Poly(lactic acid)/Carbon Nanotube Fibers as Novel Platforms for Glucose Biosensors.

Juliano Elvis Oliveira,Valtencir Zucolotto,Eliton Souto Medeiros,Luiz Henrique Capparelli Mattoso

doi:10.3390/bios2010070

Abstract

The focus of this paper is the development and investigation of properties of new nanostructured architecture for biosensors applications. Highly porous nanocomposite fibers were developed for use as active materials in biosensors. The nanocomposites comprised poly(lactic acid)(PLA)/multi-walled carbon nanotube (MWCNT) fibers obtained via solution-blow spinning onto indium tin oxide (ITO) electrodes. The electrocatalytic properties of nanocomposite-modified ITO electrodes were investigated toward hydrogen peroxide (H2O2) detection. We investigated the effect of carbon nanotube concentration and the time deposition of fibers on the sensors properties, viz., sensitivity and limit of detection. Cyclic voltammetry experiments revealed that the nanocomposite-modified electrodes displayed enhanced activity in the electrochemical reduction of H2O2, which offers a number of attractive features to be explored in development of an amperometric biosensor. Glucose oxidase (GOD) was further immobilized by drop coating on an optimized ITO electrode covered by poly(lactic acid)/carbon nanotube nanofibrous mats. The optimum biosensor response was linear up to 800 mM of glucose with a sensitivity of 358 nA·mM−1 and a Michaelis-Menten constant (KM) of 4.3 mM. These results demonstrate that the solution blow spun nanocomposite fibers have great potential for application as amperometric biosensors due to their high surface to volume ratio, high porosity and permeability of the substrate. The latter features may significantly enhance the field of glucose biosensors.

Highlights

Glucose biosensors constitute a very important and widespread class of enzymatic biosensors, due to the relevance of glucose determinations in biomedical diagnosis and food technology [1,2,3,4]
Standard heterogeneous electron transfer rate constant for the Fe(CN)63−/4− redox couple between nanocomposite fibers and the indium tin oxide (ITO) surface was estimated at 7.2 s−1 by the Laviron method [39]. The latter value is higher than that of carbon nanotube powder microelectrodes (2.48 s−1) [40], or carbon nanotube-based electrodes (1.53 ± 0.45 s−1) [41]. These results suggest that the non-woven fiber mat greatly facilitates the electron transfer kinetics in the multi-walled carbon nanotubes on ITO
We developed a solution blow spun fibrous nanocomposite (PLA/multi-walled carbon nanotube (MWCNT)) modified electrode for detection of hydrogen peroxide

Summary

Introduction

Glucose biosensors constitute a very important and widespread class of enzymatic biosensors, due to the relevance of glucose determinations in biomedical diagnosis and food technology [1,2,3,4]. Glucose oxidase (GOD) from Aspergillus niger is a slightly elongated globular flavoprotein with an average diameter of 8 nm that catalyzes the oxidation of β-D-glucose to D-glucono-δ-lactone and H2O2 using molecular oxygen as an electron acceptor [5,6,7]. This reaction occurs via a redox process, in which the reduction process comprises the oxidation of β-D-glucose to D-glucono-δ-lactone, which is hydrolyzed to gluconic acid. The latter method seems to be the simplest one, through which fibers with small diameters and a very fast production rate can be obtained [21]

Methods

Results

Conclusion