A contact lens with embedded sensor for monitoring tear glucose level

Abstract

We report the design, construction, and testing of a contact lens with an integrated amperometric glucose sensor, proposing the possibility of in situ human health monitoring simply by wearing a contact lens. The glucose sensor was constructed by creating microstructures on a polymer substrate, which was subsequently shaped into a contact lens. Titania sol-gel film was applied to immobilize glucose oxidase, and Nafion® was used to decrease several potential interferences (ascorbic acid, lactate, and urea) present in the tear film. The sensor exhibits a fast response (20 sec), a high sensitivity (240 µAcm −2 mM −1 ) and a good reproducibility after testing a number of sensors. It shows good linearity for the typical range of glucose concentrations in the tear film (0.1-0.6 mM), and acceptable accuracy in the presence of interfering agents. The sensor can attain a minimum detection of less than 0.01 mM glucose.

The Electrical Response to Injury: Molecular Mechanisms and Wound Healing

“…Contact lenses with integrated electric circuits have been proposed. 78,79 Pharmacological stumulation of ion pumping to enhance the transcorneal potential and the wound EF and to enhance wound healing appears to be a promising strategy in the cornea. 11,13,16,62 See also the Diabetic disease model section.…”

Powering electronic contact lenses: current achievements, challenges, and perspectives

“…Drawing on the advances within nanotechnology, it has become technically feasible to fit electronics, for example, sensors, transmitters, amplifiers, and even displays, within the confinements of a standard-sized contact lens [5][6][7][8][9]. As regards sensors, they can be designed to gauge various features of biomarkers present in lachrymal fluid, while the complete circuitry arrangement, form factor, and opacity can be chosen not to impair vision.…”

“…Contact lenses are minimally invasive, and electronic lenses will offer real-time, non-traumatic biomarker probing, among many different possible applications. It should be emphasized, however, that whereas reports in popular media concerning smart contact lenses are stunningly impressive [1][2][3][4], actual, bona fide contact lens-based gadgets presented in the scientific literature are still quite far from real practical applications [5][6][7][8][9][10][11]. As the name implies, electronic circuitry relies on electric power, and even though the power demands of state-of-the-art micro-or even nano-electronics are minimal, some power is nonetheless needed.…”

“…While there is not much to say about the first approach [5,8,9], which is obviously a reasonable approach for scientific studies but certainly inappropriate for an end user, the second group is very diverse and includes over-the-air (OTA) electric power delivery [2,6,8,11], as well as solar [7] and electrochemical cells [12,13].…”

Metabolómica de la lágrima

“…-La presencia de glucosa en la lágrima es bien conocida desde hace más de un siglo, pero existe una gran variabilidad interindividual, quizás por desviaciones a nivel de recogida, medida y razones biológicas sin determinar. Distintos grupos trabajan en nuevas técnicas y sensores para la determinación de la glucosa con mayor exactitud, sensibilidad y correlación con niveles séricos [12][13][14][15] . -Martin y Brennan demostraron la presencia de serotonina en la lágrima, sin diferencia entre sexos, y elevación de niveles tras un estímulo emocional.…”