In vivo transfection is the process of introducing foreign genetic material, such as DNA or RNA, into living organisms, typically for the purpose of studying gene function, disease modeling, or gene therapy. In contrast to in vitro transfection, which occurs in cultured cells, in vivo transfection occurs within a living organism, such as a mouse or other laboratory animal. This approach provides a more physiologically relevant context for studying the effects of genetic manipulation.
There are several methods available for in vivo transfection:
- Viral vectors: These are engineered viruses that have been modified to deliver genetic material to the target cells within an organism. Examples include adeno-associated viruses (AAV), lentiviruses, and adenoviruses. Viral vectors have high transduction efficiency and can be used to achieve stable gene expression.
- Non-viral methods: These include physical and chemical methods that do not rely on viral vectors for delivery. Examples are:a. Lipid-based nanoparticles: These nanoparticles can encapsulate DNA or RNA and facilitate their entry into target cells in vivo. Examples include liposomes and lipid nanoparticles (LNPs).b. Electroporation: This technique uses an electrical field to create temporary pores in the cell membrane, allowing genetic material to enter target cells within the living organism.c. Hydrodynamic injection: A method that involves rapid, high-pressure injection of a large volume of a solution containing the genetic material into the bloodstream or directly into an organ, which can result in efficient gene delivery to target cells.
- Gene editing tools: CRISPR/Cas9, TALENs, and zinc-finger nucleases (ZFNs) can also be used for in vivo genome editing. These tools can be delivered using viral or non-viral methods, allowing for targeted modification of the host organism’s genome.
Each of these methods has its advantages and limitations, and the choice of method depends on factors such as the target cell type, the desired duration of gene expression, the size of the genetic material to be delivered, and the organism in which the study is being conducted. Additionally, ethical considerations, especially in the case of human subjects, must be taken into account when designing and conducting in vivo transfection experiments.