2026-10-06T12:37:10Z https://api.figshare.com/v2/oai

oai:figshare.com:article/32805803 2026-10-01T16:12:53Z portal_1172 item_type_8 month_year_10_2026

Design and development of an effective cell penetrating peptide carrier for successful mRNA delivery Andrew Farkas (6409886) PUREID: 689221785 Cell penetrating peptide RALA hydrophobicity helix destablisation nucleic acid alpha-helix beta-methyl branching amino acid Protein modelling The primary objective of this thesis was to examine whether specific amino acid alterations in a well-established cell-penetrating peptide used to form nanoparticles, RALA, improve or hinder the performance in the delivery of nucleic acids. The alterations were based on substituting amino acid residues in the peptide, with respect to side-chain length, the potential for disulphide linkage between separate subunits, hydrophobicity, and α-helix destabilisation. The delivery of nucleic acids for nucleic acid therapy is challenging as physiological barriers must be bypassed. Cell-penetrating peptides have emerged as highly effective candidates, crossing cellular membranes without compromising structural integrity and have demonstrated low cytotoxicity. Over the past decade, RALA, with its cationic nature, has proven to be a highly effective nucleic acid delivery carrier, successfully delivering large amounts of cargo. However, recent research on specific amino acid substitutions in other peptides has shown a performance improvement; therefore, substitutions were made to RALA to establish RALA variants and to observe if they had a beneficial impact. With the RALA variants, one which demonstrated significant improvement was the RALA D variant, which involved substitutions of glutamic acid with aspartic acid, while the possibility of disulphide linkage was maintained. Transfection in NCTC-929s improved by over 20% relative to RALA. Another variant, which showed improvement, included RALA KVIV 3, which suggested that hydrophobic amino acids clustered near the C-terminus improved performance. There was also RALA Isoleucine 2, implying that a β-methyl helix destabilising amino acid, positioned near a terminal end, may improve performance. 2026-10-01T16:12:53Z Text Thesis 10.17034/32805803.v1 https://figshare.com/articles/thesis/Design_and_development_of_an_effective_cell_penetrating_peptide_carrier_for_successful_mRNA_delivery/32805803 All Rights Reserved