Cell-Penetrating Peptide-engineered Solid Lipid Nanoparticles for Enhanced Endocytotic Internalization and Transdermal Penetration

Efficient drug delivery across biological barriers remains a fundamental challenge, particularly for rigid nanocarriers whose penetration mechanisms are poorly understood. Here we demonstrate that Laminin-332-functionalized solid lipid nanoparticles (SLN_Lam) overcome cellular barriers through receptor-mediated endocytosis and achieve substantial transdermal penetration. SLN_Lamparticles, engineered via site-specific thiol-maleimide chemistry, maintain crystalline structural integrity while enabling precise surface modification at controlled peptide densities. Biolayer interferometry reveals that binding kinetics correlate directly with α3β1 integrin surface density, confirming molecular recognition as the primary interaction mechanism. Dissipative particle dynamics simulations elucidate interaction energetics, demonstrating adhesion-dependent membrane fusion behavior. Mechanistic studies in HaCaT keratinocytes establish lipid raft-mediated endocytosis as the predominant uptake pathway, with methyl-β-cyclodextrin treatment significantly attenuating internalization while ATP-dependent and clathrin-mediated pathways remain unaffected. Ex vivo analysis using porcine skin demonstrates concentration-dependent cargo delivery enhancement, with mathematical modeling revealing exponential decay kinetics (I(z) = I₀e^-kz) where penetration constants are proportional to Laminin-332 density. These findings establish that receptor-targeted surface engineering enables efficient barrier penetration through specific adhesion mechanisms, providing a robust framework for advancing rigid nanocarrier delivery systems with transformative implications for pharmaceutical and cosmetic applications.