Synthesis of nucleobase-functionalized peptides and investigation on their self-assembly properties with mRNA as cargo.

Non-covalent interactions are crucial in biological systems, e.g. during cell division process, assembly and desassembly of double stranded DNA. Furthermore, interactions between proteins and nucleoacids play important roles during various cell processes. This study focuses on the synthesis and characterization of thymine and lysine-bearing PEG-peptide conjugates, which leverage these interactions for nanoparticle formation. Using solid-phase peptide synthesis (SPPS), we successfully incorporated nucleobases into peptides, enabling complementary base pairing with nucleic acids. The resulting nanoparticles were characterized using transmission electron microscopy (TEM) and dynamic light scattering (DLS), confirming their uniform size and low polydispersity. We investigated the interaction of these nanoparticles with polyA-tail of mRNA. We demonstrated with the example of eGFP-mRNA, effective cellular uptake and transfection capabilities. PEGylated peptide functionalized with 6 Thymine bases, exhibited enhanced stability and transfection efficiency compared to the other variants tested. Cytotoxicity assays indicated favorable biocompatibility across various cell lines. Overall, our findings underscore the potential of nucleopeptides in developing novel gene delivery systems and advancing biotechnological applications.