Hydrodynamic Layer-By-Layer Assembly of Transferrable Enzymatic Conductive Nano-Networks for Enzyme-Sticker-Based Contact-Printing of Electrochemical Biosensors

Realizing high-performance electrochemical biosensors in a simple contact-printing-based approach significantly increases the applicability of integrated flexible biosensors. Herein, an enzyme-sticker-based approach that enables flexible and multi electrochemical sensors via simple contact-transfer-printing is reported. The enzyme sticker consists of an enzymatic conductive network film and a polymeric support. The enzyme-incorporated nanostructured conductive network showing efficient electrical coupling was assembled via hydrodynamic layer-by-layer assembly of redox enzymes, polyelectrolytes, single-walled carbon nanotubes and biological glue material, M13 phage. The enzymatic conductive network on a polymeric membrane support was facilely wet contact-transfer-printed onto integrated electrode systems by exploiting varying degrees of hydrophilicity displayed by the enzymatic electronic film, polymeric support and receiving electrodes of the sensor system. The glucose sensors fabricated using the enzyme sticker detected glucose at a concentration of as low as 35 μM and showed high selectivity and stability. Furthermore, a flexible dual sensor array capable of detecting both glucose and lactate was demonstrated using the versatile enzyme-sticker concept. This work presents a new route toward assembling and integrating hybrid nanomaterials with efficient electrochemical coupling for high-performance biosensors and health-monitoring devices as well as for emerging bioelectronics and electrochemical devices.