Current cancer treatment often struggles with a fundamental limitation: how to deliver drugs deep inside tumours without damaging healthy tissue. A breakthrough approach led by Dr Ambarish Ghosh at the Indian Institute of Science seeks to overcome this barrier using magnetic nanorobots—microscopic machines capable of navigating blood vessels, dense tissues and even individual cells. The work has earned him the 2025 Transformation Prize jointly awarded by the New York Academy of Sciences and Tata Sons, underlining its global scientific and clinical relevance.
Why drug delivery remains the weakest link in cancer therapy
Most anti-cancer drugs fail not because they are ineffective, but because they cannot reach the tumour core in sufficient concentration. Solid tumours develop dense extracellular matrices and irregular blood vessels that block drug penetration. Conventional chemotherapy therefore spreads throughout the body, leading to systemic toxicity, severe side effects and incomplete tumour destruction. Targeted and personalised medicine depends critically on solving this delivery challenge.
How magnetic nanorobots navigate the human body
The nanorobots developed at IISc are inspired by bacteria that move using helical flagella. Each nanobot has a corkscrew-like tail that rotates under an external magnetic field, allowing it to drill forward through viscous fluids and dense tissues. A magnetic component—typically iron—caps the helix, while the body is made of biocompatible silica. This design turns the nanobot into a controllable “nanoswimmer” that can be guided precisely to a tumour site.
Precision targeting and multi-functional action
What sets these nanorobots apart is not just mobility, but functional precision. Once guided magnetically to the tumour, the nanobot can:
- Deliver drugs coated on its surface or tip directly to cancer cells.
- Preferentially bind to malignant cells while sparing healthy tissue.
- Generate localised heat above 42°C under a magnetic field, killing cancer cells through magnetic hyperthermia.
In effect, the nanobot itself can act as both drug carrier and therapeutic agent, reducing the need for high systemic drug doses.
Seeing and guiding nanorobots in real time
An important extension of this platform is imaging. By modifying the nanobot’s structure, it can act as a contrast beacon during MRI scans. This allows surgeons and oncologists to visualise tumour boundaries more clearly and guide nanorobots in real time during diagnosis or therapy. Such integration of treatment and imaging—often called “theranostics”—is a key frontier in modern medicine.
Evidence from cancer and dental applications
So far, the nanorobots have shown strong efficacy in laboratory studies on ovarian and breast cancer cells, including tumours embedded in dense breast tissue that often evade conventional imaging. Beyond oncology, the same technology has been tested against drug-resistant bacteria, notably Enterococcus faecalis in root canal infections. Here, nanorobots offer a safer alternative to sodium hypochlorite, with the added potential to aid tooth remineralisation.
Challenges before clinical deployment
Despite promising results, the technology is still at an early translational stage. Research has largely been confined to cell cultures, with animal studies and human clinical trials still required. Key challenges include:
- Scaling up production at affordable costs.
- Regulatory approvals for in vivo use.
- Acceptance among clinicians and patients.
Importantly, the system does not rely on expensive superconducting magnets; simpler electromagnets are sufficient, improving its prospects for cost-effective adoption.
What to note for Prelims?
- Magnetic nanorobots use helical propulsion inspired by bacterial flagella.
- They enable targeted drug delivery and magnetic hyperthermia.
- Materials used include biocompatible silica and iron.
- The technology has applications beyond cancer, including dentistry.
What to note for Mains?
- Significance of targeted drug delivery in reducing systemic toxicity of cancer therapies.
- Role of nanotechnology in advancing personalised medicine.
- Ethical, regulatory and cost-related challenges in deploying nanorobots in healthcare.
- India’s growing contribution to frontier biomedical research and innovation.
