Stabilization and Protection of Biomaterial through Biomineralization via Surface Interaction: An Astrobiological Approach
A Cytosine (CYN), core constituent of both RNA and DNA, is a well-known functional biomaterial of living system. Adsorption of such molecule on primigenial mineral surfaces transacts a very specific and selective role in biocompatibility and biomineralization. The adsorption behaviour of CYN, with change in pH, concentration, time and temperature on siliceous Montmorillonite (MMT) surface, a prominent nanoclay of smectite group with specific surface area, was studied systematically and methodically using different spectral techniques (viz. UV, FTIR, SEM and XRD). Biogenic metal dication [M2+= Mg2+, Ca2+, Fe2+ and Cu2+] entrapped nanocomposites of MMT were prepared separately by cation-exchange approach. The results reveal significant role of MMT and biogenic metal ions on the quantity of CYN adsorbed. The adsorption isotherm elegantly evinces monolayer formation of the biomaterial on the surface of MMT and MMT-M2+. The Langmuir adsorption parameters (KL & Xm) delineated appreciable interaction of CYN on MMT-Fe2+ surface as compared to MMT alone and other metal confined MMTs. The present work throws light on affinity of MMT nanoclay (having multifarious applications in biological systems) involving biogenic metal ions on stabilization and protection of biomaterials through biomineralization during prebiotic chemical evolution of biomolecules. The results embarks better adsorption capability of transition metal ion incorporated MMT than the clay without metal ion and with alkaline Earth dications due to better coordination properties of transition metal ions involving their d-orbitals for stable complex formation with negative sites of cytosine molecules as ligands. Since metal ions are key components of various enzymes which can catalyse a number of biochemical reactions in the living systems, the present study give better understanding regarding the pathways of aggregation of biomonomers on solid surfaces which themselves might have catalysed the formation of complex biomolecules via polymerization and condensation in enzyme free environment of early Earth and also influences implant biocompatibility.