Bioactive Hydrogel Layers on Microdisk Electrode Arrays: Cyclic Voltammetry Experiments and Simulations

Abstract

Poly(hydroxyethylmethacrylate)-based hydrogel membranes were applied to microfabricated, microdisk electrode arrays (MDEAs) of 50 mm (5184 disks), 100 mm (1296 disks) and 250 mm (207 disks) (d/r ¼ 4; A ¼ 0.1 cm 2 ) and studied by cyclic voltammetry (CV) in 1.0 mM ferrocene monocarboxylic acid (FcCO 2 H). The membrane produced an order of magnitude decrease in current densities and a shift to quasi reversibility due to a decrease in the

Design considerations in the use of interdigitated microsensor electrode arrays (IMEs) for impedimetric characterization of biomimetic hydrogels

“…The corresponding hydrogel diffusivity is consistent with previous observations of reduced diffusivity of redox anions within hydrogels when compared with transport within buffer (Boztas and Guiseppi-Elie 2009). Boztas and Guiseppi-Elie have shown that the redox active anion, ferrocene monocarboxylic acid (FcCOOH), has an effective diffusivity, D eff ¼ 1:13 Â 10 À8 cm 2 s À1 with n= 0.482, in a 3 M% TEGDA cross-linked p(HEMA)-based hydrogel and that it is approximately two orders of magnitude lower than that of the diffusivity observed in buffer solution D eff ¼ 4:51À ð 5:73 Â 10 À6 cm 2 s À1 Þ (Justin et al 2009a). However, the calculated diffusivity is in this case 10-fold lower than expected when compared to FcCOOH within a similar hydrogel.…”

Responsive Hydrogels for Label-Free Signal Transduction within Biosensors

“…Also, Guiseppi-Elie and coworkers recently pursued the use of a commercial micro-disc electrode arrays (ABTECH Scientific, Inc.) to probe hydrogels; their goal was to optimize the design parameters (geometry of the electrodes, thickness, composition of the hydrogel, and enzyme loading) to optimize the signal of an implantable amperometric biosensor [91,92]. The reader is referred to a recent review on electroconductive hydrogels to get in depth information on the subject [93].…”

“…More recently, the focus of electrochemical transduction involving hydrogels has been towards the miniaturization of conductimetric sensors using interdigitated electrodes to probe the conductivity of pH sensitive hydrogels [ 85 ], the use of blends of conducting polymer and redox hydrogels for more rugged glucose biosensors [ 86 ], and the fabrication of hydrogel coated ISFETs (ion sensitive field effect transistors) for the sensing of nucleotides, or monosacharides [ 87 , 88 ], and the formation of arrays of electrochemical sensors to probe multiple analytes using small biological samples [ 89 , 90 ]. Also, Guiseppi-Elie and coworkers recently pursued the use of a commercial micro-disc electrode arrays (ABTECH Scientific, Inc.) to probe hydrogels; their goal was to optimize the design parameters (geometry of the electrodes, thickness, composition of the hydrogel, and enzyme loading) to optimize the signal of an implantable amperometric biosensor [ 91 , 92 ]. The reader is referred to a recent review on electroconductive hydrogels to get in depth information on the subject [ 93 ].…”

Characterization of Electroconductive Blends of Poly(HEMA-co-PEGMA-co-HMMA-co-SPMA) and Poly(Py-co-PyBA)

“…The apparent diffusion coefficient, D appt , of ferrocene monocarboxylic acid (FcCO 2 H) through a base hydrogel has previously been determined. 36 It was shown in this study that with the application of a hydrogel to the surface of an MDEA chip, a decrease in the peak current response, as well as a decrease in the gradient of the Randles-Sevcik-like plot (Ip vs υ 1/2 ) occurs. From the gradients of the unmodified and hydrogelmodified chips, the diffusion coefficients can be calculated.…”