Microfluidics-mediated spatial control of mRNA lipid nanoparticles primes translation and enhances vaccine potency.

Despite the success of mRNA lipid nanoparticle therapeutics, bottlenecks persist in limited cellular expression and uncontrolled encapsulation and release kinetics. Here we introduce a microfluidics-based method, MIMAC (microfluidic integrated mRNA amplification circuit), that restructures preformed lipid nanoparticles by inserting a metabolic enhancing RNA to an internal peripheral compartment while relocating the therapeutic RNA towards the core. Rapid shear-mediated reorganization generates a defined peripheral-to-core RNA arrangement that enables sequential cytosolic availability: early release of the metabolic RNA elevates ATP levels up to 4.2-fold and enhances following translation of the therapeutic RNA. The approach is compatible with multiple nucleic acid types-including linear, circular and self-amplifying RNA and plasmid DNA-and with varied lipid formulations. In mice, the structured lipid nanoparticles improve a human papillomavirus cancer vaccine, suppressing tumour growth by 89.2% and increasing survival. Applied to SARS-CoV-2 vaccines, our method boosts antibody titres by 62.3- to 174.8-fold while maintaining potency at one-tenth the dose. A benchtop device produces 200 doses per hour, supporting scalable use.