Ahmedabad: A team of researchers from the Indian Institute of Technology Gandhinagar (IITGN) has developed an eco-friendly and chemical-free approach to synthesise multifunctional carbon nanoparticles from commonly used medicinal plants.
The study presents a rapid microwave-assisted method for producing highly sensitive carbon nanoparticles that can detect toxic heavy metals while also demonstrating antioxidant and biomedical potential.
Heavy metals such as iron, lead, and nickel are widely used across industries but pose significant environmental and public health risks.
Released through industrial activities, mining operations, and urban waste, these contaminants accumulate in ecosystems and living organisms over time.
Their presence has been linked to serious health concerns, including inflammation, airway constriction, blood clotting, and cardiac stress. Detecting these pollutants typically requires sophisticated instruments and costly testing procedures.
Seeking a sustainable alternative, researchers at IIT Gandhinagar explored the potential of medicinal plants to create advanced carbon nanoparticles capable of sensing heavy metals and supporting biomedical applications. Their findings have been published in Nano Express.
The research team utilised five medicinal plants commonly found in Indian households: jamun (Syzygium cumini), tulsi (Ocimum sanctum), neem (Azadirachta indica), guava (Psidium guajava), and curry leaf tree (Bergera koenigii).
These plants were selected for their known antioxidant and anti-cancer properties and served as natural sources for synthesising carbon nanoparticles.
Carbon nanoparticles, commonly referred to as CNPs, are nanoscale carbon-based materials with promising applications in metal ion detection, bio-imaging, antimicrobial activity, and biomedical research.
Due to their biocompatibility and low toxicity, carbon nanoparticles have attracted growing interest among researchers.
In line with increasing emphasis on green nanotechnology, natural and renewable plant sources are being used to produce carbon nanoparticles while reducing dependence on hazardous chemicals and energy-intensive manufacturing processes.
Using a rapid microwave-assisted synthesis technique, the IITGN researchers generated five different types of carbon nanoparticles. All of them exhibited bright red fluorescence when exposed to ultraviolet light.
This property proved valuable for pollutant detection, as specific heavy metal ions reduced the fluorescence intensity of the nanoparticles upon interaction.
The study revealed distinct sensing capabilities among the plant-derived carbon nanoparticles. Guava-derived nanoparticles demonstrated sensitivity toward nickel ions.
Neem-derived and jamun-derived nanoparticles effectively detected iron ions, with neem responding to ferrous ions and jamun responding to ferric ions. Tulsi-derived carbon nanoparticles showed the ability to detect both ferrous iron ions and lead ions.
Commenting on the findings, Parul Singh, a final-year PhD student in the Department of Electrical Engineering at IIT Gandhinagar, said, “Fascinatingly, the decrease in fluorescence intensity became more pronounced with increasing heavy metal ion concentration! The curry-leaf-derived CNPs did not show this behaviour, which could be attributed to factors such as their non-selectivity toward the metal ions used in this study.”
Beyond environmental sensing, the carbon nanoparticles demonstrated notable antioxidant properties. The researchers observed that jamun-derived nanoparticles exhibited the strongest antioxidant activity, followed by tulsi, guava, neem, and curry leaf-derived nanoparticles.
Antioxidants help neutralise free radicals, unstable molecules associated with ageing, cellular damage, and various diseases. During laboratory experiments, the team used two free radicals and observed a visible colour change from violet and blue-green to light yellow after exposure to the carbon nanoparticles, confirming their antioxidant behaviour.
The researchers also evaluated the biocompatibility of the carbon nanoparticles using a cell line and found minimal toxicity at low concentrations.
Among the different variants, tulsi-derived nanoparticles emerged as the most biocompatible. These findings indicate potential applications of carbon nanoparticles in diagnostics and therapeutic interventions.
According to Dr Jhuma Saha, Assistant Professor in the Department of Electrical Engineering at IIT Gandhinagar, “Our work shows that components from medicinal plants can serve as building blocks for nanomaterials with optical, sensing, and biomedical capabilities.
Future research is needed to explore the scalability of our synthesis technique and the practical use of our CNPs in environmental remediation and biological applications.”
The research team included Prof Dhiraj Bhatia, Prof Mukesh Danka, Ms Hitasha Vithalani, Mr Aniruddha Dan, and Mr Nihal Singh from the Department of Biological Sciences and Engineering, as well as Ms Padma Priya Kannan from the Department of Materials Science and Engineering.
As the world marks World Environment Day and World Oceans Day during June, the study highlights how sustainable innovations such as plant-derived carbon nanoparticles can contribute to cleaner ecosystems and improved environmental monitoring.
The research aligns with the Government of India’s Mission on Nano Science and Technology, which focuses on developing nanotechnology-based applications, and Mission LiFE, which promotes environmental protection and sustainable lifestyles.
The development of carbon nanoparticles from readily available medicinal plants also reflects the vision of Atmanirbhar Bharat by encouraging indigenous and sustainable technological solutions.
Furthermore, the study supports the objectives of the United Nations Sustainable Development Goal 6 on clean water and sanitation and Goal 9 on Industry, Innovation and Infrastructure.
