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A comparative study of covalent glucose oxidase and laccase immobilization techniques at powdered supports for biosensors fabrication
Tvorynska, Sofiia ; Barek, J. ; Josypčuk, Bohdan ; Nesměrák, K.
In order to develop the optimal strategy and to deepen the knowledge in the field of enzyme immobilization, three different techniques of covalent binding for two enzymes (glucose oxidase and laccase) at powdered surfaces were compared. Immobilization protocol was optimized by changing supports (two mesoporous silica powders (SBA−15, MCM−41) and a cellulose powder), the functionalized\ngroups introduced at support surfaces (−NH and −COOH), and the methods of activation (glutaraldehyde and carbodiimide). Amino and carboxyl functionalized mesoporous silica and cellulose powders\nwere prepared by silanization using (3-aminopropyl)triethoxysilane and carboxyethylsilanetriol, respectively. It was found that coupling of both enzymes by their –NH groups through glutaraldehyde to -NH functionalized supports, in particular SBA15−NH and cellulose−NH for glucose oxidase, MCM41−NH for laccase, showed the highest activity and the best stability.
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Construction and Application of Flow Amperometric Biosensor Based on Enzymatic Reactor for Determination of Choline
Tvorynska, Sofiia ; Barek, J. ; Josypčuk, Bohdan
In this contribution, a novel fast, simple and stable biosensor with the enzymatic reactor based on choline oxidase (ChOx) was developed and applied for the determination of choline using flow injection analysis with amperometric detection. The preparation of the reactor is based on the covalent immobilization of ChOx with glutaraldehyde to mesoporous silica powder (SBA-15) previously covered by NH2-groups. The experimental parameters affecting the sensitivity and stability of the biosensor were optimized. The proposed biosensor with the newly developed ChOx-based reactor possesses good repeatability, reproducibility, long-term stability, and reusability. It was successfully applied for the determination of choline in commercial pharmaceuticals.
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Electrochemical biosensors with flow-through enzymatic reactors
Josypčuk, Oksana ; Josypčuk, Bohdan
Twelve enzymatic biosensors with various silica powder reactors were fabricated and tested.\nExperiments with six silica materials showed that mesoporous silica SBA-15 was the best one\nin terms of covering by enzymes, sensitivity and lifetime of biosensors. The current response\nof the SBA15-glucose oxidase (GOx) sensor started to decrease only after 200-day testing.\nThe used amalgam tubular detector in a flow system allowed working at highly negative\npotentials. Statistical results of parallel measurements of model solutions with the fabricated\nbiosensors show their high accuracy and sensitivity. The proposed SBA15-GOx biosensor\nwas used for determination of glucose in commercial honey.
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