Influence of electrostatic interactions on the behaviour of ferritin adsorption and desorption

The effects of various parameters influencing the electrostatic and hydrophobic interactions oc'curring during the adsorption process of ferritin onto Au or PS- PFEMS (polystyrene-block-poly(ferroceny1ethylmethylsilane)) nanopatterned diblock copolymer surfaces have been investigated. The effects of pH change of the buffering media and applied potential change have been studied in-situ on the Au surface. The influence of a chemically nanopatterned surface and the change of ionic strength have been investigated by ex-situ methods. For ex-situ measurements an AFM (atomic force microscope) and for in-situ measurements an EQCM (electrochemical quartz crystal microbalance) were used. Sudden changes in the pH of the buffering solution enabled control over the amount of ferritin adsorbed on the Au surface. More reliable control over adsorption was achieved by controlling the potential applied to the Au surface. By changing the applied potential the electrostatic and hydrophobic properties are changed simultaneously, in-situ. Under the conditions studied, the electrostatic forces had greater influence on the adsorption and desorption behaviour of ferritin than the hydrophobic interactions. To investigate the effect of potential control on the nanoscale, ex-situ AFM measurements were made. These measurements supported the data gained by EQCM. Furthermore they showed that there is no observable ordering during adsorption. Comparison of the adsorption and desorption behaviour of ferritin monomers, dimers and agglomerates controlled by potential change showed that our technique is sensitive enough to distinguish among them . . The dependence of the affinity of adsorption of ferritin on the electrostatic and hydrophobic interactions made it possible to try to pattern ferritin with the help of a chemically patterned surface. It has been shown that there is preference of adsorption to one of the blocks, and that this can be influenced by controlling the pH and ionic strength.EThOS - Electronic Theses Online ServiceGBUnited Kingdo