The long-term objective of this work is to develop nano-machine technology for observing and interacting with the human body at the cellular level. The project's focus is a remotely powered and controlled artificial electrocyte (electric-organ cell) able to perform high precision neuro-stimulation. The same machine could also be used as a nano-sensor that would be delivered to its target by chemical tags or during surgical intervention. Such sensors may reveal never before seen intimate details of the transmission of neural signals and of their pathological interruption. The nano-machine will be self-assembled using the DNA """"""""origami"""""""" approach. With this method a platform of the order of 500 nanometers (nm) across will be built with all its onboard components integrated into their designed locations with 2 nm precision. The on-board components include a liposome-based artificial electrocyte. The basic charge transfer unit is an artificial reaction center coupled to a quinoine-based redox loop that functions as a photodriven proton pump incorporated in the liposome wall. It is discharged on command by the opening of proton channels in the wall using a spiropyran-based photochromically active molecule. The power and command is provided through light that is amplified by on-board tuned plasmonic antennas. Thousand-fold amplification of the incident light has been reported for these nanostructures. The development proceeds in a stepping-stone approach where every component is assembled onto the platform and tested individually both in bulk (in solution) and in detail (using Atomic Force Microscopy, Scanning Microscopy and Single Molecule Electronics measurements). The key milestones are: (i) Verification of antenna amplification using a fluorescent molecule precisely positioned at the antenna's calculated """"""""hot spot"""""""". (ii) Chemical verification of proton pump function (iii) Verification of assembly of insulated electrocyte chain. (iv) Verification of discharge function by measuring the voltage developed at the end of a single-chain liposome electrocyte. (v) Final assembly and test. Even if this decade does not see the advent of the in vivo nano-machine, the technology developed working towards this goal has many other near-term bio-science applications. The DNA self-assembly process can be applied to the manufacture of nano-instruments on the tips of existing micro-devices. The light-powered artificial electrocyte could become a new tool in micro-surgery and in the study of cell cultures, human and bacterial. In fact, the in vitro applications of these nano-machines to the study of cell colonies would, in itself, constitute a novel and powerful tool for the advancement of cellular biology.
Infectious and degenerative diseases progress through the breakdown of the body's cellular systems at the microscopic level. Therefore, the ultimate way to observe, understand and combat disease is to operate at the same level using microscopic machines. Such nanomachines could offer new, less intrusive methods to perform deep brain stimulation as well as provide detailed data on the nerve surface damage leading to Multiple Sclerosis.
