Water soluble poly(histamine acrylamide) with superior buffer capacity mediates efficient and nontoxic in vitro gene transfection

Abstract

Water-soluble cationic polymers, poly(histamine acrylamide)s (PHAs), with superior buffer capacity at the endosomal pH range were designed, prepared, and investigated for non-viral gene transfection. PHAs were obtained with molecular weights ranging from 9.2 to 28.7 kDa through controlled radical polymerization of histamine acrylamide (HA). Acid-base titration results displayed that all PHA polymers had a remarkably high buffer capacity of about 70% at pH 5.1-7.2. 12.7-28.7 kDa PHAs were able to effectively condense DNA into nanosized (<220 nm) polyplexes with moderate positive surface charges (þ13-þ19 mV) at N/P ratios !10/1. CCK assays indicated that polyplexes of 12.7 and 17.5 kDa PHAs were nontoxic to COS-7 cells up to a tested N/P ratio of 20/1. Interestingly, the in vitro transfection using pCMV-Luc and pEGFP-C1 plasmid DNA as reporter genes showed that polyplexes of 12.7 kDa PHA formed at an N/P ratio of 20/1 mediated efficient transfection in COS-7 cells under 10% serum conditions, with transfection efficiencies comparable to that of 25 kDa polyethylenimine control. Their versatile design of structures, controlled synthesis, low cytotoxicity, and high transfection activity render PHA-based cationic polymers particularly interesting for the development of safe and efficient non-viral gene delivery systems.

Histamine-functionalized copolymer micelles as a drug delivery system in 2D and 3D models of breast cancer

“…51 The fact that histamine has a pKa in a physiological relevant pH range (6.0–7.4) in combination with its biocompatibility makes it highly useful in a number of biomedical applications. 44, 50, 60, 61 For instance, Wooley et al 44 developed histamine-containing shell cross-linked NPs for siRNA delivery and found that the histamine content contributed to reduced cytotoxicity and assisted in endosomal escape. Liu et al 50 utilized an amphiphilic chondroitin sulfatehistamine conjugate to achieve pH-triggered doxorubicin (DOX) release in vitro .…”

Endosomal escape and siRNA delivery with cationic shell crosslinked knedel-like nanoparticles with tunable buffering capacities

“…One way to circumvent these challenges is to complex the negatively-charged siRNA with positively-charged lipids/polymers, where electrostatic interactions between siRNA and cationic carriers result in the formation of positively-charged nanocomplexes, which partially protect the siRNA against degradation and enhance cellular uptake [9–12]. In addition, several types of membrane disruptive polymers and imidazole-containing polymers have been investigated to facilitate escape from the endosomes and achieve efficient transportation of genetic materials into the cytosol [13–18]. In particular, imidazole-containing polymers have gained much attention recently, as they exhibit p K a ~6 and can undergo protonation in the acidic endosomal environment leading, eventually, to efficient endosomal disruption [17,18].…”

“…In addition, several types of membrane disruptive polymers and imidazole-containing polymers have been investigated to facilitate escape from the endosomes and achieve efficient transportation of genetic materials into the cytosol [13–18]. In particular, imidazole-containing polymers have gained much attention recently, as they exhibit p K a ~6 and can undergo protonation in the acidic endosomal environment leading, eventually, to efficient endosomal disruption [17,18]. …”

Poly[N-(2-aminoethyl)ethyleneimine] as a New Non-Viral Gene Delivery Carrier: The Effect of Two Protonatable Nitrogens in the Monomer Unit on Gene Delivery Efficiency

“…The buffer capacity of PFEEI and PAEEI was determined by an acid-base titration method (39,40).In short, the polymers were dissolved at a concentration of 50 mM of theoretical protonatable nitrogen atoms in 150 mM NaCl. The pH of the obtained solutions (10 mL) was adjusted to 2.0 using 1.0 M HCl to protonate almost all nitrogen atoms (41).…”