Related Experiment Video
Updated: Aug 7, 2026
Porous Silicon Microparticles for Delivery of siRNA Therapeutics
Published on: January 15, 2015
Biophysical and structural characterization of polyethylenimine-mediated siRNA delivery in vitro
Amy C Richards Grayson1, Anne M Doody, David Putnam
1Department of Biomedical Engineering, The School of Chemical and Biomolecular Engineering, 270 Olin Hall, Cornell University, Ithaca, New York 14853, USA.
Purpose:
The goals of this study were as follows: 1) to evaluate the efficacy of different polyethylenimine (PEI) structures for siRNA delivery in a model system, and 2) to determine the biophysical and structural characteristics of PEI that relate to siRNA delivery.
Materials And Methods:
Biophysical characterization (effective diameter and zeta potential), cytotoxicities, relative binding affinities and in vitro transfection efficiencies were determined using nano-complexes formed from PEI's of 800, 25,000, (both branched) and 22,000 (linear) molecular weights at varying N:P ratios and siRNA concentrations. The HR5-CL11 cell line stably expressing luciferase was used as a model system in vitro.
Results:
Successful siRNA delivery was observed within a very narrow window of conditions, and only with the 25,000 branched PEI at an N:P ratio of 6:1 and 8:1 and with 200 nM siRNA. While the zeta potential and size of PEI:siRNA complexes correlated to transfection efficacy in some cases, complex stability may also affect transfection efficacy.
Conclusions:
The ability of PEI to transfer functionally active siRNA to cells in culture is surprisingly dependent on its biophysical and structural characteristics when compared to its relative success and ease of use for DNA delivery.
More Related Videos
09:09Preparation of Neutrally-charged, pH-responsive Polymeric Nanoparticles for Cytosolic siRNA Delivery
Published on: May 2, 2019
09:36Polyethyleneimine-coated Iron Oxide Nanoparticles as a Vehicle for the Delivery of Small Interfering RNA to Macrophages In Vitro and In Vivo
Published on: February 5, 2019
Related Concept Videos
02:30siRNA - Small Interfering RNAs
In the cytoplasm, siRNA is processed from a double-stranded RNA, which comes from either endogenous DNA transcription or exogenous sources like a virus. This double-stranded RNA is then cleaved by the ATP-dependent...
02:15Experimental RNAi
01:23RNA Interference
This process occurs naturally in cells, often through the activity of genomically-encoded microRNAs. Researchers can take advantage of this mechanism by introducing synthetic RNAs to deactivate specific genes for research or therapeutic purposes. For example, RNAi could be used...