Heparin-Templated Bio-Organic Conjugates for Efficient Light-Harvesting

Work done in the lab of Dr. Supratim Banerjee at Indian Institute of Science Education and Research Kolkata 

About author

Dr. Shubhra Kanti Bhaumik pursued his B.Sc. and M.Sc. degrees in Chemistry from Vidyasagar University, Medinipur, West Bengal. To explore his utmost interest in supramolecular chemistry, he joined the Department of Chemical Sciences (DCS) at the Indian Institute of Science Education and Research Kolkata (IISER-K) headed by Dr. Supratim Banerjee as a junior research fellow (JRF) with INSPIRE fellowship. During his doctoral studies, he received training as a supramolecular and physical-organic chemist. His research work mainly focuses on luminescent self-assembled systems and their various potential applications in aqueous media based on amphiphilic cyanostilbene derivatives and phenylpyridine derivatives. At present, he is a postdoctoral fellow at Ben-Gurion University of the Negev, Israel in Prof. Raz Jelinek’s group. He is currently working in the fabrication of solar-powered organic supercapacitors and in the design of fluorescent markers for amyloids. During his leisure time, he loves to sing songs and recite poems.

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Shubhra Kanti Bhaumik

Interview

How would you explain your research outcomes to the non-scientific community?

In natural photosynthetic systems i.e., in plants and green bacteria, sunlight is captured by chlorophylls which act as antennae, and the light energy is transferred to the reaction centre where it is stored as sugar (photosynthesis). Therefore, mimicking natural photosynthetic systems and understanding the fundamental processes of the energy transfer process has gained enormous interest in recent years. In this direction, we have demonstrated an artificial light-harvesting system based on α-cyanostilbene, a highly emissive organic fluorophore, and heparin, a well-known therapeutically important biomolecule that is used as an anticoagulant during surgery and also in post-operative treatments, and also Nile Red, a red-emitting dye. The cyanostilbene derivatives and heparin formed tubular nanostructures that acted as efficient energy donors (antennae) to Nile Red and thus these artificial light-harvesting systems were constructed. The phenomenon we demonstrated in our study is known as FRET (Förster resonance energy transfer) which has significant importance in different applications such as the determination of DNA/RNA structures, mapping biological membranes, real-time PCR tests, etc. The future is moving towards the conversion of solar energy to chemical energy or as electricity for storage and the process of energy transfer is a key factor for such applications.

Luminescent supramolecular nanotubes derived from the co-assembly of cyanostilbene-based supramolecular polymers and bio-polyanion heparin have demonstrated efficient energy transfer to Nile Red and Nile Blue in aqueous media.

How do these findings contribute to your research area?

Our findings represent supramolecular systems that have potential applications in the area of light-harvesting applications. Although in this direction a few systems have been reported earlier in aqueous media based on DNA, viral proteins, and a few polysaccharides, but we demonstrated the use of heparin as a biomolecular scaffold to construct efficient light-harvesting systems in aqueous media for the first time. Moreover, fabrication of such systems in aqueous media is highly challenging as most of the organic fluorophores undergo emission quenching in aqueous media upon aggregation, which is detrimental for light-harvesting applications. Our systems displayed one of the best energy transfer efficiency values and amplification of acceptor emission (antenna effect) by FRET in aqueous media. In addition, we utilized these systems for multicolour emission, data encryption-decryption applications, and as ratiometric fluorescent thermometers.

“Our findings represent supramolecular systems that have potential applications in the area of light-harvesting applications.”

What was the exciting moment during your research?

Being a supramolecular and physical-organic chemist, working in a supramolecular and functional organic materials lab, it was always exciting to work with fluorescent molecules. The cyanostilbene derivatives not only acted as efficient fluorescent sensors for heparin but also acted as efficient donors embedded in heparin co-assembly to construct light-harvesting systems. The characterization of the self-assembled nanofibers of the cyanostilbene derivatives transforming into nanotubes upon the formation of co-assemblies was the most exciting part of this work. Our findings may open the scope of using heparin as an alternative biomolecular scaffold to design aqueous-based light-harvesting biomaterials.

What do you hope to do next?

I am always eager to explore new scientific challenges. Currently, as a postdoctoral fellow, I am working on device fabrication that can harvest sunlight and store it as electrical energy. I hope to continue my career in the direction of sustainable energy storage materials research.

Where do you seek scientific inspiration from?

My interest in science started from my higher secondary education. I have found my passion to work in the field of supramolecular chemistry and materials science since my postgraduate studies. I am grateful to Dr. Supratim Banerjee for having him as my PhD supervisor. His interests in research projects, queries, and enthusiasm enchanted me to widen my knowledge and interests from a research perspective.

How do you intend to help Indian science improve?

I believe India is a powerhouse of potential future scientists who can excel in research and make India proud. However, we need more funding towards fundamental as well as applied research areas. This can be executed by more collaboration with institutes and industries. In my opinion, more scientific outreach programs and demonstrations would attract students to grow interest in science. I wish to continue my career in academia and research, and help encourage students in science. 

Reference

K. Bhaumik, D. Maity, I. Basu, S. Chakrabarty and S. Banerjee, Efficient light harvesting in self-assembled organic luminescent nanotubes. Chem. Sci., 2023, Advance Article (DOI: 10.1039/d3sc00375b) https://pubs.rsc.org/en/content/articlelanding/2023/SC/D3SC00375B

Copy Editor

Ritvi Shah

Postgraduate at Vikram Sarabhai Institute

Postgraduate at Vikram Sarabhai Institute of Cell and Molecular Biology, Gujarat. She is a neuroscience enthusiast. Apart from that, she enjoys reading and trying her hand at sciart.

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