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Biosensor for pesticides detection in food

Carmen Moldovan 

National Institute for Research and development in Microtechnologies (IMT-Buchares), P.O.Box 38-160, Bucharest 023573, Romania

Abstract

The chemistry of a deposited enzymatic layer (AChE enzyme) has been developed (concentration, enzymatic activity measuring, deposition protocol), the immobilization technique for AChE, the fabrication technique  and the electrical characteristiques of the enzymatic sensor.  The acethylcholinesterase (AChE) immobilization was performed by ionic adsorption on chitosane or polyethilenglicol (PEG) bio-polymeric substrate, by including in the gel. The method for enzyme complexation  to this support is simple, being based mainly on the potential interactions between the rests of amino acids from the enzyme molecule, the cationic character and the non-solubility of chitosane at high pH values. The membrane is obtained by drying the gel in air flow and loosing of water molecules facilitates the enzyme accessibility to the support linking sites, by the interactions between the rest of polar and non-polar amino acids, ionic forces, hydrogen bridges and van der Waals forces. The advantage of this method: the enzyme immobilization is performed at room temperature, in aqueous environment, assuring an adequate homogeneity of the sample and reducing the possibility for enzyme inactivation. The sensor substrate is silicon with gold interdigitated electrodes on top. The plasma treatment in O2 + Surface functionalization with APTS (3 aminopropiltrietoxisilan), 0.1µL have been performed.

The accurately deposition and immobilization only on the surface of the working electrodes has been achieved.

The microelectrodes fabrication, the functionalization of electrodes and deposition of biomaterials ideposition will be presented. The  electrodes  deposited with biomaterial have been inserted into the microfluidic channels and tested from electrical and microfluidic point of view, achieving the micro/nano bio integration. Insertion of electrolyte plus choline into the channels is leading to activate the enzyme and the measurements are realized under the strict control of temperature and pH.

 

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Related papers

Presentation: Poster at E-MRS Fall Meeting 2008, Symposium H, by Carmen Moldovan
See On-line Journal of E-MRS Fall Meeting 2008

Submitted: 2008-05-16 18:03
Revised:   2009-06-07 00:48