Abstract
In this work, a novel ratiometric fluorescent sensor, based on carbon dots (CDs) and gold nanoclusters (AuNCs), is developed for highly sensitive and selective visual colorimetric detection of Cu2+ and alkaline phosphatase (ALP). The ratiometric fluorescent sensor was synthesized by covalently linking 11-mercaptoundecanoic acid (11-MUA)–stabilized AuNCs to the surface of amino-functionalized CD/SiO2 nanoparticles. The red fluorescence of the AuNCs can be quenched by Cu2+ owing to coordination between Cu2+ and 11-MUA; however, the blue emission of the CDs was insensitive to Cu2+ owing to the protective silica shell. The quenching of the AuNCs’ fluorescence returned when PPi was added because of the higher affinity between Cu2+ and PPi than that between Cu2+ and 11-MUA. In the presence of ALP, PPi was catalytically hydrolyzed into phosphate (Pi), which showed a much weaker affinity for Cu2+. Thus, Cu2+ ions were released, and the fluorescence of the AuNCs was quenched once more. Based on this principle, Cu2+ and ALP could be simultaneously detected. The developed ratiometric fluorescent sensor could detect Cu2+ over a range from 0.025 to 4 μM with a detection limit of 0.013 μM and ALP over a range from 0.12 to 15 U/L with a detection limit of 0.05 U/L. The present method was successfully applied for the detection of Cu2+ and ALP in real water samples and in human serum samples, respectively. This ratiometric fluorescent approach may provide a highly sensitive and accurate platform for visual Cu2+ and ALP sensing in environmental monitoring and medical diagnosis.
Similar content being viewed by others
References
Hepel M, Stobiecka M. Interactions of adsorbed albumin with underpotentially deposited copper on gold piezoelectrodes. Bioelectrochemistry. 2007;70:155–64.
Stobiecka M, Hepel M, Radecki J. Transient conformation changes of albumin adsorbed on gold piezoelectrodes. Electrochim Acta. 2005;50:4873–87.
Barnham KJ, Masters CL, Bush AI. Neurodegenerative diseases and oxidative stress. Nat Rev Drug Discov. 2004;3:205–14.
Viles JH. Metal ions and amyloid fiber formation in neurodegenerative diseases. Copper, zinc and iron in Alzheimer’s, Parkinson’s and prion diseases. Coord Chem Rev. 2012;256:2271–84.
Liu J, Lu Y. A DNAzyme catalytic beacon sensor for paramagnetic Cu2+ ions in aqueous solution with high sensitivity and selectivity. J Am Chem Soc. 2007;129:9838–9.
Liu Y, Schanze KS. Conjugated polyelectrolyte-based real-time fluorescence assay for alkaline phosphatase with pyrophosphate as substrate. Anal Chem. 2008;80:8605–12.
Jiang H, Wang X. Alkaline phosphatase-responsive anodic electrochemiluminescence of CdSe nanoparticles. Anal Chem. 2012;84:6986–93.
Hu XL, Wu XM, Fang X, Li ZJ, Wang GL. Switchable fluorescence of gold nanoclusters for probing the activity of alkaline phosphatase and its application in immunoassay. Biosens Bioelectron. 2016;77:666–72.
Qian Z, Chai L, Tang C, Huang Y, Chen J, Feng H. Carbon quantum dots-based recyclable real-time fluorescence assay for alkaline phosphatase with adenosine triphosphate as substrate. Anal Chem. 2015;87:2966–73.
Liu S, Pang S, Na W, Su X. Near-infrared fluorescence probe for the determination of alkaline phosphatase. Biosens Bioelectron. 2014;55:249–54.
Yaffe MB. Phosphotyrosine-binding domains in signal transduction. Nat Rev Mol Cell Biol. 2002;3:177–86.
Julien SG, Dube N, Hardy S, Tremblay ML. Inside the human cancer tyrosine phosphatome. Nat Rev Cancer. 2011;11:35–49.
Li G, Fu H, Chen X, Gong P, Chen G, Xia L, et al. Facile and sensitive fluorescence sensing of alkaline phosphatase activity with photoluminescent carbon dots based on inner filter effect. Anal Chem. 2016;88:2720–6.
Ooi K, Shiraki K, Morishita Y, Nobori T. High-molecular intestinal alkaline phosphatase in chronic liver diseases. J Clin Lab Anal. 2007;21:133–9.
Choi Y, Ho N, Tung C. Sensing phosphatase activity by using gold nanoparticles. Angew Chem Int Ed. 2007;46:707–9.
Wei H, Chen C, Han B, Wang E. Enzyme colorimetric assay using unmodified silver nanoparticles. Anal Chem. 2008;80:7051–5.
Hasegawa T, Sugita M, Takatani K, Matsuura H, Umemura T, Haraguchi H. Assay of alkaline phosphatase in salmon egg cell cytoplasm with fluorescence detection of enzymatic activity and zinc detection by ICP-MS in relation to metallomics research. Bull Chem Soc Jpn. 2006;79:1211–4.
Murata T, Yasukawa T, Shiku H, Matsue T. Electrochemical single-cell gene-expression assay combining dielectrophoretic manipulation with secreted alkaline phosphatase reporter system. Biosens Bioelectron. 2009;25:913–9.
