Application of bismuth modified disposable screen printed carbon electrode for metal- plant thiols complexation studies

The application of Bismuth modified cheap and disposable screen printed carbon electrode (BiSPCE) for voltammetric studies of metal–thiol rich peptides complexation was evaluated considering systems consisting of cadmium as a metal and GSH and PC2 as thiol peptides. Comparison of the performance of BiSPCE with the commonly used glassy carbon electrode (BiFE) was made. The information obtained about the complexation sequence using the former electrode was quite consistent with previous studies made on GSH and Cd systems using the conventional mercury electrodes due to the absence of signal splitting, the good sensitivity and the wider linearity range. In contrast with the conventional mercury electrodes, the anodic signals associated with bismuth electrode material were observed to be weakened and all the available signals were well resolved which shows the suitability of Bismuth based electrode for metal- thiol complexation studies. MCR-ALS could not be applied due to the continuous shift of the peak potentials, loss of linearity of the species and anomalous shape of the complex signal formed between Cd and GSH. Therefore, the complexation sequence between GSH and Cd2+ was evaluated qualitatively. However, a relatively well defined shape and intense voltammograms were observed for Cd-PC2 system and consequently, MCR-ALS was applied after correction of the continuous peak potential shift for the complex signals. The peak intensity associated with complex signal was dominated by the intense signal of the free metal reduction in acidic and fairly basic medium. However a relatively intense signal of the complexes was obtained at pH 7.5 in borate buffer solution. In addition extensive Bi complexation was observed from ESI-MS experiment which proves the suitability of ex situ mode of Bi film preparation for thiol- metal complexation studies by voltammetric titration technique

WY500_501: Twillingate

Twillingate: Vacation School (Interdenominational) - Boys Camp (Tyro, TR) - Minty Farm 195

Basic properties of PEI inks at different polymer concentrations.

<p>(A) Viscosity, (B) surface tension, (C) effect of PEI concentration in the ink on anti-CRP antibody binding capacity of PMMA substrate (5µg/ml anti-CRP, 500 ng/ml CRP, 0.0132 mg/ml secondary antibody; n = 2).</p

XPS spectra of native PMMA, PEI patterned native PMMA and PEI patterned plasma activated PMMA surface.

<p>XPS spectra of native PMMA, PEI patterned native PMMA and PEI patterned plasma activated PMMA surface.</p

AFM images of (A) native PMMA (1 µm×1 µm) (B) PEI patterned native PMMA (20 µm×20 µm) (C) PEI patterned plasma treated PMMA (20 µm×20 µm) (D) antibody patterned PEI-GA film on plasma treated PMMA (20 µm×20 µm).

<p>AFM images of (A) native PMMA (1 µm×1 µm) (B) PEI patterned native PMMA (20 µm×20 µm) (C) PEI patterned plasma treated PMMA (20 µm×20 µm) (D) antibody patterned PEI-GA film on plasma treated PMMA (20 µm×20 µm).</p

Inkjet printing of antibody array and assay format.

<p>(A) Schematic of the two-stage antibody patterning using the PEI and GA cross linker system. PEI ink was first deposited by piezoelectric inkjet printing in discrete regions of a PMMA foil. After activating the PEI patterned surface with glutaraldehyde, anti-CRP antibody was deposited locally in a second inkjet printing step. (B) A multichannel R2R hot embossed PMMA microfluidic chip is aligned and bonded permanently with the antibody patterned PMMA foil by solvent bonding lamination. Blocking reagent, mixture of sample and detection antibody, and wash buffer are sequentially introduced at one end of the microchip by pipette and drawn using syringe.</p

Mean (±SD)^a values of mass fractions of elements on native, PEI patterned native and PEI patterned oxygen plasma treated PMMA surface.

a<p>mean and SD were calculated from three measurements on different area of a sample surface, and ^bnot detected with a method with detection limit of 0.2% mass fraction.</p

Reproducibility of fluorescence intensity of patterned anti-CRP spots in three different channels.

<p>Reproducibility of fluorescence intensity of patterned anti-CRP spots in three different channels.</p

Microfluidic biochip responses for detection of CRP antigen.

<p>(A) Fluorescence image of the biochip after immunoassay. Each microfluidic channel was patterned with three replicate CRP capture antibody spots. Samples containing CRP at concentration of 0, 10, 50, 100, 200, 500, 1000, 1500 ng/ml were infused through separate sample channels (rows 1–8, respectively). In each channel the bound antigen was detected with fluorescently labelled secondary antibody (0.0132 mg/ml). (B) Dose response curves for CRP antigen. Fluorescence values were plotted for each CRP concentration. Each data point represents the mean ± SD for the three spots within each microchannel.</p

Reproducibility of fluorescence intensity of CRP binding to the patterned anti-CRP spots in one channel.

<p>Reproducibility of fluorescence intensity of CRP binding to the patterned anti-CRP spots in one channel.</p