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Kong Y, Liu D, Guo X, Chen X. Fluorescence detection of three types of pollutants based on fluorescence resonance energy transfer and its comparison with colorimetric detection. RSC Adv 2023; 13:22043-22053. [PMID: 37483672 PMCID: PMC10359850 DOI: 10.1039/d3ra02647g] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 06/28/2023] [Indexed: 07/25/2023] Open
Abstract
This study aimed at three representative pollutants, benzidine, cyromazine, and streptomycin, which were commonly used and posed a great threat to both environment and human health, mainly to explore a fast, simple, sensitive, visible naked-eye detection method. Colorimetric detection by gold nanoparticles (AuNPs) was first attempted. The cross-linking reaction occurred owing to the strong forces between the targets and AuNPs, leading to aggregation and color change. However, large-scale aggregation was easily formed and settled, which failed to achieve accurate quantification. Thus, AuNPs are considered to be used in fluorescence detection as reaction bridges. The introduction of AuNPs could effectively quench the fluorescence of Rhodamine B based on fluorescence resonance energy transfer (FRET). Moreover, a classical "on-off-on" fluorescence detection system was constructed based on nanomaterials. When AuNPs were added, the red fluorescence of the Rhodamine B solution could be effectively quenched (the "off" reaction). However, the tight cross-linking reaction between the three targets and AuNPs occurred through the strong affinity, causing Rhodamine B to dissociate in the solution. The fluorescence was rapidly restored, accompanied by a significant enhancement of fluorescence intensity (the "on" reaction). The fluorescent responses toward the three targets were established, resulting in good linearity in a wide range with low detection limits. Moreover, through the investigation of specificity, the fluorescence sensor exhibited satisfying selectivity and high binding affinity to the detected targets among the same types of inferences, indicating great potential for practical application. This simple, fast and sensitive fluorescence detection system was first used for simultaneously detecting three types of pollutants and finally successfully applied to real samples.
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Affiliation(s)
- Yifei Kong
- School of Pharmacy, Lanzhou University Lanzhou 730000 P. R. China +86-15293109642
| | - Dan Liu
- School of Pharmacy, Lanzhou University Lanzhou 730000 P. R. China +86-15293109642
| | - Xinran Guo
- School of Pharmacy, Lanzhou University Lanzhou 730000 P. R. China +86-15293109642
| | - Xinyue Chen
- School of Pharmacy, Lanzhou University Lanzhou 730000 P. R. China +86-15293109642
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Zang S, Wu S, Xiao L, Deng X, Zhao Y. Hyperbranched Tetraphenylethylene Derivatives with Low Non-specific Aggregation-Induced Emission for Fluorescence Recognition of Proteins with Hydrophobic Pockets. Anal Chem 2022; 94:8365-8372. [PMID: 35653302 DOI: 10.1021/acs.analchem.2c00872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Proteins play an important role in the physiological process of many organisms, and their abnormal level often indicates the occurrence of some diseases. Therefore, protein analysis has important reference value and clinical significance for early diagnosis and therapy of disease. Using human serum albumin (HSA) as a model protein, a series of super-branched tetraphenylethylene (TPE) derivatives with different branching structures and terminal groups are reported herein for highly sensitive and specific recognition of proteins with hydrophobic cages. Benefiting from the hyperbranched structures, these probes showed much higher critical micelle concentrations (CMCs) than most linear TPE-based amphiphilic molecules since the hyperbranched structure not only improved their solubility but also amplified the steric hindrance effect and electrostatic repulsive force to prevent their aggregation. Dynamic light scattering experiments proved that these probes formed dense aggregates at CMC, and such aggregate structures would lead to a higher background fluorescence noise. Hence, a higher CMC is more conducive to the detection of the target with low backgrounds. Among them, P3-COOH with -COOH as the terminal unit and a relatively longer branch showed the highest CMC and the best signal to background ratio (S/N). Mechanism studies showed that P3-COOH was bound to HSA mainly through a hydrophobic force, resulting in a limited P3-COOH molecular movement and less attack from quenchers in solutions, thus leading to greatly enhanced fluorescence intensity. In addition, P3-COOH was also applied to the determination of HSA content in actual human serum samples.
