ROS responsive polyethylenimine-based fluorinated polymers for enhanced transfection efficiency and lower cytotoxicity

Abstract

Cationic polymer polyethylenimine (PEI) plays a crucial role in gene delivery. However, high molecular weight PEI leads to higher efficient transfection efficacy and higher cytotoxicity while low molecular weight PEI exhibits lower transfection performance with lower toxicity. Therefore, effective chemical modification of PEI is required to enhance transfection activity and improve biocompatibility. Here, reactive oxygen species (ROS) responsive PEI-based fluorinated polymers (TKPF) with three degrees of fluorination (TKPF12.5%, TKPF25% and TKPF50%) were designed and synthesized by crosslinking low molecular weight PEI (PEI 1.8K) with a thioketal (TK) linker and then modifying heptafluorobutyric anhydride onto their surface. Such gene vectors exhibited the following features: (1) fluorination reduced the positive charge density and endowed hydrophobic and lipophobic characteristics to resist serum interactions; (2) The fluorophilic effect mediated efficient cellular uptake and endosomal escape; (3) ROS-responsive TK linker allowed the polyplex disassembly to decrease the cytotoxicity of the polycations and improve the release of payloads at specific sites. TKPFs attained superior transfection efficiency in multiple cell lines (293TN cells and B16F10 cells) in vitro and showed excellent biocompatibility. Notably, TKPFs also exhibited great serum resistance in gene delivery and TKPF50% transfected nearly 80% cells in the presence of 70% FBS. These results demonstrates that the fluorination and ROS responsiveness combined polycations are excellent gene-delivery vectors with serum-resistant capacity for further application.

Microneedle-assisted dual delivery of PUMA gene and celastrol for synergistic therapy of rheumatoid arthritis through restoring synovial homeostasis

“…The fabrication process of TPH and CH nanocomplex is illustrated in Scheme 1 . For the construction of TPH nanocomplex, ROS-responsive polyethylenimine-based fluorinated polymers ( TK PF) was first synthesized by crosslinking PEI 1.8 K with the thioketal linker, followed by the modification of heptafluorobutyric anhydride to obtain the thioketal-crosslinked fluorinated polyethyleneimine as our previous work reported [ 19 , 20 ]. The binary nanocomplex was obtained via electrostatic interactions by mixing the cationic polymer TK PF and negatively charged PUMA plasmid at the ratio of 10:1, which showed a particle size of 168 ± 4 nm with polydispersity index (PDI) of 0.26 ± 0.02) and a positive zeta potential of +33.1 ± 1.2 mV ( Fig.…”

“…TK PF was synthesized as our group previously reported [ 19 , 20 ]. To prepare binary TK PF/pDNA NCs, pDNA (250 μg/mL) was mixed with TK PF (5 mg/mL) at a mass ratio of 10:1 and incubated for a duration of 30 min.…”

“…Delivering proapoptotic gene PUMA via viral vectors has been proven to be an effective apoptotic therapy for RA FLS [ 14 , 15 ], but the actual therapeutic efficacy of gene therapy based on viral vectors is restricted by the carcinogenesis, immunogenicity and limited packaging capacity [ [16] , [17] , [18] ]. Our group has developed a reactive oxygen species (ROS) responsive polyethylenimine-based fluorinated polymers ( TK PF) for the delivery of gene drugs and has been used for cancer therapy [ 19 , 20 ], which could overcome the limitations of viral vectors and realized enhanced transfection efficiency and decreased cytotoxicity. Thus, developing non-viral gene vectors based on TK PF with enhanced stability, controlled payload release, and increased transfection capacity to regulate RA FLS is promising for RA gene therapy.…”

The menace of severe adverse events and deaths associated with viral gene therapy and its potential solution

“…360 PEI cytotoxicity can also be reduced via crosslinking low molecular mass PEI, which is considered to be less cytotoxic, with biodegradable linkers. Hua et al 361 synthesized a polymer that consists of low molecular mass (1.8 kDa) PEI crosslinked with reactive oxygen species (ROS)-responsive thioketal linker, which undergoes degradation in the cytoplasm. This crosslinked polymer was shown to be less cytotoxic than 25 kDa PEI.…”