A research team from the Indian Institute of Technology, Mandi, has developed complex nano-dimensional capsules that can be used for multimodal imaging and treatment of tumours. Their work paves the way for better understanding and development of theranostic techniques for cancer and other diseases, and was recently published in the Journal of ChemNanoMat.

Theranostics is an emerging field in medicine, especially in oncology, and combines “diagnostics” — the detection of abnormalities and maladies — with “therapeutics”— treatment of the malady. It involves the use of a single multifunctional agent that can diagnose ailments, deliver drugs and monitor treatment efficacy. The promise of theranostics is that it could enable treatment options that are individual-specific, which can conceivably result in better prognoses. This research, however, does not imply a cure for cancer.

“Nano-materials — materials that are approximately few thousand times smaller than the thickness of a single human hair — have brought the concept of theranostics closer to reality”, said Amit Jaiswal, assistant professor, School of Basic Sciences, IIT-Mandi, who led the team. The unique size scale of the particles can result in enhancedpermeability-and-retention effect in tumour targeting and treatment

Jaiswal and his team have developed a “smart” nano-material that can serve as an effective theranostic agent. Their plasmonic nano-capsules have functionalities that make them useful in diagnosis through a technique called Surface-Enhanced Raman Spectroscopy in addition to carrying a cancer drug in it, which can be released simultaneously. Their nano-capsules comprise a solid gold core, which is surrounded by a porous gold layer, the two layers forming what they term a “gold nano-rattle”. This nan-orattle has electromagnetic hotspots, in addition to being able to bind to a Raman-active compound called BDT, and together serve as a Raman reporter, the diagnostic part of the functionality. This ensemble is further encapsulated, first by a solid silica layer, which keeps the underlying BDT from leaching out. Surrounding this is a porous silica layer, into which is loaded, the chemotherapy drug, Doxorubicin — the therapeutic part of the theranostic agent.

The team is excited about this development. The smart core-shell type nanocapsules “enable an extraordinary nanotheranostic platform that can perform bimodal SERS and fluorescence based bioimaging, and at the same time function as an efficient drug delivery vehicle for therapeutic applications”, the researchers write in their recently published paper. The nanostructured capsules developed by Jaiswal and his research students, Shounak Roy, Ankita Sarkar (in photo) and Monika Ahlawat, can potentially extend the existing paradigms in therapeutic procedures by allowing imaging to be performed not only before and after, but also during a treatment regimen.

Challenges, however, remain, including understanding the toxicity issues involved in using nano-sized materials in biological domains, and specific targeting issues, which must be addressed before theranostics can transition from the lab to clinical practice. That said Jaiswal and his team’s work offers a launch pad in India for more extensive research that can eventually enable the transition.