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Home    Ακινητοποίηση ακετυλοχολινεστεράσης σε νανοπορώδη υλικά για την ανάπτυξη βιοαισθητήρα οργανοφωσφορικών παρασιτοκτόνων  

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Identifier 000278111
Title Ακινητοποίηση ακετυλοχολινεστεράσης σε νανοπορώδη υλικά για την ανάπτυξη βιοαισθητήρα οργανοφωσφορικών παρασιτοκτόνων
Alternative Title Immobilization of acetylcholinesterase in nanoporous materials for the development of a pesticide biosensor
Author Σωτηροπούλου, Σοφία
Thesis advisor Χανιωτάκης, Νικόλαος
Abstract Biosensors have been under development for over 30 years while research in this field has become very popular the last 15. This research has been partly successful, leading to the acquisition of some electrochemical biosensor companies by large diagnostic firms and the concomitant commercial production of some diagnostic tools based on biosensor technology. However, the issue of biosensor widespread application still remains. In so far, biosensor show some disadvantages that have impeded their large application as reliable analytical tools, the most important ones being their stability, reproducibility in manufacturing and their inadequate sensitivity. These characteristics depend largely on the interaction between the immobilized enzyme and the transducer surface, a filed that is currently under intense investigation. At the same time it has become apparent that biosensors can mostly serve as single use screening tools, which has turned research towards the development of micro or even nano-systems, simple in use. Thus, today research for the optimization of bio-analytical systems has turned towards two directions: The optimization of the intrinsic properties of the biomolecule, with the aid of genetic engineering and the design and development of nano-systems based on novel nanomaterials. The stability of biomolecules and more specifically of enzymes, as well as their sensitivity and selectivity towards specific substrates, can be optimized with the appropriate genetic engineering. Until recently, the enzymes that were mainly used for the development of biosensors were only the commercially available ones that could be obtained in sufficient quantities with a relatively low cost. However, recent advances in gene expression have simplified the overall procedure, allowing the production of different variants in high yield. This has resulted in the production of a variety of enzymes (native or genetically engineered) in sufficient quantities for further study and use. Moreover, the aminoacid sequences of many microorganisms have been resolved and the protocols used for genetic engineering have progressed, allowing the directed evolution of enzymes. Therefore, genetic engineering emerges as a powerful strategy to optimize biosensor performance. Materials with at least one of their critical dimensions in the range of 100 nanometers, are characterized as nano-materials. Nanomaterials are mainly divided into 3 categories: nanoparticles, nanowires and nanoporous materials. The nanoparticles have highly interesting optical, electronic, and catalytic properties. Their most important feature is that their physicochemical properties depend largely and in a predictable manner by their geometry and their dimensions. This allows the synthesis of a large variety of materials with properties (optical, electronic, magnetic etc.) tuned for specified applications. The interesting properties of nanomaterials can be utilized in a wide range of fields, but amongst the most anticipated ones is their application for clinical and medicinal purposes. Nanomaterials functionalized with biological molecules are envisaged as tags for in vivo magnetic imaging, for controlled drug delivery and release etc. However, such applications of nanomaterials require a better understanding and control over their properties and the synthetic procedures. In the field of bio-analytical devices and more precisely in biosensors, their high surface ratio, their catalytic activity and their electron transfer properties make them ideal immobilization matrices, transduction platforms and mediators. Yet again nanomaterials are just beginning to be employed in the design of biosensor systems. Most of the relevant publications examine either the interaction of nanomaterials with biological molecules or optimize the immobilization protocols. In most cases of biosensors the transduction method of choice is either optical or electrochemical. A short survey on the existing literature of nanomaterials-based biosensors follows.
Language Greek
Issue date 2005-04-12
Collection   School/Department--School of Sciences and Engineering--Department of Chemistry--Doctoral theses
  Type of Work--Doctoral theses
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