Feed the Seed: Let It Grow Stronger

Work done in the lab of Prof. Subi J. George, Professor and Chair, New Chemistry Unit (NCU) at Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Bangalore

About author

Souvik Sarkar completed his B.Sc. in chemistry from St. Xavier’s College, Kolkata, West Bengal in 2015. Subsequently, he moved to the Indian Institute of Technology (IIT) Madras, Tamil Nadu in 2017 to pursue his M. Sc. in Chemical Science. After finishing M.Sc., he joined JNCASR as a Ph. D. student under Prof. Subi J. George. His research work at Supramolecular Chemistry Laboratory focused on programmable supramolecular polymerization using molecular chirality and secondary nucleation.

Raju Laishram obtained his B.Sc. and M.Sc. in chemistry from the University of Delhi in 2010 and 2012 respectively. Subsequently, he joined in the group of Prof. Uday Maitra at IISc, Bangalore. After finishing PhD in 2017, he moved to Imperial College London followed by CEA Grenoble, France for the postdoctoral experience. In 2020, Dr. Laishram joined the group of Prof. Subi George, JNCASR as research associate where his research work was focused on kinetically controlled living supramolecular polymerization.

Interview: This is in conversation with one of the co-authors Souvik Sarkar

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

Higher-ordered structures are ubiquitous in Nature They create the most unique and exquisite structures that have been essential in forming the building blocks and also to perform functions more precisely, selectively, and efficiently. For instance, the machinery involved in changing shape of cells, relies on the assembly of globular proteins to provide branched and crosslinked networks. Achieving such precise control and understanding the mechanistic insights into the driving forces that govern topology of man-made self-assembled systems is a key ambitious goal of supramolecular chemistry, systems chemistry, and materials science. Thus, scientists have long been trying to mimic or replicate higher-ordered structures in synthetic systems for developing programmable soft nanostructured materials with predictive and precise functions.

Through our research, we report an unprecedented molecular-level control on the fibrous network (branching, cross-linking, or bundling) of supramolecular hydrogels by biasing the assembly pathways through surface catalyzed secondary nucleation, a microscopic step involved in the autocatalytic proliferation of amyloid filaments. Like seed-crystal-induced bulk crystallization processes, we uncover seed-induced instantaneous supramolecular gelation methodology to modulate the secondary nucleation events for controlling the gel network topology. This further results in modulating the mechanical property of hydrogel. The rarely explored secondary nucleation-triggered seed-induced methodology presented here is a much simpler yet highly effective strategy.

How do these findings contribute to your research area?

Supramolecular hydrogels are the class of soft materials that hold much attention in tissue engineering, crystal growth, or medium for controlled drug delivery. Tuning the mechanical strength in these materials is of great interest, especially for fields such as multidimensional cell culture platforms. In fact, the intra- and extracellular mechanics at all biological levels are governed by the mechanical properties of protein self-assembly. Hence, constructing functional biomimetic hydrogel which will provide modulating mechanical strength is highly demanding. So far, attempts included either by varying concentration, temperature, pH, or through aging, incorporating additives and molecular cross-linkers. Our research discloses seed-induced supramolecular gelation, a novel and efficient strategy to modulate the gel stiffness and this methodology can be considered as a “non-covalent cross-linking strategy” to control the mechanical property of soft materials.

What was the exciting moment during your research?

The starting point and as well as the most exciting moment of this research is one particular evening time. When we intentionally added one small piece of preformed gel (seed) into the induction period of the growth phase of gel. We were completely surprised after seeing the instantaneous gelation phenomenon and from where the work started.

“Our research discloses seed-induced supramolecular gelation, a novel and efficient strategy to modulate the gel stiffness and this methodology can be considered as a “non-covalent cross-linking strategy” to control the mechanical property of soft materials.”

What do you hope to do next?

I am very passionate about research. Solving a research problem is very exciting and always gives me thrills. I feel that research should be considered in this way. Now coming to the question, as you have noticed that the next level of challenge will be the topology and functional control in synthetic systems by programming the molecular assembly pathways like many bio-polymers do in cells.

Where do you seek scientific inspiration from?

I must say, eminent scientists always fascinate me with how to think so deeply to execute a particular scientific problem. From the beginning, I constantly read the background history of scientific discoveries irrespective of any fields, and try to imagine the thought process behind it. So, I would say it’s the life and journey of the scientists that always keep me motivated to do good research. In that way, I am lucky to whomever I met during my academic career. I must especially mention my guide Prof. Subi George, with whom the enormous amount of discussion about his vast experience, way to solve scientific problems, and stories of his encounters with scientists always enriched me to keep it going.

How do you intend to help Indian science improve?

Indian Science is already at its peak now, but to progress it further I must say that we should encourage the young generations to embrace basic sciences. Students should be taught how to approach new problems, and obviously, keep them motivated in searching for new ideas.

Reference

Laishram, R.;┴ Sarkar, S.; ┴ Seth, I.; Khatun, N.; Aswal, V.K.; Maitra, U.; George, S.J. Secondary Nucleation-Triggered Physical Cross-Links and Tunable Stiffness in Seeded Supramolecular Hydrogels, J. Am. Chem. Soc. 2022, 144,11306–11315 (┴ = equal contributions) (https://pubs.acs.org/doi/10.1021/jacs.2c03230)

Copy Editor

Nivedita Kamath

Postgraduate in Biotechnology

Nivedita is a Postgraduate in Biotechnology, with one year Project Assistantship experience at inStem, DBT. She is currently a UPSC aspirant planning to appear for 2021 CSE. Although switching from science career to focus on governance policy and administration, her love for science remains ever-etched in all that she does. On her journey from a researcher toward public administrator, she believes in the critical role of science communication and journalism in bridging the gap between lab benches and public fields. Being part of BioPatrika is her being one stone laid for that very bridge.

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