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Scleral Lens Sensor for Ocular Electrolyte Analysis
Author(s) -
Yetisen Ali K.,
Jiang Nan,
Castaneda Gonzalez Carmen M.,
Erenoglu Zeynep Izlen,
Dong Jie,
Dong Xingchen,
Stößer Simon,
Brischwein Martin,
Butt Haider,
Cordeiro Maria F.,
Jakobi Martin,
Hayden Oliver,
Koch Alexander W.
Publication year - 2020
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201906762
Subject(s) - scleral lens , fluorescence , materials science , ion , analytical chemistry (journal) , contact lens , lens (geology) , detection limit , chemistry , optics , chromatography , physics , organic chemistry
The quantitative analysis of tear analytes in point‐of‐care settings can enable early diagnosis of ocular diseases. Here, a fluorescent scleral lens sensor is developed to quantitatively measure physiological levels of pH, Na + , K + , Ca 2+ , Mg 2+ , and Zn 2+ ions. Benzenedicarboxylic acid, a pH probe, displays a sensitivity of 0.12 pH units within pH 7.0–8.0. Crown ether derivatives exhibit selectivity to Na + and K + ions within detection ranges of 0–100 and 0–50 mmol L −1 , and selectivities of 15.6 and 8.1 mmol L −1 , respectively. A 1,2 bis( o ‐aminophenoxy)ethane‐ N , N ,‐ N ', N '‐tetraacetic‐acid‐based probe allows Ca 2+ ion sensing with 0.02–0.05 mmol L −1 sensitivity within 0.50–1.25 mmol L −1 detection range. 5‐Oxazolecarboxylic acid senses Mg 2+ ions, exhibiting a sensitivity of 0.10–0.44 mmol L −1 within the range of 0.5–0.8 mmol L −1 . The N ‐(2‐methoxyphenyl)iminodiacetate Zn 2+ ion sensor has a sensitivity of 1 µmol L −1 within the range of 10–20 µmol L −1 . The fluorescent sensors are subsequently multiplexed in the concavities of an engraved scleral lens. A handheld ophthalmic readout device comprising light‐emitting diodes (LEDs) and bandpass filters is fabricated to excite as well as read the scleral sensor. A smartphone camera application and an user interface are developed to deliver quantitative measurements with data deconvolution. The ophthalmic system enables the assessment of dry eye severity stages and the differentiation of its subtypes.