◥ Speaker: Prof. Masahiko Hara (Tokyo Institute of Technology)
◥ : March 15(Fri), 2019 / 10:00
◥ Place: Seminar room 1 (#1101) @ W1-3 Bldg.
◥ Title: Nano-Spectroscopic Studies of Chemical Evolution at Interfaces – Ultimate Self-Assembly and Origins of Life –
The origin of life, though it remains a mystery, is believed to have been chemical reactions at
mineral surfaces on the earth during the Hadean period. Although there have been many
proposals and preliminary experiments on this topic, no definitive origin has been reported yet
because of a lack of nanoscopic studies. Herein, we present the first material surface observations
intended to elucidate the origin of life at the molecular level. These observations were made using
a combination of novel techniques, specifically, Raman spectroscopy and atomic force
microscopy (AFM). Pyrite (FeS2) is known to be one of the most common minerals that can
provide condensation and reaction surfaces for chemical evolution. However, this mineral has
mostly been studied from a crystallographic viewpoint or in bulk systems, and such investigations
cannot fully resolve the exact mechanisms of the specific interactions that occur on this mineral.
Moreover, no direct experimental evidence has been reported regarding pyrite initiating chemical
evolution at the nano-scale when it is used as a reaction surface. In this study, the quantitative
force analysis performed by using AFM, in which the residue of a single amino acid was mounted
on AFM tips, enabled us to locate the reaction sites and to study the interaction forces between
the amino acid and the pyrite surface. Our Raman spectroscopy and AFM results revealed for the
first time that defective areas, with the molecular composition FeS2-x, increase the adsorption
probabilities of amino acid residues in chemical reactions on the surface of pyrite.
Keyword: Nanotechnology, Scanning Probe Microscopy, Atomic Force Microscopy (AFM), Raman
Spectroscopy, Self-Assembly, Bio-Interface, Chemical Evolution, and Origins of Life.