Online

Miao, Tianxin

Bioengineering Graduate Program

2016

Ph. D.

In the field of biomaterials, naturally-derived and synthetic polymers are utilized individually or in combination with each other, to create bio-inspired or biomimetic materials for various bioengineering applications, including drug delivery and tissue engineering. Natural polymers, such as proteins and polysaccharides, are advantageous due to low or non-toxicity, sustainable resources, innocuous byproducts, and cell-instructive properties. Synthetic polymers offer a variety of controlled chemical and physical characteristics, with enhanced mechanical properties. Together, natural and synthetic polymers provide an almost endless supply of possibilities for the development of novel, smart materials to resolve limitations of current materials, such as limited resources, toxic components and/or harsh chemical reactions. Herein is discussed the synthetic-biological material formation for cell-instructive tissue engineering and controlled drug delivery. We hypothesized that the combination of hydrogel-based scaffold and engineered nanomaterials would assist in the development or regeneration of tissue and disease treatment. Chemically-modified alginate was formed into alginate-based nanoparticles (ABNs) to direct the intracellular delivery of proteins (e.g., growth factors) and small molecular drugs (e.g., chemotherapeutics). The ABN surface was modified with cell-targeting ligands to control drug delivery to specific cells. The ABN approach to controlled drug delivery provides a platform for studying and implementing non-traditional biological pathways for disease (e.g., osteoporosis, multiple sclerosis) and cancer treatment. Through traditional organic and polymer chemistry techniques, and materials engineering approaches, a stimuli-responsive alginate-based smart hydrogel (ASH) was developed. Physical crosslinks formed based on supramolecular networks consisting of [beta]-cyclodextrin-alginate and a tri-block amphiphilic polymer, which also provided a reversible thermo-responsiveness to the hydrogel. The hydrogel was shear-thinning, and recovered physical crosslinks, i.e., self-healed, after un-loading. The ASH biomaterials provide a platform for injectable, therapeutics for tissue regeneration and disease treatment. Indeed, various hydrogel constituents and tunable mechanical properties created cell-instructive hydrogels which promoted tissue formation.