transfected

Transfected is an adjective describing a cell that has taken up nucleic acids through transfection, a laboratory process used to introduce exogenous DNA or RNA into eukaryotic cells. Transfection is distinct from transformation, which refers to bacterial uptake of DNA, and from transduction, which uses viral vectors to deliver genetic material. In transfection, the nucleic acid may be a plasmid, mRNA, small interfering RNA (siRNA), short hairpin RNA (shRNA), CRISPR components, or other constructs designed to express a gene, silence expression, or edit the genome. Following uptake, expression of the introduced genetic material may be transient or stable, depending on the method and whether the nucleic acid integrates into the genome or persists episomally.

Methods: Chemical transfection uses lipid or polymer reagents forming complexes with nucleic acids to facilitate cellular uptake; physical methods include electroporation, microinjection, and particle delivery. Some cells are hard to transfect and require optimization. Viral-based delivery (transduction) is sometimes contrasted with chemical/physical transfection, though it serves a similar purpose. Efficiency varies by cell type, construct, and reagent, and toxicity must be managed.

Applications: transfection is widely used for gene expression studies, protein localization, functional analyses, screening, production of recombinant proteins, and gene therapy research. Successful transfection is typically evaluated with reporter genes (e.g., GFP) or molecular assays demonstrating DNA, RNA, or protein expression. Safety and biosafety considerations apply, including containment and ethical issues for certain cell types and genetic constructs.