{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,1]],"date-time":"2026-10-01T10:01:22Z","timestamp":1790848882451,"version":"4.1.0"},"reference-count":45,"publisher":"MDPI AG","issue":"19","license":[{"start":{"date-parts":[[2026,10,1]],"date-time":"2026-10-01T00:00:00Z","timestamp":1790812800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>An intrinsic optical fiber uric acid (UA) sensor has been developed using a molecularly imprinted chitosan (MIC) membrane-coated optical fiber as a transducer. The MIC was prepared by crosslinking chitosan with glutaraldehyde as a crosslinking reagent and UA as the template molecule. After an MIC membrane was coated on the surface of a bent optical fiber probe (BOFP), the template UA molecules were washed out of the membrane by using a diluted ammonia solution (0.10 M). This MIC membrane-coated BOFP was deployed into a sample solution for analyzing UA concentration. UA in the sample solution was selectively extracted\/concentrated into the MIC membrane, while interference species in the sample solution were blocked from entering into the membrane. UA extracted into the MIC membrane was detected by passing a light beam through the BOFP and the intrinsic optical absorption signal at 315 nm by UA itself was detected as a sensing signal. There is no chemical reaction involved, and no chemical reagent is needed when using this sensor to analyze UA in a sample solution. Compared with a bare fiber BOFP, MIC membrane extraction of UA from a sample solution increased the sensor\u2019s sensitivity by 1.0 \u00d7 104 times. The sensor achieved a detection limit of 0.049 \u00b5g\/mL with a linear calibration concentration that ranged up to 5.0 \u00b5g\/mL. The sensor demonstrates a good precision in analyzing UA in a urine sample with RSD% = 2.9%. This is a selective sensor; species potentially co-existing in regular urine samples with UA were tested, and were found not to cause interference. This sensor selectively responds to UA in its acid form, but is not sensitive to urate anions, which is different from most reported methods for analyzing UA. The sensor has been tested for analyzing UA in a urine sample and the obtained results demonstrate the feasibility of this sensor in real-world applications of analyzing UA in urine samples.<\/jats:p>","DOI":"10.3390\/s26196239","type":"journal-article","created":{"date-parts":[[2026,10,1]],"date-time":"2026-10-01T09:38:16Z","timestamp":1790847496000},"page":"6239","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["An Intrinsic Optical Fiber Uric Acid Sensor Using a Molecularly Imprinted Chitosan Membrane-Coated Optical Fiber as a Transducer"],"prefix":"10.3390","volume":"26","author":[{"given":"Geraldine","family":"Medina","sequence":"first","affiliation":[{"name":"Department of Chemistry and Physics, West Texas A&M University, WTAMU Box 60732, Canyon, TX 79106, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shiquan","family":"Tao","sequence":"additional","affiliation":[{"name":"Department of Chemistry and Physics, West Texas A&M University, WTAMU Box 60732, Canyon, TX 79106, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,10,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"31","DOI":"10.1007\/s12325-014-0175-z","article-title":"A Review of Uric Acid, Crystal Deposition Disease, and Gout","volume":"32","author":"Dalbeth","year":"2015","journal-title":"Adv. Ther."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"487","DOI":"10.1016\/j.jare.2017.03.003","article-title":"Physiological functions and pathogenic potential of uric acid: A review","volume":"8","author":"Tallima","year":"2017","journal-title":"J. Adv. Res."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Guan, H., Zheng, Y., Zhou, X., Xu, Y., Fu, C., Xiao, J., and Ye, Z. (2020). Efficacy of Different Urinary Uric Acid Indicators in Patients with Chronic Kidney Disease. BMC Nephrol., 21.","DOI":"10.1186\/s12882-020-01953-z"},{"key":"ref_4","unstructured":"Centers for Disease Control and Prevention (2026, September 26). Laboratory Procedure Manual: Uric Acid in Refrigerated Serum. National Health and Nutrition Examination Survey (NHANES), Available online: https:\/\/wwwn.cdc.gov\/nchs\/data\/nhanes\/public\/2015\/labmethods\/BIOPRO_I_MET_URIC_ACID_DXC800and660i.pdf."