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Affiliation(s)
- Shiyu Zang
- School of Chemical Engineering, Dalian University of Technology, Dalian 116023, PR China
| | - Shuo Wu
- School of Chemical Engineering, Dalian University of Technology, Dalian 116023, PR China
| | - Lili Xiao
- School of Chemical Engineering, Dalian University of Technology, Dalian 116023, PR China
| | - Xunxun Deng
- School of Chemical Engineering, Dalian University of Technology, Dalian 116023, PR China
| | - Yanqiu Zhao
- School of Chemical Engineering, Dalian University of Technology, Dalian 116023, PR China
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Phosphorylation-Dependent SERS Readout for Activity Assay of Protein Kinase A in Cell Extracts. NANOMATERIALS 2020; 10:nano10030575. [PMID: 32235706 PMCID: PMC7153394 DOI: 10.3390/nano10030575] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 03/17/2020] [Accepted: 03/18/2020] [Indexed: 12/13/2022]
Abstract
Protein kinases are key regulators of cell function, the abnormal activity of which may induce several human diseases, including cancers. Therefore, it is of great significance to develop a sensitive and reliable method for assaying protein kinase activities in real biological samples. Here, we report the phosphorylation-dependent surface-enhanced Raman scattering (SERS) readout of spermine-functionalized silver nanoparticles (AgNPs) for protein kinase A (PKA) activity assay in cell extracts. In this assay, the presence of PKA would phosphorylate and alter the net charge states of Raman dye-labeled substrate peptides, and the resulting anionic products could absorb onto the AgNPs with cationic surface charge through electrostatic attraction. Meanwhile, the Raman signals of dyes labeled on peptides were strongly enhanced by the aggregated AgNPs with interparticle hot spots formed in assay buffer. The SERS readout was directly proportional to the PKA activity in a wide range of 0.0001-0.5 U·μL-1 with a detection limit as low as 0.00003 U·μL-1. Moreover, the proposed SERS-based assay for the PKA activity was successfully applied to monitoring the activity and inhibition of PKA in real biological samples, particularly in cell extracts, which would be beneficial for kinase-related disease diagnostics and inhibitor screening.
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Hu Q, Kong J, Han D, Bao Y, Zhang X, Zhang Y, Niu L. Ultrasensitive peptide-based electrochemical detection of protein kinase activity amplified by RAFT polymerization. Talanta 2020; 206:120173. [DOI: 10.1016/j.talanta.2019.120173] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 07/08/2019] [Accepted: 07/24/2019] [Indexed: 01/16/2023]
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Wang Y, Li X, Waterhouse GIN, Zhou Y, Yin H, Ai S. Photoelectrochemical biosensor for protein kinase A detection based on carbon microspheres, peptide functionalized Au-ZIF-8 and TiO 2/g-C 3N 4. Talanta 2018; 196:197-203. [PMID: 30683351 DOI: 10.1016/j.talanta.2018.12.035] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 12/04/2018] [Accepted: 12/11/2018] [Indexed: 10/27/2022]
Abstract
In this work, a novel and sensitive photoelectrochemical (PEC) strategy was designed for protein kinase A (PKA) detection, comprising carbon microsphere (CMS) modified ITO electrode, TiO2 as the phosphate group recognition material and graphite-carbon nitride (g-C3N4) as photoactive material. For the first time, gold nanoparticle decorated zeolitic imidazolate frameworks (Au-ZIF-8) was employed to fabricate biosensor for PKA activity assay with the function of substrate peptide immobilization and signal amplification. Firstly, substrate peptides were assembled on the Au-ZIF-8/CMS/ITO surface through the covalent bonding between the gold nanoparticles (AuNPs) and sulfydryl groups of the peptides. Then, in the presence of ATP, phosphorylation of the substrate peptide was achieved under PKA catalysis. Finally, TiO2-g-C3N4 composites were further modified on the electrode surface based on bonding between TiO2 and phosphate groups created via phosphorylation of the peptide (yielding TiO2-g-C3N4/P-peptide/Au-ZIF-8/CMS/ITO), which is different with our previous work by directly immobilizing g-C3N4 composite on electrode surface. The developed method showed a wide linear range from 0.05-50 U mL-1. The detection limit was 0.02 U mL-1 (S/N = 3). The constructed biosensor exhibited high detection specificity for PKA. In addition, the wide applicability of this biosensor was demonstrated by evaluating the inhibition ability of ellagic acid towards PKA.
