Study of the Nanostructure Effect on Polyalkylthiophene Derivatives Films Using Impedance Spectroscopy

In this paper, devices fabricated with a diode-like structure (electrode/polymer/electrode) from spin-coated and nanostructured (Langmuir-Schaefer) films of polythiophene derivatives were characterized by impedance spectroscopy and studied by theoretical fitting to reach a better understanding of the physical processes in the devices. The materials used for this research were the polyalkylthiophene (P3AT) derivatives poly(3-butylthiophene) (P3BT), poly(3-hexylthiophene) (P3HT), poly(3-octylthiophene) (P3OT) and poly(3-decylthiophene) (P3DT). Electrical measurements were performed from 1 Hz to 1 MHz (100 mV ac) while increasing the dc bias in the range from 0 to 2.5 V. The fittings of the experimental results were performed using equivalent circuits. By plotting the theoretical and experimental spectra on a single graph, it was possible to obtain information related to the film morphology, interfacial effects, resistance, capacitance and conductivity of the polymer, thereby enhancing the understanding of this particular type of device. Among the P3AT films, those grown by the Langmuir-Schaefer technique showed higher electrical conductivity, with the only exception being that of P3BT

A microfluidic e-tongue system using layer-by-layer films deposited onto interdigitated electrodes inside a polydimethylsiloxane microchannel

An electronic tongue (e-tongue) is a multisensory system employed in the analysis of liquid samples, transforming the raw data into specific recognition patterns through computational and statistical analysis. Distinct types of e-tongues have been reported in the literature, with a plethora of applications in several areas of research. Recently, e-tongues have been integrated into microfluidic devices, which offer advantages such as the use of continuous flow for faster and more accurate analysis, and reduction in size of the devices and volumes for sampling and discharge, which in turn reduces waste and cost. Here we describe the procedures and methodologies recently used in our research group in the development of a microfluidic e-tongue sensing system2027141150CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPNão temNão tem2014/03691-7; 2015/14836-9; 2017/11277-4Authors are grateful for the financial support of the Brazilian research funding agencies: FAPESP (Grants n° 2014/03691-7, 2015/14836-9 and 2017/11277-4), CAPES, and CNPq. They also thank LNNano/CNPEM (LMF project n° 21340

Familial Exudative Vitreoretinopathy or Retinopathy of Prematurity

Retinopathy of prematurity (ROP) and familial exudative vitreoretinopathy (FEVR) can have very similar clinical presentations. Both diseases have abnormal development of retinal vessels and lead to severe vitreoretinopathy which causes blindness in newborn infants. The single most important difference is prematurity. In ROP, the most important risk factors are gestational age and low birth weight. In FEVR, it is the genetic mutation. Identifying the underlying mutations in the causative gene can predict the prognosis of patients with FEVR. ROP tends to resolve naturally or with treatment, but FEVR is a lifelong disease. Even we know that the clinical characteristics and risk factors between both diseases are different; the clinical similarity makes differential diagnosis difficult, especially in FEVR patients who were born prematurely. In such a scenario, patients could exhibit features of FEVR or ROP or both and found to have a discrepancy between birth history and fundus appearance, thus ROPER/fROP was used to describe these patients under such conditions