Biossensores de glicose nanoestruturados baseados em dendrímeros pamam e filmes finos de in2o3:sn

Abstract

Dendrimers are isomolecular polymers with a very well controlled architecture that have many potential applications in medicine, including diagnosis and therapeutic procedures. Bioconjugated dendrimers and enzymes are of great interest for clinical applications in biosensors design because of the way in which their chemical properties can be tailored. In this work, the poly(amidoamine) dendrimer (PAMAM) of generation 4 was synthesized by divergent route and characterized by UV-Vis, FTIR and NMR spectroscopy. The electrical conductivity of the PAMAM dendrimers was dependent of their generation number. To better understand the electronic transport through PAMAM films a molecular theoretical model using the quantum chemistry method was developed. The properties of a thin film of indium tin oxide (ITO) contact as a hole injecting material for the design of glucose biosensors based on the bioconjugated poly(amide amine) dendrimers (PAMAM)-Glucose oxidase (GOx)-Peroxidase (HRP) (PAMAM-GOx-HRP) thin films is presented. The fairly large electron affinities (or work function) of ITO thin films may be adequate to improve the electron transfer processes at redox-enzyme interface of the PAMAM-GOx-HRP nanobiosensor. Nanosized thin layers (1–2 nm) of ITO were obtained on a glass substrate through the chemical vapor deposition (CVD) technique. The synthesized ITO thin film was characterized by using UV-Vis spectroscopy and X-ray diffraction technique. The surface of the ITO thin film was smooth and presents high transparency as the result of the nanosized crystallites of ITO. The bioconjugate PAMAM-GOx-HRP was deposited onto ITO crystalline films. The biosensing properties of the obtained glucose biosensor were sufficiently reproducible and the response times measured with respect to glucose concentration meet the requirement for glucose biosensor elements