siRNA delivery mediated by pH and redox responsive p(DEAEMA-co-HEMA-g-PEGMA) nanogels
Martine K. Notabi, Eva C. Arnspang, Nicholas A. Peppas, Morten Østergaard Andersen
Abstract
Small interfering RNAs (siRNA) have enabled novel, specific, and efficient treatment of diseases, including cancer. To obtain sufficient and well-controlled intracellular delivery, a drug delivery system is essential. Herein a delivery system for siRNA, composed of cationic biodegradable nanogels, is presented. P(DEAEMA-co-HEMA-g-PEGMA) nanogels with varying ratios of 2-diethyl aminoethyl methacrylate (DEAEMA) and 2-Hydroxyethyl methacrylate (HEMA), crosslinked with tetraethylene glycol dimethacrylate or disulfide-crosslinker bis(2-methacryloyloxy ethyl), are synthesized. The pH-depended nanogel swelling facilitates siRNA loading and endosomal disruption. The disulfide-crosslinker ensures siRNA release by GSH-mediated particle disassociating. The nanogels are within the sub-100nm range in their collapsed state, have a PDI ≥0.4, and a ζ-potential ranging from approximately 5-10 in the swollen state and 22–30 V in the collapsed state and have a swelling ratio up to 1.6 in diameter. Furthermore, the nanogels show good serum-stability, and are capable of delivering siRNA with acceptable cytotoxicity levels. The nanogels induced >90% eGFP-silencing in lung cancer cells, and gene-silencing of the cancer target POLR2A led to siRNA-induced cell death in squamous carcinoma cells. The findings suggest that the nanogel-system may function as a carrier vehicle for cytoplasmic delivery of siRNA.