},{"key":"ref_5","first-page":"1306","article-title":"Spot Urine Uric Acid to Creatinine Ratio Used in the Estimation of Uric Acid Excretion in Primary Gout","volume":"28","author":"Moriwaki","year":"2001","journal-title":"J. Rheumatol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"100","DOI":"10.3126\/ijasbt.v13i3.84976","article-title":"Determination of Uric Acid in Biological Fluids with Special Emphasis on Biosensors and Sensors: A Review","volume":"13","author":"Pundir","year":"2025","journal-title":"Int. J. Appl. Sci. Biotechnol."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"69","DOI":"10.1080\/14737159.2020.1699063","article-title":"Current and Emerging Trends in Point-of-Care Urinalysis Tests","volume":"20","author":"Lei","year":"2020","journal-title":"Expert Rev. Mol. Diagn."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"027506","DOI":"10.1149\/1945-7111\/ad2281","article-title":"Disposable Point-of-Care Electrochemical Sensor for Uric Acid Determination in Human Urine Utilizing a Pencil Graphite Electrode Modified with Polydopamine\/Gold Nanoparticles","volume":"171","author":"Bayoumy","year":"2024","journal-title":"J. Electrochem. Soc."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"8555842","DOI":"10.1155\/2022\/8555842","article-title":"An Electrochemical-Based Point-of-Care Testing Methodology for Uric Acid Measurement","volume":"2022","author":"Zhao","year":"2022","journal-title":"J. Anal. Methods Chem."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1560","DOI":"10.1039\/C8AN00306H","article-title":"Undiluted Human Whole Blood Uric Acid Detection Using a Graphitized Mesoporous Carbon Modified Electrode: A Potential Tool for Clinical Point-of-Care Uric Acid Diagnosis","volume":"143","author":"Amreen","year":"2018","journal-title":"Analyst"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"145834","DOI":"10.1016\/j.electacta.2025.145834","article-title":"A Point-of-Care, Label-Free OECT Sensor for Uric Acid Detection: Validation in Human Saliva","volume":"519","author":"Ceccardi","year":"2025","journal-title":"Electrochim. Acta"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"775","DOI":"10.1021\/acsmeasuresciau.6c00046","article-title":"Fully 3D-Printed Sampling-to-Detection Electrochemical Platform for Point-of-Care Measurement of Salivary Uric Acid","volume":"6","author":"Raucci","year":"2026","journal-title":"ACS Meas. Sci. Au"},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Jarnda, K.V., Dai, H., Ali, A., Bestman, P.L., Trafialek, J., Roberts-Jarnda, G.P., Anaman, R., Kamara, M.G., Wu, P., and Ding, P. (2025). A Review on Optical Biosensors for Monitoring of Uric Acid and Blood Glucose Using Portable POCT Devices: Status, Challenges, and Future Horizons. Biosensors, 15.","DOI":"10.3390\/bios15040222"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"127709","DOI":"10.1016\/j.saa.2026.127709","article-title":"Synthesis of Fluorescent Iron-Doped Carbon Dots with Fenton Activity for Noninvasive Dual-Mode Urinary Uric Acid Monitoring toward Point-of-Care Renal Diagnostics","volume":"355","author":"Abdalla","year":"2026","journal-title":"Spectrochim. Acta Part A Mol. Biomol. Spectrosc."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"15699","DOI":"10.1021\/acs.analchem.0c03470","article-title":"Photoacoustic-Based Miniature Device with Smartphone Readout for Point-of-Care Testing of Uric Acid","volume":"92","author":"Zhang","year":"2020","journal-title":"Anal. Chem."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Lin, T.-J., Yen, K.-T., Chen, C.-F., Yan, S.-T., Su, K.-W., and Chiang, Y.-L. (2022). Label-Free Uric Acid Estimation of Spot Urine Using Portable Device Based on UV Spectrophotometry. Sensors, 22.","DOI":"10.3390\/s22083009"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"4155","DOI":"10.1016\/j.bios.2011.04.013","article-title":"Compact Optical Microfluidic Uric Acid Analysis System","volume":"26","author":"Chang","year":"2011","journal-title":"Biosens. Bioelectron."