Zirconium phosphate and phosphonate surfaces as tools for biomolecule immobilization

Zirconium phosphonate modified surfaces can specifically anchor many phosphorylated molecules, including oligonucleotides or phospholipids for bioanalytical studies. Recent research in our group has shown that DNA binds directly to zirconium phosphonate modified surfaces through a naturally occurring 5' terminal phosphate and we have demonstrated that this interaction can be used to immobilize oligonucleotide probes for DNA array applications. However, we can use this DNA binding system for other biological applications. The first half of the dissertation investigates the interactions of DNA molecules with zirconium phosphate and zirconium phosphonate particles for affinity chromatography applications. The particles are prepared via a simple and inexpensive synthesis that gives high product yields. We report the optimal conditions to bind probe ssDNA to these types of particles. Furthermore, we determine if probe DNA could hybridize with its complementary strand after immobilization on the surface of the particles. After simple rinsing procedures, non-specific interactions of DNA on zirconium phosphate and zirconium phosphonate particles are much less compared to the amount of DNA specifically bound to the surface via the 5'-terminal phosphate group. Unlike using gold or biotinylated-modified surfaces, zirconium phosphate and zirconium phosphonate particles do not have to be modified to allow for specific orientation of DNA molecules. Additionally, we show that these particles can be used to specifically bind and enrich phosphopeptides from tryptically digested beta-casein solutions, which suggests that these particles have potential as tools in affinity chromatography.;In the second half of this dissertation, we report methods to bind histagged proteins to modified zirconium phosphonate surfaces. Phytic acid can form monolayers on metal surfaces and can it form complexes with common immobilized affinity chromatography metals including Cu(II), Co(II) and Ni(II) ions. We used this knowledge to investigate immobilization of histagged proteins on metal-phytic acid modified zirconium phosphonate surfaces. These experiments produced moderate results, however, the use of NTA-functionalized bisphosphonate linkers on zirconium phosphonate surfaces for histagged proteins binding compared favorably against many commercially available Ni-NTA slides.