K18 Granted Patent for Hair Fiber-penetrating Peptides

Focused on biomimetic hair science, San Francisco-based indie brand K18 has been awarded a patent for a peptide composition distinguished by its ability to penetrate inside the human hair fiber to improve strength and hydrophobicity, and its greater affinity to hair keratin than previously developed peptides.

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Per the patent disclosure, a study by researchers at the University of Minho in March 2017 — a doctoral thesis from Celia Freitas Da Cruz, "Unravelling and modulating human hair morphology features" — brought to light a mechanistic understanding of how peptides could interact and fortify endogenous hair proteins. In their investigations, the researchers examined the influence of isoelectric point, charge and amino acid side chain functionality on the binding interactions of the screened peptides with hair proteins.

The array analysis suggested that designing peptides with small molecular weights and high affinity to human hair keratin would have a good probability of interacting with and reinforcing keratin properties when supported by surfactant agents to help increase the penetration of the peptides into the cortex. The current invention therefore incorporates two peptides, approximately 11 and 12 amino acids in size (wherein two to three are cysteines), and a suitable dermatology excipient.

More specifically, the novel peptide designs have the following characteristics:

1. At least one peptide sequence consisting of AquisPep1 or AquisPep2;
2. A low molecular weight to penetrate the core of the hair strand;
3. An affinity and the ability to interact with keratin 3;
4. A hydrophobic nature; and 
5. Work from the inside out to protect hair from water damage.

The composition additionally includes an anionic, amphoteric, cationic or nonionic surfactant, and combinations thereof; and a coloring agent/dye bound to the N or C terminus of the peptide sequence. The resulting composition is suited to treatment and grooming products for human hair.

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