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Affiliation(s)
- Yue Wang
- College of Chemistry and Material Science, Shandong Agricultural University, 271018 Taian, Shandong, People's Republic of China
| | - Xue Li
- College of Chemistry and Material Science, Shandong Agricultural University, 271018 Taian, Shandong, People's Republic of China
| | - Geoffrey I N Waterhouse
- College of Chemistry and Material Science, Shandong Agricultural University, 271018 Taian, Shandong, People's Republic of China; School of Chemical Sciences, The University of Auckland, Auckland 1142, New Zealand
| | - Yunlei Zhou
- College of Chemistry and Material Science, Shandong Agricultural University, 271018 Taian, Shandong, People's Republic of China.
| | - Huanshun Yin
- College of Chemistry and Material Science, Shandong Agricultural University, 271018 Taian, Shandong, People's Republic of China.
| | - Shiyun Ai
- College of Chemistry and Material Science, Shandong Agricultural University, 271018 Taian, Shandong, People's Republic of China
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A label-free fluorescent biosensor for the detection of protein kinase activity based on gold nanoclusters/graphene oxide hybrid materials. Anal Chim Acta 2018; 1013:71-78. [DOI: 10.1016/j.aca.2018.01.053] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Revised: 12/20/2017] [Accepted: 01/22/2018] [Indexed: 12/25/2022]
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Wang M, Lin Z, Liu Q, Jiang S, Liu H, Su X. DNA-hosted copper nanoclusters/graphene oxide based fluorescent biosensor for protein kinase activity detection. Anal Chim Acta 2018; 1012:66-73. [DOI: 10.1016/j.aca.2018.01.029] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 01/10/2018] [Accepted: 01/15/2018] [Indexed: 02/08/2023]
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Copper nanoclusters/polydopamine nanospheres based fluorescence aptasensor for protein kinase activity determination. Anal Chim Acta 2018; 1035:184-191. [PMID: 30224138 DOI: 10.1016/j.aca.2018.06.043] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 06/13/2018] [Accepted: 06/15/2018] [Indexed: 11/22/2022]
Abstract
A fluorescence aptasensor was constructed for protein kinase (PKA) activity detection by utilizing copper nanoclusters (CuNCs) and polydopamine nanospheres (PDANS). Through the π-π stacking interactions between adenosine triphosphate (ATP) aptamer and PDANS, the ATP aptamer modified CuNCs (apt-CuNCs) were absorbed onto PDANS surface, thus the fluorescence of apt-CuNCs were quenched through fluorescence resonance energy transfer (FRET) from apt-CuNCs to PDANS. In the presence of ATP, ATP specifically bound to aptamer, causing the dissociation of apt-CuNCs from PDANS surface and restoring the fluorescence of apt-CuNCs. However, PKA translated ATP into adenosine diphosphate (ADP), and ADP had no competence to combine with ATP aptamer, thus, apt-CuNCs were released and absorbed onto the PDANS surface to cause the fluorescence quenching of apt-CuNCs again. Therefore, PKA activity was conveniently detected via the fluorescence signal change. Under the optimal conditions, PKA activity was detected in the range of 0.05-4.5 U mL-1 with a detection limit of 0.021 U mL-1. Furthermore, the feasibility of the aptasensor for kinase inhibitor screening was explored via assessment of kinase inhibitor H-89 as one model. This aptasensor was also performed for PKA activity determination in HepG2 cell lysates with satisfactory results.
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Determination of protein kinase A activity and inhibition by using hydroxyapatite nanoparticles as a fluorescent probe. Mikrochim Acta 2018; 185:225. [PMID: 29594552 DOI: 10.1007/s00604-018-2754-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 03/01/2018] [Indexed: 10/17/2022]
Abstract
The authors describe a fluorometric method for the determination of the activity and inhibition of protein kinase A (PKA). In the presence of ATP, PKA catalyzes the transfer of phosphate groups from ATP to a peptide, and the generated phosphorylated peptide quenches the fluorescence (measured at excitation/emission peaks of 340/440 nm) of the hydroxyapatite nanoparticles (HAP-NPs). A linear logarithmic relationship of PKA concentrations with fluorescence intensity in the range from 1 to 50 U·L-1 was obtained, and the lower limit of detection (LOD) is 0.5 U·L-1. This is much lower than LODs reported in the literature. The PKA inhibitor H-89 was studied, and the inhibition plot has a sigmoidal shape with a half-maximal inhibitory concentration of around 750 nM of H-89. At a 4.5 nM level of H-89, fluorescence of HAP-NPs fell to levels of no PKA controls, demonstrating that the assay is a viable tool to screen for kinase inhibitors. An assay with Hela cell lysates in combination with forskolin (an activator of adenylyl cyclase) and IBMX (a phosphodiesterase inhibitor used to activate the cellular activity of PKA) resulted in decreased fluorescence of HAP-NPs. This suggests that the assay can be applied for testing in vitro cell kinase activity. In our perception, this method will enable high-throughput screening for kinase-related drugs and fluorometric enzymatic detection in various areas. Graphical abstract Fluorescence assay based on hydroxyapatite nanoparticles (HAP) fluorescence quenching was developed for analysis of the activity and inhibition of protein kinase A (PKA).
