Wireless Non‐Invasive Monitoring of Cholesterol Using a Smart Contact Lens

Abstract

Herein, a wireless and soft smart contact lens that enables real‐time quantitative recording of cholesterol in tear fluids for the monitoring of patients with hyperlipidemia using a smartphone is reported. This contact lens incorporates an electrochemical biosensor for the continuous detection of cholesterol concentrations, stretchable antenna, and integrated circuits for wireless communication, which makes a smartphone the only device required to operate this lens remotely without obstructing the wearer's vision. The hyperlipidemia rabbit model is utilized to confirm the correlation between cholesterol levels in tear fluid and blood and to confirm the feasibility of this smart contact lens for diagnostic application of cholesterol‐related diseases. Further in vivo tests with human subjects demonstrated its good biocompatibility, wearability, and reliability as a non‐invasive healthcare device.

Applications of Microwaves in Medicine

“…Electronic sensors and actuators integrated into a contact lens, generally called Smart Lens [168], [169], have been attracting a lot of attention due to their convenience, ubiquity and noninvasiveness. 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].…”

Emerging Bio‐Interfacing Wearable Devices for Signal Monitoring: Overview of the Mechanisms and Diverse Sensor Designs to Target Distinct Physiological Bio‐Parameters

“…d) Reproduced with permission. [85] Copyright 2022, The Authors, published by Wiley-VCH. e) Reproduced with permission.…”

“…[219] These two studies are significant in that they integrated multifunctional features into a single device and brought reliability to the analysis of biosignals detected from the physical sensors. However, more development of multifunctional sensors still is required to overcome the electrical 3D microporous mesh [45] Microfiber [37] Expandable fiber [38] ECoG Silicon nanomembrane [40] Ultrathin PEDOT:PSS [41] Ultrathin mesh [44] EEG Large-area mesh [43] Cardiac signal Patch-type electrode Wireless contact [53] Tattooable electrode Drawn-on-skin electrode [55] Serpentine structure [56] Transistor AgNW-based [59] Paintable paste [61] Neuromuscular signal Wired device Facial valence [69] Electrode array Hand gesture recognition [72] Skin attachable electrode array Organic bioelectronics [76] Epidermal electronics [77] Wireless device [67] Electrochemical Tear fluids Smart contact lens Optical monitoring [109] Biocompatible polymer [110] Fluorescent probe [111] Nanoporous hydrogels [112] Remote therapy [86] Serpentine antenna [85] Microfluidic [120] Optical monitoring [121] Glucose sensor [123] Sweat fluid Patch-type Microfluidic [171] Silk fabric electrode [172] Dual iontophoresis Microfluidic [175] Multiplex microfluidic [83] Saliva fluid Mouthguard Interference membrane [87] Screen printed electrode [181] Microfluidic [179] Patch-type (tooth) Graphene-based [182] Intraoral electronics Intraoral hybrid …”

Materials and Structural Designs for Neural Interfaces

“…The electrical characteristics of this stretchable electrode were maintained even though an Au microcrack formed in a condition where the mechanical properties were modified due to the strain applied. By adding a wireless system, − high-quality recordings of rat renal sympathetic nerve activity were obtained as chronic conditions . Lee et al monitored ECoG electrical pulses from optogenetic rats with transparent MEA using PEDOT:PSS (Figure f) .…”