Soft Actuator And Sensor For Underactive Bladder Treatment

Researchers at the National University of Singapore have developed a soft sensor and actuator to monitor bladder volume and help empty it on-demand. The device is intended to be implanted on the bladder surface during a surgical procedure to treat patients who cannot completely empty their bladders voluntarily.

Patients can suffer from an underactive bladder following a spinal cord injury, meaning that they cannot easily sense when the bladder is full, or completely empty it. Approximately 80% of patients who suffer a spinal cord injury will demonstrate some bladder dysfunction. Not only is this inconvenient and upsetting for patients, but it can lead to various issues such as urinary tract infections.

There is currently no effective treatment for the condition, with current implantable devices only emptying the bladder up to 43% of their full volume. “To help these patients, what clinicians need is an integrated bladder system that achieves both volume sensing capability and high voiding efficiency,” said Nitish Thakor, a researcher involved in the study. “Given that the urinary bladder is unique among human organs as it undergoes large volume changes during the storage and urination phases, the device requires careful compatibility considerations to avoid interference with the extreme volume changes of the bladder.”

To address this, these researchers have developed a new soft device incorporating a sensor that can monitor urine volumes in the bladder, and an actuator that can apply gentle pressure to the bladder during urination. The sensor contains a shape memory spring to ensure that it maintains constant contact with the bladder surface, where it can infer how full the bladder is.

So far, the research team has shown that the device can help to empty the bladder by 70–100%. “This is a significant achievement as its performance is comparable to the efficiency of intermittent catheterization treatment currently being used, which has many shortcomings,” said Dr Arab Hassani, a researcher involved study. “We need a soft but efficient device to help a weak bladder.”

Strikingly, the device may have potential for manipulating other organs and structures within the body for therapeutic effects. “Our soft system demonstrated on a bladder can serve as a model for augmenting other organs as well,” said Thakor. “I believe this novel design can pave the way for the development of sensors and actuators that are compatible with other soft and distensible organs like blood vessels, the heart, and the gastrointestinal system, as these organs require both sensing and actuation to achieve functions like pumping and peristalsis under soft actuation and control.”

Study in Science Advances: Soft sensors for a sensing-actuation system with high bladder voiding efficiency

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