William Frantz didn’t walk away with the top prize at this year’s Lab Venture Challenge (LVC), but his research may still be a winner for future cancer patients.

Frantz, a PhD student in the Biomedical Engineering Program (BME) at CU Boulder, is developing microscopic droplets designed to help doctors track radiation therapy in real time. His finalist pitch at the 2025 LVC competition highlighted how the technology could one day make cancer treatment more precise and less harmful, particularly for pediatric patients.

“In the lab, we believe we have a great idea,” said Frantz. “Our research and spin-out is still in its early stages, but this could be something that has the potential to help a lot of people in the future.”

The work centers on what Frantz calls vaporizable exoskeletal droplets—microscopic droplets that can be injected into the body and used as ultrasound contrast agents. 

 

William Frantz (right) working in the Borden Research Lab.

The tiny droplets are a staple in the Borden Research Lab because of their ability to vaporize into microbubbles and reflect ultrasound, improving imaging and therapeutic outcomes. However, Frantz’s research shows the droplets are capable of much more.

During a collaborative project with CU Anschutz, Frantz began modifying the exoskeletal droplets to respond to radiation. From there, a new startup—Radiosensitive VEDs—created alongside Professor Mark Borden was born.

The team began their journey right away, participating in university entrepreneurship and startup accelerator initiatives such as Catalyze CU and the Innovation & Entrepreneurship Fellowship Program (I&E). But Frantz says their participation in the National Science Foundation’s I-Corps program was what really helped the group build their venture.

“The program really encouraged us to do customer discovery interviews to find out exactly where our technology fits inside of a large field like radiation therapy,” Frantz said. “We started talking to medical physicists and they really helped guide our company’s research and thinking.”

Their findings helped narrow their focus to proton therapy. Typical radiation therapy involves x-rays or photon beams to blast cancer cells with radiation. However, these x-ray beams have a tendency to travel through a patient entirely, which can expose healthy tissue to radiation and increase the risk of side effects.

Proton therapy on the other hand, uses positively charged particles that behave differently once inside the body. Instead of passing completely through tissue like x-rays, protons can be calibrated to travel a specific distance and then stop, depositing most of their energy directly into the tumor site.

But according to Frantz, the increased precision that proton therapy offers still isn’t perfect. 

“Imagine you’re trying to hit a tumor mass with a proton beam, but the patient lost weight between treatments, the tumor shifted, or their breathing patterns are causing the protons to travel a little too far or short than what was originally planned for,” said Frantz. “Not only are you missing the tumor site and irradiating healthy tissue, but you are also decreasing the amount of radiation delivered to the cancer cells and the benefit of proton therapy.”

 

Frantz during his finals pitch at the Lab Venture Challenge (LVC) competition.

That’s where Frantz and Borden’s research fits in. The modified exoskeletal droplets they have created can vaporize under proton radiation and form a microbubble. The team can track that bubble using ultrasound, measuring where the protons are stopping in real-time and verify that the therapy is being delivered as intended. 

If proton radiation is deviating from its intended target, physicists and oncologists can stop and use this information to make fine-tuned adjustments to the proton beam or the overall treatment plan.

Frantz said this added layer of clarity will not only help them ensure the proton therapy is as effective as possible, but it will also help minimize healthy tissue exposure—something that’s especially important for children.

 

Frantz working in the Borden Research Lab.

“Proton therapy is gaining a lot of traction for pediatric cancer patients because they are extremely sensitive to the ill effects of radiation. Radiating their healthy tissue can lead to chronic lung and heart diseases and musculoskeletal issues. They can even develop cancer later in life,” Frantz said. “If we can make it even just a little bit more accurate, we can help decrease these risks of chronic health conditions and they can live a long healthy life.”

The team’s impactful research earned their startup a spot as a finalist in this year’s LVC community showcase. The competition, hosted by Venture Partners, allows top innovators across Colorado to compete for a combined $750,000 in startup funding grants for projects that address a commercial need, have a clear path to a compelling market and have strong scientific support.

Despite a strong pitch and a lot of public support, Frantz and Borden were not selected as winners of the competition. But Frantz said they learned a lot that they can use moving forward.

“It’s all about focusing on the business model,” said Frantz. “We have confidence that this can be used in the clinic. Now it’s about doing more customer discovery and market research. It’s about answering these big supply chain distribution and even administrative healthcare questions to show that we have an economically-viable product.”

He even said the competition helped him develop a new passion for the entrepreneurial process that he never thought he would have. 

“My long-term goal has always been to become a professor,” Frantz said. “I still want to do that, but I can definitely see myself being involved in entrepreneurship, as well.”

Regardless of what path he chooses, the LVC hasn’t seen the last of Frantz and his team.

“We’re really grateful to CU Venture Partners and the I&E Fellowship for all of these opportunities,” said Frantz. “We’re going to try and roll with the punches this year. Maybe next year we’ll come back to LVC with a vengeance and secure some funding to continue pushing this technology towards the market."