Nanobiotechnological engineering of the M13 phage into an orthogonal platform for biomedical applications

M13 bacteriophage, a naturally multifunctional nanoplatform, comprises thousands of distinct protein subunits arranged in a filamentous viral capsid. These proteins have the ability to be tailored for the binding and nucleation of inorganics and nanoparticles as well as for the production of ligands, functional moieties, and even enzymes. In the first study, we demonstrate the potential of using M13 bacteriophage conjugated with rose bengal (RB) for antimicrobial photodynamic therapy (PDT). To further improve the specificity of the therapy, we genetically modified M13 to express a C20 nanobody in fusion with the pIII protein. This modification resulted in a specific tropism for A. baumannii, and when conjugated with RB, the modified phages could selectively kill A. baumannii in PDT. Additionally, we developed a wider spectrum activity phage for antimicrobial PDT by encoding an LPS binding peptide in fusion with the pIII protein. Our results showed that this new phage only targets gram-negative bacteria such as P. aeruginosa and A. baumannii, while gram-positive bacteria like S. aureus are not bound. M13 anti-LPS conjugated with RB can selectively kill gram-negative bacteria when irradiated with light. In the second study, M13 was engineered to display the GFP11 β strand of a fluorescence complementation system for a cost-effective and easy production biodetection tool than may be further fine-tuned for the development of new point-of-care biosensors. The same system was used for the immobilization of Horseradisch perxidases (HRP) to M13 as a proof-of-concept strategy for the development of enzymatic farms. Finally, in the third study, M13 was conjugated with a poly lysines anchored SIINFEKL peptide for novel cancer vaccine platform. The proposed multimodal, nanoplatform is re-designable for applications in diagnostics, nanomaterials, and a variety of disease kinds.