Layer-by-Layer Assembly of Carbon Nanotubes Modified with Invertase/Glucose Dehydrogenase Cascade for Sucrose/O₂Biofuel Cell

Abstract

A layer-by-layer (LbL) assembly technique was employed to modify glassy carbon electrodes (GCEs) and screen printed electrodes (SPEs) utilizing multiwalled carbon nanotubes (MWCNTs)/polyelectrolyte binary composites and an enzyme cascade to facilitate efficient electron transfer in sucrose/O 2 biofuel cell. In this study, MWCNTs immobilized invertase (INV) and glucose dehydrogenase (GDH) were alternatively assembled upon polyethyleneimine (PEI) and DNA nanocomposites to construct a bioanode.[Ni(phendion)(phen)]Cl 2 complex and methylene green (MG) were investigated as redox mediators for electrocatalytic oxidation of NADH at reduced overpotentials. The LbL architecture showed advantages for sequential enzymatic reaction that favored the efficient penetration of substrate and products in a cascade system while MWCNTs facilitated the efficient electron transfer from sucrose oxidation and enhancement of the current density. With a GCE bioanode modified with a MG or Ni complex, the biofuel cell produced a higher power density (μW/cm 2 ) with 145.8% and 130.11% enhancement comparing to a SPE bioanode, respectively. Moreover, the Ni complex modified GCEs and SPEs produced power densities (μW/cm 2 ) 93.7% and 107.0% higher compared to MG modified bioanodes, respectively. The maximum current density of 1400 ± 46 μA/cm 2 was obtained with the Ni complex on GCE at an OCP of 604 ± 17 mV with a maximum power density of 405 ± 6 μW/cm 2 . The LbL assembly showed great feasibility as a simple and efficient way to construct controlled MWCNT-multi-enzyme modified electrodes for biofuel cell applications. Biofuel cells convert the chemical energy of biofuels into electric energy via the enzymatically catalyzed oxidation and reduction reactions. One of the most important factors affecting the performance of fuel cell is the fabrication of bioanode which has great influence in generation of electrical power outputs. Therefore developing effective bioanodes remains critical. Till date, several reports have been published on various approaches to assemble enzymes on the anodes in BFCs utilizing carbon based materials.1-4 Amongst those layerby-layer (LbL) assembly technique via electrostatic interactions of oppositely charged species has emerged as a very attractive way to construct multilayer films of polyelectrolytes, biomolecules, 5 and organic materials 6-8 offering advantages in various fields, such as surface functionalization, 9,10 drug delivery, 11,12 and biosensing. [13][14][15] Its application was considered plausible in the development of amperometric biosensors initiating vast research activities on biosensors comprised of LbL organized multilayers. LbL nanostructures decorated with multi-enzymes were proven to be one of the successful strategies to establish high electrical performance, long-term stability and long lifetime in bioelectronics devices.14,16-18 For example, LbL structures consisting of Au nanoparticles (AuNPs), thiol-functionalized polyaniline and glucose oxidase (GOx) were fabricated for glucose biosensing ...

Multi‐Enzyme Immobilized Anodes Utilizing Maltose Fuel for Biofuel Cell Applications

“…Figures 3a and 4a confirm several times higher current density between 0.05 and 0.34 V in the CNT/TX/CFE than that in the CNT/CTAB/CFE which is due to the TTF redox couple, because of more TTF molecules adsorbed on CF electrode with increased electrode surface area in CNT/TX/CFE. In addition, this electrode exhibits the higher oxidative current in the maltose solution than that in glucose one throughout the whole potential range, lower onset potential of −0.2 V in the maltose solution, and the maximum current of 17 mA cm −2 at 0.34 V, which is the largest value compared with others reported in the literatures on the multi‐enzyme immobilized bioanode for disaccharides as far as we know ,,,,,. These excellent results are mostly attributed to the good dispersion of the CNT on the carbon fibers of CF, the suppressed deactivation of enzymes, and the suppressed leakage of enzymes from the CNT/TX/CFE into a solution.…”

“…The CNT/TX/CF bioanode‐based cell demonstrates an open‐circuit voltage of 0.69 V, a short‐circuit current density of 7.8 mA cm −2 and a maximum power density of 2.3 mW cm −2 at 0.60 V in the optimized buffer solution. These results are much better than those of the EFC equipped with our conventional CNT/CTAB/CF bioanode, and much higher than those of other disaccharide biofuel cells in previous literatures showing power density less than 1 mW cm −2 ,. This improvement is ascribed to the improved distribution of CNT and the higher activity of immobilized MAL and MUT, as described above.…”

“…We also reported on a sucrose bioanode for EFCs on the basis of the multi‐enzyme design to enable to utilize sucrose, glucose, and fructose by adopting four enzymes, invertase, mutarotase, glucose oxidase, and fructose dehydrogenase . Moreover, our sucrose/O 2 biofuel cell with the improved rate‐determining step of the isomerization reaction delivered an open‐circuit voltage of 0.69 V and a maximum power density of 2.90 mW cm −2 at 0.30 V, which is larger than the results of other sucrose biofuel cells reported ,…”

Magnetically induced enzymatic cascades – advancing towards multi-fuel direct/mediated bioelectrocatalysis

“…[47][48][49][50] When putting our results into perspective one should take into account that (i) unlike almost all other studies, in our biofuel cell both electrodes were operated through enzymatic cascades; (ii) whereas the direct loading of the enzymes is in many cases not reported, in our study it was much lower than on, e.g. carbon felt or nanotube modied electrodes; 42-44 (iii) no mediator molecules were incorporated into our assembly in contrast to other similar constructs; 19,44,51,52 and (iv) we applied no mechanical stirring or rotation to the fuel cell. Furthermore, our approach using a cathodic cascade enables the use of H 2 O 2 as an internal oxidizer source, which signicantly enhances the power outputs and paves the way for future potent enzymatic biofuel cells.…”

Review—Nanocarbon-Based Multi-Functional Biointerfaces: Design and Applications

“…The maximum power density from MG and [Ni(phendion)(phen) 2 ]Cl 2 were 209 ± 3 μW/cm 2 and 405 ± 6 μW/cm 2 on GCE succeeding most of other reported disaccharides biofuel cells in literature. 98,99 The Table I shows some of the examples of single, bi and cascade enzyme electrodes constructed for biofuel cell applications using different immobilization strategies and Lbl.…”