A non-invasive method for an in vivo assessment of corneal epithelium permeability through tetrapolar impedance measurements

• Published in: Biosensors & bioelectronics Vol. 31; no. 1; pp. 55 - 61
• Main Authors: Guimera, A., Gabriel, G., Plata-Cordero, M., Montero, L., Maldonado, M.J., Villa, R.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15.01.2012; Elsevier
• Subjects: Animals; Barrier function; Biological and medical sciences; Biosensing Techniques - instrumentation; Biotechnology; Conductometry - instrumentation; Corneal epithelium; Electric Impedance; Electrical impedance spectroscopy; Electrodes; Epithelium, Corneal - physiology; Equipment Design; Equipment Failure Analysis; Feasibility Studies; Fundamental and applied biological sciences. Psychology; Non-invasive; Permeability; Plethysmography, Impedance - instrumentation; Rabbits; Translayer electrical resistance; Corneal epithelium; Translayer electrical resistance; Permeability; Non-invasive; Electrical impedance spectroscopy; Barrier function; Resistance; In vivo; Spectrometry; Non invasive method; Epithelium; Electrical impedance
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2011.09.039

► Impedance measurements were performed with four electrodes placed on the corneal surface. ► Methods based on the electrical properties are the most suitable to evaluate corneal permeability. ► The permeability of a rabbit corneal epithelium was monitored. ► The sensor can be used for in vivo studies and clinical settings. The permeability of the cornea epithelial layer has an important role in optimal function of the cornea. To assess this property quantitatively, methods must be based on the passive electrical properties of living tissues, as they can take advantage of the fundamental role that ionic permeability plays in such properties. For such techniques, measurement of the translayer electrical resistance (TER) has been consistently used to examine the ion transport mechanisms in the corneal epithelial cells; however, this technique has been only possible in vitro. To enhance the applications of this method, in this work we present a novel sensor to perform non-invasive in vivo TER measurements. Herein, the epithelial permeability was assessed using non-invasive tetrapolar impedance measurements that were performed with four electrodes placed on the corneal surface. The geometry of these electrodes was previously optimized to maximize the sensitivity of the corneal epithelium. To evaluate the feasibility of this sensor, the permeability of a rabbit corneal epithelium was monitored by applying a solution of benzalkonium chloride (0.05% BAC). The results validate the capability of the sensor to evaluate the cornea epithelial permeability in vivo.