No abstract

Phage therapy has significant potential in specifically targeting bacterial pathogens in food and medicine. There is a significant interest to combine phages with materials to enhance and broaden potential applications of phages. This study compares nonspecific adsorption, protein-ligand binding, and electrostatic interactions on cellulose microfibers without any chemical or genetic modification of phages. Success in immobilization of phages on biomaterials without genetic and chemical modification can enable effective translation of naturally occurring phages and their cocktails for antimicrobial applications. The immobilization approaches were characterized by phage loading efficiency, phage distribution, and phage release from fibers. The results indicated that non-specific adsorption and protein-ligand binding had insignificant phage loading while electrostatic interactions yielded approximately 15-25% phage loading normalized to the initial titer of the phage loading solution. Confocal imaging of the electrostatically immobilized phage fibers revealed a random phage distribution on the fiber surface. Phage release from the electrostatically immobilized phage fibers indicated a slow release over a period of 24 h. Overall, the electrostatic immobilization approach bound more active phages than non-specific adsorption and protein-ligand binding and thus may be considered the optimal approach to immobilizing phages onto biomaterial surfaces.

No abstract

A highly ordered array of T7 bacteriophages was created by the electrophoretic capture of phages onto a nanostructured array with wells that accommodated the phages. Electrophoresis of bacteriophages was achieved by applying a positive potential on an indium tin oxide electrode at the bottom of the nanowells. Nanoscale arrays of phages with different surface densities were obtained by changing the electric field applied to the bottom of the nanowells. The applied voltage was shown to be the critical factor in generating a well-ordered phage array. The number of wells occupied by a phage, and hence the concentration of phages in a sample solution, could be quantified by using a DNA intercalating dye that rapidly stains the T7 phage. The fluorescence signal was enhanced by the intrinsic photonic effect made available by the geometry of the platform. It was shown that the quantification of phages on the array was 6 orders of magnitude better than could be obtained with a fluorescent plate reader. The device opens up the possibility that phages can be detected directly without enrichment or culturing, and by detecting phages that specifically infect bacteria of interest, rapid pathogen detection becomes possible.

The practical application is to prevent bacterial cross contamination of fresh produce by using a combination of edible coating with bacteriophages. The results demonstrate enhanced loading and stability of phages on fresh produce when used in combination with an edible coating.