Researchers packaged the anti‑aging peptide GHK‑Cu inside tiny lipid bubbles (liposomes) and showed that this delivery method keeps the peptide stable, gets it into the skin, and cuts elastase activity (which breaks down skin elasticity) by about half. The best recipe used positively‑charged lipids at a specific concentration, achieving around 30% loading efficiency and particles about 100 nm in size.

Liposomes are self-assembled spherical systems composed of amphiphilic phospholipids. They can be used as carriers of both hydrophobic and hydrophilic substances, such as the anti-aging and wound-healing copper-binding peptide, GHK-Cu (glycyl-L-histidyl-L-lysine). Anionic (AL) and cationic (CL) hydrogenated lecithin-based liposomes were obtained as GHK-Cu skin delivery systems using the thin-film hydration method combined with freeze-thaw cycles and the extrusion process. The influence of total lipid content, lipid composition and GHK-Cu concentration on the physicochemical properties of liposomes was studied. The lipid bilayer fluidity and the peptide encapsulation efficiency (<i>EE</i>) were also determined. Moreover, in vitro assays of tyrosinase and elastase inhibition were performed. Stable GHK-Cu-loaded liposome systems of small sizes (approx. 100 nm) were obtained. The bilayer fluidity was higher in the case of cationic liposomes. As the best carriers, 25 mg/cm³ CL and AL hydrated with 0.5 mg/cm³ GHK-Cu were selected with <i>EE</i> of 31.7 &#xb1; 0.9% and 20.0 &#xb1; 2.8%, respectively. The obtained results confirmed that the liposomes can be used as carriers for biomimetic peptides such as copper-binding peptide and that the GHK-Cu did not significantly affect the tyrosinase activity but led to 48.90 &#xb1; 2.50% elastase inhibition, thus reducing the rate of elastin degeneration and supporting the structural integrity of the skin.