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Yang, Z., Cai, G., Zhao, J., and Feng, S. (2022). An Optical POCT Device for Colorimetric Detection of Urine Test Strips Based on Raspberry Pi Imaging. Photonics, 9.","DOI":"10.3390\/photonics9100784"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"2049","DOI":"10.1021\/acssensors.2c00854","article-title":"Digital Quantification Method for Sensitive Point-of-Care Detection of Salivary Uric Acid Using Smartphone-Assisted \u03bcPADs","volume":"7","author":"Fan","year":"2022","journal-title":"ACS Sens."},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Islam, M.N., Ahmed, I., Anik, M.I., Ferdous, M.S., and Khan, M.S. (2018). Developing Paper-Based Diagnostic Technique to Detect Uric Acid in Urine. Front. Chem., 6.","DOI":"10.3389\/fchem.2018.00496"},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Liu, Z., Quan, Y., Hu, T., and Chen, K. (2024). High Performance Paper-Based CdTe QDs Sensors for Point-of-Care Testing of Uric Acid in Human Urine. Proceedings of the IEEE 6th Advanced Information Management, Communicates, Electronic and Automation Control Conference (IMCEC), IEEE.","DOI":"10.1109\/IMCEC59810.2024.10575356"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1409","DOI":"10.1016\/0043-1354(82)90226-3","article-title":"The use of uric acid as a method of tracing domestic sewage discharges in riverine, estuarine and coastal water environments","volume":"16","author":"Brown","year":"1982","journal-title":"Water Res."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Honeychurch, K.-C. (2025). High-Performance Anion Exchange Chromatography Electrochemical Determination of Uric Acid as a Contamination Marker. Sci, 7.","DOI":"10.3390\/sci7020040"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"02001","DOI":"10.1051\/bioconf\/20237602001","article-title":"Uric acid as a marker of milk microbiological spoilage","volume":"76","author":"Khamzina","year":"2023","journal-title":"BIO Web Conf."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"359","DOI":"10.1080\/10408347.2019.1637711","article-title":"Recent progress on uric acid detection: A review","volume":"50","author":"Wang","year":"2020","journal-title":"Crit. Rev. Anal. Chem."},{"key":"ref_26","first-page":"1","article-title":"Analytical methods for measuring uric acid in biological samples and food products","volume":"70","author":"Pachla","year":"1987","journal-title":"J. Assoc. Off. Anal. Chem."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"711","DOI":"10.1016\/S0039-9140(02)00377-6","article-title":"Simultaneous Determination of Uric Acid and Creatinine in Urine by an Eco-Friendly Solvent-Free High Performance Liquid Chromatographic Method","volume":"58","author":"Jen","year":"2002","journal-title":"Talanta"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"122588","DOI":"10.1016\/j.jchromb.2021.122588","article-title":"Novel LC-MS-TOF Method to Detect and Quantify Ascorbic and Uric Acid Simultaneously in Different Biological Matrices","volume":"1168","author":"Borras","year":"2021","journal-title":"J. Chromatogr. B Anal. Technol. Biomed. Life Sci."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"127","DOI":"10.1016\/j.ab.2008.04.014","article-title":"Determination of Uric Acid in Human Urine and Serum by Capillary Electrophoresis with Chemiluminescence Detection","volume":"378","author":"Zhao","year":"2008","journal-title":"Anal. Biochem."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"18","DOI":"10.1016\/j.chroma.2007.10.024","article-title":"Molecularly imprinted polymer-based solid-phase extraction combined with molecularly imprinted polymer-based sensor for detection of uric acid","volume":"1173","author":"Prasad","year":"2007","journal-title":"J. Chromatogr. A"},{"key":"ref_31","first-page":"302","article-title":"Advances in solid phase microextraction and perspective on future directions","volume":"90","author":"Gionfriddo","year":"2017","journal-title":"Anal. Chem."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"145414","DOI":"10.1016\/j.foodchem.2025.145414","article-title":"An Optical Fiber Caffeic Acid Sensor Using a Molecularly-Imprinted Chitosan Membrane as a Transducer","volume":"492","author":"Arana","year":"2025","journal-title":"Food Chem."