Project description

The goal of BIOMICROTECH project is the development of miniaturized biosensors technology integrated in microfluidic chips, for the detection in the ng/L domain of organophosphorus insecticides from food (milk, juices from fruits and vegetables) and water by involving the microtechnology techniques on silicon and microbiology techniques, accessible to project consortium. A sensitive acetylcholinesterase (AChE) amperometric biosensor proposed in the project is single use, reproducible, mass production, low cost and has commercial value. Due to the small dimensions (hundreds of microns per chip) the integrated microbiosensors represent a rapid, selective and sensitive solution for direct determination of these kinds of contaminations. For obtaining the microelectrodes used like transducers for depositing biological material the optimization of MEMS (Micro Electro Mechanical Systems) technologies is required, such as: realization of 2D configuration and respective masks for microelectrodes structures, depositing dielectric on silicon substrate, metal (Ti/Au) deposition and patterning, PSG or Si3N4 deposition as passivation layers for protection of the metal. Deposition of biological material on substrate correlated with the study of the surface functionalisation for reactive surface linkers for the adherence of biological material on substrate, there were studied and optimized, too. Because the characteristics of the answer of biosensor, as: selectivity and sensitivity depend of the immobilization and the linkage of the bio component to substrate, the procedures for the functionalisation of the substrate (microelectrode) and the adherence of the enzyme are studied. The functionalisation techniques will be study in order to improve the enzyme adherence from mechanical (physic) and chemical point of view. The biopolymer (bovine serum albumin) acting as an addition layer for acetylcholinesterase (AChE) immobilization on the interdigital gold electrodes on silicon substrate will be studied and optimized.
There are two techniques studied, for surface functionalisation: the organofunctionalisation method (organic compounds with: thiol (-SH) group, amino (-NH2) group, medium modifier is organic group) and inorganofunctionalisation method (a metal (gold), Au<111>, for the adherence of the bovine serum albumin (BSA) to the substrate. The study of the functionalization techniques will permit us to optimize the adherence process through combine the two quoted techniques or to choose one of them. The realization of this project takes place into special clean spaces (clean room, class 100 ) and involves characteristic technological process, such as: micro and nano technologies and unique equipments in our country, available to the coordinator, INCD-for Microtechnology next to performant equipments used currently for pesticides detection at the project partners sites (UPB, ISPB). Miniaturized biosensors realization for organophosphorus insecticides detection must carry out a lot of characteristics, as: high selectivity to insecticides studied (O-pinacolyl methylphosphonofluoridate, O-isopropyl methylphosphonofloridate, cyclohexyl methylphosphonofluoridate, ethyl N,N imethylphosphoramidocyanidate which have a linear answer in the range of the concentration: 0,1÷100ng/L, a short time of the answer and fast return back (1÷3) minutes, a reproducibility of the real miniaturized probes in the practical conditions of the applications, minimized devices.