2.8. In vivo gene expression
Two groups of young BALB/c mice (n = 6) were injected with either 1.8 µg of naked pEGFP or 1.8 µg of pEGFP delivered via nanoparticle formulation. Both groups of mice were injected intraperitoneally. Seven days post-injection, mice were sacrificed and their lungs, livers, spleens and lymph nodes were harvested under aseptic conditions. The tissue extracts were prepared in PBS by homogenization and centrifugation (12,000 rpm/4 °C). The tissue homogenates were assayed for total protein using Lowry’s method. Each tissue was normalized for protein and assayed for the expressed green fluorescence protein (GFP) using fluorimeter (excitation filter 365 nm and emission filter 510 nm). The background fluorescence (RFU) obtained from the tissue homogenates of untreated mice was subtracted from the RFU obtained from each of the tissue homogenates of pEGFP treated mice.