2008 NSTI Nanotechnology Conference and Trade Show - Nanotech 2008 - 11th Annual

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Clean Technology 2008

Biosensor for pesticides detection in food

C. Moldovan, R. Iosub, C. Radu, D. Necula, M. Ion
IMT-Bucharest, RO

Keywords:
enzimatic sensor, silicon, microfluidic, biomaterial, pesticides

Abstract:
The paper is presenting the chemistry of a deposited enzymatic layer (AChE enzyme) developed (concentration, enzymatic activity measuring, deposition protocol) for demonstration purposes, 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 microelectrodes fabrication : Si substrate, p type, 16Wcm, oxidation, Ti/Au deposition, patterning, PSG 4% deposition leaving openings for the pads connections and biomaterial deposition. The functionalized 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 have been done under the strict control of temperature and pH and will be presented. The sensitivity and selectivity of the sensor have been measured and calculated.


Nanotech 2008 Conference Program Abstract