Miao P, Ning L, Li X, Shu Y, Li G. An electrochemical alkaline phosphatase biosensor fabricated with two DNA probes coupled with lambda exonuclease. Biosens Bioelectron. 2011;27:178–82.
Ino K, Kanno Y, Arai T, Inoue KY, Takahashi Y, Shiku H, et al. Novel electrochemical methodology for activity estimation of alkaline phosphatase based on solubility difference. Anal Chem. 2012;84:7593–8.
Diaz AN, Sanchez FG, Ramos MC, Torijas MC. Horseradish peroxidase sol-gel immobilized for chemiluminescence measurements of alkaline-phosphatase activity. Sensors Actuators B Chem. 2002;82:176–9.
Ingram A, Moore BD, Graham D. Simultaneous detection of alkaline phosphatase and beta-galactosidase activity using SERRS. Bioorg Med Chem Lett. 2009;19:1569–71.
Park KS, Lee CY, Park HG. A sensitive dual colorimetric and fluorescence system for assaying the activity of alkaline phosphatase that relies on pyrophosphate inhibition of the peroxidase activity of copper ions. Analyst. 2014;139:4691–5.
Zheng F, Guo S, Zeng F, Li J, Wu S. Ratiometric fluorescent probe for alkaline phosphatase based on betaine-modified polyethylenimine via excimer/monomer conversion. Anal Chem. 2014;86:9873–9.
Song Z, Kwok RTK, Zhao E, He Z, Hong Y, Lam JWY, et al. A ratiometric fluorescent probe based on ESIPT and AIE processes for alkaline phosphatase activity assay and visualization in living cells. ACS Appl Mater Interfaces. 2014;6:17245–54.
Li Y, Li Y, Wang X, Su X. A label-free conjugated polymer-based fluorescence assay for the determination of adenosine triphosphate and alkaline phosphatase. New J Chem. 2014;38:4574–9.
An LL, Tang YL, Feng FD, He F, Wang S. Water-soluble conjugated polymers for continuous and sensitive fluorescence assays for phosphatase and peptidase. J Mater Chem. 2007;17:4147–52.
Freeman R, Finder T, Gill R, Willner I. Probing protein kinase (CK2) and alkaline phosphatase with CdSe/ZnS quantum dots. Nano Lett. 2010;10:2192–6.
Jia L, Xu J, Li D, Pang S, Fang Y, Song Z, et al. Fluorescence detection of alkaline phosphatase activity with beta-cyclodextrin-modified quantum dots. Chem Commun. 2010;46:7166–8.
Zhou Q, Lin Y, Xu M, Gao Z, Yang H, Tang D. Facile synthesis of enhanced fluorescent gold-silver bimetallic nanocluster and its application for highly sensitive detection of inorganic pyrophosphatase activity. Anal Chem. 2016;88:8886–92.
Hepel M, Blake D, McCabe M, Stobiecka M, Coopersmith K. Assembly of gold nanoparticles induced by metal ion. In: Hepel M, Zhong CJ, editors. Functional nanoparticles for bioanalysis, nanomedicine, and bioelectronic devices, ACS Symposium Series, vol. 1. Oxford: Oxford University Press; 2012. p. 207–40.
Hepel M, Zhong C. Functional nanoparticles for bioanalysis, nanomedicine, and bioelectronic devices 1. Washington, DC: American Chemical Society; 2012. p. 147–76.
Hepel M. Functional gold nanoparticles for biointerfaces. In: Hepel M, Zhong CJ, editors. Functional nanoparticles for bioanalysis, nanomedicine, and bioelectronic devices 1. Washington, DC: American Chemical Society; 2012. p. 147–76.
Baker SN, Baker GA. Luminescent carbon nanodots: emergent nanolights. Angew Chem Int Ed. 2010;49:6726–44.
Shen J, Zhu Y, Yang X, Li C. Graphene quantum dots: emergent nanolights for bioimaging, sensors, catalysis and photovoltaic devices. Chem Commun. 2012;48:3686–99.
Zhu S, Meng Q, Wang L, Zhang J, Song Y, Jin H, et al. Highly photoluminescent carbon dots for multicolor patterning, sensors, and bioimaging. Angew Chem Int Ed. 2013;52:3953–7.
Lu Y, Chen W. Sub-nanometre sized metal clusters: from synthetic challenges to the unique property discoveries. Chem Soc Rev. 2012;41:3594–623.
Zhang L, Wang E. Metal nanoclusters: new fluorescent probes for sensors and bioimaging. Nano Today. 2014;9:132–57.
Chen L, Wang C, Yuan Z, Chang H. Fluorescent gold nanoclusters: recent advances in sensing and imaging. Anal Chem. 2015;87:216–29.
Sun J, Yang F, Zhao D, Yang X. Highly sensitive real-time assay of inorganic pyrophosphatase activity based on the fluorescent gold nanoclusters. Anal Chem. 2014;86:7883–9.
