Transfection is a laboratory technique used to introduce foreign genetic material, such as DNA or RNA, into cells. This process allows researchers to study gene function, protein expression, and cellular responses. Transfection can be achieved through various methods, including chemical, physical, and viral approaches, each with its own advantages and limitations. The success of transfection depends on factors like the type of cells being targeted and the method used. Common applications of transfection include gene therapy, vaccine development, and the production of recombinant proteins. Overall, transfection is a crucial tool in molecular biology and biotechnology research.