Adeno-associated virus capsid as a scaffold for metal binding and nanoparticle synthesis
Doctor of Philosophy
Viruses, natural biological entities that have developed complex and compact mechanisms to deliver genetic material to target cells through natural evolution, can be repurposed for new nanoscale applications in a broad range of fields, including being used as biologically relevant therapeutics. Rationally designed genetic enhancements, chemical modifications, and hybrid linkages to other nanoscale materials can make viral vectors even more attractive as cargo-carrying compounds in cells. The motley array of amino acids on the surface of a virus capsid, which contains different side chains that have certain charge, hydrophobicity, and polarity properties, can be modified in order to bind inorganic metals and other metal ions for the purpose of synthesizing new compounds. Nanoscale metal and composite nanoparticles may have unique nanoscale properties that have relevance in a biological research setting, such as providing high signal over background contrast in crowded tissue compartments, Individual viruses can function as scaffolds, providing a surface for synthesis of these inorganic nanoparticles in order to combine the advantages of each individual element into a single hybrid compound. In this thesis, I first present my efforts to study a type of inorganic nanoparticle, which has been shown to generate high contrast nonlinear optical signal for biological imaging applications. Specifically, I created a hybrid labeling and delivery system by modifying the inorganic nanoparticles with a specific polymer compound, endowing them with the ability to condense DNA as well as to enter cells to deliver a genetic payload. Next, I detail a method of producing gold nanoparticles with variable morphology and dispersity using an adeno-associated virus as a scaffold for precursor nucleation. Finally, I describe how I generated mutant virus capsids that can bind metal ions after responding to an external stimulus that causes a conformational change in capsid subunits, externalizing metal binding domains. These detailed studies of hybrid molecules show that attractive properties of individual components of these nanomaterials can be combined or leveraged in a controlled manner in order to generate new materials for biologically relevant applications in the future.