Probing Endosomal Escape Using pHlexi Nanoparticles

Abstract

The effective escape of nanocarriers from endosomal compartments of the cell remains a major hurdle in nanomedicine. The endosomal escape of pH-responsive, self-assembled, dual component particles based on poly[2-(diethylamino)ethyl methacrylate)(PDEAEMA) and poly(ethylene glycol)-b-poly[2-(diethylamino)ethyl methacrylate) (PEG-b-PDEAEMA) has been recently reported. Herein, we report that polymer molecular weight (M ) can be used to tune endosomal escape of nanoparticle delivery systems. PDEAEMA of M 7 kDa, 27 kDa, 56 kDa and 106 kDa was synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization and co-assembled with PEG-b-PDEAEMA (16 kDa) via nanoprecipitation. All particles had similar size, displayed pH-responsive behaviour, and low toxicity regardless of molecular weight. Ovalbumin was loaded in the particles to demonstrate loading and release capabilities and as a marker to study internalization and endosomal escape. Association and endosomal escape was found to depend on molecular weight, with enhanced escape observed for high M PDEAEMA: 42% of cells with particle induced endosomal escape for 106 kDa nanoparticles, compared to minimal escape for 7 kDa particles. The results show that a simple variation in molecular weight can enhance the endosomal escape of polymeric carriers, and thus improve their effectiveness for intracellular delivery of therapeutics.

Nanoescapology: progress toward understanding the endosomal escape of polymeric nanoparticles

“…This suggests that release was more likely due to a membrane disrupting or pore‐forming mechanism than complete vesicle rupture. Later work showed that the endosomal escape of these pHlexi particles could be tuned by the molecular weight of the polymer building blocks . This indicates that small variations in nanoparticle properties can also play an important role in cellular behavior.…”

Engineered Polymeric Materials for Biological Applications: Overcoming Challenges of the Bio–Nano Interface

“…This was thought to be by pH-dependent membrane interaction. A major limitation of the current pH-responsive nanoparticle strategies based on membrane interaction is the size of cargo that can escape the endosome, as there are numerous reports of the escape of small cargo but limited examples of large cargo [189,190,191]. Further understanding on strategies to facilitate the endosomal escape of large material are needed to enable the efficient intracellular delivery of biological therapeutics.…”

Understanding Cell Interactions Using Modular Nanoparticle Libraries

“…In a subsequent study, we developed a library of nanoparticles to test the effect of polymer molecular weight on membrane interaction and endosomal escape. [14] A range of PDEAEMA homopolymers were synthesised with molecular weights of 7, 27, 56 and 106 kDa using reversible addition-fragmentation chain transfer (RAFT). These polymers were combined with PEG-b-PDEAEMA of 16 kDa to form nanoparticles using nanoprecipitation.…”