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"4732","DOI":"10.1007\/s11694-025-03958-4","article-title":"The Development of an Optical Fiber Gallic Acid Sensor with a Molecularly Imprinted Chitosan Membrane Coated on an Optical Fiber Surface as a Transducer for Analyzing Gallic Acid in Food Products","volume":"20","author":"Miller","year":"2026","journal-title":"J. Food Meas. Charact."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"46","DOI":"10.1007\/s12161-025-02942-4","article-title":"An Optical Fiber Chemical Sensor Using a Molecularly Imprinted Polymer Membrane as a Transducer for Analyzing Chlorogenic Acid in Coffee Products","volume":"19","author":"Mendoza","year":"2026","journal-title":"Food Anal. Methods"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"113422","DOI":"10.1016\/j.microc.2025.113422","article-title":"An Optical Fiber Aspirin Sensor with Molecularly-Imprinted Polymer Coating on Fiber Core Surface as Transducer","volume":"212","author":"McCaslin","year":"2025","journal-title":"Microchem. J."},{"key":"ref_36","first-page":"202","article-title":"A Folic Acid Sensor with a Molecularly Imprinted Chitosan Polymer Membrane Coated on an Optical Fiber Core Surface as a Transducer","volume":"11","author":"Mendoza","year":"2025","journal-title":"J. Food Nutr."},{"key":"ref_37","unstructured":"American Chemical Society (2026). Uric Acid. ACS Molecule of the Week (ACS150), American Chemical Society. Available online: https:\/\/www.acs.org\/molecule-of-the-week\/archive\/u\/uric-acid.html."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"89","DOI":"10.1016\/S0925-4005(01)00995-9","article-title":"Fabrication and Characterization of U-Shaped Fiber-Optic pH Probes","volume":"82","author":"Gupta","year":"2002","journal-title":"Sens. Actuators B Chem."},{"key":"ref_39","first-page":"449","article-title":"Fiber Optic Chemical Sensors for Environmental Monitoring","volume":"Volume 3","author":"Grimes","year":"2006","journal-title":"Encyclopedia of Sensors"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"115054","DOI":"10.1016\/j.colsurfb.2025.115054","article-title":"Controlled Drug Release Properties of Allopurinol-Incorporated Double-Layered Chitosan\/Starch Patches for Gout Therapy","volume":"256","author":"Kim","year":"2025","journal-title":"Colloids Surf. B Biointerfaces"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"564","DOI":"10.1016\/j.semnephrol.2020.12.003","article-title":"Uric acid and urate in urolithiasis: The innocent bystander, instigator, and perpetrator","volume":"40","author":"Adomako","year":"2020","journal-title":"Semin. Nephrol."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"335","DOI":"10.1016\/j.ucl.2007.05.001","article-title":"Uric acid nephrolithiasis","volume":"34","author":"Cameron","year":"2007","journal-title":"Urol. Clin. N. Am."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"2314","DOI":"10.1039\/C5TB02765A","article-title":"Synthesis of a Three-Layered SiO2@Au Nanoparticle@Polyaniline Nanocomposite and Its Application in Simultaneous Electrochemical Detection of Uric Acid and Ascorbic Acid","volume":"4","author":"Hou","year":"2016","journal-title":"J. Mater. Chem. B"},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"363","DOI":"10.1016\/j.bios.2012.03.018","article-title":"Determination of Glucose and Uric Acid with Bienzyme Colorimetry on Microfluidic Paper-Based Analysis Devices","volume":"35","author":"Chen","year":"2012","journal-title":"Biosens. Bioelectron."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"327","DOI":"10.1007\/s00706-017-2107-5","article-title":"Solubility equilibria in the uric acid\u2013ammonium urate\u2013water system","volume":"149","author":"Wang","year":"2018","journal-title":"Monatshefte Chem.-Chem. Mon."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/26\/19\/6239\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,10,1]],"date-time":"2026-10-01T09:40:11Z","timestamp":1790847611000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/26\/19\/6239"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,10,1]]},"references-count":45,"journal-issue":{"issue":"19","published-online":{"date-parts":[[2026,10]]}},"alternative-id":["s26196239"],"URL":"https:\/\/doi.org\/10.3390\/s26196239","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,10,1]]}}}