Design considerations in the use of interdigitated microsensor electrode arrays (IMEs) for impedimetric characterization of biomimetic hydrogels
- 675 Downloads
Microlithographically fabricated interdigitated microsensor electrodes (IMEs) were cleaned, surface activated, chemically functionalized (amine) and derivatized with an Acrloyl-PEG-NHS to receive a spun-applied monomer cocktail of UV polymerizable monomer. IMEs were 2050.5, 1550.5, 1050.5 and 0550.5 possessing lines and spaces that were 20, 15, 10, and 5 μm respectively; 5 mm line lengths and were 50 lines on each opposing bus. Bioactive hydrogels were synthesized from spun-applied and UV-crosslinked tetraethyleneglycol diacrylate (TEGDA) (crosslinker), 2-hydroxyethylmethacrylate (HEMA), polyethyleneglycol(200) monomethacrylate (PEGMA), N-[tris(hydroxymethyl)methyl]-acrylamide (HMMA) and poly(HEMA) (MW 60,000) (viscosity modifier) and 2,2-dimethoxy-2-phenylacetophenone (DMPA) (photoinitiator) to produce a 5 μm thick p(HEMA-co-PEGMA-co-HMMA) hydrogel membrane on the IMEs. Unmodified and hydrogel coated IMEs where characterized by AC electrical impedance spectroscopy using 50 mV p-t-p over the frequency range from 10 Hz to 100 kHz in aqueous PBS 7.4 buffer and in buffer containing 50 mM [Fe(CN)6]3-/4− solution at RT. Impedimetric responses were found to scale with the device geometric parameters. Equivalent circuit modeling revealed deviations from ideality at lower device dimensions suggesting an implication of the substrate surface charge on the double layer capacitance of the electrodes. Diffusion coefficients derived from the Warburg component are in accord with literature values.
KeywordsMicrofabrication IME Arrays Hydrogels Impedance Biosensors
L. Yang acknowledges support from NC BIOIMPACT initiative and the Gold Leaf foundation. A Guiseppi-Wilson acknowledges the support of ABTECH Scientific, Inc. and A. Guiseppi-Elie acknowledges support from the US Department of Defense (DoDPRMRP) grant PR023081/DAMD17-03-1-0172 and the Consortium of the Clemson University Center for Bioelectronics, Biosensors and Biochips (C3B).
- T. Blythe, D. Bloor, Electrical properties of polymers (Cambridge University Press, London, 2005)Google Scholar
- L. Doretti, P. Gattolin et al., Amperometric choline sensor with enzyme immobilized by gamma-irradiation in a biocompatible membrane. Anal. Lett. 27(13), 2455–2470 (1994)Google Scholar
- W. Laureyn, F. Frederix, et al. Nanoscaled interdigititated gold electrodes for impedimetric immunosensing. Transducer’99. Sendai, Japan, Digest of Technical Papers, pp 1884–1185 (1999a)Google Scholar
- W. Laureyn, D. Nelis, et al. Nanoscaled interdigititated titanium electrode for impedimetric biosensing. Eurosensors XIII. Hague, The Netherland. Proceeding for the 13th European Conference on Solid-State Transducers. (1999b).Google Scholar
- E. Mack, T. Okano et al., Hydrogels in medicine and pharmacy. Polymers vol II (CRC Press, Boca Raton, 1988)Google Scholar
- R.M. Ottenbrite, K. Park et al. (eds.), Biomedical applications of hydrogels handbook (New York, Springer, 2010)Google Scholar
- R. Trigo, M. Blanco, et al., L-Ascorbic acid release from poly(2-hydroxyethyl methacrylate) hydrogels. Polym. Bull. 31, 577–584 (1993)Google Scholar