Transfection, the process of introducing foreign nucleic acids into eukaryotic cells, has become a cornerstone of modern molecular biology, biotechnology, and therapeutic development. Since its early experimental roots in the 1960s, transfection has evolved from simple chemical techniques into a sophisticated array of chemical, physical, and viral methods capable of delivering DNA, RNA, and proteins into diverse cell types. This technological evolution has enabled critical advances in gene expression studies, recombinant protein production, gene editing, and cell-based therapies. The following timeline highlights the key milestones in the development and application of transfection technologies, tracing their impact from foundational laboratory research to large-scale industrial and clinical use.
1960s–1970s: Foundations of Gene Transfer
- 1962 – First report of nucleic acid uptake by mammalian cells using DEAE-dextran (chemical method).
- 1973 – First successful gene transfer into mammalian cells using calcium phosphate co-precipitation.
- 1977 – Demonstration of stable gene integration in mammalian cells by Wigler et al., using calcium phosphate transfection.
1980s: Method Development and Early Applications
- 1983 – Introduction of electroporation, a physical method using electrical pulses to increase cell membrane permeability.
- 1984 – Liposome-mediated transfection introduced, allowing for encapsulation of DNA in lipid vesicles for cell delivery.
- 1987 – Development of the first cationic lipid reagents (e.g., Lipofectin), which improved transfection efficiency and reduced toxicity.
- Late 1980s – Transient and stable transfection become standard tools in molecular biology research.
1990s: Rise of Commercial Reagents and Mammalian Systems
- Early 1990s – Launch of optimized commercial reagents (e.g., Lipofectamine, Fugene) improves reproducibility and efficiency.
- Mid-1990s – HEK293 and CHO cells become widely used platforms for recombinant protein expression via transfection.
- Late 1990s – Introduction of PEI (polyethylenimine) for cost-effective transient transfection, enabling large-scale use in suspension cultures.
2000s: Scale-Up and Industrial Use
- 2000–2005 – Optimization of suspension-adapted mammalian cell lines (e.g., HEK293F, CHO-S) for use in bioreactors.
- 2006 – Transient gene expression (TGE) adopted for early-stage therapeutic protein and antibody production.
- Late 2000s – Transfection techniques integrated with high-density cell culture and wave/stirred-tank bioreactors for gram-scale yields.
2010s–Present: Innovation and Expansion
- 2010s – Emergence of gene editing tools (CRISPR/Cas9) and transfection of mRNA/proteins alongside plasmid DNA.
- 2012 – Transfection of mammalian cells used in CAR-T cell manufacturing and personalized therapies.
- 2020–2021 – Transfection technologies contribute to rapid development and production of recombinant protein-based COVID-19 vaccines.
- 2020s – Advances in non-viral delivery systems, automation, and synthetic biology expand the use of transfection in cell therapy and biomanufacturing.
