title: Augmented cellular trafficking and endosomal escape of porous silicon nanoparticles via zwitterionic bilayer polymer surface engineering.
abstract: The development of a stable vehicle with low toxicity, high cellular internalization, efficient endosomal escape, and optimal drug release profile is a key bottleneck in nanomedicine. To overcome all these problems, we have developed a successful layer-by-layer method to covalently conjugate polyethyleneimine (PEI) and poly(methyl vinyl ether-co-maleic acid) (PMVE-MA) copolymer on the surface of undecylenic acid functionalized thermally hydrocarbonized porous silicon nanoparticles (UnTHCPSi NPs), forming a bilayer zwitterionic nanocomposite containing free positive charge groups of hyper-branched PEI disguised by the PMVE-MA polymer. The surface smoothness, charge and hydrophilicity of the developed NPs considerably improved the colloidal and plasma stabilities via enhanced suspensibility and charge repulsion. Furthermore, despite the surface negative charge of the bilayer polymer-conjugated NPs, the cellular trafficking and endosomal escape were significantly increased in both MDA-MB-231 and MCF-7 breast cancer cells. Remarkably, we also showed that the conjugation of surface free amine groups of the highly toxic UnTHCPSi-PEI (Un-P) NPs to the carboxylic groups of PMVE-MA renders acceptable safety features to the system and preserves the endosomal escape properties via proton sponge mechanism of the free available amine groups located inside the hyper-branched PEI layer. Moreover, the double layer protection not only controlled the aggregation of the NPs and reduced the toxicity, but also sustained the drug release of an anticancer drug, methotrexate, with further improved cytotoxicity profile of the drug-loaded particles. These results provide a proof-of-concept evidence that such zwitterionic polymer-based PSi nanocomposites can be extensively used as a promising candidate for cytosolic drug delivery.
authors.affiliation: Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, FI-00014 Helsinki, Finland. Electronic address: m.a.shahbazi@helsinki.fi.
authors.forename: Mohammad-Ali
authors.initials: MA
authors.lastname: Shahbazi
authors.affiliation: Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, FI-00014 Helsinki, Finland.
authors.forename: Patrick V
authors.initials: PV
authors.lastname: Almeida
authors.affiliation: Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, FI-00014 Helsinki, Finland; Laboratory of Industrial Physics, Department of Physics and Astronomy, University of Turku, FI-20014, Finland.
authors.forename: Ermei M
authors.initials: EM
authors.lastname: Mäkilä
authors.affiliation: Laboratory of Industrial Physics, Department of Physics and Astronomy, University of Turku, FI-20014, Finland.
authors.forename: Martti H
authors.initials: MH
authors.lastname: Kaasalainen
authors.affiliation: Laboratory of Industrial Physics, Department of Physics and Astronomy, University of Turku, FI-20014, Finland.
authors.forename: Jarno J
authors.initials: JJ
authors.lastname: Salonen
authors.affiliation: Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, FI-00014 Helsinki, Finland.
authors.forename: Jouni T
authors.initials: JT
authors.lastname: Hirvonen
authors.affiliation: Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, FI-00014 Helsinki, Finland. Electronic address: helder.santos@helsinki.fi.
authors.forename: Hélder A
authors.initials: HA
authors.lastname: Santos
mesh_terms: D000964:Antimetabolites, Antineoplastic / Q000008:administration & dosage* / Q000494:pharmacology; D001943:Breast Neoplasms / Q000188:drug therapy; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D003692:Delayed-Action Preparations / Q000737:chemistry / Q000378:metabolism*; D011992:Endosomes / Q000378:metabolism*; D005260:Female; D006801:Humans; D007477:Ions / Q000737:chemistry / Q000378:metabolism; D061986:MCF-7 Cells; D008298:Maleates / Q000737:chemistry / Q000378:metabolism*; D008727:Methotrexate / Q000008:administration & dosage* / Q000494:pharmacology; D053758:Nanoparticles / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D011094:Polyethyleneimine / Q000737:chemistry / Q000378:metabolism*; D011095:Polyethylenes / Q000737:chemistry / Q000378:metabolism*; D011108:Polymers; D016062:Porosity; D012825:Silicon; D013499:Surface Properties
chemical_list: D000964:Antimetabolites, Antineoplastic; D003692:Delayed-Action Preparations; D007477:Ions; D008298:Maleates; D011095:Polyethylenes; D011108:Polymers; D011094:Polyethyleneimine; C043105:poly(methyl vinyl ether-co-maleic anhydride); D008727:Methotrexate; D012825:Silicon
keywords: Cellular uptake; Endosomal escape; Poly(methyl vinyl ether-co-maleic acid); Polyethyleneimine; Porous silicon nanoparticles; Surface functionalization