Development of a novel reagentless, screen-printed amperometric biosensor based on glutamate dehydrogenase and NAD+, integrated with multi-walled carbon nanotubes for the determination of glutamate in food and clinical applications

Abstract

Disclaimer UWE has obtained warranties from all depositors as to their title in the material deposited and as to their right to deposit such material. UWE makes no representation or warranties of commercial utility, title, or fitness for a particular purpose or any other warranty, express or implied in respect of any material deposited. UWE makes no representation that the use of the materials will not infringe any patent, copyright, trademark or other property or proprietary rights.UWE accepts no liability for any infringement of intellectual property rights in any material deposited but will remove such material from public view pending investigation in the event of an allegation of any such infringement. The biosensor was fabricated by sequentially depositing the components on the surface of the transducer (MB-SPCE) in a layer-by-layer process, details of which are included in the paper. Each layer was optimized to construct the reagentless device.The biosensor was used in conjunction with amperometry in stirred solution using an applied potential of +0.1V (vs. Ag/AgCl). Optimum conditions for the analysis of glutamate were found to be: temperature, 35°C; phosphate buffer, pH 7 (0.75 mM, containing 0.05 M NaCl).The linear range of the reagentless biosensor was found to be 7.5 µM to 105 µM, and limit of detection was found to be 3 µM (based on n = 5, CV: 8.5% based on three times signal to noise) and the sensitivity was 0.39 nA/µM (± 0.025, coefficient of variation (CV) of 6.37%, n = 5). The response time of the biosensor was 20 -30 seconds.A food sample was analysed for monosodium glutamate (MSG). The endogenous content of MSG was 90.56 mg/g with a CV of 7.52%.The reagentless biosensor was also used to measure glutamate in serum. The endogenous concentration of glutamate was found to be 1.44 mM (n = 5), CV: 8.54%. The recovery of glutamate in fortified serum was 104% (n = 5), CV of 2.91%.

Phytohormonal cross-talk modulate Bipolaris sorokiniana (Scc.)interaction with Zea mays

“…Reaction was started by adding 500 mL G6P (500 mM) into reaction mixture. OD was monitored on 340 through spectrophotometer (Hughes et al, 2015). Cofactor FAD + (Flavin adnenine dinucleotide) was determined by adding 2 mL sample (LE or RE) into reaction mixture containing 1 mL HEPES (50 mM), 100 µL ascorbic acid (250 mM) and 100 µL FADH.…”

Recent Advances in the Fabrication and Application of Screen-Printed Electrochemical (Bio)Sensors Based on Carbon Materials for Biomedical, Agri-Food and Environmental Analyses

“…The biosensor was further developed by immobilizing all the components onto the surface of the transducer [24]. A layer-by-layer drop-coating fabrication procedure was employed, as illustrated in Figure 3.…”

Enzyme-Based Electrochemical Glutamate Biosensors

“…Hughes et al described the development and optimization of a disposable screen-printed amperometric biosensor for glutamate based on GLDH [79]. The authors also developed a stable, reagentless amperometric glutamate biosensor by incorporating the GLDH biorecognition components using a layer-by-layer deposition involving chitosan and MWCNTs on SPCE [81]. The new reagentless biosensor was applied to the measurement of glutamate in beef stock cubes and serum samples.…”