An Electroactive and Self‐Assembling Bio‐Ink, based on Protein‐Stabilized Nanoclusters and Graphene, for the Manufacture of Fully Inkjet‐Printed Paper‐Based Analytical Devices

Abstract

Hundreds of new electrochemical sensors are reported in literature every year. However, only a few of them makes it to the market. Manufacturability, or rather the lack of it, is the parameter that dictates if new sensing technologies will remain forever in the laboratory in which they are conceived. Inkjet printing is a low‐cost and versatile technique that can facilitate the transfer of nanomaterial‐based sensors to the market. Herein, an electroactive and self‐assembling inkjet‐printable ink based on protein‐nanomaterial composites and exfoliated graphene is reported. The consensus tetratricopeptide proteins (CTPRs), used to formulate this ink, are engineered to template and coordinate electroactive metallic nanoclusters (NCs), and to self‐assemble upon drying, forming stable films. The authors demonstrate that, by incorporating graphene in the ink formulation, it is possible to dramatically improve the electrocatalytic properties of the ink, obtaining an efficient hybrid material for hydrogen peroxide (H2O2) detection. Using this bio‐ink, the authors manufactured disposable and environmentally sustainable electrochemical paper‐based analytical devices (ePADs) to detect H2O2, outperforming commercial screen‐printed platforms. Furthermore, it is demonstrated that oxidoreductase enzymes can be included in the formulation, to fully inkjet‐print enzymatic amperometric biosensors ready to use.

Engineering Proteins for PEDOT Dispersions: A New Horizon for Highly Mixed Ionic‐Electronic Biocompatible Conducting Materials

“…[39] This versatility makes them ideal candidates for interfacing with other functional elements and materials to create new types of materials. As evidence of its robustness and versatility, in previous studies CTPR proteins have been used as scaffolds to stabilize metallic clusters for bioimaging, [40] combined with graphene to improve the long-term performance of electrochemical sensors, [41][42][43] template gold nanoparticles at specific positions through bioconjugation to form self-assembled conducting materials, [44] organize carbon nanotubes and porphyrin by protein-material hybridization resulting in photoconductive systems, [45] and stabilize redox active FeS 2 clusters for electron transfer conduits. [46] Moreover, CTPR demonstrated wire-like performance as molecular electronic components, showing improvement compared with tailored molecules.…”