Polymer composites and a cancer cure
He holds a doctorate in chemical engineering, has a joint appointment by courtesy in material science, completed a (second) post doc in applied physics, and happens to have a passion for finding a cure for cancer. “Even while doing my PhD, and even through a couple of post-docs,” says Won, “I never formally did biology. But I always had interest in it.”
Now as a nanobioengineer, Won is applying his know-how with polymers to a promising cancer therapy mechanism called RNA interference (RNAi). RNAi is an approach developed by genomic researchers to “knock down” oncogene transcripts responsible for cancer development using sequence-matched short interfering RNA (siRNA). The problem has been in figuring out an efficient, effective way to deliver the therapeutic siRNA to the tumor cells so that it can “interfere” with the cancer genes.
Won has developed a new approach to the problem. He synthesizes a fully synthetic triblock copolymer nanoparticle, adds water to create a micelle, and then, through convenient self-assembly, the siRNA conjugates with the micelle to form an “siRNA micelleplex.” This elegant system is effective because “the size of the carrier is key,” explains Won. “Tumor tissue has anomalous blood vascularization, making it naturally ‘leaky.’ If we can create a particle of the appropriate size, we can use that leakiness to our advantage.” Won’s carrier system is small enough (<100 nm) to enter the leaky vascular tissue of the tumor, but big enough (>10 nm) not to be diffused back into the blood stream.
At 50 nm, Won’s siRNA micelleplex can therefore be injected into the bloodstream, and from there the polymer complex targets the tumor and delivers the siRNA to do its curative work. “Things look quite promising,” according to Won. He has used real breast cancer cells in mice and has seen dramatic reduction in tumor size just days after therapy.
Won hopes to be in clinical human trials within a year. He is excited about the relative simplicity of the technique: no wildly expensive equipment or materials are needed to produce the micelleplex. Not surprisingly, Won’s project is attracting the attention of the pharmaceutical industry. “We have filed for a provisional patent for this delivery technique,” he says. “The Purdue Research Foundation’s Office of Technology Commercialization is helping us connect to biotech firms, and there is already serious interest.”