High-Density Single-Layer Coating of Gold Nanoparticles onto Multiple Substrates by Using an Intrinsically Disordered Protein of α-Synuclein for Nanoapplications

Functional graffiti of nanoparticles onto target surface is an important issue in the development of nanodevices. A general strategy has been introduced here to decorate chemically diverse substrates with gold nanoparticles (AuNPs) in the form of a close-packed single layer by using an omni-adhesive protein of α-synuclein (αS) as conjugated with the particles. Since the adsorption was highly sensitive to pH, the amino acid sequence of αS exposed from the conjugates and its conformationally disordered state capable of exhibiting structural plasticity are considered to be responsible for the single-layer coating over diverse surfaces. Merited by the simple solution-based adsorption procedure, the particles have been imprinted to various geometric shapes in 2-D and physically inaccessible surfaces of 3-D objects. The αS-encapsulated AuNPs to form a high-density single-layer coat has been employed in the development of nonvolatile memory, fule-cell, solar-cell, and cell-culture platform, where the outlying αS has played versatile roles such as a dielectric layer for charge retention, a sacrificial layer to expose AuNPs for chemical catalysis, a reaction center for silicification, and biointerface for cell attachment, respectively. Multiple utilizations of the αS-based hybrid NPs, therefore, could offer great versatility to fabricate a variety of NP-integrated advanced materials which would serve as an indispensable component for widespread applications of high-performance nanodevices.