Enhanced integrin affinity and neural differentiation of induced pluripotent stem cells using Ln5-P4-grafted...

Amphiphilic solid lipid nanoparticles (ASLNs) with surface PPFLMLLKGSTR peptide (Ln5-P4) (Ln5-P4/ASLNs) were prepared to load nerve growth factor (NGF) and retinoic acid (RA) and to guide the differentiation of induced pluripotent stem cells (iPSCs) toward neurons. Beeswax (BW) and lecithin played predominant roles in microemulsion and in the average diameter, zeta potential, encapsulation efficiency of NGF and RA and release kinetics of NGF- and RA-loaded Ln5-P4/ASLNs (Ln5-P4/NGF-RA-ASLNs). An increasing BW weight percentage from 0% to 75% decreased the particle size and zeta potential along with improved encapsulation efficiency of RA and NGF with enhanced positive expression of β-tubulin III to 93.72% in cultured cells. Strong affinity of Ln5-P4/NGF-RA-ASLNs to α₃β₁ integrin expressed on iPSCs facilitated internalization of Ln5-P4/NGF-RA-ASLNs. The capability of Ln5-P4/NGF-RA-ASLNs to induce neuronal differentiation was much higher than that of free NGF-ASLNs and RA-ASLNs, as visualized using immunochemical staining. Flow cytometry analysis indicated that Ln5-P4 on NGF-RA-ASLNs promoted the uptake of NGF and RA by iPSCs and accelerated neuronal production. Ln5-P4/NGF-RA-ASLNs are a promising colloidal delivery system to generate mature neurons from iPSCs and can be potential for treating neurodegenerative disease and nerve injury in regeneration medicine.