Characterization and compatibility of hydroxyethyl starch–polyethylenimine copolymers for DNA delivery

Abstract

Hydroxyethyl starch (HES) has been proposed as a biodegradable polymer for shielding of DNA polyplexes, where the feasibility of this approach was shown both in vitro and in vivo. In this study, we report on the physicochemical characterization, the in vitro cytocompatibility and hemotoxicity of HES-decorated polyplexes. For this purpose, various HES molecules were coupled to a 22 kDa linear polyethylenimine (LPEI22) to produce a library of nine different HES-PEI conjugates. Particle analysis using dynamic light scattering showed that, neither the molar mass of HES nor the amount of HES in the polyplexes affected the particle diameter, as it was consistently around 70-80 nm. Imaging using atomic force microscopy and transmission electron microscopy showed that, both naked and HESylated polyplexes were in the same size range and had a spherical morphology. Meanwhile, the HES-mediated particle-shielding effect, manifested as reduction in the surface charge, strongly correlated with the molar mass of HES, where the charge decreased linearly with the increase in molar mass. Ethidium bromide binding assay showed that HES-PEI did not negatively affect DNA condensation at N/P ratios higher than 4. HES conjugation also showed a stabilizing effect against salt-induced particle disassembly, and particle aggregation in protein-containing media. Compatibility tests included cellular viability, as well as erythrocyte aggregation and hemolysis assays. HES-PEI conjugates showed lower cytotoxicity, no aggregation, and much lower hemolysis compared to unmodified PEI. In conclusion, these results show that the HES-PEI conjugates are promising gene delivery polymers with favorable physicochemical properties and compatibility profile.

Design and Application of Hybrid Polymer-Protein Systems in Cancer Therapy

“…CKAs can be copolymerized with vinyl monomers to produce functional aliphatic polyesters which are degradable polymers widely used in medical science [52][53][54]. In addition, there are some natural polymer analogs, such as peptides [55] and hydroxyethyl starch (HES) [56], which are degradable in vivo. Various proteins have been conjugated to synthetic polypeptides, and although these peptides are stable, they can be degraded in vivo by proteases.…”

Hydroxyethyl starch based smart nanomedicine

“…To investigate physicochemical characterization, the in vitro cytocompatibility and hemotoxicity of HES-decorated polyplexes, Noga et al prepared a series of HES–PEI conjugates coupled to a 22 kDa linear polyethylenimine (LPEI22). 98 It is noteworthy that various HES-decorated polyplexes had hydrodynamic diameters of approximately 70–80 nm, which meant that the amount of HES in the polyplexes didn't play an important role in the particle diameter. At the same time, the HES-mediated particle shielding effect was manifested by a decrease in surface charge that was strongly correlated to the molar mass of HES, where the charge decreases linearly with increasing molar mass.…”

Cationic Polymers for the Delivery of Therapeutic Nucleotides

“…Efforts have, therefore, been made to develop biodegradable and less toxic polymers with high transfection efficiency . Some modifications for this purpose include hydroxyethyl starch-PEI (Noga et al 2014), poly(vinyl alcohol)-PEI (Goyal et al 2011), and poly(ethyleneimineco-L-lactamide-co-succinamide) (Petersen et al 2002).…”