GUWAHATI, Sept 30 - A team of researchers from the Indian Institute of Technology (IIT) Guwahati has developed nanomaterials derived from nature to deliver drugs to the human body in a controlled and specific manner.
Such biocompatible vehicles could potentially carry chemotherapy drugs directly to the cancer cells.
The research team led by Dr Biman B Mandal, Associate Professor of the Department of Biosciences and Bioengineering of IIT Guwahati, along with Dr Jadi Praveen Kumar, Dr Rocktotpal Konwar, Dr Manishekhar Kumar and Ankit Gangrade, studied various types of nanomaterials for use as carriers in targeted drug delivery.
The concept of targeted drugs is not new. German Nobel Laureate Paul Ehrlich (1854-1915) had proposed the concept of �Magische Kugel� or magic bullet � a drug that can target the disease like a missile fired towards a target.
While early developments on targeted drugs focused on treating infections, the past two decades have seen a surge in the development of targeted drugs for cancer and other tumors.
�Developments in targeted drug delivery have been driven by developments in nanomaterials,� said Dr Mandal.
A nanometre is one millionth of a millimetre and nanomaterials are made of particles that are 1,00,000 times smaller than the diameter of a human hair.
In chemotherapy, nanoparticles loaded with drugs can be targeted at tumour cells, bypassing healthy cells, thus avoiding non-specific biodistribution, drug resistance, and unwanted adverse effects.
Nanotubes of carbon are particularly attractive for targeted drug delivery.
The IIT Guwahati research team has developed a hydrogel system made of silk and carbon nanotubes loaded with drug molecules for controlled release of drugs. Hydrogels are polymeric networks that absorb huge volumes of water and swell.
The high water content makes hydrogels similar to tissues, enhancing biocompatibility, and also allows easy encapsulation and release of drugs at targeted sites.
The researchers at IIT Guwahati combined silk with drug-loaded carbon nanotubes, which offered better mechanical strength to the silk hydrogels, in addition to enabling slow and controlled release of the drug at the target site.
�Our injectable hybrid hydrogel system had pH, temperature, and near-infrared (NIR) light-dependent drug release properties,� added Dr Mandal.
In their work, the results of which were published recently in ACS Biomaterials Science & Engineering, they used intermittent NIR light to control the release of functionally bioactive model drug compound called doxorubicin (DOX) molecules attached to the hybrid hydrogel.
The hybrid hydrogel is injectable and designed to serve as a reservoir for anti-cancer drugs at the local site of tumour.
The team has also applied for a patent for the new technology. Ankit Gangrade has co-authored the paper with Dr Mandal.
Talking about the treatment methods for cancer, Dr Mandal said, �Although conventional chemotherapy is one of the most widely used treatment methods for cancer, its drawbacks include poor bioavailability at the actual cancerous regions, which necessitates high-dose injections and serious side effects that arise because the drugs destroy healthy cells along with the cancer cells in the body. Both these problems can be solved by delivering drugs exclusively to the target cancerous zones, and our silk nanotube and nanodot based vehicles would serve as good carriers of such drugs.�
In an earlier study, Dr Mandal and his team used bio-derived carbon nanodots as vehicles for drug delivery.
It is attractive to produce such nanodots from biological sources to avoid the use of toxic products, and there have been attempts to produce carbon nanodots from bread, jaggery, banana, and even milk.
In an Indian twist to these attempts, the research team produced carbon nanodots from lassi, the yogurt-based drink.
The researchers heated store-bought lassi in the microwave oven for about six and a half minutes and separated the carbonized portion that contained carbon nanodots. The researchers then loaded the nanodots with Dox.
The Dox-loaded carbon nanoparticles released the drug in response to the change in acid content in the surrounding medium.
The drug was delivered into the target cell directly. The results from this work were published in ACS Sustainable Chemistry & Engineering last year.