American scientists have suggested that a groundbreaking light therapy could kill cancer cells in just 30 minutes, and while the research is in its earliest stages, they said that ultimately, it could become a treatment that tackles the cells directly without damaging health tissues.
Daily Mail reports that the study team, from the University of Texas, Austin, had fired infrared light from LED bulbs at test tubes that contained human skin cancer or colon cancer cells and healthy human skin cells.
The tubes also contained nanoscopic flakes of tin oxide, or SnOx nanoflakes, which were absorbed by the cancer cells.
The scientists found that when the light was fired at the cells, the nanoscopic flakes absorbed it and heated up, turning into ‘microscopic heaters’ that damaged cancer cells and caused them to die, while leaving the healthy cells mostly undamaged.
After 30 minutes, they found treatment had killed up to 92% of skin cancer cells and 50% of colon cancer cells, while the healthy cells remained largely unaffected.
They said that while the research is still in its infancy and probably years away from becoming available, their study offers hope that a new treatment could become available that targets cancer cells directly without damaging healthy tissue.
Current cancer treatments that include surgery, chemotherapy or radiation also harm healthy cells by directly removing them or by damaging their DNA and interfering with cell division. Chemotherapy and radiation have a range of potentially debilitating side effects, including hair loss, fatigue, nausea, a weakened immune system and pain.
Dr Jean Anne Incorvia, a nanodevice researcher at the University of Texas-Austin, who led the study, said: “Our goal was to create a treatment that is not only effective but also safe and accessible.
“With the combination of LED light and SnOx nanoflakes, we’ve developed a method to precisely target cancer cells while leaving healthy cells untouched.”
It is the latest development in photothermal therapy, a technique that uses light to kill cancer cells.
This technique normally uses specialised lasers and is expensive, only carried out in specialist facilities, but the team behind the new method said that because it uses LED lights, it is cheaper and could become more widely available.
The method was tested only on skin and colon cancer cells, but it is likely that it could be tested for treating a range of other cancers.
More than 5m people are diagnosed with skin cancer in the US every year and about 9 000 die from the condition. The cancer is often caught in the early stages and easily treated.
Only about 4% of patients are diagnosed at stage four, where the cancer is much harder to treat.
For colon cancer, about 152, 000 people are diagnosed with the disease every year and 50 000 die from the cancer.
Unlike skin cancer, the disease often does not cause any symptoms until the later stages, when it has spread in the body and becomes harder to treat.
Estimates suggest that about 20% to 23% of cases are diagnosed at stage four.
Both cancers are on the rise, with the rate of melanoma, the most aggressive form of skin cancer, rising from 15.1 cases per 100 000 people in the US in 1999 to 23 per 100 000 in 2021, according to estimates.
For colon cancer, there is a sharp rise among young adults, with the number of cases diagnosed among 20- to 39-year-olds rising by about 2% every year since the mid-1990s.
The latest research, published in the journal ACS Nano, found that the temperature of the nanoparticles rose 19 degrees Celsius after 30 minutes of being exposed to the light.
Heating nanoparticles inside a cancer cell causes cell death because the heat disrupts and damages the cell’s internal structure. The higher temperatures can also cause proteins in the cell to denature, or stop working properly, and disrupt its membrane.
It may also be possible that the cell death could trigger an immune response, prompting the immune system to attack the cancer cells.
Scientists hope that the therapy could offer a safer alternative to traditional photothermal therapy (PTT) and chemotherapy and radiation treatments.
Chemotherapy is infused directly into the veins and travels around the whole body, potentially damaging healthy cells.
Radiation therapy uses high-energy rays to damage and kill cancer cells by firing the radiation directly at the cells in a tumour. But by firing the rays into the body, it can also cause damage to healthy cells, with the radiation potentially disrupting their DNA.
Dr Artur Pinto, a researcher at Porto University in Portugal who was also involved in the research, added: “Our ultimate goal is to make this technology available to patients everywhere, especially in places where access to specialised equipment is limited, with fewer side effects and lower cost.
“For skin cancer patients in particular, we envision that one day, treatment could move from the hospital to the patient's home.
“A portable device could be placed on the skin after surgery to irradiate and destroy any remaining cancer cells, reducing the risk of recurrence.”
The FDA has not approved photothermal therapy in the US as a standalone treatment for cancer to date, although a number of treatments are being investigated.
The agency has approved this treatment, however, for helping to treat certain skin conditions.
Study details
SnOx Nanoflakes as Enhanced Near-Infrared Photothermal Therapy Agents Synthesised from Electrochemically Oxidized SnS2 Powders
Hui-Ping Chang, Filipa Silva, Eva Nance et al.
Published in ACS Nano on 16 September 2025-10-27
Abstract
Near-infrared (NIR) photothermal therapy (PTT) using nanomaterials is a promising strategy for selective cancer treatment. We report two tin-based two-dimensional (2D) nanoflakes─defective SnS2 (SnS2–x) and mixed-phase SnOx─synthesized via top-down ultrasonication and electrochemical exfoliation with oxidation, respectively. Both nanoflakes have thicknesses below 20 nm, and their lateral sizes (<400 nm) were confirmed by AFM, DLS, atomic force microscopy, dynamic light scattering, and transmission electron microscopy (TEM). Despite a similar optical band gap (∼1.89 eV), SnO2 nanoflakes display a significantly enhanced NIR photothermal performance under 810 nm light emitting diode (LED) irradiation. A 3 mg/mL SnOx dispersion increases in temperature by ∼19 °C after 30 min, and a 0.25 mg/mL sample achieves a photothermal conversion efficiency of 93%. X-ray photoelectron spectroscopy and TEM analyses show that SnOx consists of interconnected SnO and SnO2 nanocrystals (<5 nm), which promote nonradiative energy release due to exciton confinement effects, unlike the planar SnS2–x nanoflakes that show negligible heating. In vitro studies demonstrate selective cytotoxicity: SnOx combined with NIR light (100–200 μg/mL, 30 min, 115.2 mW/cm2) reduces viability in SW837 colorectal (−50%) and A431 skin carcinoma cells (−92%), with no cytotoxicity toward human skin fibroblasts. Importantly, the SnOx nanoflakes retain both their photothermal efficiency and structural integrity after four cycles of NIR irradiation, demonstrating stability for repeated therapeutic applications. This work presents a green and scalable method to convert NIR-inactive SnS2 into photothermally active SnOx nanoflakes using only aqueous media and validates SnOx as an efficient, biocompatible PTT agent using low-cost LED sources.
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