Reproducibility screen-printed electrodes

MWNTs favored the detection of insecticide from 1.5 to 80 nM with a detection limit of InM at an inhibition of 10% (Fig. 2.7). Bucur et al. [58] employed two kinds of AChE, wild type Drosophila melanogaster and a mutant E69W, for the pesticide detection using flow injection analysis. Mutant AChE showed lower detection limit (1 X 10-7 M) than the wild type (1 X 10 6 M) for omethoate. An amperometric FIA biosensor was reported by immobilizing OPH on aminopropyl control pore glass beads [27], The amperometric response of the biosensor was linear up to 120 and 140 pM for paraoxon and methyl-parathion, respectively, with a detection limit of 20 nM (for both the pesticides). Neufeld et al. [59] reported a sensitive, rapid, small, and inexpensive amperometric microflow injection electrochemical biosensor for the identification and quantification of dimethyl 2,2 -dichlorovinyl phosphate (DDVP) on the spot. The electrochemical cell was made up of a screen-printed electrode covered with an enzymatic membrane and combined with a flow cell and computer-controlled potentiostat. Potassium hexacyanoferrate (III) was used as mediator to generate very sharp, rapid, and reproducible electric signals. Other reports on pesticide biosensors could be found in review [17],... 

Screen-printing allows the fast mass production of highly reproducible electrodes at low cost for disposable use. A variety of screen-printed thick-film devices can be produced and in Fig. 25.2 an example of carbon screen-printed electrode is shown. 

Fig. 3. Explosive detection at single-use screen-printed electrodes. Assays of river water (A) and groundwater (B) samples. Response to the sample (a) as well as for subsequent concentration increments of 3 ppm TNT (b-d). Reproduced with permission from Wang et al. [12].

Figure 6.19. Nyquist plots of the screen-printed electrode (0.1/0.15 mg Ptcm 2) at different cell voltages [18]. (Reproduced from Abaoud HA, Ghouse M, Lovell KV, Al-Motairy GN, Alternative formulation for proton exchange membrane fuel cell (PEMFC) electrode preparation, Journal of New Materials for Electrochemical Systems 2003 6(3) 149-55, with permission from JNMES.)...

Fig. 2.12. Response of a HRP-screen printed electrode (CLS, UK) on hydrogen peroxide and cumene hydroperoxide. The working potentiail is — 50 mV. (Reproduced from Ref [106] with permission from Elsevier.)...

Fig. 9.18. Typical plasma emission spectra obtained in different zones of a screen-printed electrode (A) working electrode, (B) reference electrode, (C) electrical contacts and (D) polymeric coating used as insulator. Atomic emission lines used in the LIBS-PCA analysis are indicated. (Reproduced with permission of Elsevier.)...

Fig. 9.19. Graphical representation of the results obtained by PCA-CA treatment of the spectroscopic information obtained after (A) the first, (B) the third, (C) the sixth and (D) the tenth laser shot in zone A of a target screen-printed electrode. (Reproduced with permission of Elsevier.)...

As it has been shown in previous sections, the use of screen-printed electrodes as support for genosensor devices offers enormous opportunities for their application in molecular diagnosis. The technologies used in the fabrication of these electrodes allow the mass production of reproducible, inexpensive and mechanically robust strip solid electrodes. Other important advantages of these electrodes are the possibility of miniaturization as well as their easy manipulation in a disposable manner and therefore the use of small volumes, diminishing the cost of the analysis. This is an important issue that makes this methodology for the detection of DNA more attractive. 

HPLC with UV-based diode array detection (DAD-UV) or electrochemical detection is normally used to determine ascorbic acid. Many types of electrochemical determinations of ascorbic acid have been proposed. Although the electrochemical determinations using enzyme-based biosensors exhibited high specificity and sensitivity, these methods suffer in the fabrication of the electrodes and in automatic analysis. Recently, chemically modified screen-printed electrodes have been constructed for the determination of ascorbic acid. This is one of the most promising routes for mass production of inexpensive, reproducible, and reliable electrochemical sensors. 

Fig. 6.12 Assembly process of tyrosinase (Tyr) modified An nanoparticles (NPs) on chemically functionalized graphene oxide (GO) sheets by 1-pyraiebntanoic acid, succinimidyl ester (PASE) anchoring, and subsequent deposit on screen-printed electrodes. The formation of Tyr-Au/PASE-GO occurs via the formation of an amide bond between the amine residue on Tyr-Au and the PASE carboxylate functionality (Reprinted with permission of the authors. Reproduced from Ref. [152] with the permission of Elsevier)...

Figure 8.11 Fabrication of a boronic acid based immune-assay sensor on a screen printed electrode platform. (Reproduced from ref. 83 with the permission of Elsevier.)...

Fig, 12 SEM micrographs of the various screen printed electrodes SPEs edge-like plane ESPE (A) basal-like plane BSPE (B) and graphene SPE from different commercially graphene inks GSPEl (C) and GSPE2 (D). Reproduced from Randviir etal. with permission of publisher. 

Fig. 16 (A) Screen printed electrode SPE platform, (B) TEM micrographs of the mesoporous carbons on SPE and (C) structures of poly (2-hydroxyethyl methacrylate) (PEIEMA), poly (hydroxybutyl methacrylate) (PEIBMA), poly (tert-butyl methacrylate) (PTBMA) and poly (n-propyl methacrylate) (PPMA) polymer binders. Reproduced from Dai et a/. with permission of publisher.

F. 21 Overall procedure for fabricating Ru02/PED0T PSS/graphene screen-printed electrode and photograph of screen-printed electrode. Reproduced with permission [184] from Copyrights (2015) The American Chemical Society... 

As the measuring element, screen-printed electrodes (SPE) are widely applied due to easy and reproducible fabrication at both laboratory and mass production scales. The low production costs allow a single use of the resulting immrmosensors thus, no complicated regeneration procedures are required. The... 

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