This study has contributed to the developing understanding of fundamental principles through which interactions at peptide-inorganic interfaces occur. The inorganic materials; crystalline zinc oxide (ZnO) and platinum (Pt) together with specific binding peptides identified using the phage display technique and alanine scanning for mutant sequences selected on the basis of peptide stability calculated in silico were synthesized, extensively characterized and the mechanisms of their interaction and the effects thereof studied. Firstly ZnO growth was monitored during solution synthesis from precursors using two different ZnO methods in the absence and presence of ZnO binding peptides (ZnO-BPs); G-12 (GLHVMHKVAPPR), its mutants (G-12A6, G-12A11, G-12A12) and GT-16 (GLHVMHKVAPPR-GGGC). Secondly, adsorption characteristics and thermodynamics of interaction of ZnO with ZnO-BPs and Pt with platinum binding peptides (Pt-BPs) were studied using biophysical tools; quartz crystal microbalance with dissipation monitoring (QCM-D) and isothermal titration calorimetry (ITC). The outcomes of the ZnO synthesis studies demonstrated that peptides are smart, versatile tools possessing different mechanisms through which material formation processes and resultant morphologies can be modulated. Biphasic isotherms were observed in the adsorption of the ZnO-BPs on ZnO consisting of an endothermic and an exothermic event with ΔG values between -6 and -8.5 kcal/mol and high adsorption affinity values indicating the occurrence of favourable interactions. Among the examined ZnO-BPs, G-12 had the highest affinity for ZnO. QCM-D studies of Pt and Pt-BPs revealed that peptides TLHVSSY and SSFPQPN adsorbed strongly to the predominantly Pt (111) surface whereas TLTTLTN had a weak reversible interaction with the surface. Information from QCM-D studies was instrumental for experimental design and data interpretation of ITC experiments for the same counterparts. Differences in isothermal profiles of the Pt-BPs with Pt nanoparticles show their unique adsorption behaviours. The adsorption of peptides on inorganic surfaces is driven by kinetic and thermodynamic factors and varies depending on inherent properties of the peptide, physico-chemical properties of the inorganic surface and reaction conditions. ITC has shown great potential for use as a standard technique to monitor peptide-inorganic interactions and for possible application in peptide design.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:635144 |
| Date | January 2013 |
| Creators | Limo, M. J. |
| Publisher | Nottingham Trent University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://irep.ntu.ac.uk/id/eprint/216/ |
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