DNA-Recombinant Azurin Conjugation as a Biomemory Platform with Enhanced Sensitivity

Abstract

Biocomputing devices with DNA, protein/enzymes and other biomaterials have been studied to develop unconventional computing devices. However, the high sensitivity of these devices is still in doubt due to difficulty detecting the efficient electron transfer between biomolecules and the device surface. In this study, oligonucleotides were introduced to the recombinant azurin to enhance the current signal. The recombinant azurin self-assembled on the gold surface due to the formation of gold-sulfur covalent bonds. Single stranded DNA (ssDNA) sequences were further conjugated with self-assembled recombinant azurin via a chemical linker. The fabricated biofilm was confirmed by cyclic voltammetry (CV) and atomic force microscopy (AFM). Moreover, enhancement of the electrochemical signal sensitivity and durability to harsh pH conditions were achieved by conjugation with biomolecular oligonucleotides that can contain Pb2+. The biofilm consisting of DNA and recombinant azurin was further verified to be a suitable platform for biomemory. The sensitivity and durability of the biomemory platform was enhanced by simply by introducing DNA into the system, without any other labels or nanoparticles. The proposed biofilm can be applied to bioelectronics devices such as bioprocessors and biocomputers.