A Smartphone-Assisted Schirmer Strip for Rapid Dual Colorimetric Sensing of Tear Glucose and pH Level
5 affiliations
- 1Kayseri State Hospital , , ,
- 2Erciyes University , , ,
- 3Yıldız Technical University , , , ,
- 4Kirsehir Ahi Evran University , , ,
- 5University of Health Sciences , , ,
Abstract
Although tear biomarkers are routinely determined using various clinical methods, most current techniques are complex, time-consuming, and require expensive equipment. Therefore, point-of-care (POC) testing is attracting considerable attention for rapid and noninvasive analyses. Here, we present a dual-function colorimetric Schirmer strip for the simultaneous determination of tear glucose and pH using the naked eye and image processing software. In our approach, horseradish peroxidase-glucose oxidase nanoflowers (HRP–GOx@NF) are used for glucose detection, and red cabbage-derived anthocyanins are used as a pH-sensitive, nontoxic indicator. In glucose detection, the catalytic stepwise reaction of HRP–GOx@NF produced a distinct blue color within 30 s by enabling the rapid oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of glucose, and this optimized platform exhibited a visual detection limit of 0.5 mM. Additionally, the anthocyanin-modified Schirmer strip simultaneously displayed distinct color transitions in response to varying pH values of the artificial tear fluid. This work presents a novel multiparametric paper platform that uniquely upgrades standard Schirmer strips for simultaneous, single-step tear collection, glucose sensing, and pH mapping without altering fluid flow. Like this, it demonstrates a rapid, cost-effective, and easy-to-prepare diagnostic tool offering significant advantages over conventional methods.
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BibTeX
@article{cetinkaya2026smartphoneassisted,
title = {{A Smartphone-Assisted Schirmer Strip for Rapid Dual Colorimetric Sensing of Tear Glucose and pH Level}},
author = {Zekeriya Cetinkaya and Nimet Temur and Umut Gorkem Kocabas and Sadik Kucukgunay and Humeyra Aslaner and Ismail Ocsoy},
journal = {ACS Omega},
year = {2026},
month = oct,
doi = {10.1021/acsomega.6c10289},
url = {https://pubs.acs.org/acsodf/article/11/42/65895/5450545/A-Smartphone-Assisted-Schirmer-Strip-for-Rapid},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - A Smartphone-Assisted Schirmer Strip for Rapid Dual Colorimetric Sensing of Tear Glucose and pH Level
AU - Zekeriya Cetinkaya
AU - Nimet Temur
AU - Umut Gorkem Kocabas
AU - Sadik Kucukgunay
AU - Humeyra Aslaner
AU - Ismail Ocsoy
PY - 2026
DA - 2026/10/13
JO - ACS Omega
DO - 10.1021/acsomega.6c10289
UR - https://pubs.acs.org/acsodf/article/11/42/65895/5450545/A-Smartphone-Assisted-Schirmer-Strip-for-Rapid
AB - Although tear biomarkers are routinely determined using various clinical methods, most current techniques are complex, time-consuming, and require expensive equipment. Therefore, point-of-care (POC) testing is attracting considerable attention for rapid and noninvasive analyses. Here, we present a dual-function colorimetric Schirmer strip for the simultaneous determination of tear glucose and pH using the naked eye and image processing software. In our approach, horseradish peroxidase-glucose oxidase nanoflowers (HRP–GOx@NF) are used for glucose detection, and red cabbage-derived anthocyanins are used as a pH-sensitive, nontoxic indicator. In glucose detection, the catalytic stepwise reaction of HRP–GOx@NF produced a distinct blue color within 30 s by enabling the rapid oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of glucose, and this optimized platform exhibited a visual detection limit of 0.5 mM. Additionally, the anthocyanin-modified Schirmer strip simultaneously displayed distinct color transitions in response to varying pH values of the artificial tear fluid. This work presents a novel multiparametric paper platform that uniquely upgrades standard Schirmer strips for simultaneous, single-step tear collection, glucose sensing, and pH mapping without altering fluid flow. Like this, it demonstrates a rapid, cost-effective, and easy-to-prepare diagnostic tool offering significant advantages over conventional methods.
SN - 2470-1343
ER -