Subphthalocyanines as electron mediators in biosensors based on phenol oxidases: Application to the analysis of red wines

Abstract

The electron mediator properties of three subphthalocyanines (SubPcs) [hexa-chloro boron subphthalocyanine (ClSubPc), tri-tert-butyl boron subphthalocyanine (t-BuSubPc) and hexa-phenoxy boron subphthalocyanine (PhOSubPc)] in Tyrosinase and Laccase biosensors (deposited on ITO glass) for the detection of catechol and hydroquinone were evidenced. A particularly remarkable performance was observed in the PhOSubPc-Tyr sensor, which takes account of the p-p interactions between subphthalocyanine rings and the active sites of the enzymes. Mediated electron transfer between redox enzymes and the ITO electrode improved the limits of detection by one order of magnitude, reaching 10 À7 molÁL À1 values. Studies at increasing scan rates confirmed the improvement of the charge transfer rates caused by the presence of the SubPcs. A bioelectronic tongue formed by an array of the SubPc based biosensors has been able to discriminate red wines according to their Total Polyphenol Index.

Variables of the Analytical Electrochemical Data Acquisition for Boron Subphthalocyanines

“…Current responses associated with various analyte concentrations are useful for detection limit determination while scan rate modulation is important for kinetic studies. For example, this approach was taken for detecting quercetin, a natural therapeutic drug, via a modified glassy carbon electrode with titanium oxide and a Pt‐based porphyrin; [5] for quantifying L‐cysteine via a gold electrode modified with a peripherally alkanethiolated‐CoPc; [6] for sensing anionic pollutants using ferrocene‐containing macrocyclic amides; [7] and sensing industrially and environmentally relevant phenols with biosensors based on ITO and peripherally substituted boron subphthalocyanines (BsubPcs) [8] . In the latter case, improved responses were observed when using modified BsubPc‐electrodes with enzymes (phenyl oxidases), especially when the BsubPc molecule had 6 peripheral phenoxy groups (ie.…”

“…In the latter case, improved responses were observed when using modified BsubPc‐electrodes with enzymes (phenyl oxidases), especially when the BsubPc molecule had 6 peripheral phenoxy groups (ie. Cl−(PhO) 6 BsubPc, Scheme 1A), attributed to the π−π interactions between the phenoxy groups and the enzyme active sites [8] . The mechanism of this enhanced electron transfer process must take into account other factors, such as the electron donor ability of various peripheral substituents, the π‐electron conjugated ring system, molecular stacking, etc.…”

Electrochemical Sensors Modified with Combinations of Sulfur Containing Phthalocyanines and Capped Gold Nanoparticles: A Study of the Influence of the Nature of the Interaction between Sensing Materials

“…One possible strategy to improve the performance of electrochemical sensors could be to develop composites formed by combinations of electrocatalytic materials, in order to generate synergistic effects [13,31,32]. Synergistic effects have been observed in AuNP/Pcs composites obtained by introduction weak interactions between both materials by means of mixing [32,33,34], self-assembling [35], the Langmuir-Blodgett (LB) [36,37], or electrodeposition techniques [38].…”

Biosensors Platform Based on Chitosan/AuNPs/Phthalocyanine Composite Films for the Electrochemical Detection of Catechol. The Role of the Surface Structure

“…FTIR spectra of the LbL platforms deposited on zinc sulfide (ZnS) were also recorded. They displayed the expected vibrational modes of the three components present in the layers: CHI (3385 cm −1 , 1667 cm −1 , 1422 cm −1 and 1397 cm −1 ); CuPcS (1457 cm −1 , 1335 cm −1 , 1149 cm −1 and 1033 cm −1 ) and the COO stretch of the citrate at 1720 cm −1 ( Figure S4) [16,34]. Again, FTIR spectra were identical, regardless of the structure of the LbL films.…”

“…Owing to their high specific surface area and excellent electrocatalytic properties, nanomaterials such as graphene or metallic nanoparticles have been widely used to improve the performance of biosensors dedicated to the detection of phenols [6][7][8][9][10]. Other electrocatalysts, such as conducting polymers [11,12], porphyrins [13,14] or phthalocyanines [15][16][17], have also been successfully incorporated into LbL films as electrocatalytic materials in electrochemical biosensors. On the other hand, LbL films are ideal structures to incorporate linkers able to capture the enzymatic probes.…”