RESEARCH SUMMARY
1. Doctoral Research: March 2018- July 2018:
Understanding the role of non-covalent interactions in regulating biological surface phenomenon. To study the effect of aromaticity on membrane bending during endocytosis processes, a model membrane was developed with amphiphilic character from essential and non-essential amino acid precursors. The synthetic amphiphiles, resembling A-B-A type pseudo copolymers, formed well-defined nanosized vesicles: unilamellar vesicles (diameter <50 nm), giant unilamellar vesicles (diameter >100 nm) and stacked vesicles in aqueous solutions. These further transitioned small spherical micelles (diameter <10 nm) into giant worm-like micelles (linear size >1 Micron!) instantaneously under the influence of strong cation-pi interaction. The display of rich morphology of the exclusive aggregates in the present systems, is not only rare for single chain amphiphiles, the biocompatibility of the aromatic aminoacid esters make them highly potential contender for drug delivery vehicle and drug vectors as well.
2. Post-doctoral research associate: September 2018 – May 2019:
Involved study of the kinetics and ultrafast spectroscopy of photodynamic species (spiropyran, SP, viz., 1,3,3 Trimethylindolinobenzopyrylospiran) in the vicinity of the biomimicking surfaces i.e., cationic, anionic and non-ionic micelles as well as large biopolyelectrolytes such as Histone (H1) and DNA. We reported that at room temperature, the non-activated spiropyran undergoes significant structural isomerization to merocyanine and binds strongly to H1, and becomes sandwiched between H1 and negatively charged DNA via strong non-covalent interactions. (Similar activity is otherwise demonstrated by non-substituted SP normaly at -700C!) The significant structural isomerization of the non-substituted spiropyran at room temperature depending on its microenvironmental stimuli may find potential use in target-oriented drug delivery applications.
3. National post-doctoral fellow: June 2019-June 2021:
Here, mainly the experimental validation of non-covalent interaction in modifying the instantaneous membrane surface curvature was sought. It was observed that the stacking of aromatic compounds in nanoaggregates is governed by a delicate balance between cation-pi and pi-pi interactions.
Research Highlights
(i) First quantitative report on surface active nature of aromatic alcohols (naphthols). (doi.org/10.1016/j.colsurfa.2016.12.025)
(ii) Synthesis and characterization new class of aromatic aminoacid based amphiphiles with high surface active and self-aggregating nature. (doi/abs/10.1021/acs.langmuir.7b01651)
(iii) Noncovalent interactions induces molecular unfolding in aqueous medium. (doi/abs/10.1021/acs.jpcb.7b11167)
(iv) Formation of thermo-responsive, metal tolerant viscoelastic gels comprised of giant elongated micelles under neutral salt-free condition. (doi.org/10.1016/j.molliq.2020.114013)
(v) Activity of non-activated spiropyrans at biological medium at room temperature. (Otherwise observed at -300C). (doi.org/10.1016/j.jphotochem.2022.113958)
(vi) Elastic deformation of spherical micelle via non-covalent interaction- Impact on viral endocytosis. (doi.org/10.1002/cphc.202100582)
(vii) Report on vesicular nanoaggregates formed by single-tailed synthetic aromatic amino-acid based amphiphiles (normally formed by double tailed surfactant).