{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T03:33:57Z","timestamp":1760240037220,"version":"build-2065373602"},"reference-count":35,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2019,2,22]],"date-time":"2019-02-22T00:00:00Z","timestamp":1550793600000},"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>In this work, a novel, simple, and time-saving fluorescence approach for the detection of biothiols (glutathione and cysteine) was developed by employing a DNA probe labeled with 2-aminopurine. As an adenine analogue, 2-aminopurine exhibits high fluorescence intensity that can be rapidly quenched in the presence of DNA. In the presence of Ag+, the fluorescence increased significantly, which was a result of the formation of cytosine\u2013Ag+\u2013cytosine base pairs and the release of 2-aminopurine. Upon addition of either glutathione or cysteine, the structure of cytosine\u2013Ag+\u2013cytosine was disrupted, a product of the stronger affinity between biothiols and Ag+. As a result, the 2-aminopurine-labeled DNA probe returned to its former structure, and the fluorescence signal was quenched accordingly. The detection limit for glutathione and cysteine was 3 nM and 5 nM, respectively. Furthermore, the determination of biothiols in human blood serum provided a potential application for the probe as a diagnostic tool in clinical practice.<\/jats:p>","DOI":"10.3390\/s19040934","type":"journal-article","created":{"date-parts":[[2019,2,22]],"date-time":"2019-02-22T11:26:14Z","timestamp":1550834774000},"page":"934","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Fluorescent Method for the Detection of Biothiols Using an Ag+-Mediated Conformational Switch"],"prefix":"10.3390","volume":"19","author":[{"given":"Han","family":"Zhao","sequence":"first","affiliation":[{"name":"School of Life Sciences, Central South University, Changsha 410083, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mingjian","family":"Chen","sequence":"additional","affiliation":[{"name":"School of Life Sciences, Central South University, Changsha 410083, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Changbei","family":"Ma","sequence":"additional","affiliation":[{"name":"School of Life Sciences, Central South University, Changsha 410083, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2019,2,22]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"10690","DOI":"10.1002\/anie.201103759","article-title":"Conjugate Addition\/Cyclization Sequence Enables Selective and Simultaneous Fluorescence Detection of Cysteine and Homocysteine","volume":"50","author":"Yang","year":"2011","journal-title":"Angew. Chem. Int. Ed."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"2585","DOI":"10.1016\/j.bios.2010.11.011","article-title":"Oligonucleotide-stabilized fluorescent silver nanoclusters for sensitive detection of biothiols in biological fluids","volume":"26","author":"Han","year":"2011","journal-title":"Biosens. Bioelectron."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"514","DOI":"10.1111\/j.1749-6632.1989.tb14973.x","article-title":"Mechanism of Interaction of Vitamin E and Glutathione in the Protection against Membrane Lipid Peroxidation","volume":"570","author":"Scholz","year":"1989","journal-title":"Ann. N. Y. Acad. Sci."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1153","DOI":"10.1105\/tpc.11.6.1153","article-title":"Phytochelatin Synthase Genes from Arabidopsis and the Yeast Schizosaccharomyces pombe","volume":"11","author":"Ha","year":"1999","journal-title":"Plant Cell"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"135","DOI":"10.1007\/BF02912897","article-title":"Study of oxidative stress and enzymatic antioxidants in normal pregnancy","volume":"22","author":"Patil","year":"2007","journal-title":"Ind. J. Clin. Biochem."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"3325","DOI":"10.1007\/s00604-017-2343-8","article-title":"Ultrasensitive fluorometric glutathione assay based on a conformational switch of a G-quadruplex mediated by silver(I)","volume":"184","author":"Ji","year":"2017","journal-title":"Microchim. Acta"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"269","DOI":"10.1007\/s00604-012-0925-z","article-title":"Nanosensor for dopamine and glutathione based on the quenching and recovery of the fluorescence of silica-coated quantum dots","volume":"180","author":"Xiangzhao","year":"2012","journal-title":"Microchim. Acta"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"42","DOI":"10.1016\/j.mam.2008.05.005","article-title":"Regulation of glutathione synthesis","volume":"30","author":"Lu","year":"2009","journal-title":"Mol. Aspects Med."