What’s genetic medicine?
Genetic medicine is an approach to drug development wherein nucleic acids, such as DNA and RNA, are used to alter gene expression. Nucleic acids pass instructions into the body, allowing us to treat the root cause of a disease instead of its symptoms. These therapies offer hope for advanced vaccines, cell therapy, immunology, and more. One example is recent COVID-19 mRNA vaccines.
To make a genetic medicine, a strand of nucleic acid is encapsulated in a lipid nanoparticle (LNP). Nucleic acids, such as mRNA, are the active ingredient in nanomedicines, but are fragile and cannot be delivered into the body directly. LNPs prevent the nucleic acid payload (i.e. active ingredient) from being broken down in biological fluids, allow drug accumulation in target tissues, and deliver the nucleic acid payload directly into cells. LNPs are made by mixing ethanol-based lipid solutions with water-based payload solutions in a microfluidic device. Some examples of microfluidic device designs that accomplish this mixing are shown below.
Mixing in microfluidic devices is laminar, forming LNPs with uniform size. These LNPs can then enter the body. LNPs are comprised of three major components that self-assemble around nucleic acids through a mix of electrostatic and hydrophilic/hydrophobic interactions:
- The cationic ionizable lipid grabs nucleic acid while particles are forming, and its composition can be adjusted to control the delivery location of its payload nucleic acid.
- The helper lipids act like “glue” to hold particles together, and are constant between different formulations.
- The PEG lipid is a structural component, which holds particles together, and prevents them from breaking up if they crash together in solution.
