The depicted particles are called Photorhabdus virulence cassettes (PVCs), which are molecular syringes produced by bacteria. The PVCs (which we have been informed look like construction nails) bind to cells on the broader end (the head of the nail) and use a spring-loaded mechanism to inject a needle into the cell, delivering the protein cargo within. We are exploring the use of engineered PVCs to deliver therapeutic proteins into human cells to treat disease, including cancer.

We use transmission electron microscopy (TEM) to visualize the PVCs to ensure they are properly assembled and are free of cellular contaminants.