Mechanism of Plasmon-Driven Molecular Jackhammers in Mechanical Opening and Disassembly of Membranes

Plasmon-driven molecular jackhammers (MJH) are a type of molecular machine that converts photon energy into mechanical energy. Upon insertion into lipid bilayers followed by near infrared light activation, plasmon-driven MJH mechanically open cellular membranes through a process that is not inhibited by reactive oxygen species (ROS) inhibitors and does not induce thermal heating. The molecular mechanism by which the plasmon-driven MJH open and disassembles cellular membranes has not hitherto been established. Here we differentiate the mechanical mechanism in MJH from the ROS-mediated chemical effects in photodynamic therapy or thermal effects in photothermal therapy. We further present a detailed molecular mechanism for the plasmon-driven MJH disassembly of lipid bilayers. The mechanical studies on plasmon-driven MJH disassembly processes on artificial lipid bilayers are done using ROS-unreactive saturated phytanoyl phospholipids. We were able to capture in real-time the lipid bilayer disassembly by MJH using fluorescence confocal microscopy on saturated phospholipids in giant unilamellar vesicles.