Chirality of proteinoid nanoparticles made of lysine and phenylalanine

Proteinoid nanoparticles composed of l-lysine and l-phenylalanine were prepared and showed enantioselective adsorption of l-amino acids at various pH values, emphasizing the chiral nature of the particles. The adsorption was examined using circular dichroism, isothermal titration calorimetry and ζ-potential measurements. Positively charged ammonium moieties on the proteinoid surface are most likely responsible for the enantioselective adsorption owing to their chirality which originates from l-lysine. Accordingly, a higher enantiomeric excess was found for amino acids such as alanine with a more negative charge.