Rational design and characterisation of an amphipathic cell penetrating peptide for non-viral gene delivery

RALA is a cationic amphipathic peptide which has shown great promise as an efficient, multifunctional delivery system for the delivery of nucleic acids. Rational peptide design was utilised in this study to understand the essential amino acids required for delivery and if any improvements to the RALA peptide could be made. Six amphipathic peptides were synthesised with strategic sequences and amino acid substitutions to reduce peptide sequence, while maintaining the functional characteristics of RALA including amphipathicity, alpha-helicity and pH responsiveness for endosomal escape. Data demonstrated that all six peptides complexed pEGFP-N1 to produce cationic nanoparticles <200 nm in diameter, but not all peptides resulted in successful transfection; indicating the influence of peptide design for cellular uptake and endosomal escape. Pep2, produced nanoparticles with similar characteristics and transfection efficiency to the parent peptide, RALA. However, Pep2 had issues with toxicity and a lack of pH-responsive alpha-helcity. Therefore, RALA remains the superior sequence for non-toxic gene delivery.

Automated summary

RALA, a cationic amphipathic peptide, has shown promise as an efficient nucleic acid delivery system. Rational peptide design was used to create six amphipathic peptides with potential for nucleic acid delivery, but not all were successful in transfection, highlighting the importance of peptide design for cellular uptake and endosomal escape. Pep2 showed similar characteristics to RALA but had issues with toxicity and lack of pH-responsiveness, making RALA the superior choice for non-toxic gene delivery.