This study highlights lipid nanoparticle (LNP) formulations incorporating DOTMA or DOTAP as cationic lipids for the delivery of mRNA encoding Enhanced Green Fluorescent Protein (eGFP-mRNA). The performance of these tailored formulations was benchmarked against a commercial formulation (LipidFlex®, Precigenome), which can also be combined with DOTMA or DOTAP but contains helper lipids of undisclosed composition. LNPs were synthesized using a microfluidic device equipped with a passive Y-shaped microchip, operating at an optimized total flow rate of 6 mL/min and a flow rate ratio of 1:3, with a total lipid concentration ranging from 0.7 to 30 mM. This method produced Single Unilamellar Vesicles (SUVs) with an average size of 150 ± 53 nm and a surface charge of 18 mV. The nitrogen-to-phosphate (N/P) ratio was varied between 250 and 6, modulating the surface charge (from 48 to 18 mV) and the mRNA-eGFP encapsulation efficiency (from 80 % to 70 %, respectively). Cytotoxicity assays and IC