Development of a Bienzymatic Amperometric Glucose Biosensor Using Mesoporous Silica (MCM‐41) for Enzyme Immobilization and Its Application on Liquid Pharmaceutical Formulations

Abstract

This paper describes the development and optimization of an amperometric bienzymatic biosensor for glucose, based on glucose oxidase (GOX) and peroxidase (HRP), immobilized on mesoporous silica with hexagonal symmetry (MCM‐41). The mesoporous material was immobilized by Nafion assisted adsorption on a glassy carbon electrode, which was used as working electrode. Measurements were performed in a conventional three electrode cell using a Ag/AgCl reference electrode and platinum wire as counter electrode. Operating parameters such as GOX/HRP enzyme ratio, mediator (catechol) concentration, applied potential and pH were optimized. The proposed biosensor showed excellent analytical performance with detection and quantification limits of 8.6×10−6 M and 2.5×10−5 M, respectively; analytical sensitivity of 4.67×10−4 AM−1, repeatability <5 % RSD and a long‐term stability of 10 days (5 daily measurements). Also, five possible interferences were studied and only ascorbic acid showed an amperometric signal, which can be removed with 5 % iodine pretreatment. The biosensor was successfully tested for glucose determination in pharmaceutical formulations, and compared well with an established commercial photometric enzymatic kit (Megazyme).

Mesoporous Materials‐Based Electrochemical Enzymatic Biosensors

“…The silica‐based materials used to date in electrochemical biosensors are mainly MCM‐41 99, 102, 117, 118, 121, 124, 128–132, 134, 136, 137, SBA‐15 101, 104, 107, 110, 112, 114, 122, 133, HMS 97, 98, 100 and FSM8 111, 125, 126. MSU 109, bimodal mesoporous silica 103, mesocellular foams 108, 157, mesoporous silica hollow sphere 115, and vesicle‐like mesoporous particles 119, were also applied in this field of research.…”

“…MSU 109, bimodal mesoporous silica 103, mesocellular foams 108, 157, mesoporous silica hollow sphere 115, and vesicle‐like mesoporous particles 119, were also applied in this field of research. Most of the works have been developed with mesoporous materials in the form of particles 97–104, 107–115, 117–122, 124–126, 128–134, 136, 137, sometimes as nanospheres 129, 131. Only few examples of electrodes modified with mesoporous silica films are reported 105, 123.…”

Bienzymatic Biosensor for Malic Acid Based on Malate Dehydrogenase and Transaminase Immobilized onto a Glassy Carbon Powder/Carbon Nanotubes/Nad+ Composite Electrode

“…On the other hand, an interference study was carried out by checking the effect of different organic acids present in fruit juices, namely, citric acid, lactic acid, tartaric acid, oxalic acid and ascorbic acid (1.0 ⋅ 10 −4 M, each one). Under the same experimental conditions used for malate determination, only ascorbic acid showed significant amperometric responses at 0,4 V. This interference could be entirely reduced by pre‐oxidation of ascorbic acid with iodine in the sample, as previously reported by us . After such pre‐treatment, there was no significant ascorbic acid concentration in the sample.…”

Sol-Gel Synthesis of TiO2 Mesoporous Thin Films on Silicon

“…In the synthesis of TiO 2 sols tetraisopropyl titanate, polyethylene glycol (M 3000 and 4000, mole fraction 0.003-0.05), diethanolamine, HNO 3 , and isopropyl alcohol are usually used [4][5][6].…”

“…The synthesis was carried out at the molar ratio (i-PrO) 4 Ti-PEG-(NOSN 2 CH 2 ) 2 NH-H 2 O-HNO 3 -i-PrOH 1 : Y : 0.5 : 150 : 1.5 : 18 [4][5][6]. The surface area of pores was regulated by changing the PEG mole fraction (Y) and its molecular weight.…”