Biomimetic hydrogels for biosensor implant biocompatibility: electrochemical characterization using micro-disc electrode arrays (MDEAs)

Abstract

Our interest is in the development of engineered microdevices for continuous remote monitoring of intramuscular lactate, glucose, pH and temperature during post-traumatic hemorrhaging. Two important design considerations in the development of such devices for in vivo diagnostics are discussed; the utility of micro-disc electrode arrays (MDEAs) for electrochemical biosensing and the application of biomimetic, bioactive poly(HEMA)-based hydrogel composites for implant biocompatibility. A poly(HEMA)-based hydrogel membrane containing polyethylene glycol (PEG) was UV cross-linked with tetraethyleneglycol diacrylate following application to MDEAs (50 mum discs) and to 250 mum diameter gold electrodes within 8-well culture ware. Cyclic voltammetry (CV) of the MDEAs revealed a reduction in the apparent diffusion coefficient of ferrocenemonocarboxylic acid (FcCO(2)H), from 6.68 x 10(-5) to 6.74 x 10(-6) cm(2)/s for the uncoated and 6 mum thick hydrogel coated devices, respectively. Single frequency (4 kHz) temporal impedance measurements of the hydrogels in the 8-well culture ware showed a reversible 5% change in the absolute impedance of the hydrogels when exposed to a pH change between 6.1 to 7.2 and a 20% drop between pH 6.1 and 8.8.

Properties and Customization of Sensor Materials for Biomedical Applications

“…The major mechanism of failure is the biodegradation of the sensing layer and the changing diffusional barrier that arises from the host's response toward the implanted sensor (12). Current devices cannot be used for prolonged periods of measurement because of endogenous interferences, fouling, and so on (13)(14)(15). However, there are few examples of commercially available sensors that are suitable for short-term continuous monitoring of clinical relevant markers.…”

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

“…The disks were arranged in a hexagonal close packed array with center-to-center distances that were 4 times that of the disk radius (100, 200, and 500 mm, respectively). The detailed fabrication procedure of the MDEA electrodes is described elsewhere [3,4]. Figure 1a illustrates the hexagonal closed pack (HCP) arrangement of the microdisks and the diffusion hemispherical domains of the individual disks.…”

Redox Cycling Effect on the Surface-enhanced Raman Scattering Signal of Crystal Violet Molecules at Nanostructured Interdigitated Array Electrodes

“…4 The miniaturized sizes of these devices have been exploited in many applications, such as lab-on-a-chip systems, [5][6][7][8][9] a scanning electrochemical microscope (SECM), 10 analysis in a single biological cell 11 and so on. The interdigitated array (IDA) electrode involves one of the most effective structures to improve the sensitivity in detecting electroactive species through a redox cycling mechanism.…”