Hadi Mohammadi, an associate professor at UBC's School of Engineering.
Researchers at UBC's Okanagan and Vancouver campuses are developing a softer testicular implant that could offer patients a more natural feel following surgical reconstruction.
The prototype uses a water-rich material called a hydrogel to better reproduce how natural tissue responds to pressure and movement. Laboratory findings reported in two recent publications offer a promising foundation for further testing.
Dr. Hadi Mohammadi, an associate professor of biomedical and mechanical engineering at UBC Okanagan's School of Engineering, says the work addresses a concern that can affect how patients experience life with an implant.
"An implant's success involves more than its shape or whether it holds up over time," he says. "We also need to understand how it feels to the person living with it. That experience is central to what we are trying to improve."
Patient experiences with current implant technology can vary widely, he says.
In one published study involving 171 implant recipients, more than half considered their implant too firm, despite generally high overall satisfaction.
Working with Dr. Ryan Flannigan at UBC's Department of Urologic Sciences and the Reproductive and Sexual Medicine Centre, Dr. Mohammadi and his team are investigating whether a different material could help address that concern.
"For someone considering a testicular implant, how it will feel is an important part of the conversation," says Dr. Flannigan. "This collaboration allows us to bring that patient perspective into the design process and investigate materials that may better meet those expectations."
Dr. Ryan Flannigan
Testicular cancer is the most commonly diagnosed cancer in Canadian men aged 15 to 34, and many of those who undergo surgery to remove a testicle are left weighing whether to get an implant that, by some patient accounts, doesn't feel like natural tissue.
The new UBC prototype is made from polyvinyl alcohol (PVA) hydrogel-a network of polymers that hold water to form a soft, flexible material. Repeated freezing and thawing strengthen the network without adding chemicals to bind the polymers together.
Adjusting the formulation allows researchers to change firmness.
"Natural tissue yields under pressure and recovers afterward," explains Dr. Mohammadi. "We can adjust the hydrogel to bring its behaviour closer to that response. The goal is a prosthesis that feels more like the tissue it replaces."
To arrive at their current prototype, the team compared different hydrogel formulations with natural testicular tissue and a commercially available silicone implant. Testing examined how the materials responded to compression, stretching, sustained pressure and repeated loading.
A formulation containing 10 per cent PVA provided the closest overall match to natural tissue. It also maintained stable mechanical performance through 1,000 compression cycles.
The prototype is currently in the laboratory stage, with further testing needed before it could be offered to patients.
"We still need to understand how the material interacts with the body and how it holds up over time," notes Dr. Mohammadi. "Clinical studies will also be needed to establish safety and determine whether the implant improves patient comfort and satisfaction."
Heart Valve Performance Laboratory researchers Ruby Dhaliwal and Jaymes Schmidt helped develop and test the prototype, connecting engineering research with clinical needs.
The collaboration also extends to experimental penile implants that use soft robotics and electronic controls to explore new approaches to treating erectile dysfunction.
"What makes this work meaningful is the opportunity to connect engineering with people's comfort, confidence and dignity," says Dr. Mohammadi. "Our laboratory findings are an encouraging step. The next challenge is to establish whether those improvements translate into a better experience for patients."
The research appears in The Journal of Sexual Medicine and Medical Engineering & Physics . It is made possible thanks to support from Mitacs Accelerate and Vancouver Coastal Health.
