Organic‐phase biosensors based on the entrapment of enzymes within poly(ester‐sulfonic acid) coatings

Abstract

The utility and advantages of the poly(ester-sulfonic acid) ionomer (Eastman AQ-55D, Eastman Chemical Products) for entrapping enzymes onto electrodes for organic-phase biosensing are described. This type of immobilization scheme relies on the stability of Eastman AQ films in various organic solvents. The resulting organic-phase enzyme elecrodes couple the entrapment of high enzyme loadings with discrimination against anionic interferences, short response times, and a rapid stabilization of the baseline current. The immobilization of the enzymes tyrosinase and horseradish peroxidase (HW) is evaluated in connection with the biosensing of phenolic and peroxide compounds in acetonitrile solutions. Various conditions of this simple preparation route are explored.

Amperometric tyrosinase based biosensor using an electropolymerized PTS-doped polypyrrole film as an entrapment support

“…Nevertheless, these methods are not simple. Wang et al [13][14][15] have reported sensitive amperometric biosensors for phenolic compounds. Such devices rely on the immobilization of tyrosinase on to graphite-epoxy resin, poly(estersulfonic acid) ionomer and sol-gel-polymer composite and the low potential detection of the liberated quinone product.…”

Biossensores amperométricos para determinação de compostos fenólicos em amostras de interesse ambiental

“…Os esforços para usar tirosinase como uma ferramenta analítica para a determinação de fenóis e catecóis com transdução eletroquímica iniciaram em 1977 com o trabalho de Macholan e Schanel 58 . Desde então, muitos biossensores baseados em tirosinase têm sido elaborados para a determinação de fenol envolvendo várias formas de detecção eletroquímica: detecção do consumo de oxigênio [58][59][60] , redução direta da o-quinona gerada [34][35][61][62][63][64][65][66][67][68][69][70][71] e redução mediada da o-quinona 72, 73 . O princípio da detecção do consumo de oxigênio está baseado no eletrodo de oxigênio de Clark, ao qual é incorporado um biocatalisador que utiliza oxigênio na presença de um substrato específico 74 .…”

On-line monitoring of methanol in n-hexane by an organic-phase alcohol biosensor

“…It has been recognised that the way an enzyme was entrapped within hydrophilic or hydrogel polymer is a paramount important strategy for relieving the deleterious effect of organic solvent on the immobilised enzyme (Wang et al, 1993(Wang et al, , 2004Guo and Dong, 1997). As such, the polymer can retain the intrinsic enzymatic activity of an entrapped enzyme more effectively when it serves as a heterogeneous biocatalyst in organic solvent system; as compared with enzyme being exposed directly to solvent, no matter it is immobilised or free (Duff and Murray, 1989).…”

“…The film/membrane techniques of enzyme immobilisation based on some relatively high-specific activity enzymes such as tyrosinase and horseradish peroxidase (HRP) have been successfully developed in numerous organic-phase biosensors (Wang et al, 1993;Guo and Dong, 1997). When the substrate mass transfer process becomes the major rate-limiting factor, the high enzymatic activity will turn into an insignificant factor for achieving good reproducibility for biosensing.…”