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Hu K, Chen X, Chen W, Zhang L, Li J, Ye J, Zhang Y, Zhang L, Li CH, Yin L, Guan YQ. Neuroprotective effect of gold nanoparticles composites in Parkinson's disease model. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2018; 14:1123-1136. [PMID: 29474924 DOI: 10.1016/j.nano.2018.01.020] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2017] [Revised: 01/24/2018] [Accepted: 01/30/2018] [Indexed: 12/21/2022]
Abstract
Parkinson's disease (PD) is second most common neurodegenerative disorder worldwide. Although drugs and surgery can relieve the symptoms of PD, these therapies are incapable of fundamentally treating the disease. For PD patients, over-expression of α-synuclein (SNCA) leads to the death of dopaminergic neurons. This process can be prevented by suppressing SNCA over-expression through RNA interference. Here, we successfully synthesized gold nanoparticles (GNP) composites (CTS@GNP-pDNA-NGF) via the combination of electrostatic adsorption and photochemical immobilization, which could load plasmid DNA (pDNA) and target specific cell types. GNP was transfected into cells via endocytosis to inhibiting the apoptosis of PC12 cells and dopaminergic neurons. Simultaneously, GNP composites are also used in PD models in vivo, and it can successfully cross the blood-brain barrier by contents of GNP in the mice brain. In general, all the works demonstrated that GNP composites have good therapeutic effects for PD models in vitro and in vivo.
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Affiliation(s)
- Kaikai Hu
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou, China; Joint Laboratory of Laser Oncology with Cancer Center of Sun Yet-sen University, South China Normal University, Guangzhou, China
| | - Xiaohui Chen
- School of Life Science, South China Normal University, Guangzhou, China
| | - Wuya Chen
- School of Life Science, South China Normal University, Guangzhou, China
| | - Lingkun Zhang
- School of Life Science, South China Normal University, Guangzhou, China
| | - Jian Li
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou, China; Joint Laboratory of Laser Oncology with Cancer Center of Sun Yet-sen University, South China Normal University, Guangzhou, China
| | - Jialin Ye
- School of Life Science, South China Normal University, Guangzhou, China
| | - Yuxiao Zhang
- School of Life Science, South China Normal University, Guangzhou, China
| | - Li Zhang
- School of Life Science, South China Normal University, Guangzhou, China
| | - Chu-Hua Li
- School of Life Science, South China Normal University, Guangzhou, China
| | - Liang Yin
- School of Life Science, South China Normal University, Guangzhou, China
| | - Yan-Qing Guan
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou, China; Joint Laboratory of Laser Oncology with Cancer Center of Sun Yet-sen University, South China Normal University, Guangzhou, China; School of Life Science, South China Normal University, Guangzhou, China.
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Xu Y, Shi W, He X, Wu X, Li X, Ma H. Facile and Sensitive Method for Protein Kinase A Activity Assay Based on Fluorescent Off-On PolyU-peptide Assembly. Anal Chem 2017; 89:10980-10984. [PMID: 28937207 DOI: 10.1021/acs.analchem.7b02815] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Phosphorylation mediated by protein kinases plays a pivotal role in metabolic and cell-signaling processes, and the dysfunction of protein kinases such as protein kinase A (PKA) may induce several human diseases. Therefore, it is of great significance to develop a facile and effective method for PKA activity assay and high-throughput screening of inhibitors. Herein, we develop a new fluorescent off-on method for PKA assay based on the assembly of anionic polyuridylic acid (polyU) and cationic fluorescent peptide. The phosphorylation of the peptide disrupts its electrostatic binding with polyU, suppresses the concentration quenching effect of polyU, and thus causes fluorescence recovery. The recovered fluorescence intensity at 585 nm is directly proportional to the PKA activity in the range of 0.1-3.2 U/mL with a detection limit of 0.05 U/mL. Using our method, the PKA activity in HeLa cell lysate is determined to be 58.2 ± 5.1 U/mg protein. The method has also been employed to evaluate the inhibitory effect of PKA inhibitors with satisfactory results and may be expected to be a promising candidate for facile and cost-effective assay of kinase activity and high-throughput inhibitor screening.
