Abstract:We present a new biosensor for hydrogen peroxide (H 2 O 2 ) detection. The biosensor was based on the immobilization of horseradish peroxidase (HRP) enzyme on layered double hydroxides-(LDH-) modified gold surface. The hydrotalcite LDH (Mg 2 Al) was prepared by coprecipitation in constant pH and in ambient temperature. The immobilization of the peroxidase on layered hybrid materials was realized via electrostatic adsorption autoassembly process. The detection of hydrogen peroxide was successfully observed in P… Show more
“…1 a, b, respectively. The curve for PBS is also reported, showing a behavior similar to that shown elsewhere 27 . Figure 1 Cyclic voltammetry of potassium ferricyanide (K 3 [Fe(CN) 6 ]), 25 mM, in PBS (pH 7.4), 100 mM (scan rates 25, 50, 100, 150, 200 and 300 mV/s) carried out using ( a ) a SPE equipped with Au working and counter electrodes and Ag/AgCl reference electrode; ( b ) the same measurement as in ( a ) using a homologue SPE where the working electrode is covered by a PEGDA:PEDOT layer; ( c ) anodic and cathodic peak positions extracted from ( a ) as a function of the square root of the scan rates (related fitting curves, solid lines); ( d ) anodic and cathodic peak positions extracted from ( b ) as a function of the square root of the scan rates (related fitting curves, solid lines).…”
Rapid Prototyping (RP) promises to induce a revolutionary impact on how the objects can be produced and used in industrial manufacturing as well as in everyday life. Over the time a standard technique as the 3D Stereolithography (SL) has become a fundamental technology for RP and Additive Manufacturing (AM), since it enables the fabrication of the 3D objects from a cost-effective photocurable resin. Efforts to obtain devices more complex than just a mere aesthetic simulacre, have been spent with uncertain results. The multidisciplinary nature of such manufacturing technique furtherly hinders the route to the fabrication of complex devices. A good knowledge of the bases of material science and engineering is required to deal with SL technological, characterization and testing aspects. In this framework, our study aims to reveal a new approach to obtain RP of complex devices, namely Organic Electro-Chemical Transistors (OECTs), by SL technique exploiting a resin composite based on the conductive poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) and the photo curable Poly(ethylene glycol) diacrylate (PEGDA). A comprehensive study is presented, starting from the optimization of composite resin and characterization of its electrochemical properties, up to the 3D OECTs printing and testing. Relevant performances in biosensing for dopamine (DA) detection using the 3D OECTs are reported and discussed too.
“…1 a, b, respectively. The curve for PBS is also reported, showing a behavior similar to that shown elsewhere 27 . Figure 1 Cyclic voltammetry of potassium ferricyanide (K 3 [Fe(CN) 6 ]), 25 mM, in PBS (pH 7.4), 100 mM (scan rates 25, 50, 100, 150, 200 and 300 mV/s) carried out using ( a ) a SPE equipped with Au working and counter electrodes and Ag/AgCl reference electrode; ( b ) the same measurement as in ( a ) using a homologue SPE where the working electrode is covered by a PEGDA:PEDOT layer; ( c ) anodic and cathodic peak positions extracted from ( a ) as a function of the square root of the scan rates (related fitting curves, solid lines); ( d ) anodic and cathodic peak positions extracted from ( b ) as a function of the square root of the scan rates (related fitting curves, solid lines).…”
Rapid Prototyping (RP) promises to induce a revolutionary impact on how the objects can be produced and used in industrial manufacturing as well as in everyday life. Over the time a standard technique as the 3D Stereolithography (SL) has become a fundamental technology for RP and Additive Manufacturing (AM), since it enables the fabrication of the 3D objects from a cost-effective photocurable resin. Efforts to obtain devices more complex than just a mere aesthetic simulacre, have been spent with uncertain results. The multidisciplinary nature of such manufacturing technique furtherly hinders the route to the fabrication of complex devices. A good knowledge of the bases of material science and engineering is required to deal with SL technological, characterization and testing aspects. In this framework, our study aims to reveal a new approach to obtain RP of complex devices, namely Organic Electro-Chemical Transistors (OECTs), by SL technique exploiting a resin composite based on the conductive poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) and the photo curable Poly(ethylene glycol) diacrylate (PEGDA). A comprehensive study is presented, starting from the optimization of composite resin and characterization of its electrochemical properties, up to the 3D OECTs printing and testing. Relevant performances in biosensing for dopamine (DA) detection using the 3D OECTs are reported and discussed too.
“…As seen in Figure 3.c, according to the cyclic voltammetry (CV) measurement, the current passing through the modified gold surface [39] decreased compared to the bare gold surface. [40] By CV measurement, we have shown the current difference according to the potential change as a result of the impedance change on the bare gold surface and the modified surface. The results of the CV measurement were consistent with the literature and the modification on the gold surface was confirmed by CV analysis.…”
The potential health hazards of pathogens, such as Escherichia coli (E. coli), have recently received extensive attention. However, the concentration change of E. coli in sewage sludge during the vermicomposting process is still relatively unexplored. In this study, sewage sludge, a byproduct of wastewater treatment, was used as bed materials with cow dung to produce valuable liquid organic fertilizer (vermicompost tea). A unique quartz crystal microbalance (QCM) detection system with a novel surface functionalization procedure, which allows selectively captured analytes to be removed from the surface in a controlled manner for possible extra genetic and serological detections, was also developed for low level detection of E. coli in vermicompost tea (VT) medium. The results indicate that sewage sludge became a valuable liquid organic fertilizer, which has total nitrogen and phosphorus content 22 % and 11 % higher than their initial levels, respectively. The QCM‐based biosensing showed good detection sensitivity and stability at near 102 CFU mL−1 level in VT samples. The developed QCM based method with a novel surface controllable biosensing mechanism provides a reliable and selective detection approach allowing other post analyses if needed for sensitive measurement of E. coli in vermicompost tea or different aqueous solutions. After the determination of pathogenic levels in vermicompost tea could be used as liquid organic fertilizer for a sustainable organic farming system.
“…The new biosensor reached its maximum performance at pH 7 and it had superior analytical performances in terms of selectivity and detection limit in comparison with C-Dots/GCE, CoFeLDH/GCE, C-Dots/CoFeLDH/GCE formulation [44]. HRP was also immobilized on MgAlLDH [45], NiAlLDH [46]. Furthermore, horseradish peroxidase and glucose oxidase (GOX) were immobilized together on ZnCrLDH-ABTS composite.…”
Section: Enzyme-ldhs As Biohybrid In Biosensors Designmentioning
Layered double hydroxides are known for over 150 years. The first discovered natural mineral with this structure was hydrotalcite [5], reported by Hochstetter in 1842, synthesized 100 years later by Feitknecht [6]. The structure of this compound is related to that of brucite in which part of Mg 2+ cations are replaced by Al3+. Carbonate anions are intercalated between the layers to maintain the electroneutrality of material. The presence of hydrotalcite in nature is reduced. For this reason, the synthesis of LDHs was
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