Liu H, Li M, Xia Y, Ren X. A turn-on fluorescent sensor for selective and sensitive detection of alkaline phosphatase activity with gold nanoclusters based on inner filter effect. ACS Appl Mater Interfaces. 2017;9:120–6.
Zhang K, Zhou H, Mei Q, Wang S, Guan G, Liu R, et al. Instant visual detection of trinitrotoluene particulates on various surfaces by ratiometric fluorescence of dual-emission quantum dots hybrid. J Am Chem Soc. 2011;133:8424–7.
Wang Y, Zhao T, He X, Li W, Zhang Y. A novel core-satellite CdTe/silica/Au NCs hybrid sphere as dual-emission ratiometric fluorescent probe for Cu2+. Biosens Bioelectron. 2014;51:40–6.
Yan X, Li H, Zheng W, Su X. Visual and fluorescent detection of tyrosinase activity by using a dual-emission ratiometric fluorescence probe. Anal Chem. 2015;87:8904–9.
Ju E, Liu Z, Du Y, Tao Y, Ren J, Qu X. Heterogeneous assembled nanocomplexes for ratiometric detection of highly reactive oxygen species in vitro and in vivo. ACS Nano. 2014;8:6014–23.
Wang C, Lin H, Xu Z, Huang Y, Humphrey MG, Zhang C. Tunable carbon-dot-based dual-emission fluorescent nanohybrids for ratiometric optical thermometry in living cells. ACS Appl Mater Interfaces. 2016;8:6621–8.
Yan X, Li H, Li Y, Su X. Visual and fluorescent detection of acetamiprid based on the inner filter effect of gold nanoparticles on ratiometric fluorescence quantum dots. Anal Chim Acta. 2014;852:189–95.
Han B, Li Y, Hu X, Yan Q, Jiang J, Yu M, et al. Paper-based visual detection of silver ions and l-cysteine with a dual-emissive nanosystem of carbon quantum dots and gold nanoclusters. Anal Methods. 2018;10:3945–50.
Sun J, Mei H, Gao F. Ratiometric detection of copper ions and alkaline phosphatase activity based on semiconducting polymer dots assembled with rhodamine B hydrazide. Biosens Bioelectron. 2017;91:70–5.
Yang Z, Li L, Sun Z, Ming T, Li G, Wang J, et al. Direct encoding of silica submicrospheres with cadmium telluride nanocrystals. J Mater Chem. 2009;19:7002–10.
Vashist SK, Lam E, Hrapovic S, Male KB, Luong JHT. Immobilization of antibodies and enzymes on 3-aminopropyltriethoxysilane-functionalized bioanalytical platforms for biosensors and diagnostics. Chem Rev. 2014;114:11083–130.
Chang H, Chang Y, Fan N, Ho JA. Facile preparation of high-quantum-yield gold nanoclusters: application to probing mercuric ions and biothiols. ACS Appl Mater Interfaces. 2014;6:18824–31.
Guo Y, Wang Z, Shao H, Jiang X. Stable fluorescent gold nanoparticles for detection of Cu2+ with good sensitivity and selectivity. Analyst. 2012;137:301–4.
Chen Y, Li W, Wang Y, Yang X, Chen J, Jiang Y, et al. Cysteine-directed fluorescent gold nanoclusters for the sensing of pyrophosphate and alkaline phosphatase. J Mater Chem C. 2014;2:4080–5.
Deng J, Yu P, Yang L, Mao L. Competitive coordination of Cu2+ between cysteine and pyrophosphate ion: toward sensitive and selective sensing of pyrophosphate ion in synovial fluid of arthritis patients. Anal Chem. 2013;85:2516–22.
Zhao Y, Zhang X, Han Z, Qiao L, Li C, Jian L, et al. Highly sensitive and selective colorimetric and off-on fluorescent chemosensor for Cu2+ in aqueous solution and living cells. Anal Chem. 2009;81:7022–30.
Vashist SK, Luppa PB, Yeo LY, Ozcan A, Luong JHT. Emerging technologies for next-generation point-of-care testing. Trends Biotechnol. 2015;33:692–705.
Vashist SK, Mudanyali O, Schneider EM, Zengerle R, Ozcan A. Cellphone-based devices for bioanalytical sciences. Anal Bioanal Chem. 2014;406:3263–77.
Funding
This work was supported by the Chinese National Scientific Foundation (21375146 and 21775163) and The National Key Research and Development Program of China (2016YFC0501205 and 2016YFC0501208).
Author information
Authors and Affiliations
Corresponding authors
Ethics declarations
Ethical approval
All biological experiments were performed with the approval of the Human Ethics Committee, China Agricultural University. Informed consent was obtained from all individual participants included in the study.
Conflict of interest
The authors declare that they have no competing interests.
Additional information
Publisher’s note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Electronic supplementary material
ESM 1
(PDF 958 kb)
Rights and permissions
About this article
Cite this article
Liu, H., Jia, L., Wang, Y. et al. Ratiometric fluorescent sensor for visual determination of copper ions and alkaline phosphatase based on carbon quantum dots and gold nanoclusters. Anal Bioanal Chem 411, 2531–2543 (2019). https://doi.org/10.1007/s00216-019-01693-6
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00216-019-01693-6