title: Intracellular pH-Induced Tip-to-Tip Assembly of Gold Nanorods for Enhanced Plasmonic Photothermal Therapy.
abstract: The search for efficient plasmonic photothermal therapies using nonharmful pulse laser irradiation at the near-infrared (NIR) is fundamental for biomedical cancer research. Therefore, the development of novel assembled plasmonic gold nanostructures with the aim of reducing the applied laser power density to a minimum through hot-spot-mediated cell photothermolysis is an ongoing challenge. We demonstrate that gold nanorods (Au NRs) functionalized at their tips with a pH-sensitive ligand assemble into oligomers within cell lysosomes through hydrogen-bonding attractive interactions. The unique intracellular features of the plasmonic oligomers allow us to significantly reduce the femtosecond laser power density and Au NR dose while still achieving excellent cell killing rates. The formation of gold tip-to-tip oligomers with longitudinal localized surface plasmon resonance bands at the NIR, obtained from low-aspect-ratio Au NRs close in resonance with 800 nm Ti:sapphire 90 fs laser pulses, was found to be the key parameter for realizing the enhanced plasmonic photothermal therapy.
authors.affiliation: Departamento de Química Física I, Universidad Complutense de Madrid , Avda. Complutense s/n, 28040 Madrid, Spain.
authors.forename: Rubén
authors.initials: R
authors.lastname: Ahijado-Guzmán
authors.affiliation: Departamento de Química Física I, Universidad Complutense de Madrid, Avda. Complutense s/n, 28040 Madrid, Spain; BioNanoPlasmonics Laboratory, CIC biomaGUNE, Paseo de Miramon 182, 20009 Donostia/San Sebastián, Spain.
authors.forename: Guillermo
authors.initials: G
authors.lastname: González-Rubio
authors.affiliation: Departamento de Química Física I, Universidad Complutense de Madrid , Avda. Complutense s/n, 28040 Madrid, Spain.
authors.forename: Jesús G
authors.initials: JG
authors.lastname: Izquierdo
authors.affiliation: Departamento de Química Física I, Universidad Complutense de Madrid , Avda. Complutense s/n, 28040 Madrid, Spain.
authors.forename: Luis
authors.initials: L
authors.lastname: Bañares
authors.affiliation: Departamento de Química Física I, Universidad Complutense de Madrid, Avda. Complutense s/n, 28040 Madrid, Spain; Instituto de Investigación Hospital 12 de Octubre i+12, Avda. de Córdoba s/n, 28041 Madrid, Spain.
authors.forename: Iván
authors.initials: I
authors.lastname: López-Montero
authors.affiliation: Instituto de Microelectrónica de Madrid (IMM, CSIC) Isaac Newton 8, Tres Cantos, 28760 Madrid, Spain.
authors.forename: Alicia
authors.initials: A
authors.lastname: Calzado-Martín
authors.affiliation: Instituto de Microelectrónica de Madrid (IMM, CSIC) Isaac Newton 8, Tres Cantos, 28760 Madrid, Spain.
authors.forename: Montserrat
authors.initials: M
authors.lastname: Calleja
authors.affiliation: Departamento de Química Física I, Universidad Complutense de Madrid , Avda. Complutense s/n, 28040 Madrid, Spain.
authors.forename: Gloria
authors.initials: G
authors.lastname: Tardajos
authors.affiliation: Departamento de Química Física I, Universidad Complutense de Madrid , Avda. Complutense s/n, 28040 Madrid, Spain.
authors.forename: Andrés
authors.initials: A
authors.lastname: Guerrero-Martínez