A new proton sponge polymer synthesized by RAFT polymerization for intracellular delivery of biotherapeutics

Abstract

A spermine-like polymer was synthesized via reversible addition-fragmentation chain transfer polymerization as a potential endosomal escaping agent. A new methacrylate monomer, 2-((tertbutoxycarbonyl)(2-((tert-butoxycarbonyl)amino)ethyl)amino)ethylmethacrylate (BocAEAEMA), was prepared and then polymerized via RAFT polymerization at constant monomer or initiator concentration increase in M n with monomer conversion was also observed. P(BocAEAEMA)s with controlled molecular weights and narrow molecular weight distributions were obtained. The in vitro cytotoxicity and proton sponge capacity of deprotected polymers P(AEAEMA) were investigated in comparison with a widely used endosomal-disruptive polymer, PEI. P(AEAEMA)s were found to possess proton sponge capacity comparable with PEI. More importantly, P(AEAEMA)s were not toxic on NIH 3T3 cells at concentrations where PEI (25 kDa) was highly toxic (0.4 mM and above). P(AEAEMA) was able to fully condense a DNA fragment at nitrogen/phosphate (N/P) ratios of 10 and above, as evidenced by gel electrophoresis. P(BocAEAEMA) was then chain-extended with a model sugar monomer, mannose-acrylate (ManAc), to yield P(AEAEMA)-b-P(ManAc) block copolymers, to potentially provide cell-recognition ability to the polyplex particles. Although the presence of the P(ManAc) block partially inhibited the interaction of P(AEAEMA) with DNA, P(AEAEMA) 13 -b-P(ManAc) 7 was able to form polyplexes with DNA at N/P ratios ranging between 20/1 and 2/1. Dynamic light scattering measurements showed that while P(AEAEMA) (M n ¼ 5.5 kDa) and DNA formed polyplex particles having a hydrodynamic diameter (D h ) of 125 AE 51 nm, P(AEAEMA) 13 -b-P(ManAc) 7 and DNA formed particles with a smaller D h of 38 AE 10 nm.

RAFT made methacrylate copolymers for reversible pH‐responsive nanoparticles

“…Three different commercially available amino methacrylates that have tertiary (DMAEMA), secondary ( t BAEMA) and protonated primary amine functionalities (AEMA · HCI) were used as comonomers. The utilized CTA CPADB has previously been successfully applied to mediate the RAFT polymerization of amino methacrylates . [M]/[CTA] was kept constant at a ratio of 100/1 with a monomer concentration of 2 mol L −1 in order to obtain relatively low molar mass polymers, considering the increased toxicity of high molar mass polycations .…”

“…A series of amino-functionalized PMMA based copolymers was synthesized via RAFT polymerization due to its versatility and suitability for the synthesis of well-defined amino methacrylate copolymers. 28,29 Three different commercially available amino methacrylates that have tertiary (DMAEMA), secondary (tBAEMA) and protonated primary amine functionalities (AEMAÁHCI) were used as comonomers. The utilized CTA CPADB has previously been successfully applied to mediate the RAFT polymerization of amino methacrylates.…”

“…The utilized CTA CPADB has previously been successfully applied to mediate the RAFT polymerization of amino methacrylates. 29,30 [M]/[CTA] was kept constant at a ratio of 100/1 with a monomer concentration of 2 mol L 21 in order to obtain relatively low molar mass polymers, considering the increased toxicity of high molar mass polycations. 31 Depending on previous research in our group, the [CTA]/[AIBN] ratio was kept at 1/0.25 regarding polymerization rate and control over the molar mass.…”

Degradable Ketal-Based Block Copolymer Nanoparticles for Anticancer Drug Delivery: A Systematic Evaluation

“…52,53,54 Compared to other controlled radical polymerizations (CRP), such as nitroxide-mediated polymerization (NMP) and atom transfer radical polymerization (ATRP), RAFT polymerization excels in its versatility. 55,56,57 A wide variety of (functional) monomers can be prepared by RAFT polymerization in different solvents under mild reaction conditions. Finally, the technique' s high end-group fidelity at reasonably high conversion (80 %) offers the opportunity for pre-and post-functionalization, e.g.…”

Controlled release of anticancer drug Paclitaxel using nano-structured amphiphilic star-hyperbranched block copolymers

“…Their controllable size distributions also make it possible to obtain macromolecules small enough to penetrate vascular defects of solid tumor as well as large enough to prevent renal clarification permitting longer bioavailability 10,13 . Besides, they are suitable to be further modified for targeting and/or imaging purposes 14,15,16,17 . In our previous study, we have shown that PMMA-b-PHEMA micelles can further be modified with arginylglycylaspactic acid (RGD) and Trans-Activator of Transcription (TAT) peptide to enhance cell selectivity and membrane penetration properties 7 which is similar to peptide modified conducting polymer structures in the field of biobased covering materials 18,19 .…”