Femtosecond Laser Ablation Assisted NFC Antenna Fabrication for Smart Contact Lenses

Abstract

Smart contact lenses (SCLs) have drawn substantial interest for continuous health monitoring applications. Even though most of the reported works utilize near‐field communication (NFC) or inductive coupling for wireless powering and data transmission, developing a scalable and rapid fabrication technique for annular ring antennas confined in a small contact lens area is still an unsolved challenge. Here, femtosecond laser ablation is employed for the first time as a simple, single‐step, and highly precise fabrication technique for NFC antennas using conventional flexible printed circuit board materials. Antenna lines with depth and width of 9 and 35 μm are achieved, respectively. The antenna with a footprint of 19.5 mm2 is characterized in biological solution followed by aging, and bending tests, and a frequency deviation of less than %1 is recorded. A real‐life application is demonstrated by fabricating an SCL embedded with the antenna, an NFC chip, and an electrochemical sensor for wireless monitoring of glucose in artificial tear solution by a smartphone. The device could successfully quantify biologically relevant glucose concentrations ranging from 0.2 to 1 mM with a limit‐of‐detection of 66 μM. In addition, device response to interfering molecules is less than ±1 nA, and the spike‐and‐recovery test is successfully demonstrated.

Photolithography‐Based Microfabrication of Biodegradable Flexible and Stretchable Sensors

“…These devices can be used as an antenna for near-field communication (NFC) or Bluetooth wireless communication allowing simultaneous power and data transmission between devices by inductive coupling. [54,55] Radiofrequency (RF) based standalone devices consist of an antenna that can be used for wireless communication or energy harvesting, in particular, stretchable antennas are more suitable for wearable healthcare devices. [56] Zhang et al developed a 3D microstrip antenna for wearable applications with improved stretchability and resonance frequency insensitivity to strain.…”

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

“…[ 31,50 ] The integration of the NFC interface into SCLs enables communication with smartphones in real time. [ 41,122 ] Traditional detection instruments are large and not portable. Ku et al.…”

“…As personal health information can be monitored in real-time by using SCLs, patients no longer need to go to the hospital or rely on large medical equipment. [38][39][40][41][42] Therefore, the development of SCL devices in view of the rapid advances in IoT technology is an important research topic.In this review, we focus on the latest progress and prospects of integrated biosensors, circuits, and HMI systems on SCLs under the background of the rapid development of the IoT technology, as shown in Figure 1. First, we discuss the integration of biosensors on SCLs for physiological information monitoring of the eyes, including IOP monitoring, corneal sensing, color signals sensing, tear pH monitoring, and glucose sensing.…”

Microfluidic contact lenses for ocular diagnostics and drug delivery

“…[5,18,19] Contact lenses have further evolved in the last decade by integrating smart microfluidic sensing systems, allowing the screening and diagnosis by tear analyte detection and therapy through drug delivery. [8] In addition to vision correction [9] and health monitoring through tear analytes, [20] functional contact lens technologies have been developed [21] for providing aseptic ocular screening with high quality, [4] disease diagnostics, [22,23] and drug delivery. [24] Minimally-invasive nature of the application and user comfort make contact lenses an attractive platform.…”

“…In addition to vision correction [ 9 ] and health monitoring through tear analytes, [ 20 ] functional contact lens technologies have been developed [ 21 ] for providing aseptic ocular screening with high quality, [ 4 ] disease diagnostics, [ 22,23 ] and drug delivery. [ 24 ] Minimally‐invasive nature of the application and user comfort make contact lenses an attractive platform.…”