TRANSDUCTIONAL ELASTIC PROTEIN-BASED POLYMERS AS NANOSENSORS BY AFM/DFS

This Phase I SBIR to DARPA brings together five remarkable elements relevant to elastic protein-based polymers for the development of diverse nanosensors: i. the incomparable protein compositional control of biology, ii. a consilient mechanism of energyconversion utilizing inverse temperature transitions capable of eighteen classes of pair-wise energy conversions, iii. polymers that develop the highest known acoustic absorption on undergoing the transition, iv. polymers with perfectly reversibleelasticity for efficient mechanics-based transduction, and v. adding dynamic force spectroscopy capacity to atomic force microscopy for monitor the free energy transduction.The technical objectives are:(1) To design, prepare and verify a specific elastic protein-based polymer composition for development as nanoscale chemo-mechanical and electro-mechanical transducers,(2) To assemble polymer chains into multi-stranded twisted nanofilaments capable of chemo-mechanical transduction using the COOH/COO- chemical couple and of electro-mechanical transduction using the NAD+/NADH redox couple.(3) To develop the capacity of Dynamic Force Spectroscopy to measure changes in the acoustic absorption of twisted bioelastic nanofilaments suspended between cantilever tip and substrate surface of an AFM apparatus, and(4) To detect free energy transduction at the nanoscale due to the chemical and electrochemical potential changes noted above in (2), that is, to develop these specific nanosensors. The anticipated benefits flow from the extreme versatility of the nanosensor design that employs elastic protein-based (bioelastic) polymers and their inverse temperature transitions capable of eighteen classes of pair-wise energy conversions involvingthe intensive variables of mechanical force, temperature, pressure, chemical potential, electrochemical potential and electromagnetic radiation. As a protein-based nanosensor, it promises the famed selectivity and efficiency of protein-based machines.When combined with atomic force microscopy (AFM) and dynamic force spectroscopy (DFS), there is potential for the ultimate in sensitivity, i.e., single molecule detection. Design of the device removes the repeated requirement to scan in the z-directionusing a piezo with strain gauge, but rather allows for the more robust circumstance of a fixed z setting and detects changes in the acoustic absorption attending the transductional event. While the number of applications appears to be limitless with thisdesign of nanosensor, we might note detection of nerve gases, explosives (DNT, TNT), assay of kinase activities for medical diagnostics, etc.