Light-powered nanobots offer a smarter way to treat breast cancer

Scientists in India have developed a new light-responsive nanobot that can actively move toward breast cancer cells and destroy them with remarkable precision. The innovation, created by researchers at the Institute of Nano Science and Technology (INST), Mohali, could open the door to more effective cancer treatment with fewer side effects than conventional chemotherapy.

The study, published in ACS Applied Materials & Interfaces, introduces a fuel-free nanobot that responds to near-infrared (NIR) light, allowing researchers to guide it directly toward tumors while activating two cancer-killing mechanisms at the same time.

A smarter approach to targeted cancer treatment

Breast cancer remains one of the most common causes of cancer-related deaths among women across the world. Although chemotherapy is widely used, it often affects healthy tissues because cancer drugs spread throughout the body instead of staying confined to the tumor. This can lead to serious side effects, while many tumors also become resistant to treatment over time.

Researchers have been working on nanomedicines that accumulate inside tumors, but these systems mostly depend on passive delivery. Their ability to reach deep tumor tissues is limited, and doctors have little control over where the particles travel after they enter the body.

The research team at INST wanted to solve these challenges by combining nanorobotics with phototherapy, creating a tiny machine that could be controlled from outside the body using light while carrying out targeted cancer treatment.

Nanobots that move with light and attack tumors

The project was led by Dr. Jiban Jyoti Panda of INST, Mohali, in collaboration with Dr. Santosh K. Gupta of Bhabha Atomic Research Centre (BARC), Mumbai. Swapnil Srivastava served as the first author of the study, while Annu Balhara, Pankaj Kharra and Jyoti Yadav were also part of the research team.

The scientists designed nanobots using upconversion nanoparticles coated with polydopamine. When exposed to a 980 nm near-infrared laser, the coating produces localized heat that creates a temperature gradient. This causes the nanobots to move toward the light source in a process known as phototaxis.

The researchers also attached a photosensitizer to the nanobots, enabling them to generate reactive oxygen species after NIR exposure. The combination of heat and these highly reactive molecules damages and destroys cancer cells more effectively than either method alone.

Designed to recognise breast cancer cells

To improve accuracy, the team functionalized the surface of the nanobots with folic acid. Many breast cancer cells carry a high number of folate receptors, allowing the nanobots to identify and bind to these cells more selectively while reducing unwanted effects on healthy tissues.

The therapeutic activity of the nanobots can also be regulated by factors such as laser intensity, pH and glutathione concentration, giving researchers greater external control during treatment. Since the system uses biologically compatible near-infrared light instead of ultraviolet or visible light, it offers deeper tissue penetration with reduced risk of damaging surrounding healthy cells.

Successful results in laboratory and animal studies

The research team demonstrated the effectiveness of the nanobots in laboratory-grown cancer cells as well as breast tumor-bearing mice. The results showed stronger tumor inhibition through the combined photothermal and photodynamic treatment, supported by the nanobots' ability to actively move toward the targeted area.

The researchers believe this multifunctional platform could become an important step toward precision cancer therapy by providing externally controlled, minimally invasive treatment that delivers therapeutic action exactly where it is needed. Further studies will be required before the technology can move toward clinical applications in humans.