Engineered Doxorubicin Delivery System Using Proteinoid-Poly (L-Lactic Acid) Polymeric Nanoparticles of Narrow Size Distribution and High Molecular Weight for Cancer Treatment

Abstract

Stella Kiel, Michal Kolitz-Domb, Enav Corem-Salkmon, Igor Grinberg and Shlomo Margel

Doxorubicin (Dox), a widely used anti-cancer drug, was encapsulated within new special-tailored proteinoid nanoparticles (NPs), with the intention to overcome side effects while keeping the drug potency. The synthesis and characterization of four newly-made proteinoids of very high molecular weights (122-149 kDa) and low polydispersity (1.01-1.03) is presented. The proteinoids were synthesized from L-lysine, L-arginine, L-histidine, L-phenylalanine and poly-L-lactic acid (PLLA) segments, and are named P(KRHF-PLLA). Using this selection of amino acids provides basic positive-charged novel tailored proteinoids, with a rigid and biodegradable backbone, achieved by the incorporation of PLLA. The proteinoids self-assemble to yield NPs of a narrow-size distribution. This self-assembly procedure was utilized to encapsulate Dox within the NP core. The optimal Dox-encapsulated NPs were chosen by a study of their size, size distribution and Dox content. The chosen NPs, 15% Dox-loaded P(KRHF-PLLA) NPs were checked for their stability in different conditions. In order to improve tumor uptake and time of circulation in the blood, the chosen NPs were further PEGylated and the effects of PEGylation of the NPs, as well as the effect of the environment, on the release rate of Dox from the NPs were investigated. Additionally, the cytotoxicity of the PEGylated and non-PEGylated Dox-containing NPs was studied by XTT assay and their generation of immune-response was investigated by cytokines induction assay. Overall, the Dox-loaded NPs were found stable, non-immunogenic and showed good cell toxicity, making them good candidates to be used against cancer, while PEGylation improved all parameters.

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