Folic acid incorporated nitrogen‐doped carbon dots as a turn‐on fluorescence probe for homocysteine detection

• Published in: Luminescence (Chichester, England) Vol. 38; no. 1; pp. 19 - 27
• Main Authors: Anju, Saralammma Madanan, Aswathy, Asokan Omana, Varghese, Susan, Abraham, Merin Kodinattumkunnel, Lekshmi, Ragini Sanjeevan, Ibrahim Shkhair, Ali, Lekha, Girija Muraleedharan, Syamchand, Sasidharanpillai S., George, Sony
• Format: Journal Article
• Language: English
• Published: England Wiley Subscription Services, Inc 01.01.2023
• Subjects: bio thiols; biomarker; biosensor; Carbon; Carbon dots; Carbon sources; Citric acid; cysteine; Detection; Fluorescence; Fluorescent Dyes; Fluorescent indicators; Folic Acid; Glutathione; Homocysteine; inflammation; Nitrogen; paper strip assay; Quantum Dots; Spectrometry, Fluorescence - methods; Urea; homocysteine; paper strip assay; biosensor; inflammation; cysteine; bio thiols; biomarker
• ISSN: 1522-7235; 1522-7243
• DOI: 10.1002/bio.4411

This study describes the development of a low‐cost fluorescence assay for detecting homocysteine (Hcy) without the interference of cysteine and glutathione using carbon quantum dots. Herein nitrogen‐doped carbon quantum dots (NCDs) were synthesized from citric acid as the carbon source and urea as the dopant using a one‐pot microwave‐assisted method. The obtained NCDs were incorporated with folic acid (FA) by the direct ex situ addition method and were used as a fluorescence probe to detect Hcy. The probe exhibited a fluorescence turn‐on response with increased Hcy concentration up to 50 μM with a limit of detection of 2.276 μM. The point of care detection of Hcy using the probe was also tested with a paper‐based assay strip. The study describes the use of folic acid incorporated nitrogen‐doped carbon dots as a fluorescence probe for the detection of homocysteine without the interference of cysteine and glutathione. The folic acid quenched fluorescence of NCD was retrieved by the addition of Hcy which leads to its detection linearly. The probe's LoD was found to be 2.276 μM.