Self-Assembled Oleic Acid-Modified Polyallylamines for Improved siRNA Transfection Efficiency and Lower Cytotoxicity

Abstract

Small interference RNA (siRNA) is a tool for gene modulation, which can silence any gene involved in genetic disorders. The potential of this therapeutic tool is hampered by RNA instability in the blood stream and difficulties to reach the cytosol. Polyamine-based nanoparticles play an important role in gene delivery. Polyallylamine hydrochloride (PAH) is a polycation displaying primary amines that can be easily chemically modified to match the balance between cell viability and siRNA transfection. In this work, PAH has been covalently functionalized with oleic acid at different molar ratios by carbodiimide chemistry. The substituted polymers form polyplexes that keep positive surface charge and fully encapsulate siRNA. Oleic acid substitution improves cell viability in the pulmonary cell line A549. Moreover, 6 and 14% of oleic acid substitution show an improvement in siRNA transfection efficiency. CD47 is a ubiquitous protein which acts as “don’t eat me signal.” SIRPα protein of macrophages recognizes CD47, leading to tumor cell phagocytosis by macrophages. By knocking down CD47 with siRNA, cancer cells become vulnerable to be eliminated by the immune system. PAH–oleic acid substitutes show high efficacy in silencing the CD47 protein, making them a potential candidate for immunotherapy.

Positron Emission Tomography Studies of the Biodistribution, Translocation, and Fate of Poly Allyl Amine‐Based Carriers for Sirna Delivery by Systemic and Intratumoral Administration

“…We believe the reason behind the similarity in overall distribution pattern but with differences in absolute values of concentration of radioactivity is due to the fact that PAH Oleic not complexed with siRNA can be self‐assembled into NPs without siRNA, as we have shown previously. [ 22 ] When we label the siRNA we only trace the fraction of nanoparticles carrying the siRNA. When we label PAH Oleic we trace both the polyplexes and self‐assembled NPs without siRNA.…”

“…[21] NPs made of oleic acid-modified PAH show indeed low toxicity with a transfection efficacy similar to Lipofectamine reagents. [22] In this work, we studied the biodistribution and fate of PAHbased siRNA carriers by PET imaging. siRNAs were radiolabeled with a prosthetic group carrying the positron emitter fluorine-18 ( 18 F).…”

“…[ 21 ] NPs made of oleic acid‐modified PAH show indeed low toxicity with a transfection efficacy similar to Lipofectamine reagents. [ 22 ]…”

Gene Transfection Efficiency Improvement with Lipid Conjugated Cationic Carbon Dots

“…Lipids, compounds containing hydrophilic head groups and hydrophobic tails, have a high affinity to cellular membranes and show abilities for cell membrane destabilization and endosome escape. According to published literature, lipids and their derivatives, especially which are incorporated with unsaturated fatty acid such as oleic acid (OA) as lipid tails, have been widely investigated for gene delivery as nonviral carriers to improve the transfection efficiency. − Thus, in theory, conjugation of lipids with appropriate CCDs can be applied to make CCDs with a good transfection efficiency. To test this hypothesis, the CCDs named as APCDs were first synthesized by a microwave-mediated approach using arginine (Arg) and PEHA as precursors, followed by conjugating with OA.…”