Design and Testing of an Impedance-Based Sensor for Monitoring Drug Delivery
Open Access
- 1 January 2005
- journal article
- Published by The Electrochemical Society in Journal of the Electrochemical Society
- Vol. 152 (1), H6-H11
- https://doi.org/10.1149/1.1824045
Abstract
A new impedance-based sensor to monitor drug delivery from an implantable microelectromechanical systems (MEMS) device has been fabricated and tested. The sensor consists of two electrodes on opposing sides of a pyramidal drug reservoir. The dissolution of the drug and advance of solution into the reservoir cause the impedance to change over time. A 100 times scale model of the sensor was constructed to examine the effects of electrode geometry on solution resistance. An equivalent circuit was formulated to interpret the impedance signal in terms of the resistance and double-layer capacitance of the solution in the reservoir. The circuit was validated by impedance measurements on reservoirs filled with phosphate-buffered saline solutions of varying concentrations. The sensor was then used to monitor the dissolution of the model drug mannitol from the drug delivery MEMS device. The measured solution resistance and double-layer capacitance are related to the rate of transport of drug from the device, making this sensor a potential instrument for noninvasive monitoring of drug transport from the implant in vivo. Experimental results agree closely with the expected values of capacitance, resistance, and dissolution time calculated from physical parameters. © 2004 The Electrochemical Society. All rights reserved.Keywords
This publication has 26 references indexed in Scilit:
- Biocompatibility of implantable synthetic polymeric drug carriers: focus on brain biocompatibilityBiomaterials, 2003
- Implantable chemical sensors for real-time clinical monitoring: progress and challengesCurrent Opinion in Chemical Biology, 2002
- Reducing capsular thickness and enhancing angiogenesis around implant drug release systemsJournal of Controlled Release, 2001
- Silica xerogel as an implantable carrier for controlled drug delivery—evaluation of drug distribution and tissue effects after implantationBiomaterials, 1999
- Engineering the tissue which encapsulates subcutaneous implants. I. Diffusion propertiesJournal of Biomedical Materials Research, 1997
- Assessment of a model for measuring drug diffusion through implant-generated fibrous capsule membranesBiomaterials, 1995
- Interspecies differences in systemic drug availability following subscutaneous pulsatile administration in cattle, sheep, dogs, and ratsJournal of Biomedical Materials Research, 1994
- Bioartificial endocrine pancreas: foreign-body reaction and effectiveness of diffusional transport of insulin and oxygen after long-term implantation of hollow fibers into ratsZeitschrift für Die Gesamte Experimentelle Medizin, 1992
- The role of the fibrous capsule in the function of implanted drug‐polymer sustained release systemsJournal of Biomedical Materials Research, 1981
- The physiological disposition of the carcinostatic 1,3‐bis(2‐chloroethyU‐l‐nitrosourea (BCNU) in man and animalsClinical Pharmacology & Therapeutics, 1967