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"909","DOI":"10.1016\/0140-6736(92)90939-Z","article-title":"Glutathione deficiency and human immunodeficiency virus infection","volume":"339","author":"Staal","year":"1992","journal-title":"Lancet"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"699","DOI":"10.1016\/S0891-5849(97)00286-4","article-title":"Glutathione in Human Plasma: Decline in Association with Aging, Age-Related Macular Degeneration, and Diabetes","volume":"24","author":"Samiec","year":"1998","journal-title":"Free Radic. Biol. Med."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"32","DOI":"10.1016\/j.trac.2019.01.019","article-title":"Tapiero, Assay for alkaline phosphatase activity: Progress and prospects","volume":"113","author":"Tang","year":"2019","journal-title":"Trends Anal. Chem."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"65","DOI":"10.1016\/j.bios.2013.01.047","article-title":"A label-free method for detecting biological thiols based on blocking of Hg2+-quenching of fluorescent gold nanoclusters","volume":"45","author":"Park","year":"2013","journal-title":"Biosens. Bioelectron."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"5569","DOI":"10.1021\/ac900769h","article-title":"Sensitive and Selective Sensor for Biothiols in the Cell Based on the Recovered Fluorescence of the CdTe Quantum Dots\u2212Hg(II) System","volume":"81","author":"Han","year":"2009","journal-title":"Anal. Chem."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"216","DOI":"10.1016\/0304-3940(90)90814-P","article-title":"Plasma cysteine and sulphate levels in patients with motor neurone, Parkinson\u2019s and Alzheimer\u2019s disease","volume":"110","author":"Heafield","year":"1990","journal-title":"Neurosci. Lett."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"564","DOI":"10.1002\/bmc.357","article-title":"Platinum particles-modified electrode for HPLC with pulsed amperometric detection of thiols in rat striatum","volume":"18","author":"Cao","year":"2010","journal-title":"Biomed. Chromatogr."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"7654","DOI":"10.1021\/acs.analchem.6b01491","article-title":"Ultrasensitive Glutathione Detection Based on Lucigenin Cathodic Electrochemiluminescence in the Presence of MnO2 Nanosheets","volume":"88","author":"Gao","year":"2016","journal-title":"Anal. Chim."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1485","DOI":"10.1021\/ac0517646","article-title":"Nile Red-Adsorbed Gold Nanoparticle Matrixes for Determining Aminothiols through Surface-Assisted Laser Desorption\/Ionization Mass Spectrometry","volume":"78","author":"Huang","year":"2006","journal-title":"Anal. Chim."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"9221","DOI":"10.1021\/ac4019457","article-title":"Detection of Cellular Glutathione and Oxidized Glutathione Using Magnetic\u2013Plasmonic Nanocomposite-Based \u201cTurn-Off\u201d Surface Enhanced Raman Scattering","volume":"85","author":"Saha","year":"2013","journal-title":"Anal. Chem."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.trac.2018.09.013","article-title":"Thioflavin T as a fluorescence probe for biosensing applications","volume":"109","author":"Khusbu","year":"2018","journal-title":"TrAC Trends Anal. Chem."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"347","DOI":"10.1007\/s00604-018-2885-4","article-title":"Fluorometric aptamer-based determination of ochratoxin A based on the use of graphene oxide and RNase H-aided amplification","volume":"185","author":"Ma","year":"2018","journal-title":"Microchim. Acta"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"110","DOI":"10.1007\/s00604-019-3247-6","article-title":"Fluorometric determination of the activity of uracil-DNA glycosylase by using graphene oxide and exonuclease I assisted signal amplification","volume":"186","author":"Chen","year":"2019","journal-title":"Microchim. Acta"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"273","DOI":"10.1016\/j.foodchem.2018.10.130","article-title":"Sensitive aptamer-based fluorescene assay for ochratoxin A based on RNase H signal amplification","volume":"277","author":"Wu","year":"2019","journal-title":"Food Chem."