Author(s): Calmeiro, Tomás R.
Date: 2013
Persistent ID: http://hdl.handle.net/10362/10851
Origin: Repositório Institucional da UNL
Subject(s): Atomic force microscopy; AFM; Bionanotechnology; DNA-protein interaction; AFM probe modifications; Focused ion beam
Dissertation to obtain a Master degree in Biotechnology
Studies of atomic force microscopy (AFM), a technique commonly associated with material sciences, in the field of biotechnology, with special emphasis on molecular biology and bionanotechnology elements, are presented herein. DNA, insulin and restriction enzymes were analysed as isolated objects, in order to document properties like morphology and behaviour, and also on the interactions between each other. The interaction between DNA and the EcoRV restriction endonuclease was especially highlighted. Gold nanoparticles were also studied in an attempt to establish a relationship between functionalization and average diameter shifts, as perceived by AFM. Given the nature of these objects of study, both immobilization and preparation protocols were modified and evaluated, considering measurements in air or in liquid. To serve the objective of developing probes with higher sensitivity and resolution, especially for liquid measurements, AFM cantilevers were modified through metallic coatings and scanning electron microscopy assisted with focused ion beam (SEM-FIB). Tests performed with these probes confirmed that the modifications were successful, the probes are functional and can aid in the production of better quality images, through the acquisition of sharper data in comparison with non-modified probes.
