On the Possibility of Fluorescent Capture Immunoassays on a Contact Lens

Blood samples and testing are routine in healthcare. Presently, there is a growing interest in using tear samples in place of blood. Tear samples can be obtained non-invasively and collection does not require the skills of a trained phlebotomist. Red blood cells and other cells are not present in te...

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Main Authors: Kundan Sivashanmugan, E. Albert Reece, Joseph R. Lakowicz
Format: Article
Language:English
Published: MDPI AG 2025-05-01
Series:Biosensors
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Online Access:https://www.mdpi.com/2079-6374/15/5/326
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author Kundan Sivashanmugan
E. Albert Reece
Joseph R. Lakowicz
author_facet Kundan Sivashanmugan
E. Albert Reece
Joseph R. Lakowicz
author_sort Kundan Sivashanmugan
collection DOAJ
description Blood samples and testing are routine in healthcare. Presently, there is a growing interest in using tear samples in place of blood. Tear samples can be obtained non-invasively and collection does not require the skills of a trained phlebotomist. Red blood cells and other cells are not present in tears, which avoids centrifugation. Importantly, basal tear samples contain most of the biomarkers present in blood. The difficulty is the small volume of basal tears, which is about 7 μL in each eye. Any contact with the eye results in additional reflex tears with a different chemical composition. The small tear samples are collected with capillary tubes and then sent out for amplified assays, such as enzyme-linked immunosorbent assay (ELISA) or polymerase chain reaction (PCR). The results are not available for several days or a week and, therefore, are less useful in an ophthalmology office. We propose the use of a contact lens that contains bound antibodies for fluorescence immunoassays. The lenses could be removed from the patient for point-of-care measurements at the bedside. To prove that this concept is possible, we performed a three-layer protein capture assay that mimics an immunoassay. For convenience, we used lysozyme (Lys), which spontaneously coats silicon hydrogel (SiHG) contact lenses (CL). Anti-lysozyme IgG was the second layer captured, with anti-lysozyme considered to be the target biomarker. The third layer was rhodamine or Alexa Fluor-labeled Ab against the IgG Fc region, considered to be the detection antibody. The multiple protein layers were stable and did not wash off the SiHG lenses. These results strongly suggest the contact lens can be used for capture immunoassays for a wide variety of biomarkers.
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spelling doaj-art-4cb0a09579c24f4e9173601462ec96332025-08-20T01:56:17ZengMDPI AGBiosensors2079-63742025-05-0115532610.3390/bios15050326On the Possibility of Fluorescent Capture Immunoassays on a Contact LensKundan Sivashanmugan0E. Albert Reece1Joseph R. Lakowicz2Center for Fluorescence Spectroscopy, Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 721 West Lombard St., Baltimore, MD 21201, USADepartment of Obstetrics, Gynecology and Reproductive Sciences, University of Maryland School of Medicine, 655 W., Baltimore, MD 21201, USACenter for Fluorescence Spectroscopy, Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 721 West Lombard St., Baltimore, MD 21201, USABlood samples and testing are routine in healthcare. Presently, there is a growing interest in using tear samples in place of blood. Tear samples can be obtained non-invasively and collection does not require the skills of a trained phlebotomist. Red blood cells and other cells are not present in tears, which avoids centrifugation. Importantly, basal tear samples contain most of the biomarkers present in blood. The difficulty is the small volume of basal tears, which is about 7 μL in each eye. Any contact with the eye results in additional reflex tears with a different chemical composition. The small tear samples are collected with capillary tubes and then sent out for amplified assays, such as enzyme-linked immunosorbent assay (ELISA) or polymerase chain reaction (PCR). The results are not available for several days or a week and, therefore, are less useful in an ophthalmology office. We propose the use of a contact lens that contains bound antibodies for fluorescence immunoassays. The lenses could be removed from the patient for point-of-care measurements at the bedside. To prove that this concept is possible, we performed a three-layer protein capture assay that mimics an immunoassay. For convenience, we used lysozyme (Lys), which spontaneously coats silicon hydrogel (SiHG) contact lenses (CL). Anti-lysozyme IgG was the second layer captured, with anti-lysozyme considered to be the target biomarker. The third layer was rhodamine or Alexa Fluor-labeled Ab against the IgG Fc region, considered to be the detection antibody. The multiple protein layers were stable and did not wash off the SiHG lenses. These results strongly suggest the contact lens can be used for capture immunoassays for a wide variety of biomarkers.https://www.mdpi.com/2079-6374/15/5/326contact lenssilicon hydrogel lenseslysozymebiomarker detectingtearsfluorescein
spellingShingle Kundan Sivashanmugan
E. Albert Reece
Joseph R. Lakowicz
On the Possibility of Fluorescent Capture Immunoassays on a Contact Lens
Biosensors
contact lens
silicon hydrogel lenses
lysozyme
biomarker detecting
tears
fluorescein
title On the Possibility of Fluorescent Capture Immunoassays on a Contact Lens
title_full On the Possibility of Fluorescent Capture Immunoassays on a Contact Lens
title_fullStr On the Possibility of Fluorescent Capture Immunoassays on a Contact Lens
title_full_unstemmed On the Possibility of Fluorescent Capture Immunoassays on a Contact Lens
title_short On the Possibility of Fluorescent Capture Immunoassays on a Contact Lens
title_sort on the possibility of fluorescent capture immunoassays on a contact lens
topic contact lens
silicon hydrogel lenses
lysozyme
biomarker detecting
tears
fluorescein
url https://www.mdpi.com/2079-6374/15/5/326
work_keys_str_mv AT kundansivashanmugan onthepossibilityoffluorescentcaptureimmunoassaysonacontactlens
AT ealbertreece onthepossibilityoffluorescentcaptureimmunoassaysonacontactlens
AT josephrlakowicz onthepossibilityoffluorescentcaptureimmunoassaysonacontactlens