Abstract
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.
Original language | English |
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Article number | 2102008 |
Number of pages | 12 |
Journal | Small |
Volume | 17 |
Issue number | 38 |
Early online date | 19 Aug 2021 |
DOIs | |
Publication status | Published - 23 Sept 2021 |
Bibliographical note
Funding Information:The authors would like to acknowledge the support of LASEA SA, Belgium, within the framework of the ESIF project “Smart Factory Hub” (SmartFub). R.M. acknowledges the University of Birmingham, UK, for funding. A.K.Y. thanks the Engineering and Physical Sciences Research Council (EPSRC) for a New Investigator Award (EP/T013567/1).
Publisher Copyright:
© 2021 Wiley-VCH GmbH
Keywords
- Contact lenses
- Femtosecond Laser Ablation
- Lab-on-a-Chip
- Microfluidics
- Wearable Sensors
ASJC Scopus subject areas
- Biotechnology
- Biomaterials
- Chemistry(all)
- Materials Science(all)