Fluorescent Magnetopolymersomes: A Theranostic Platform to Track Intracellular Delivery

Abstract

We present a potential theranostic delivery platform based on the amphiphilic diblock copolymer polybutadiene-block-poly (ethylene oxide) combining covalent fluorescent labeling and membrane incorporation of superparamagnetic iron oxide nanoparticles for multimodal imaging. A simple self-assembly and labeling approach to create the fluorescent and magnetic vesicles is described. Cell uptake of the densely PEGylated polymer vesicles could be altered by surface modifications that vary surface charge and accessibility of the membrane active species. Cell uptake and cytotoxicity were evaluated by confocal microscopy, transmission electron microscopy, iron content and metabolic assays, utilizing multimodal tracking of membrane fluorophores and nanoparticles. Cationic functionalization of vesicles promoted endocytotic uptake. In particular, incorporation of cationic lipids in the polymersome membrane yielded tremendously increased uptake of polymersomes and magnetopolymersomes without increase in cytotoxicity. Ultrastructure investigations showed that cationic magnetopolymersomes disintegrated upon hydrolysis, including the dissolution of incorporated iron oxide nanoparticles. The presented platform could find future use in theranostic multimodal imaging in vivo and magnetically triggered delivery by incorporation of thermorepsonsive amphiphiles that can break the membrane integrity upon magnetic heating via the embedded superparamagnetic nanoparticles.

Light-Triggered Polymersome-Based Anticancer Therapeutics Delivery

“…Among the supramolecular architectures, the features of polymersomes make them amenable for simultaneously encapsulating both hydrophilic and hydrophobic cargoes in their core and membrane, respectively, and functionalizing their surface for cell recognition and targeted transport of therapeutic agents [ 14 , 15 , 16 ]. It is achievable, due to the overexpression of specific biomarkers on the cell membrane that interact with functionalized polymeric vesicles, for cargo uptake and release, cell imaging, diagnosis, and theragnostic duties [ 16 , 17 , 18 , 19 , 20 ]. Additionally, the great variety of polymers in type, composition and molecular weight, and formation methodologies contribute to tuning the physicochemical properties of the resulting polymersomes [ 18 , 21 ].…”

Recent Advances in Multimodal Molecular Imaging of Cancer Mediated by Hybrid Magnetic Nanoparticles

“…Dispersion in nanoassemblies (supramolecular assembly). Several studies describing different types of molecular matrices composed of polymers [ 80 , 81 , 82 , 83 , 84 , 86 , 87 , 88 ], lipids [ 76 ], polymer dots (PDots) [ 89 , 90 ], and organic molecules [ 91 , 92 , 93 ] can be encountered in the literature. For example, Chen et al [ 94 ] encapsulated superparamagnetic iron oxide nanoparticles (SPIONs) into liposomes containing PEG, a tumor-targeted peptide (RGD sequence), and ICG (indocyanine green, the only near-infrared dye approved by the Food and Drug Administration (FDA) in the United States for clinical use) ( Figure 9 ) [ 95 ].…”

Luminophore and Magnetic Multicore Nanoassemblies for Dual-Mode MRI and Fluorescence Imaging

“…The use of magneto-fluorescent nanoassemblies provides generally biodegradable systems that advantageously avoid bioaccumulation. In this context, several molecular matrices are envisaged composed of polymers [151][152][153][154][155][156][157][158][159], lipids [160][161][162][163], PDots [164][165][166][167] or organic molecule [168][169][170][171][172] ( Figure 6). In this type of organization we will distinguish the assemblies with inert matrices of those composed of active units.…”