The Phage Nanoparticle Toolkit
This chapter will review the physical and biological properties of filamentous phage that have made them a flexible platform for development of new nanoparticles. The long, thin virion is extraordinarily robust, being tolerant of harsh physical conditions, extensive chemical modification, and genetic fusion of foreign “guest” peptides and proteins to its exposed coat proteins. As much as twenty percent of its outer surface can be modified without impairing phage assembly or infectivity. Virions can be reliably produced in great abundance and purified to a high degree of purity by simple, scalable processes. Most importantly, their ability to replicate has opened up invention strategies that depend on selecting particles with desired properties from vast populations with random variations, rather than on rational design. Growing knowledge of the unusual infection cycle, along with more than three decades of experience in manipulating filamentous phages for biotechnological ends, have resulted in an extensive “toolkit” of useful, broadly applicable techniques for enhancing a new initiative's chance of success.