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bioRxiv · 10.1101/2025.04.25.650611

Hydrophobic Ion Pairing for Simple, Non-Toxic Transfection

Gray, M. A.·Seeler, M.·Montoya, C.·Park, J.·Mai, L. D.·Whitehead, K. A.·Champion, J. A.
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Abstract

Although biomacromolecules require intracellular delivery for therapeutic effect, existing transfection agents are often characterized by high cost, low efficiency, and/or cytotoxicity. Here, we describe a new transfection approach based on hydrophobic ion pairing (HIP), which involves the simple mixing of a hydrophobic counterion with charged biomacromolecules. Among tested cargoes (proteins, siRNA, and pDNA), the HIP siRNA system performed especially well, achieving silencing in fibroblasts (80%), T cells (90%), and neurons (70%). HIP siRNA was also highly potent in mice, with tropism dependent on the route of administration. Most notably, intraperitoneal administration enabled [~]40% LAMP-1 knockdown in the pancreas, and intravenous delivery resulted in a remarkable 80% silencing in the heart. Heart delivery was also highly selectively, with no significant knockdown in the liver. Together, these data demonstrate a new, inexpensive approach to biomacromolecular delivery with the potential to target difficult-to-transfect organs, thus expanding the therapeutic potential of nucleic acids.

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Gray, M. A., Seeler, M., Montoya, C., Park, J., Mai, L. D., Whitehead, K. A., Champion, J. A.. 2025-04-28. Hydrophobic Ion Pairing for Simple, Non-Toxic Transfection. https://doi.org/10.1101/2025.04.25.650611

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