Abstract

Water is often found at the surfaces of small nano-sized objects, like micelles, proteins and grooves of DNA , and also in the interior of small objects like reverse micelles and rocks. The nature of such constrained and confined water can be quite different from bulk water. A large number of experimental studies have explored the properties of such water in recent years, often with interesting new results that have given rise to a lot of discussions. For example, dynamics of protein hydration layer behaves differently under different probes. In another example, the value of the static dielectric constant (SDC) remains universally low for water in small confinements, and it is different for different dielectric boundaries. In our quest to develop a microscopic understanding, we study the structure and dynamics of the water molecules in different layers of nano-confined water. We apply our knowledge to understand dissociation of insulin dimer, and insulin hexamer. Acknowledgement : I thank Dr. Puja Banerjee, Dr. Sayantan Mondal and Dr. Saumyak Mukherjee for collaborations. I thank DST -SERB (India) for an National Science Chair Professorship and DST -SERB for support.

REFERENCES 1. Mondal, S. and Bagchi, B., Water Layer at Hydrophobic Surface: Electrically Dead but Dynamically Alive?. Nano Lett. 20 (12), p.8959 (2020). 2. Mondal, S. and Bagchi, B., Water in carbon nanotubes: Pronounced anisotropy in dielectric dispersion and its microscopic origin. J. Phys. Chem. Lett., 10(20), p.6287 (2019). 3. Mondal, S., Acharya, S. and Bagchi, B., Altered polar character of nanoconfined liquid water. Phys. Rev. Research, 1(3), p.033145 (2019). 4. Mondal, S. and Bagchi, B., How different are the dynamics of nanoconfined water?. J. Chem. Phys., 152(22), p.224707 (2020). 5. Bagchi, B., Water dynamics in the hydration layer around proteins and micelles. Chem. Rev., 105(9), p.3197 (2005). 6. Bagchi, B., “Water in Chemistry and Biology : From Structure and Dynamics to Function” (Cambridge, UK, 2013)