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Affiliation(s)
- Yanhui Xu
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, China.,University of Chinese Academy of Sciences , Beijing 100049, China
| | - Wen Shi
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, China.,University of Chinese Academy of Sciences , Beijing 100049, China
| | - Xinyuan He
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, China
| | - Xiaofeng Wu
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, China
| | - Xiaohua Li
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, China
| | - Huimin Ma
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, China.,University of Chinese Academy of Sciences , Beijing 100049, China
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Liu Q, Na W, Wang L, Su X. Gold nanocluster-based fluorescent assay for label-free detection of protein kinase and its inhibitors. Mikrochim Acta 2017. [DOI: 10.1007/s00604-017-2349-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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13
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Zhang J, Lv J, Wang X, Li D, Wang Z, Li G. A simple and visible colorimetric method through Zr4+–phosphate coordination for the assay of protein tyrosine phosphatase 1B and screening of its inhibitors. Analyst 2015; 140:5716-23. [DOI: 10.1039/c5an00970g] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Inhibitors of protein tyrosine phosphatase 1B (PTP1B) are promising agents for the treatment of type 2 diabetes and obesity, so a colorimetric method has been developed in this work for PTP1B assay and screening of its inhibitors.
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Affiliation(s)
- Juan Zhang
- Laboratory of Biosensing Technology
- School of Life Sciences
- Shanghai University
- Shanghai 200444
- PR China
| | - Jun Lv
- Laboratory of Biosensing Technology
- School of Life Sciences
- Shanghai University
- Shanghai 200444
- PR China
| | - Xiaonan Wang
- Laboratory of Biosensing Technology
- School of Life Sciences
- Shanghai University
- Shanghai 200444
- PR China
| | - Defeng Li
- Laboratory of Biosensing Technology
- School of Life Sciences
- Shanghai University
- Shanghai 200444
- PR China
| | - Zhaoxia Wang
- Department of Oncology
- The Second Affiliated Hospital of Nanjing Medical University
- Nanjing 210011
- PR China
| | - Genxi Li
- Laboratory of Biosensing Technology
- School of Life Sciences
- Shanghai University
- Shanghai 200444
- PR China
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Song J, Wu FY, Wan YQ, Ma LH. Ultrasensitive turn-on fluorescent detection of trace thiocyanate based on fluorescence resonance energy transfer. Talanta 2014; 132:619-24. [PMID: 25476353 DOI: 10.1016/j.talanta.2014.10.023] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Revised: 10/05/2014] [Accepted: 10/10/2014] [Indexed: 10/24/2022]
Abstract
Thiocyanate (SCN(-)) is a small anion byproduct of cyanide metabolism. Several methods have been reported to measure SCN(-) above the micromolar level. However, SCN(-) is derived from many sources such as cigarettes, waste water, food and even car exhaust and its effect is cumulative, which makes it necessary to develop methods for the detection of trace SCN(-). In this paper, a simple and ultrasensitive turn-on fluorescence assay of trace SCN(-) is established based on the fluorescence resonance energy transfer (FRET) between gold nanoparticles (AuNPs) and fluorescein. The detection limit is 0.09 nM, to the best of our knowledge, which has been the lowest detection LOD ever without the aid of costly instrumentation. The fluorescence of fluorescein is significantly quenched when it is attached to the surface of AuNPs. Upon the addition of SCN(-), the fluorescence is turned on due to the competition action between SCN(-) and fluorescein towards the surface of AuNPs. Under an optimum pH, AuNPs size and concentration, incubation time, the fluorescence enhancement efficiency [(IF-I0)/I0] displays a linear relationship with the concentration of SCN(-) in the range of 1.0 nM to 40.0 nM. The fluorescein-AuNP sensor shows absolutely high selectivity toward SCN(-) than other 16 anions. The common metal ions, amino acids and sugars have no obvious interference effects. The accuracy and precision were evaluated based on the recovery experiments. The cost effective sensing system is successfully applied for the determination of SCN(-) in milk products and saliva samples.
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Affiliation(s)
- Juan Song
- Department of Chemistry, Nanchang University, Nanchang 330031, China
| | - Fang-Ying Wu
- Department of Chemistry, Nanchang University, Nanchang 330031, China.
| | - Yi-Qun Wan
- Department of Chemistry, Nanchang University, Nanchang 330031, China
| | - Li-Hua Ma
- Department of Chemistry, Nanchang University, Nanchang 330031, China.
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