A bacteriophage (phage) is a virus that only infects bacteria, not humans. Phages have two components: their DNA and an outer protein coating. Phage display is the process of inserting genetic material into the bacteriophage genome so that when the bacteriophage is made, the peptide, or small-protein bit, that is encoded by the DNA is displayed on the protein coating, which is used to infect bacteria.
In phage display, each phage receives a different gene. By doing this, scientists create a “library” of billions of different phages with billions of different peptides. This library is then screened in a high-throughput manner (quickly and with small amounts of tumor cells) to identify peptides that will bind to pancreatic cancer.
These peptides can then be chemically synthesized as imaging agents for the early detection of pancreatic cancer or used for targeted drug delivery, decreasing the side effects of chemotherapeutics by delivering more drugs to the tumor and less to normal cells.