Transfection involves the incorporation of nucleic acids (DNA & RNA) into various cells with the help of artificial procedures. Brain transfection is the incorporation of nucleic acids into the neuronal cells or endothelial cells of brain capillaries. Transfection is done with the help of nonviral means. Transfection is important for the investigation of the various aspects of neuronal cell biology. Transfection explores the function of genes and their proteins by knocking down our target genes and proteins respectively using microRNAs and RNA interference (RNAi), tracks cellular and subcellular locations of the proteins, analyzes the functions of particular domains of a protein, and minimizes the disease complexities.  Brain transfection can also detect the level of gene expression using various reporter proteins