Kidney stones affect nearly 11% of Americans, causing severe pain and driving billions in annual healthcare costs. During laser lithotripsy, urologists use a laser to break these stones into small fragments for removal. However, stronger lasers generate excessive heat that can damage surrounding tissue, limiting how finely the stones can be broken down. Now, new research could improve the performance of existing lasers in removing kidney stones.

Researchers from the University of Chicago Pritzker School of Molecular Engineering (UChicago PME, Chicago, IL, USA) and Duke University (Durham, NC, USA) have developed an innovative way to make existing lasers more efficient — without changing the laser itself. Their study, published in Advanced Science, introduces a nanoparticle-enhanced saline solution that redirects more laser energy to the stones instead of dissipating as heat.

The method modifies the saline irrigation fluid used during surgery by adding dark nanoparticles that absorb laser wavelengths, helping focus the energy on the kidney stones. Laboratory tests showed this “nanofluid” increased ablation efficiency by 38–727% in spot treatments and 26–75% in scanning treatments, while also proving nontoxic and biocompatible.

This breakthrough could cut procedure time from 30 minutes to about 10 minutes, reducing patient discomfort and preventing heat-related tissue injury. The approach is compatible with the holmium:yttrium-aluminum-garnet (Ho:YAG) laser, the current gold standard for lithotripsy, and could enhance the performance of other laser systems as well.

“Obviously, you don't want to over-pump the energy into your kidney, because that's something that's very dangerous,” said UChicago PME Asst. Prof. Po-Chun Hsu. “What we demonstrate in our work is a way to better utilize the laser energy that is already being employed.”

“Some lasers perform well in dusting, other lasers perform better in fragmenting, but no laser can perform exceptionally well both in dusting and fragmenting,” said Duke University engineering Prof. Pei Zhong. “Unless you are at a major hospital like the University of Chicago or Duke, community doctors may not be able to afford multiple lasers. Nanofluid has the potential to enhance the performance of each laser under different clinical scenarios.”

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