Enzyme-polyelectrolyte multilayer assemblies on reduced graphene oxide field-effect transistors for biosensing applications

Abstract

We present the construction of layer-by-layer (LbL) assemblies of polyethylenimine and urease onto reduced-graphene-oxide based field-effect transistors (rGO FETs) for the detection of urea. This versatile biosensor platform simultaneously exploits the pH dependency of liquid-gated graphene-based transistors and the change in the local pH produced by the catalyzed hydrolysis of urea. The use of an interdigitated microchannel resulted in transistors displaying low noise, high pH sensitivity (20.3µA/pH) and transconductance values up to 800 µS. The modification of rGO FETs with a weak polyelectrolyte improved the pH response because of its transducing properties by electrostatic gating effects. In the presence of urea, the urease-modified rGO FETs showed a shift in the Dirac point due to the change in the local pH close to the graphene surface. Markedly, these devices operated at very low voltages (less than 500mV) and were able to monitor urea in the range of 1-1000µm, with a limit of detection (LOD) down to 1µm, fast response and good long-term stability. The urea-response of the transistors was enhanced by increasing the number of bilayers due to the increment of the enzyme surface coverage onto the channel. Moreover, quantification of the heavy metal Cu(with a LOD down to 10nM) was performed in aqueous solution by taking advantage of the urease specific inhibition.

Recent Advances in Sensing Applications of Graphene Assemblies and Their Composites

“…a) Illustration of the solution‐gated rGO FET, the interdigitated channel, the urease–PEI mjultilayered film, and the urease‐catalyzed hydrolysis of urea, and the LbL deposition process. Reproduced with permission . Copyright 2016, Elsevier.…”

“…Graphene transistors are suitable for real‐time, high‐throughput, and highly sensitive detection of various analytes in clinical diagnosis. A versatile biosensor platform was constructed by Piccinini et al for urea detection. The sensor was fabricated by depositing GO onto the surface of 3‐aminopropyl‐triethoxysilane self‐assembled monolyered functionalized interdigitated microelectrodes.…”

Molecular Design of Solid‐State Nanopores: Fundamental Concepts and Applications

“…In recent years, the modification of solid‐state nanopores via polyelectrolyte assembly/adsorption has gained increasing interest . The LbL assembly of polyelectrolytes represents a very simple and versatile chemical method to create functional thin films with nanoscale precision . This functionalization method is based on the alternate deposition of polyanions and polycations on solid surfaces leading to the formation of polyelectrolyte multilayers .…”

A novel biocatalytic system obtained via immobilization of aminoacylase onto sol–gel derived ZrO2·SiO2 binary oxide material: physicochemical characteristic and catalytic activity study

“…The many different supports commonly used in the immobilization of enzymes include inorganic oxides such as SiO 2 (Kolodziejczak-Radzimska 2017; Jin et al 2018), TiO 2 (Zivkovic et al 2016;Haghighi et al 2017) and ZrO 2 (Masuda et al 2014), minerals such as bentonite (Cengiz et al 2012) and halloysite (Zhai et al 2010;Chao et al 2013), and carbon materials (Mohiuddin et al 2014;Wu et al 2017;Das et al 2018). These materials have been used in the immobilization of lipase (Cai et al 2016;Zdarta et al 2015;Kolodziejczak-Radzimska et al 2018b;Heater et al 2018), cysteine (Xiao et al 2010;Noori et al 2016), urease (Piccinini et al 2017;Tak et al 2017), α-amylase (Demkina et al 2017, tyrosinase (Abdollahi et al 2017), laccase (Pogorilyi et al 2017) and other enzymes. As it can be seen a number of enzymes have been immobilized onto different materials.…”