How do Nucleotides Adsorb Onto Clays?

Area of Science:

• Astrobiology
• Geochemistry
• Mineralogy

Background:

• The emergence of life on Earth may involve the adsorption of prebiotic building blocks onto mineral surfaces.
• Early Earth environments likely offered diverse geochemical settings conducive to such processes.
• Phyllosilicates, abundant and high-surface-area minerals, are prime candidates for facilitating prebiotic chemistry.

Purpose of the Study:

• To investigate the interaction between nucleotides (RNA and DNA building blocks) and phyllosilicates under various conditions.
• To develop a generalized model for nucleotide adsorption mechanisms on phyllosilicate particles.
• To acquire direct data on nucleotide adsorption configurations and localization on mineral surfaces.

Main Methods:

• Batch adsorption studies varying temperature, pH, and salinity.
• Surface chemistry and geochemistry techniques including vibrational spectroscopy and X-ray microscopy.
• Theoretical simulations to complement experimental findings.

Main Results:

• A comprehensive model of nucleotide adsorption on phyllosilicates was established, primarily driven by phosphate reactivity.
• Experimental and theoretical approaches provided insights into adsorption mechanisms.
• Advanced surface techniques confirmed and refined the existing adsorption model, despite detection challenges.

Conclusions:

• Nucleotide adsorption onto phyllosilicates is a plausible mechanism in prebiotic chemistry.
• Phosphate reactivity is a critical factor governing nucleotide-mineral interactions.
• Understanding these interactions is crucial for identifying potential biosignatures on early Earth and other planetary bodies.