title: Intracellular guest exchange between dynamic supramolecular hosts.
abstract: Decyl and oligo(ethylene glycol) chains were appended to the same poly(methacrylate) backbone to generate an amphiphilic polymer with a ratio between hydrophobic and hydrophilic segments of 2.5. At concentrations greater than 10 μg mL(-1) in neutral buffer, multiple copies of this particular macromolecule assemble into nanoparticles with a hydrodynamic diameter of 15 nm. In the process of assembling, these nanoparticles can capture anthracene donors and borondipyrromethene acceptors within their hydrophobic interior and permit the transfer of excitation energy with an efficiency of 95%. Energy transfer is observed also if nanocarriers containing exclusively the donors are mixed with nanoparticles preloaded separately with the acceptors in aqueous media. The two sets of supramolecular assemblies exchange their guests with fast kinetics upon mixing to co-localize complementary chromophores within the same nanostructured container and enable energy transfer. After guest exchange, the nanoparticles can cross the membrane of cervical cancer cells and bring the co-entrapped donors and acceptors within the intracellular environment. Alternatively, intracellular energy transfer is also established after sequential cell incubation with nanoparticles containing the donors first and then with nanocarriers preloaded with the acceptors or vice versa. Under these conditions, the nanoparticles exchange their cargo only after internalization and allow energy transfer exclusively within the cell interior. Thus, the dynamic character of such supramolecular containers offers the opportunity to transport independently complementary species inside cells and permit their interaction only within the intracellular space.
authors.affiliation: Laboratory for Molecular Photonics, Department of Chemistry, University of Miami , 1301 Memorial Drive, Coral Gables, Florida 33146-0431, United States.
authors.forename: Subramani
authors.initials: S
authors.lastname: Swaminathan
authors.forename: Colin
authors.initials: C
authors.lastname: Fowley
authors.forename: Bridgeen
authors.initials: B
authors.lastname: McCaughan
authors.forename: Janet
authors.initials: J
authors.lastname: Cusido
authors.forename: John F
authors.initials: JF
authors.lastname: Callan
authors.forename: Françisco M
authors.initials: FM
authors.lastname: Raymo
mesh_terms: D000873:Anthracenes / Q000737:chemistry; D002462:Cell Membrane / Q000378:metabolism; D004735:Energy Transfer; D006367:HeLa Cells; D006801:Humans; D053758:Nanoparticles; D011092:Polyethylene Glycols / Q000737:chemistry*; D011109:Polymethacrylic Acids / Q000737:chemistry*; D011162:Porphobilinogen / Q000031:analogs & derivatives / Q000737:chemistry
chemical_list: D000873:Anthracenes; D011109:Polymethacrylic Acids; C507544:dipyrromethene; C030613:polymethacrylic acid; D011092:Polyethylene Glycols; D011162:Porphobilinogen