Anisotropic Plasmonic Metal Heterostructures as Theranostic Nanosystems for Near Infrared Light‐Activated Fluorescence Amplification and Phototherapy. Issue 11 (5th April 2019) - Chang, Yun
Abstract: The development of sophisticated theranostic systems for simultaneous near infrared (NIR) fluorescence imaging and phototherapy is of particular interest. Herein, anisotropic plasmonic metal heterostructures, Pt end‐deposited Au nanorods (PEA NRs), are developed to efficiently produce hot electrons under 808 nm laser irradiation, exhibiting the strong electric density. These hot electrons can release the heat through electron‐phonon relaxation and form reactive oxygen species through chemical transformation, as a result of potent photothermal and photodynamic performance. Simultaneously, the confined electromagnetic field of PEA NRs can transfer energy to adjacent polyethylene glycol (PEG)‐linked NIR fluorophores (CF) based on their energy overlap mechanism, leading to remarkable NIR fluorescence amplification in CF‐PEA NRs. Various PEG linkers (1, 3.4, 5.0, and 10 kD) are employed to regulate the distance between CF and PEA NRs of CF‐PEA NRs, and the maximum fluorescence intensity is achieved in CF5k ‐PEA NRs. After further attachment with i‐motif DNA/Nrf2 siRNA chimera to simultaneously suppress both cellular antioxidant defense and hyperthermia resistance effects, the final biocompatible CF5k ‐ b PEA@siRNA NRs present promising NIR fluorescence imaging ability and 808 nm laser‐activated photothermal and photodynamic therapeutic effect in MCF7 cells and tumor‐bearing mice, holding great potential for cancer therapy. Abstract : CF5k ‐Pt end‐deposited Au (PEA)@siRNA nanorods (NRs) possess various excellent performance characteristics, including high hot electron utilization efficiency for photothermal and photodynamic property enhancement, electromagnetic field‐mediated near infrared fluorescence amplification, pH‐responsive Nrf2 siRNA release to simultaneously suppress both cellular antioxidant defense and hyperthermia resistance effects. The CF5k ‐PEA@siRNA NR holds great potential as a theranostic nanosystem for cancer diagnosis and therapy.