In an attempt to create a strain of maggots to heal wounds efficiently, North Carolina State researchers genetically engineered maggots to produce and then secrete human platelet derived growth factor-BB (PDGF-BB), which is known to aid the healing process by stimulating cell growth and survival.
Two techniques were used to reach the desired outcome.
One technique focused on heat to trigger the production of PDGF-BB in transgenic green bottle flies. The human growth factor was detectable in certain structures within the larvae after the larvae were shocked with high heat — a level of 37 degrees Celsius — but PDGF-BB was not detectable in maggot excretions or secretions, making it unworthy of clinical use.
The second technique was more successful. Scott and colleagues engineered the flies such that they only made PDGF-BB if raised on a diet that lacked the antibiotic tetracycline. PDGF-BB was made at high levels in the larvae and was found in the excretions and secretions of maggots, making the technique a potential candidate for clinical use.