Preparation and In Vitro Evaluation of Elastic Nanoliposomes for Topical Delivery of Highly Skin-Permeable Growth Factors.

Percutaneous delivery of growth factors is often used to treat wounds, and for cosmetic purposes, as a way of accelerating healing and skin regeneration, respectively. However, the therapeutic effects of growth factors are diminished by their poor absorption when delivered percutaneously, in addition to their rapid degradation by proteinases. To overcome these obstacles, we constructed two skin-permeable compounds. Basic fibroblast growth factor (bFGF) and vascular endothelial growth factor-A (VEGF-A) were both genetically paired with low-molecular-weight protamine (LMWP), to yield the compounds LMWP-bFGF and LMWP-VEGF-A, respectively. The molecular weights and N-terminal amino acid sequences of LMWP-bFGF and LMWP-VEGF-A confirmed that the N-terminus-specific conjugation of LMWP with bFGF and VEGF-A had been successful. The biological abilities of the native factors to stimulate human fibroblast (CCD-986sk) and endothelial cell proliferation were preserved. Both compounds significantly promoted wound (scratch) recovery and enhanced procollagen type I C-peptide synthesis in CCD-986sk cells (to levels 184 and 133% those of the native compounds, respectively). The LMWP-conjugated growth factors were significantly more permeable than the native forms (by 7.29- and 29.22-fold, respectively). Finally, encapsulation of the compounds in positively charged elastic nanoliposomes (115 ± 1.54 nm in diameter with a zeta potential of 57.2 ± 3.05 mV) further improved both permeation and stability. Thus, nanoliposomes loaded with LMWP-conjugated growth factors are expected to enhance skin regeneration; the materials will find applications in wound-healing therapies and anti-wrinkle cosmetics.