Cationic Hyperbranched Polymers Research Articles

Preparation of a Cationic Hyperbranched Polymer for Inhibiting Clay Hydration Swelling in the Process of Oilfield Waterflooding

In this paper, preparation and the inhibition properties of a cationic hyperbranched polymer (HBP-HTC) on clay hydration and swelling were researched. The properties of HBP-HTC, including chemical ...

Tumor Microenvironment-Regulated Redox Responsive Cationic Galactose-Based Hyperbranched Polymers for siRNA Delivery.

Tumor microenvironment redox-modulated galactose-based hyperbranched polymers (HRRP) composed of 2-lactobionamidoethylmethacrylamide (LAEMA) and 2-aminoethylmethacrylamide (AEMA) with molecular weights of 10 and 20 kDa and LAEMA:AEMA ratios (L:A) of 1.5 and 1 were prepared via thereversible addition-fragmentation chain transfer (RAFT) polymerization. The remarkable capability of these polymers to respond to the glutathione (GSH) concentration in the tumor environment is the key factor that regulates their cellular internalization and enhances selective siRNA release into the cancer cell cytoplasm. HRRP with a molecular weight of 10 kDa and L:A ratio of 1.5 was capable of forming nanosized polyplexes and achieved around 85% epidermal growth factor receptor (EGFR) silencing in cervical (HeLa) cancer cells in the presence of serum protein without compromising the biocompatibility of the system (around 95% cell viability). The excellent stability of the polyplexes in serumand low cytotoxicity in normal cell lines warrants the use of this redox-responsive galactose-based cationic hyperbranched polymers in gene silencing applications at thepreclinical level.

Achieving Safe and Highly Efficient Epidermal Growth Factor Receptor Silencing in Cervical Carcinoma by Cationic Degradable Hyperbranched Polymers.

Novel cationic hyperbranched polymers were prepared from 2-aminoethyl methacrylate (AEMA) and di(ethylene glycol) methyl ether methacrylate (DEGMA) via the reversible addition-fragmentation chain transfer (RAFT) polymerization for siRNA delivery. Non-degradable and acid-degradable hyperbranched polymers were synthesized using N,N'-methylenebis(acrylamide) (MBAm) and 2,2-dimethacroyloxy-1-ethoxypropane (DEP) cross-linkers, respectively. Both types of polymers were capable of forming very stable nanosized polyplexes with siRNA. Epidermal growth factor receptor (EGFR) silencing of 95% was achieved with the acid degradable cationic hyperbranched polymer, and no significant cytotoxicity was observed. Our results confirmed the high potency of using such hyperbranched polymers for the efficient protection and delivery of siRNA.

Cationic Hyperbranched Polymers with Biocompatible Shells for siRNA Delivery

Cationic hyperbranched polymers (HBP) were prepared by self-condensing vinyl polymerization of an atom transfer radical polymerization (ATRP) inimer containing a quaternary ammonium group. Two types of biocompatible shells, poly(oligoethylene glycol) methacrylate (polyOEGMA) and poly(2-(methylsulfinyl) ethyl methacrylate) (polyDMSO), were grafted respectively from HBP core to form core-shell structures with low molecular weight dispersity and high biocompatibility, polyOEGMA-HBP and polyDMSO-HBP. Both of the structures showed low cytotoxicity and good siRNA complexing ability. The efficacy of gene silencing against Runt-related transcription factor 2 ( Runx2) expression and the long-term assessment of mineralized nodule formation in osteoblast cultures were evaluated. The biocompatible core-shell structures were crucial to minimizing undesired cytotoxicity and nonspecific gene suppression. polyDMSO-HBP showed higher efficacy of forming polyplexes than polyOEGMA-HBP due to shell with lower steric hindrance. Overall, the gene silencing efficiency of both core-shell structures was comparable to commercial agent Lipofectamine, indicating long-term potential for gene silencing to treat heterotopic ossification (HO).

A red-emitting cationic hyperbranched polymer: facile synthesis, aggregation-enhanced emission, large Stokes shift, polarity-insensitive fluorescence and application in cell imaging

A cationic hyperbranched polymer containing TPE units demonstrates bright and stable red-emission with AEE-characteristics and good performance in cell imaging.

Novel degradable oligoethylenimine acrylate ester-based pseudodendrimers for in vitro and in vivo gene transfer

A novel class of cationic hyperbranched polymers, containing branched oligoethylenimine (OEI 800 Da) as core, diacrylate esters as linkers and oligoamines as surface modification, was synthesized and evaluated regarding their structure-activity relationship as gene carriers. We show that pseudodendritic core characteristics as well as different surface modifications on the core influence DNA-binding ability, cytotoxicity and transfection efficiency. As most promising gene carrier, the pseudodendrimer HD O, that is, the OEI 800 Da core modified with hexane-1,6-diol diacrylate and surface-modified with OEI 800 Da, was identified. HD O exhibits efficient DNA-condensing ability to nanosized polyplexes (100-200 nm), low cytotoxicity, a degradation half-life of 3 days at 37 degrees C at physiological pH and in vitro reporter gene-expression levels similar to high molecular weight linear and branched polyethylenimines (PEIs) (LPEI and BPEI). In vivo studies in mice reveal that HD O/DNA polyplexes upon i.v. tail-vein injection have the potential for transfection of tumor tissue at levels comparable to that obtained with LPEI. Importantly, HD O was better tolerated than LPEI, while transgene expression was more tumor-specific and much lower in all other investigated organs, especially in the lung (15,000-fold lower compared with LPEI).

Water Soluble Nanoparticles from PEG-Based Cationic Hyperbranched Polymer and RNA That Protect RNA from Enzymatic Degradation

Recent advances in understanding biological systems have proven that RNA is not merely the carrier of genetic information, but also a key molecule in regulation of gene expression and other crucial metabolic processes. Therefore, it is being considered as an ideal therapeutic candidate both for metabolic and genetic disorders. However, research involving RNA molecules faces a practical limitation since RNA is highly labile. We have developed a novel method to protect RNA from cleavage by complexing it with a hyperbranched cationic polymer. It was found that total cellular RNA isolated from yeast spontaneously interacts with the positively charged polymer to form a spherical nanoparticle morphology. This interaction protects the RNA against enzymatic degradation. This methodology can be easily adapted for long-term storage of RNA, long distance transfer of RNA, and genetic engineering using RNA as a building block.