently restricted to its type-locality, and we discuss the potential impact on the strategies applied to the conservation of the natural grassland formations found within the Brazilian Atlantic Forest biome in southern Brazil. We suggest that conservation strategies should be modified to guarantee the preservation of this species.</p></div

Paratypes of <i>Phyllomedusa rustica</i> sp. n. (A) Coloration pattern in the flank regions; (B) individual during call activity perched near the ground in herbaceous vegetation at the margin of a pond.

<p>Paratypes of <i>Phyllomedusa rustica</i> sp. n. (A) Coloration pattern in the flank regions; (B) individual during call activity perched near the ground in herbaceous vegetation at the margin of a pond.</p

Holotype of <i>Phyllomedusa rustica</i> sp. n. (UFMG 13360), adult specimen: (A) dorsal and lateral views of head and (B) palmar (left) and plantar (right) views.

<p>Scale Bar = 5 mm.</p

Uncorrected pairwise distances between the 12S, tRNA-val and 16S mitochondrial sequences of the species of the <i>Phyllomedusa hypochondrialis</i> group.

<p>Uncorrected pairwise distances between the 12S, tRNA-val and 16S mitochondrial sequences of the species of the <i>Phyllomedusa hypochondrialis</i> group.</p

Phylogenetic relationships of the genus <i>Phyllomedusa</i> based on 2141 bps of the mitochondrial 12S rDNA, tRNA-val and 16S rDNA mitochondrial genes.

<p>(<b>A</b>) Strict consensus cladogram inferred using the maximum parsimony (MP) criterion, implemented in the TNT program. Numbers adjacent to the nodes indicate bootstrap values. (<b>B</b>) Topology inferred from the Bayesian analysis based on the GTR+R+I model. Bayesian posterior probabilities are shown at each node. Scale bar represents the number of substitutions per site.</p

Map of Brazil showing the Atlantic Forest domain (green area).

<p>Note the type locality of <i>Phyllomedusa rustica</i> sp. n. (square symbol) in the Água Doce municipality, Santa Catarina state.</p