Synthesis and properties of osteopeptide derived surfactants

Abstract While amino acid-based surfactants have been widely applicated in daily chemical products, their further development is constrained by limited structural diversity. In contrast, polypeptide-derived surfactants exhibit brighter potential due to their abundant natural sources, structural versatility, and multifunctional properties. In this work, potassium N-lauryl osteopeptide carboxylate (PLOC) was successfully synthesized from lauryl chloride and bovine osteopeptide via Schotten-Baumann reaction. Surface tension, isoelectric point, application performance and irritation of PLOC were studied and compared with conventional surfactants. The isoelectric point of PLOC was determined to be 5.15 by pH titration, which is lower than its amino acid counterpart, potassium lauroyl glycinate (PLG, 6.51), due to the existence of acidic amino acids such as glutamic acid. The surface tension of PLOC at pH = 7 was 30.54 mN m −1 , much lower than that of PLG (37.05 mN m −1 ). Due to the high content of non-polar amino acid, PLOC exhibited less pH sensitivity. Increasing pH to 10 slightly elevated the minimum surface tension to 38.56 mN m −1 . Under neutral conditions (pH = 7), PLOC demonstrated superior emulsification efficiency and significantly reduced dermal irritation potential compared to PLG, owing to its larger hydrophilic head group structure. These results highlight the promising application potential of PLOC in household chemical formulations.