Amperometric glucose biosensing performance of a novel graphene nanoplatelets-iron phthalocyanine incorporated conducting hydrogel.

Herein, a novel one step synthesis of multicomponent three dimensional polyacrylic acid (PAA) based conducting hydrogel (CH) incorporated with iron phthalocyanine functionalised graphene nanoplatelets (GPL-FePc) is reported. An amperometric glucose biosensor was fabricated by the immobilization of glucose oxidase (GOx) onto the synthesised PAA-VS-PANI/GPL-FePc-CH (where VS-PANI is vinyl substituted polyaniline). Scanning electron microscopy reveals the presence of three dimensional microporous structure with estimated pore size of 19 µm. The 5-(trifluoromethyl)-2-mercaptopyridine substitution onto FePc enabled the solubility of FePc in water and controls the aggregation of GPL-FePc in the synthesised CH. A sharp peak around 699 nm in UV-visible spectra confirms the presence of incorporated GPL-FePc into CH. Cyclic voltammogram of the synthesised CH biosensor exhibited well defined redox peaks with a ΔEp value of 0.26 V in Fe(CN)63-/4- bench mark solution. The fabricated PAA-VS-PANI/GPL-FePc/GOx-CH amperometric biosensor resulted in remarkable detection sensitivity of 18.11 µA mM-1 cm-2 with an average response time of ∼1 s, linearity from 1 to 20 mM, and low detection limit of 6.4 µM for the determination of glucose.

A glucose biosensor based on novel Lutetium bis-phthalocyanine incorporated silica-polyaniline conducting nanobeads.

The facile preparation of highly sensitive electrochemical bioprobe based on lutetium phthalocyanine incorporated silica nanoparticles (SiO2(LuPc2)) grafted with Poly(vinyl alcohol-vinyl acetate) itaconic acid (PANI(PVIA)) doped polyaniline conducting nanobeads (SiO2(LuPc2)PANI(PVIA)-CNB) is reported. The preparation of CNB involves two stages (i) pristine synthesis of LuPc2 incorporated SiO2 and PANI(PVIA); (ii) covalent grafting of PANI(PVIA) onto the surface of SiO2(LuPc2). The morphology and other physico-chemical characteristics of CNB were investigated. The scanning electron microscopy images show that the average particle size of SiO2(LuPc2)PANI(PVIA)-CNB was between 180-220nm. The amperometric measurements showed that the fabricated SiO2(LuPc2)PANI(PVIA)-CNB/GOx biosensor exhibited wide linear range (1-16mM) detection of glucose with a low detection limit of 0.1mM. SiO2(LuPc2)PANI(PVIA)-CNB/GOx biosensor exhibited high sensitivity (38.53µAmM-1cm-2) towards the detection of glucose under optimized conditions. Besides, the real (juice and serum) sample analysis based on a standard addition method and direct detection method showed high precision for measuring glucose at SiO2(LuPc2)PANI(PVIA)-CNB/GOx biosensor. The SiO2(LuPc2)PANI(PVIA)-CNB/GOx biosensor stored under refrigerated condition over a period of 45 days retains ~ 96.4% glucose response current.

Investigations and application in piezoelectric phenol sensor of Langmuir-Schäfer films of a copper phthalocyanine derivative functionalized with bulky substituents.

An octa-substituted copper phthalocyanine was dissolved in chloroform and spread on ultrapure water subphase in a Langmuir trough. The floating films were characterized at the air-water interface by the Langmuir isotherm, Brewster angle microscopy, and UV-Vis reflection spectroscopy and transferred by Langmuir-Schäfer technique on a silicon substrate, and thickness, refractive index, and extinction coefficient of the phthalocyanine derivative thin film were calculated by means of spectroscopic ellipsometry. A different number of layers were deposited using Langmuir-Schäfer method onto QCM crystals, and the active layers were tested as sensors for the detection of phenols in aqueous solution. The piezoelectric sensor response, totally reversible, is influenced by the number of transferred layers and by the nature of the substituent; on the contrary, the pK(a) value of the injected analytes slightly affects the device performances. Repeatability of the sensor responses was tested, and the frequency variation appears unchanged at least for 100 days.

Characterisation of protein adsorption on different liquid crystal phthalocyaninethin films.

Bovine serum albumin (BSA) protein adsorption on thin spun films of different metal octakishexylthiophthalocyanine [(C(6)S)(8)PcM, M=Cu, Ni] derivatives is investigated by using three independent spectroscopic measurements namely Raman spectroscopy, ellipsometry and surface plasmon resonance imaging. Thermally induced molecular self-reorganisations in the phthalocyanine films are found to have produced the changes in the surface energy which, in turn, control protein adsorption. The amount of BSA adsorption on [(C(6)S)(8)PcNi] is more limited than that on [(C(6)S)(8)PcCu] and this observation is consistent with the results on the surface wettability obtained from the contact angle measurements. The shift from the plasmonic resonance wavelength because of the BSA adsorption was significantly larger for the heat-treated [(C(6)S)(8)PcCu] than as-deposited film. Similar measurements on the [(C(6)S)(8)PcNi] films showed a limited BSA adsorption. The results of surface plasmon resonance experiments are consistent with those obtained from Raman spectroscopic and ellipsometric techniques.

Use of the electrochromic behaviour of lanthanide phthalocyanine films for nicotinamide adenine dinucleotide detection.

Electrochromic properties of spun films of bis[octakis(hexylthio)phthalocyaninato] dysprosium(III) were investigated for determining nicotinamide adenine dinucleotide hydride (NADH) in water solutions. A spin-coated film deposited on indium tin oxide electrode displays only one redox couple (at E1/2=0.78V). The films of [(C6H13S)8Pc]2Dy were modified chemically or electrochemically for the detection of reduced NADH in water solution. The modified film in the oxidized ([(C6H13S)8Pc]2Dy)+ form is believed to be reduced to its neutral form on interaction with NADH.

[Improving the system of preventing vibration and noise-induced pathology]. / Sovershenstvovanie sistemy profilaktiki vibratsionno-shumovoi patologii.

Due to the long-term study of various machines under industrial and test conditions it became possible to determine the specific role of each chain of the man-machine system in the intensification of vibroacoustic effect on a worker and to develop a system of medical, technical and organizational preventive measures. Introduction of a set of such measures at one of the plants helped to reduce vibration disease rates by dozens of times. In order to control noise- and vibration-caused diseases it was necessary not only to improve machines' quality and service conditions but also to pay special attention to the choice of operators and to the quality of monitoring their adaptation process.