Formulation of Peptide‐Based Nanoparticles Using a Microfluidic Device

Peptide-based nanoparticles (PBN) have emerged as a promising alternative to lipid nanoparticles (LNP) for nucleic acid delivery and efficient cellular uptake. In this study, we evaluated the formulation of WRAP5 (W- and R-rich amphipathic peptide 5)-based PBN using a microfluidic device and assessed the impact of key process parameters, flow rate ratio (FRR), total flow rate (TFR), and mixing channel design, on nanoparticle characteristics. Across 72 formulations encapsulating small interfering RNA (siRNA) or plasmid DNA (pDNA), dynamic light scattering revealed consistent mean sizes ranging from 50 to 70 nm, with a low polydispersity index (PdI < 0.22), independent of FRR, TFR, or mixer type. Stability studies demonstrated that siRNA-loaded PBN exhibited moderate size increases during storage at 4°C, whereas pDNA-loaded PBN remained highly stable for up to 70 days. Biological assays confirmed robust activity: WRAP5:siRNA PBN achieved approximately 50% CDK4 silencing in GIST-T1 cells, and WRAP5:pDNA PBN mediated efficient mCHERRY expression in HeLa cells, regardless of formulation method or storage duration. These findings highlight the robustness and scalability of WRAP5-based PBN, contrasting with LNP systems that require stringent control of FRR and TFR, and partially underscore their potential for nucleic acid delivery applications.