Calcium carbonate biomineralization: A theoretical and experimental investigation of biomolecular controls on nucleation and growth

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dc.contributor.authorHamm, Laura Maeen
dc.contributor.committeechairDove, Patricia M.en
dc.contributor.committeememberHochella, Michael F. Jr.en
dc.contributor.committeememberDe Yoreo, James J.en
dc.contributor.committeememberRimstidt, J. Donalden
dc.contributor.departmentGeosciencesen
dc.date.accessioned2014-03-14T20:11:55Zen
dc.date.adate2012-05-30en
dc.date.available2014-03-14T20:11:55Zen
dc.date.issued2012-04-30en
dc.date.rdate2012-05-30en
dc.date.sdate2012-05-11en
dc.description.abstractOrganisms have evolved a remarkable ability to mineralize complex skeletons and functional biomaterials. These structures are nucleated and grown in close associaiton with macromolecular assemblages of proteins and polysaccharides that are implicated in regulating all stagees of mineralization. Because of this intimate association of organic with inorgaic components, many studies have investigated the effects of particular organic species on mineral morphology, phase, and growth rate. However, the diversity and species-specific nature of the organic assemblages associated with biominerals across a wide variety of taxa, has limited our understanding of how organisms use biomolecules to regulate skeletal formation. It is clear that a mechanistic picture of biomolecular controls on mineralization requires molecular-level investigations of the interplay between organic and inorganic components at all stages of crystallizaiton. This dissertation presents the findings from theoretical and experimental studies of the physical mechanisms that underlie biomolecule controls on mineral formation. Molecular dynamics simulations probe the effects of acidic molecules on the hydration of alkaline earth cations. After first calculating baseline hydration properties for magnesium, calcium, strontium, and barium, I determine the effects of carboxylate-containing molecules on cation hydration state as well as the kinetics and thermodynamics of water exchange. Experimental work utilizes self-assembled monolayers as proxies for matrix macromolecules in order to understand their effects on CaCO3 nucleation kinetics and thermodynamics. Estimates of nucleation rates and barriers are made from optical microscopy data and correlated with measurements of crystal – substrate rupture force from dynamic force microscopy. These investigations show that an important function of biomolecules in directing mineralization lies in their ability to modulate cation hydration. Both chemical functionality and molecular conformation are influential in regulating the kinetics and thermodynamics of mineral nucleation, and these effects may be predicted by the strength of interaction between organic and inorganic components. These findings contribute to a mechanistic understanding of how organic matrices act to regulate biomineral formation. They demonstrate a plausible physical basis for how carboxyl-rich biomolecules accelerate the kinetics of biomineral growth and suggest roles for organic species in the nucleation and pre-nucleation stages of mineralization.en
dc.description.degreePh. D.en
dc.identifier.otheretd-05112012-142331en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-05112012-142331/en
dc.identifier.urihttp://hdl.handle.net/10919/27670en
dc.publisherVirginia Techen
dc.relation.haspartHamm_LM_D_2012.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectbiomineralizationen
dc.subjectcalcium carbonateen
dc.subjectnucleation rateen
dc.subjectcation hydrationen
dc.subjectmolecular dynamicsen
dc.titleCalcium carbonate biomineralization: A theoretical and experimental investigation of biomolecular controls on nucleation and growthen
dc.typeDissertationen
thesis.degree.disciplineGeosciencesen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.leveldoctoralen
thesis.degree.namePh. D.en

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