Biomaterials are widely used in medical practice to help maintain, improve or restore diseased tissues or organs. The successful integration of biomaterials with host tissue depends on substratum surface properties, as well as host tissue quality and its regulatory environment. The overall goal of this dissertation is to incorporate these three factors to achieve better biomaterial-host tissue interactions. Important surface properties include surface topography, surface energy, chemical composition and surface charge. We designed a new titanium (Ti) substratum with modified surface chemical composition by preventing the contamination when in contact with the atmosphere. The new Ti surface has lower carbon contamination and promotes osteoblast differentiation phenotype. The osteogenic effect is synergistic with micrometer and sub-micrometer scale surface structures. To further investigate the effects of bone quality on peri-implant bone formation, we developed a novel mouse femoral medullary bone formation model. This new model will facilitate research evaluating the effects of biomaterial surface treatments in host animals with deficient bone development, including genetically engineered mice. Finally, we studied sexual dimorphism in the response of osteoblasts to systemic regulatory hormones 1¦Á,25-dihydroxyvitamin D3 and 17¦Â-estradiol. The results showed intrinsic differences in male and female osteoblasts with respect to their differentiation and their responses to hormones, suggesting that host chromosomal sex should be considered in biomaterial research. Taken together, this research provides fundamental information on biomaterial surface properties and the regulation of host tissue response, which are important in guiding biomaterial design and evaluation.

A very interesting class of nanoparticles extensively used for bio-applications is that of hydrogel particles, also called nanogels. There is an increasing interest in the design of hydrogel nanoparticles that have biofunctionality for applications in cell targeting, drug delivery, and biomedicine. The dissertation focuses on developing synthetic strategies for making diverse hydrogel nanoparticles customized to have desirable properties for various bio-applications. We have also investigated the potential of such nanoparticles as coatings for biomedical implants. Chapter 1 gives a brief introduction to hydrogel nanoparticles and the properties that make them attractive for various applications. The details of the syntheses of well defined, stable nanoparticles, commonly used in literature, are described in Chapter 2. Chapter 3 describes our synthesis of hollow sub-50 nm nanogels, which are otherwise difficult to synthesize based on the strategy discussed in Chapter 2. Chapter 4 also demonstrates how simple strategies borrowed from organic chemistry help in producing nanogels with multiple functionalities that are otherwise difficult to obtain, which also is an important advance over the synthetic methods discussed in Chapter 2. Chapter 5 describes how a general strategy based on photoaffinity labeling can yield materials with many applications ranging from optical materials, drug delivery, to biosensing. The latter part of the dissertation describes applications of various nanogels in biology especially as coatings that can control inflammation caused by biomaterials. Chapter 6 describes a method to functionalize flexible biomaterials with the nanogels, thus enabling in vivo investigations of the nanogels as potential coatings for controlling inflammation. Chapter 7 describes the biological studies performed (in collaboration with Garcia Group in the School of Mechanical Engineering at Georgia Tech) on various nanogels, aimed towards obtaining the most functional and efficient materials for implant applications. Chapter 8 describes application of hollow nanogels for covalently immobilizing biomolecules. This chapter also demonstrates how simple non-functional materials can be made unique and functional by means of traditional organic reactions. Finally, in order to broaden the applications of nanogel based materials.

Thesis (Ph. D.)--Tufts University, 2004. / Adviser: David L. Kaplan. Submitted to the Dept. of Chemical and Biological Engineering. Includes bibliographical references. Access restricted to members of the Tufts University community. Also available via the World Wide Web;

Thesis (Ph. D.)--University of Hong Kong, 2007. / Also available in print.

Thesis (M. Phil.)--University of Hong Kong, 2008. / Includes bibliographical references (leaf 128-142) Also available in print.

Thesis (M. Phil.)--University of Hong Kong, 2009. / Includes bibliographical references (leaves 124-155) Also available in print.

Thesis (M.S.)--University of Missouri-Columbia, 2008. / "May 2008" The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Includes bibliographical references.

Thesis (Ph.D.)--University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on May 6, 2009) Vita. Includes bibliographical references.

Thesis (M.S.)--Oregon Graduate Institute of Science and Technology, 1996.

Thesis (Master)--İzmir Institute Of Technology, İzmir, 2006. / Keywords: Hydroxiapatites, alumina ceramic, zirconium oxide, urea, precipitations. Includes bibliographical references (leaves. 73-75).