Laccases (Lac) are versatile oxidoreductases known by their wide applicability in wastewater treatments, textile and paper industries, delignification processes, biofuel cells and biosensors [1]. Despite their excellent catalytic properties toward several substrates, more reliable immobilization strategies are needed to stabilize the enzyme in a solid surface and to allow their reusability. Common electrode modification approaches, such as self-assembled monolayers, are not applicable to all surfaces and may involve multi-step procedures [2]. In contrast, the bio-inspired polydopamine (PDA) films can spontaneously grow on a variety of surfaces, creating a biocompatible interface with interesting adhesive properties [3]. This highly functional films enriched with quinone groups are able to covalently bind target biomolecules, through a Schiff base reaction or Michael type additions. In this work we have modified glassy carbon and graphite electrodes with spontaneously formed or electrochemically synthesized PDA films for the immobilization of commercial Laccases and magnetite nanoparticles (NPs). The excellent catalytic properties of this type of nanoparticles (with an average size of 40 nm) have been recently reported for the oxygen reduction reaction [4]. The properties of PDA films were evaluated by ellipsometry and cyclic voltammetry allowing to correlate film thicknesses with deposition conditions and electroactivity. Contact angle goniometry disclose the hydrophilic nature of PDA, whereas morphological information was provided by AFM. The catalytic performance of the enzyme modified electrodes was assessed by chronoamperometry and cyclic voltammetry toward the oxidation of 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid diammonium salt (ABTS). The results show a significant enhancement of Laccase activity in the presence of magnetite nanoparticles, revealing the great potential of these interfaces in the development of novel (bio)sensing devices
Polydopamine films modified with Laccase and magnetite nanoparticles for electrochemical biosensing
A Morana;G Squillaci;
2016
Abstract
Laccases (Lac) are versatile oxidoreductases known by their wide applicability in wastewater treatments, textile and paper industries, delignification processes, biofuel cells and biosensors [1]. Despite their excellent catalytic properties toward several substrates, more reliable immobilization strategies are needed to stabilize the enzyme in a solid surface and to allow their reusability. Common electrode modification approaches, such as self-assembled monolayers, are not applicable to all surfaces and may involve multi-step procedures [2]. In contrast, the bio-inspired polydopamine (PDA) films can spontaneously grow on a variety of surfaces, creating a biocompatible interface with interesting adhesive properties [3]. This highly functional films enriched with quinone groups are able to covalently bind target biomolecules, through a Schiff base reaction or Michael type additions. In this work we have modified glassy carbon and graphite electrodes with spontaneously formed or electrochemically synthesized PDA films for the immobilization of commercial Laccases and magnetite nanoparticles (NPs). The excellent catalytic properties of this type of nanoparticles (with an average size of 40 nm) have been recently reported for the oxygen reduction reaction [4]. The properties of PDA films were evaluated by ellipsometry and cyclic voltammetry allowing to correlate film thicknesses with deposition conditions and electroactivity. Contact angle goniometry disclose the hydrophilic nature of PDA, whereas morphological information was provided by AFM. The catalytic performance of the enzyme modified electrodes was assessed by chronoamperometry and cyclic voltammetry toward the oxidation of 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid diammonium salt (ABTS). The results show a significant enhancement of Laccase activity in the presence of magnetite nanoparticles, revealing the great potential of these interfaces in the development of novel (bio)sensing devicesI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
