Smart Contact Lens with Dual‐Sensing Platform for Monitoring Intraocular Pressure and Matrix Metalloproteinase‐9

Abstract

Contact lenses have become a popular health‐monitoring wearable device due to their direct contact with the eyes. By integrating biosensors into contact lenses, real‐time and noninvasive diagnoses of various diseases can be realized. However, current contact lens sensors often require complex electronics, which may obstruct the user's vision or even damage the cornea. Moreover, most of the reported contact lens sensors can only detect one analyte. Therefore, an optical‐based dual‐functional smart contact lens sensor has been introduced to monitor intraocular pressure (IOP) and detect matrix metalloproteinase‐9 (MMP‐9), both of which are key biomarkers in many eye‐related diseases such as glaucoma. Specifically, the elevated IOP is continuously monitored by applying an antiopal structure through color changes, without any complex electronics. Together with the peptide modified gold nanobowls (AuNBs) surface‐enhanced Raman scattering (SERS) substrate, the quantitative analysis of MMP‐9 at a low nanomolar range is achieved in real tear samples. The dual‐sensing functions are thus demonstrated, providing a convenient, noninvasive, and potentially multifunctional sensing platform for monitoring health and diagnostic biomarkers in human tears.

Applications of Microwaves in Medicine

“…Smart lenses have been proposed to measure intraocular pressures for glaucoma diagnosis and drug delivery [170], glucose levels in tears for diabetic diagnosis and therapy [171], lactic acid (lactate) for hypoxia and changes of physiological or pathological conditions [172], and cholesterol [173]. MEMS and electrochemical sensors, MEMS actuators, and drug-loaded hydrogels are utilized for sensing [174], [175] and drug delivery [176], [177], [178]. Signal transduction, sensor and electronics operation require wireless powering because contact lenses are too small or soft to contain a battery.…”

Surface-enhanced Raman scattering as a potential strategy for wearable flexible sensing and point-of-care testing non-invasive medical diagnosis

“…The wearable SERS sensor of Keisuke Goda et al ( Liu, et al, 2022 ) tested human sweat biomarkers: urea and ascorbic acid, which is capable of detecting and identifying low concentrations of different analytes on almost any arbitrary surface ( Figure 2C ), essential for a timely, accurate and comprehensive understanding of the wearer’s complex physiological and pathological condition. Wang et al ( Ye, et al, 2022 ) combined peptide-modified gold nanobowls (AuNBs) with SERS substrates to introduce a dual-functional smart contact lens sensor that enables continuous monitoring of intraocular pressure by observing structural color changes and quantitative SERS analysis of MMP-9 for the purpose of glaucoma diagnosis, effectively avoiding potential damage to the eye from electronic components ( Figure 2D ). Ling et al ( Leong, et al, 2022 ) designed a respiratory assay based on three separate sets of SERS probe molecules: 4-mercaptobenzoate (MBA), 4-mercaptopyridine (MPY), and 4-aminothiophenol (ATP), for rapid and non-invasive screening of COVID-19 individuals.…”

Smart Contact Lenses for the New Era of IoT: Integrated Biosensors, Circuits, and Human–Machine Interface Systems

“…Furthermore, Ye et al developed an SCL with an antiopal structure for monitoring changes in the IOP through changes in color (Figure 2d). [69] When the IOP increased, the radius of curvature of the eyeball increased, resulting in an increase in the refractive index of the SCL and leading to a change in color. In contrast, a peptide substrate with a fluorescent Raman tag had been integrated into the SCL for matrix metalloproteinase-9 (MMP-9) monitoring.…”