An Intracellular pH-Actuated Polymer for Robust Cytosolic Protein Delivery

Abstract

Robust cytosolic protein delivery requires both efficient protein binding with delivery vehicles and effective protein release after cell internalization. Although a variety of stimuli-responsive carriers have been designed, simultaneously integrating these two functions in one versatile carrier is challenging. Herein, we developed a polyamidoamine (PAMAM)-based polymer with an intracellular pHactuated hydrophobic-to-hydrophilic transition for this purpose. The polymer (designated as G5-C4) was synthesized by appending N,Ndibutylaminoethyl moieties to the peripheral amino groups of PAMAM dendrimer generation 5. Assisted by hydrophobic interactions, G5-C4 formed condensed nanoparticles with proteins and remained stable under physiological conditions. After efficient cell internalization, G5-C4 underwent a hydrophobic-to-hydrophilic transition at acidic endosomal pH, and thus promoted protein release and endosomal escape, which was verified by structure-activity relationship studies. Furthermore, both in vitro and in vivo studies indicated that G5-C4 achieved superior antitumor effect. This study provides a simple but effective design for stimuliresponsive cytosolic protein delivery.

Modulation of Conformational Transition of Polypeptides under Slightly Acidic Environment†

“…CDI activated diethylaminoethanol (CDI‐DE) was synthesized by a literature procedure. [ 11 ] mPEG 44 ‐PLys 86 (200 mg) was dissolved in DMF (5.0 mL), and then CDI‐DE (1.0 g) and triethylamine (100 μL) were added. The mixture was allowed to stir for 12 h at room temperature.…”

Stimuli-responsive nanoformulations for CRISPR-Cas9 genome editing

“…85% tumor inhibition was achieved in a hepatocellular carcinoma (HCC) mouse model. Xu et al [120] synthesized polyamidoamine (PAMAM) -based polymer for cytosolic delivery of protein, including CRISPR-Cas9 RNP. The incorporation of N-dibutylaminoethyl moieties strengthened the binding affinity of proteins with the hydrophobic moieties in the N,Ndialkylaminoethyl modified polymers.…”

Histidine-based coordinative polymers for efficient intracellular protein delivery via enhanced protein binding, cellular uptake, and endosomal escape

“…Besides, amphiphilic polymers were constructed to encapsulate native proteins and form stable complexes via supramolecular self-assembly. [24][25][26] The complex stability was further improved via stimuli-respon-sive cross-linking among the polymers, by which efficient cytosolic protein delivery was achieved in vivo. 27 After endocytosis, entrapment of the complexes in the endosomal-lysosomal system is another major obstacle for the existing carriers.…”