Protecting Peroxidase Activity of Multilayer Enzyme-Polyion Films Using Outer Catalase Layers

Abstract

Films constructed layer-by-layer on electrodes with architecture {protein/hyaluronic acid (HA)} n containing myoglobin (Mb) or horseradish peroxidase (HRP) were protected against protein damage by H 2 O 2 by using outer catalase layers. Peroxidase activity for substrate oxidation requires activation by H 2 O 2 , but {protein/HA} n films without outer catalase layers are damaged slowly and irreversibly by H 2 O 2 . The rate and extent of damage were decreased dramatically by adding outer catalase layers to decompose H 2 O 2 . Comparative studies suggest that protection results from catalase decomposing a fraction of the H 2 O 2 as it enters the film, rather than by an in-film diffusion barrier. The outer catalase layers controlled the rate of H 2 O 2 entry into inner regions of the film, and biased the system to favor electrocatalytic peroxide reduction over enzyme damage. Catalase-protected {protein/ HA} n films had an increased linear concentration range for H 2 O 2 detection. This approach offers an effective way to protect biosensors from damage by H 2 O 2 .

Location of molecules in layer-by-layer assembled microcapsules influences activity, cell delivery and susceptibility to enzyme degradation

“…When included in the subouter layer enzyme activity was greatest with an immediate peak of activity that resembled free enzyme. These observations of reduced enzyme activity with increased numbers of covering layers is in agreement with our previous study [13] and observations of other enzymes in both films [22] and intact capsules [11,12].…”

Carbon-felt-based Bioelectrocatalytic Flow-detectors: Optimization of the Adsorption Conditions of Horseradish Peroxidase and Thionine onto Carbon-felt for Highly Sensitive Amperometric Determination of H2O2

“…Electrical communication between redox proteins and the electrode surfaces has been improved by aligning proteins on chemically modified electrodes, 33,34 by attaching an electron-transporting group, 35,36 and by immobilizing proteins in polymer matrices tethered by redox groups. [37][38][39] Differing from these previous electron-relay systems, the present HRP/Th-CF-based flow-biosensor system is quite simple (i.e., just co-adsorption of HRP and Th onto the CF surface from the HRP/Th mixed solution). Therefore, we speculate that some kinds of interactions between Th and HRP in the solution phase and/or during the adsorption process would play important roles for an enhancement of the DET-based peak current responses.…”

Enzyme-Encapsulated Layer-by-Layer Assemblies: Current Status and Challenges Toward Ultimate Nanodevices

“…Hemoglobin (Hb) in such films was demonstrated to retain its activity for a longer period of time. Hu and coworkers also investigated the protective effect of exterior catalase layers using electroactive myoglobin (Mb) or horseradish peroxidase (HRP) in these films as a probe to monitor the extent of protein damage by H 2 O 2 [186]. The results similarly demonstrated that the outer catalase layers controlled the rate of H 2 O 2 entry into inner regions of the film.…”