AUSTRALIAN JOURNAL OF CHEMISTRY
·
2022
·Vol. 75
·期 5
·345-352
·
IF 1.224
Yuzheng Shi,Xicheng Xie,Lumei Wang,Linzheng Wang,Lingyun Li,Zhiyu Yan,Guoqing Shen,Yuzheng Shi,Xicheng Xie,Lumei Wang,Linzheng Wang,Lingyun Li,Zhiyu Yan,Guoqing Shen
This paper describes a fluorometric assay for the determination of carbendazim (CBZ) in aqueous samples based on an unmodified CBZ-specific aptamer and the fluorescent intercalator SYBR Green I (SG-I). The CBZ aptamer has double-stranded parts and G-quadruplex spatial structures, which can be recognized by SG-I. It leads to strong fluorescent emission of SG-I. In the presence of CBZ, the aptamer will bind to CBZ to form stable compounds due to its specific affinity. This will induce the conformational change of the aptamer. SG-I will then detach from the aptamer, leading to the decrease of its fluorescence. Therefore, the concentration of CBZ is determined through the changes in fluorescence of the system. This fluorometric biosensor for CBZ detection is constructed with a linear range from 3.58 to 230 nM with a limit of detection (LOD) of 3.58 nM. With great sensitivity and selectivity, this assay is efficient and convenient with a < 40 min operation time. Meanwhile, the average recovery of CBZ is 99.87–101.77% in the application of actual water samples with relative standard deviations (RSD) ranging from 1.97 to 2.63%.
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MICROCHIMICA ACTA
·
2019
·Vol. 186
·期 10
·1-9
·
IF 5.479
Yi Haoyang,Yan Zhiyu,Wang Lumei,Zhou Xiaotong,Yan Rui,Zhang Dongwei,Shen Guoqing,Zhou Shanshan
A fluorometric method is described for the determination of ofloxacin (OFL). It is based on the use of the fluorescent intercalator SYBR Green I (SG-I). The OFL-aptamer has G-quadruplex structures and can be recognized by SG-I. It results in strong fluorescence of SG-I. If OFL is present, OFL will bind to its aptamer to form stable complexes. This induces the despiralization of partial dsDNA regions, leads to changes in the structure of the aptamer. Thus, SG-I is released from the OFL-aptamer into solution. Hence, the fluorescence of SG-I drops. Fluorescence decreases linearly in the 1.1 to 200 nM OFL concentration range, and the limit of detection is 0.34 nM. The method shows good selectivity to much interference including analogues, hormones, pesticides. It is also effortless and fast with the times of measurement of <40 min. In addition, good recoveries of 91.3–119.0% were found for tap water, river water and artificial urine spiked with OFL with relative standard deviation (RSD) of ≤11.6%.
A sensitive fluorometric method is developed for ofloxacin (OFL) detection in aqueous samples based on the fluorescence intensity change of SYBR Green I (SG-I) with or without OFL.
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Analytical Methods
·
2023
·Vol. 15
·期 12
·1546-1552
·
IF 3.1
Yucui Hou,Xiaoling Lu,Jie Yang,Chunhua Tang,Hanbing Jiang,Tongji Cai,Meilun Chen,Zheng Wei,Peng Yu
Testosterone is a steroid hormone that plays an indispensable role in the normal metabolism of organisms. However, exogenous testosterone, even as low as nmol L−1, will harm the human body due to accumulation. In this study, we developed an unlabeled fluorescent sensor for testosterone based on SYBR Green I. SYBR Green I is a fluorescent dye that can be embedded into the G-quadruplex of the testosterone aptamer T5. The fluorescence quenching effect is utilized to achieve quantitative detection, which occurs by the competition between testosterone and SYBR Green I for the T5 aptamer binding sites. In this work, we optimized the detection conditions to make the fluorescent sensor more sensitive and verify the specificity, linear range, and detection ability in the buffer and real water samples. The sensor's LOD and LOQ values were 0.27 nmol L−1 and 0.91 nmol L−1, respectively, while the detection range was linear from 0.91 nmol L−1 to 2000 nmol L−1. According to the results, the sensor shows high specificity and good performance even in real sample detection such as tap water and river water, providing an alternative method for the quantitative detection of testosterone in the environment, which is more convenient and efficient.
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JOURNAL OF FOOD AND DRUG ANALYSIS
·
2022
·
IF 6.157
Jia Wang,Chengyi Hong,Zhengzhong Lin,Zhi-Yong Huang
A simple fluorescence method to quantitatively monitor malachite green (MG) was introduced based on the conformation switch effect of MG-aptamer (Apt) and the fluorochrome of SYBR Green I (SGI). SGI can embed in the stem-loop structure of Apt to produce fluorescence. However, the fluorescence will be quenched when MG is introduced because of the specific binding of Apt to MG. