Designing a Realistic Tissue-Mimicking Bladder: Improving Imaging Devices and Opening up New Recipes for Creating Model Organs
A new study on building an acoustically and mechanically accurate synthetic bladder model may become a more reliable tool for testing imaging devices.
Each year, over 1.9 billion people suffer from lower bladder issues. Diagnostic imaging plays a crucial role in helping these people, whether it be diagnosing bladder cancer or monitoring the progression of bladder inflammation.
“We rely on imaging a lot.” says Dr. Venkat Ramakrishnan, a urologist at Boston Children’s Hospital. He emphasizes the importance of reliable imaging in diagnosis and especially surgery. Without an image, surgeons could accidentally cut into organs or other body features. “It’d be like playing a guessing game with someone’s life,” Dr. Ramakrishnan explains.
Many researchers are looking to improve imaging devices for both better images and patient convenience. To do so, they need to test their devices on actual or model human bladders. Dr. Ramakrishnan emphasizes how difficult it is for researchers to get actual human bladders from organ donations to test with (as there’s a shortage of donor bladders), highlighting the importance of model bladders. However, creating accurate bladder models is challenging because they’re very dynamic structures. “Overcoming the difficulty of creating a good bladder model and employing it is going to be game changing for patients,” Dr. Ramakrishnan states.
In the past, researchers have created bladder models, also known as phantoms, but they lack the ability to thoroughly mimic certain bladder characteristics. For example, some models are acoustically accurate—they simulate how sound waves penetrate the bladder correctly—but aren’t dynamic. In other words, these model bladders don’t fill and dispense liquid like a real bladder would. “The intersectionality of these crucial properties was missing,” said Sara V. Fernandez, a graduate student in the Conformable Decoders research group at the MIT Media Lab.
In a study published in April 2024 [1], Fernandez created a bladder phantom that would have the acoustic properties of the bladder while also mimicking their urine dispensing and collecting mechanism.
Tackling this project came with many challenges. With the human torso system having five layers of different tissues, the team experimented with various recipes of materials to simulate each tissue. Another problem the team ran into was creating the hollow shape of the bladder. The team solved this issue by creating a silicone mold with a sacrificial core in the middle that would swim in water and dissolve, leaving behind a hollow shape to hold fluids such as urine in it.
Beyond creating an effective bladder phantom, the project introduced new ways to model other organs. “You can now use some of the recipes and methods we used in the paper to create other phantoms of muscles and organs, like skin and skeletal muscle,” said Fernandez. While a bladder and a stomach may be very different organs, for example, they share similar characteristics like being hollow and having the ability to contract—two important properties from the team’s bladder phantom that can be translated to creating a stomach phantom.
The researchers integrated the phantom into a torso model of a woman and simulated urinary function. Creating this torso-tank system brought their bladder phantom to life by making the device more aesthetically closer to an actual patient.
“Being able to simulate these pathologic features in a patient model [with an accurate bladder] would be great for surgeons to practice on,” Dr. Ramakrishnan remarks. “It takes the guesswork out of the equation and may help save lives.”
[1] https://onlinelibrary.wiley.com/doi/10.1002/advs.202400271