Investigations with respect to stabilization of screen-printed enzyme electrodes

Schumacher, Jens T.; Münch, I.; Richter, Tanja; Rohm, Ingrid; Bilitewski, Ursula

doi:10.1016/s1381-1177(99)00022-3

Cited by 22 publications

(16 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Previous studies showed that HRP stability was dependent on enzyme concentration in solution [14]. For example, HRP at a concentration of 0.5 μg/mL lost almost 50% of the activity within 14 days at 4°C [20]. We observed that HRP at 60 μg/mL in PBS buffer, pH 7.4, retained more than 20% of its original activity after three months storage at 4°C (Fig.…”

Section: Discussionsupporting

confidence: 54%

Stabilization of horseradish peroxidase in silk materials

Wang

Uppal

et al. 2009

Front. Mater. Sci. China

View full text Add to dashboard Cite

Horseradish peroxidase (HRP) is widely used as an indicator enzyme in enzyme immunoassays, enzyme electrodes, effluent treatment and synthetic organics. Previous studies showed that HRP was not stable in solution especially for low concentration solutions. It is important to prevent HRP from losing its activity. In the present study, we describe HRP stabilization in silk fibroin solution and in silk films. The results showed that HRP activity increased 30%-40% after being added into silk solution. The half-life time of HRP activity was 25 days at room temperature and 1 h at 60°C in silk solution while it was only 2.5 h at room temperature and 0.3 h at 60°C in PBS buffer. The HRP activity in silk film still remained at 24%, 22%, 17%, when compared with the original amount of activity, after being immobilized in silk films stored at 4°C, room temperature and 37°C for 5 months, respectively. Electrostatic interactions and hydrophobic interactions between silk and HRP might account for this improved stabilization. Silk fibroin can be used as an HRP protecting reagent in solution and in films.

show abstract

Section: Discussionsupporting

confidence: 54%

Stabilization of horseradish peroxidase in silk materials

Wang

Uppal

et al. 2009

Front. Mater. Sci. China

View full text Add to dashboard Cite

show abstract

“…An effective integration of electrodes and enzymes must be provided in order to comply with the morphological demands of these fragile biological entities. These requirements have been addressed in the past, with varying results, by immobilizing enzymes using covalent bonding, 1-4 bioaffinity attachment, 5-9 organic polymers, entrapment in redox gels, [33][34][35][36][37][38][39][40] sol-gel-derived glasses, 41,42 carbon pastes, [43][44][45] and carbonpolymer electrodes. 46,47 The enzyme immobilization strategy selected in the present investigation relies on using a protective matrix consisting of the biopolymer, chitosan.…”

mentioning

confidence: 99%

Integration of Enzymes and Electrodes: Spectroscopic and Electrochemical Studies of Chitosan−Enzyme Films

2002

View full text Add to dashboard Cite

A new film-forming solution was developed for the efficient immobilization of enzymes on solid substrates. The solution consisted of a biopolymer, chitosan (CHIT), that was chemically modified with a permeability-controlling agent, Acetyl Yellow 9 (AY9), using glutaric dialdehyde (GDI) as a molecular tether. A model enzyme, glucose oxidase (GOx), was mixed with the CHIT-GDI-AY9 solution and cast on the surface of platinum electrodes to form robust CHIT-GDI-AY9-GOx films for glucose biosensing. UV-visible and infrared spectroscopies were used to determine the composition of the films. The optimized films contained on average 1 molecule of AY9/3 glucosamine units of chitosan and 25 free GDI tethers/1 molecule of GOx. The electrochemical assays of the films indicated both a very high efficiency of enzyme immobilization (approximately 99%) and large enzyme activity (60 units cm(-2)). The latter translated into a high sensitivity (42 mA M(-1) cm(-2)) of the Pt/CHIT-GDI-AY9-GOx biosensor toward glucose. The biosensor operated at 0.450 V, had a fast response time (t90% < or = 3 s), and was free of typical interferences, and its dynamic range covered 3 orders of magnitude of glucose concentrations. The lowest actually detectable concentration was 10 microM glucose. In addition, the biosensor displayed a practical shelf life and excellent operational stability, e.g. its response was stable during 24-h testing under continuous polarization and continuous flow of 5.0 mM glucose solution. The proposed approach to enzyme immobilization is simple, efficient, and cost-effective and should be of importance in the development of biosensors based on other enzymes that are more expensive than glucose oxidase.

show abstract

“…Electrochemical lactate biosensors have been typically designed using LOx because of its accessibility and independence of external cofactors. The LOx has been immobilized in biosensors using redox polymers, − electropolymerized organic films, − polymer and polyelectrolyte layers, − cross-linked proteins, − sol−gels and hydrogels, , carbon pastes, and screen-printable pastes …”

mentioning

confidence: 99%

Coupling the Lactate Oxidase to Electrodes by Ionotropic Gelation of Biopolymer

2003

View full text Add to dashboard Cite

A direct ionotropic gelation of the polycationic biopolymer chitosan (CHIT) with the polyanionic enzyme lactate oxidase (LOx) was used to form thin biopolymer-enzyme films on the surface of platinum electrodes. The electrochemical assays of such films revealed a well-defined capacity of CHIT for the retention of LOx. The stoichiometry of the CHIT-LOx polyelectrolyte complexes was found to be approximately 1:40, i.e., on average, 1 CHIT chain retained 40 molecules of LOx in the CHIT-LOx films. The enzyme retention was ascribed to strong electrostatic interactions between the LOx and a fraction of the protonated amino groups on the CHIT chains. Although the LOx is inherently unstable outside its natural matrix, it displayed high surface activity of 0.26 units cm(-)(2) in the matrix of CHIT. This correlated with good stability of the biopolymer-enzyme films as demonstrated by a constant response of Pt/CHIT-LOx electrodes to lactate during continuous 24-h testing. When compared to other single-film lactate sensors, the Pt/CHIT-LOx electrodes displayed the best combination of analytical properties in terms of a low detection limit (50 nM), high sensitivity (0.23 A M(-)(1) cm(-)(2)), and fast response time (<1 s). Such a performance validated the CHIT-LOx system as an attractive sensing element for the development of new lactate biosensors.

show abstract

Investigations with respect to stabilization of screen-printed enzyme electrodes

Cited by 22 publications

References 18 publications

Stabilization of horseradish peroxidase in silk materials

Stabilization of horseradish peroxidase in silk materials

Integration of Enzymes and Electrodes: Spectroscopic and Electrochemical Studies of Chitosan−Enzyme Films

Coupling the Lactate Oxidase to Electrodes by Ionotropic Gelation of Biopolymer

Contact Info

Product

Resources

About