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Lab‐on‐a‐Contact Lens Platforms Fabricated by Multi‐Axis Femtosecond Laser Ablation
Author(s) -
Moreddu Rosalia,
Nasrollahi Vahid,
Kassanos Panagiotis,
Dimov Stefan,
Vigolo Daniele,
Yetisen Ali K.
Publication year - 2021
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.202102008
Subject(s) - materials science , microfluidics , femtosecond , lens (geology) , laser , resistor , laser ablation , contact lens , optoelectronics , optics , nanotechnology , electrical engineering , engineering , physics , voltage
Contact lens sensing platforms have drawn interest in the last decade for the possibility of providing a sterile, fully integrated ocular screening technology. However, designing scalable and rapid contact lens processing methods while keeping a high resolution is still an unsolved challenge. In this article, femtosecond laser writing is employed as a rapid and precise procedure to engrave microfluidic networks into commercial contact lenses. Functional microfluidic components such as flow valves, resistors, multi‐inlet geometries, and splitters are produced using a bespoke seven‐axis femtosecond laser system, yielding a resolution of 80 µm. The ablation process and the tear flow within microfluidic structures is evaluated both experimentally and computationally using finite element modeling. Flow velocity drops of the 8.3%, 20.8%, and 29% were observed in valves with enlargements of the 100%, 200%, and 300%, respectively. Resistors yielded flow rate drops of 20.8%, 33%, and 50% in the small, medium, and large configurations, respectively. Two applications were introduced, namely a tear volume sensor and a tear uric acid sensor (sensitivity 16 mg L −1 ), which are both painless alternatives to current methods and provide reduced contamination risks of tear samples.