123 Quick summary: Researchers at the Massachusetts Institute of Technology have developed an exceptionally sensitive catheter based system that uses specialised carbon nanosensors to map molecular biomarkers directly inside the bladder, allowing for the detection of recurrent tumours before they are visible on the surface. Animal trials demonstrate that this technology is thousands of times more sensitive than conventional urinalysis, enabling the precise localization of lesions as small as 16 square millimetres. These clinical findings carry profound implications for healthcare practice and public policy, offering an efficient, low cost, and less invasive screening alternative that can be performed directly in physicians’ offices to alleviate patient anxiety and improve long term survival outcomes. Researchers at Massachusetts Institute of Technology have developed a highly sensitive catheter-based system that could transform monitoring for recurrent bladder cancer by detecting tumours at much earlier stages than current methods. Each year, about 85,000 Americans are diagnosed with Bladder Cancer. While treatment is often successful, the disease has 1 of the highest recurrence rates of any cancer. Around 50% of patients develop tumours again within 5 years of treatment, making bladder cancer 1 of the most costly cancers to treat and monitor. The system uses a urinary catheter coated with specialised carbon nanosensors. Carbon nanotubes are hollow cylinders only a few nanometres thick that naturally fluoresce when exposed to laser light. Over the past decade, MIT’s Strano Lab has shown that these nanotubes can be customised to detect different molecules by coating them with synthetic antibodies, polymers designed to interact with a specific target. When the target molecule is present, the interaction causes the nanotubes to shift wavelength or change fluorescent intensity. For this application, the researchers designed a sensor targeting Nuclear Matrix Protein 22 (NMP-22), an FDA-approved biomarker for Bladder Cancer. The catheter also contains a rotating ball lens at its tip, which emits laser light and captures fluorescent signals from the nanosensors. By analysing these signals, researchers can map the precise location of detected biomarkers. Describing the technology’s imaging capability, Michael Strano, the Carbon P. Dubbs Professor of Chemical Engineering at Massachusetts Institute of Technology and senior author of the study, said: “It’s like a camera for molecules instead of light. If you have a billion nanosensors in an array, you can use them to make a chemical image that helps you locate their source.” Nuclear Matrix Protein 22 can be detected in urine samples, but it is typically diluted, degraded, and cleared after secretion, making early-stage detection difficult. By deploying sensors directly inside the bladder, the MIT team can detect the protein near the tumour, where it is present at much higher local concentrations. Tests in animal bladders showed that the device is 180 times more sensitive than conventional urinalysis and nearly 50,000 times more sensitive overall. This level of sensitivity allows the sensors to detect signals from a tumour as small as 16 square millimetres, even before it breaks through the bladder lining. Explaining the potential clinical advantage of the technology, Strano said: “Before an early-stage tumour breaks through the urothelium so that it’s visible, it’s under the surface but still emitting chemical signals that can be imaged. When a chemical hits the catheter, we don’t just detect its presence, but we collect a map that pinpoints its location.” The study, published in the journal Nature Nanotechnology, was led by postdoctoral researchers Wonjun Yim and Hohyung Kang, with contributions from graduate student Marco Machado, undergraduate student Maeve McGinnis, and postdoctoral researcher Byungha Kang. Currently, patients treated for Bladder Cancer undergo regular cystoscopy, often annually or more frequently, to monitor for recurrence. Researchers are now developing a more compact version of the prototype for clinical use, and they hope eventually to integrate the sensors directly into cystoscopes. “What we’re looking for is something that could be faster and more effective. It could be used right in a doctor’s office, and it could make that screening more efficient and less invasive, with much lower cost. The goal is to be able to detect potential tumours much earlier.” Researchers believe the platform could have applications beyond Bladder Cancer. By swapping out the nanosensors, the same catheter platform could be adapted for endoscopic detection of other cancers or diseases affecting the cardiovascular or gastrointestinal systems. “The beauty of polymer chemistry is that if we understand the molecular structures of target biomarkers and the design principles of binding sites, we can develop new sensors tailored to different diseases,” Yim said. “You can imagine if these sensors were integrated onto the catheter, they could reveal invisible biomarkers that current endoscopic procedures miss, opening the door to detecting many other diseases in the future.”