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"813","DOI":"10.1021\/ac102850y","article-title":"\u201cMolecular Beacon\u201d-Based Fluorescent Assay for Selective Detection of Glutathione and Cysteine","volume":"83","author":"Xu","year":"2011","journal-title":"Anal. Chem."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"5320","DOI":"10.1038\/srep05320","article-title":"A label-free fluorescent probe for Hg2+ and biothiols based on graphene oxide and Ru-complex","volume":"4","author":"Wang","year":"2014","journal-title":"Sci. Rep."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"8377","DOI":"10.1021\/acs.analchem.7b01632","article-title":"Gold Nanoparticle Loaded Split-DNAzyme Probe for Amplified miRNA Detection in Living Cells","volume":"89","author":"Wu","year":"2017","journal-title":"Anal. Chem."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"77","DOI":"10.1016\/j.bios.2015.02.012","article-title":"A label-free method for detecting biothiols based on poly(thymine)-templated copper nanoparticles","volume":"69","author":"Zhang","year":"2015","journal-title":"Biosens. Bioelectron."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"171","DOI":"10.1016\/j.bios.2016.08.033","article-title":"2-Aminopurine-modified DNA homopolymers for robust and sensitive detection of mercury and silver","volume":"87","author":"Zhou","year":"2017","journal-title":"Biosens. Bioelectron."},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Zhao, H., Xiang, X., Chen, M., and Ma, C. (2019). Aptamer-Based Fluorometric Ochratoxin A Assay Based on Photoinduced Electron Transfer. Toxins, 11.","DOI":"10.3390\/toxins11020065"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"142","DOI":"10.1016\/j.talanta.2018.01.075","article-title":"Label-free and nicking enzyme-assisted fluorescence signal amplification for RNase H determination based on a G-quadruplexe\/thioflavin T complex","volume":"182","author":"Wu","year":"2018","journal-title":"Talanta"},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Wu, K., Ma, C., Zhao, H., He, H., and Chen, H. (2018). Label-Free G-Quadruplex Aptamer Fluorescence Assay for Ochratoxin A Using a Thioflavin T Probe. Toxins, 10.","DOI":"10.3390\/toxins10050198"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"4825","DOI":"10.1039\/b808686a","article-title":"Specific interactions between silver(i) ions and cytosine\u2013cytosine pairs in DNA duplexes","volume":"39","author":"Ono","year":"2008","journal-title":"Chem. Commun."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"463","DOI":"10.1016\/j.snb.2014.04.006","article-title":"Indirect colorimetric detection of glutathione based on its radical restoration ability using carbon nanodots as nanozymes","volume":"199","author":"Shamsipur","year":"2014","journal-title":"Sens. Actuators B Chem."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"789","DOI":"10.1021\/ac902421u","article-title":"Ag+ and Cysteine Quantitation Based on G-Quadruplex-Hemin DNAzymes Disruption by Ag+","volume":"82","author":"Zhou","year":"2009","journal-title":"Anal. Chem."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"311","DOI":"10.1039\/C5AY02632F","article-title":"Conformational switch of G-quadruplex as a label-free platform for fluorescence detection of Ag+ and biothiol","volume":"8","author":"Yang","year":"2015","journal-title":"Anal. Methods"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"420","DOI":"10.1016\/j.bios.2013.05.051","article-title":"Stable label-free fluorescent sensing of biothiols based on ThT direct inducing conformation-specific G-quadruplex","volume":"49","author":"Tong","year":"2013","journal-title":"Biosens. Bioelectron."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/19\/4\/934\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T12:34:10Z","timestamp":1760186050000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/19\/4\/934"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2019,2,22]]},"references-count":35,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2019,2]]}},"alternative-id":["s19040934"],"URL":"https:\/\/doi.org\/10.3390\/s19040934","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2019,2,22]]}}}