Dr Fatema Alali | How Ring-Shaped Gold Nanoparticles Could Revolutionise Cancer Treatment

Photothermal therapy works by sending laser light into the body, where nanoparticles absorb it and convert it into heat that can destroy cancer cells while leaving healthy tissue largely unharmed. For this to work well, the particles must absorb light in a specific part of the spectrum known as the “near-infrared II” window, which can penetrate deeper into tissue using lower and safer laser intensities. Achieving this reliably, however, has proven challenging.

Many existing gold nanoparticles rely on sharp edges and thin frames to tune their light absorption. As Dr Alali explains, these sharp features can bend or deform during fabrication or heating, causing unpredictable shifts in how the particles respond to light. Excessive heat–induced deformation of sharp edges into curved ones shifts the absorption out of the ideal range, reducing effectiveness and reliability.

To address this, Dr Alali proposes a new approach based on torus-shaped gold nanoparticles – structures that resemble tiny rings. Using detailed computer simulations, she shows that these ring-shaped designs are far more stable than traditional cubic or spherical frames. Instead of needing to finely balance multiple design parameters, the optical response of these particles can be tuned mainly by adjusting their thickness, making them simpler and more robust.

The study examines three related designs made from multiple interconnected rings. These shapes retain strong absorption in the near-infrared II range while being less sensitive to how the particles are oriented or how the incoming light is polarised. This is especially important for medical use, where nanoparticles move freely in fluids and cannot be carefully aligned.

According to Dr Alali, the curved geometry also reduces the risk of structural damage at high temperatures, helping the particles maintain consistent performance during treatment. While fabricating such complex shapes remains a challenge, the results suggest that ring-shaped gold nanoparticles could offer a more dependable platform for future medical applications.

By combining elegant geometry with practical design principles, Dr Alali’s work points toward a new generation of nanoparticles – ones that are not only powerful, but also predictable and safe enough for real-world medical use.