Fluorinated Polyethylenimine and Fluorinated Choline Phosphate Lipids Complex System for Efficient mRNA Delivery to Deep-Seated Tumor Tissues

Efficiently delivering mRNA to the deep-seated cells of diseased tissues for therapeutic purposes remains a significant challenge. To address this, we leveraged the dual hydrophobic properties of fluorine atoms to conjugate fluorinated polyethylenimine (FPEI) with fluorinated choline phosphate (FCP) lipids. When one adjusted the ratio of N/F atoms to 2/1 and a 15% FCP content, the mRNA@FPEI-FCP carrier was optimized, achieving significant circulation and accumulation in deep tumor regions. Compared to control carriers lacking FCP or FPEI, mRNA@FPEI-FCP exhibited a 3.94-fold increase in tumor targeting and a 3.0-fold increase in deep delivery. Delivery of IL-2 mRNA to 4T1 breast tumors resulted in a tumor inhibition rate of 91.9%, with IL-2 levels reaching 149.2 pg/mL and 12.1% of CD4⁺ cells throughout the tumor, with no abnormal blood indexes. This FPEI and FCP composite delivery system demonstrates potent targeting of mRNA delivery to deep tumor tissues.