| Abstract |
Carbon nanofibers are promising materials for the development of biosensors due to their unique electrochemical properties, high surface area, as well as their high mechanical and chemical stability. Oxidation of carbon nanofibers provides the possibility of introducing new additional functional groups onto their surface, lending them more attractive as enzyme immobilization matrices. For this, the conjugation of chemically modified carbon nanofibers with enzymes can lead to the development of biosensors with improved characteristics, such as higher sensitivity and better stability.
Recently, silica biomimetic composites have proven to be an excellent matrix for the encapsulation and stabilization of enzymes. The impressive silica structures formed by diatoms are among the most remarkable examples of biological nanofabrication. It has been shown that certain proteins found in diatoms are responsible for the mediation of the formation of the biogenic silica structures. The elucidation of the chemical structures of these proteins has allowed for the design of model polypeptides which can also serve as very efficient templates for the biomimetic formation of silica nanoparticles, using silicic acid as the building block. Furthermore, utilizing specific biomacromolecules, the synthesis of new bioinspired and biomimetic materials can now be achieved. One such generic but highly efficient template for the formation of silica is the poly(L-lysine) polymer. This template can catalyze the formation of silica in vitro since it is composed of residues which are positively charged at neutral pH.
In this study, oxidized carbon nanofibers have been modified with H2O2 30%. The oxidized carbon nanofibers have been utilized for the development of glucose biosensor for the detection and monitoring of glucose. Glucose oxidase was adsorbed on the oxidized nanofibers in the presence of a mediator. The mediator allows for the reduction of the working potential to 400mV, at which potential the interferences by other redox species is minimized, allowing for the direct measurement of real samples. Finally, biomimetically synthesized silica creates a capsule of silicon round the nanocomposite CNFs/glucose oxidase/mediator, which increases the enzyme stabilization against thermal denaturation, while it protects the protein from external protease attack.
The transduction efficiency of carbon nanofibers in combination with the enhanced stabilization of glucose oxidase and in the presence of a mediator, paves the way for a new class of biosensors with enhanced analytical characteristics, which could be applied in a variety of biosensing disciplines.
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Βιοαισθητήρες γλυκόζης βασισμένοι σε νανοϊνες άνθρακα και βιομιμητικά παραγόμενο διοξείδιο το πυριτίου
