Electrochemical-Based Biomemory Regulator Chip Composed of Recombinant Azurin-DNA/Nanoparticle Conjugate

In the present study, we proposed an electrochemical-based biomemory regulator that consists of recombinant azurin/DNA conjugate and input nanoparticles. To develop the biomemory regulator, a recombinant azurin was conjugated with ssDNA using a bifunctional linkers [1,4-phenylene diisothiocyanate (PDITC)] via native chemical ligation (NCL) method. A cysteine-modified blue-copper azurin, which has a redox property, was used as the source of the biomemory. As the input receptor, the ssDNA was hybridized complementary DNA (cDNA)-silver nanoparticle (SNP) conjugate and cDNA-quantum dot (QD) nanoparticle. The conjugate was confirmed via SDS-PAGE and TBE agarose gel electrophoresis. Then, the recombinant azurin-ssDNA (rAzu-DNA) conjugate was self-assembled onto a biomemory regulating chip using a self-assembly method. The immobilization of conjugate was investigated by atomic force microscopy (AFM). The proposed regulator was found to have two distinct functions: 'biomemory increment' and 'biomemory decrement', respectively. To perform these functions, the redox properties of rAzu-DNA/cDNA-SNP, rAzu-DNA/cDNA-QD conjugates were measured via cyclic voltammetry (CV) to obtain the original redox potentials. Based on obtained redox potential values, the biomemory increment and biomemory decrement functions could be operated in correspondence to commanding materials through a chronoamperometry (CA) and differential potential voltammetry (DPV) techniques. The proposed biomemory regulator can become a novel tool to develop environment-dependent information processing system applications.