Resumo:
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
