Abstract
Increased level of CD44 protein in serum is observed in several cancers and is associated with tumor burden and metastasis. Current clinically used detection methods of this protein are time-consuming and use labeled reagents for analysis. Therefore exploring new label-free and fast methods for its quantification including its detection in situ is of importance. This study reports the first optical fiber biosensor for CD44 protein detection, based on a spherical fiber optic tip device. The sensor is easily fabricated from an inexpensive material (single-mode fiber widely used in telecommunication) in a fast and robust manner through a CO2 laser splicer. The fabricated sensor responded to refractive index change with a sensitivity of 95.76 dB/RIU. The spherical tip was further functionalized with anti-CD44 antibodies to develop a biosensor and each step of functionalization was verified by an atomic force microscope. The biosensor detected a target of interest with an achieved limit of detection of 17 pM with only minor signal change to two control proteins. Most importantly, concentrations tested in this work are very broad and are within the clinically relevant concentration range. Moreover, the configuration of the proposed biosensor allows its potential incorporation into an in situ system for quantitative detection of this biomarker in a clinical setting.
Highlights
Increased level of cluster of differentiation 44 (CD44) protein in serum is observed in several cancers and is associated with tumor burden and metastasis
We present the detection of CD44 protein using anti-CD44 antibody on a fiber optic spherical tip
A sphere was fabricated on the tip of single-mode fiber (SMF) as was demonstrated in previous work 32 which acted as a weak interferometer
Summary
Increased level of CD44 protein in serum is observed in several cancers and is associated with tumor burden and metastasis. Accumulating evidence has shown that abnormal expression of CD44 contributes to cancer progression and metastasis, including ovarian cancer, breast cancer, lung adenocarcinoma, glioblastoma, and colorectal cancer Detecting CD44 in serum was proposed as a simple, non-invasive way to study tumor burden and metastasis in gastric and colon c ancer[12]. Zhang et al developed an electrochemical sensor with multiwalled carbon nanotubes assembled on the indium tin oxide (TiO2) electrode surface using HA to detect CD44 in serum, conjugating the carbon nanotubes with HA-CD44 ligand–protein interaction[22]. Zhou et al.[25], on the other hand, developed an electrochemical biosensor using immobilized aptamers for label-free detection of CD44
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
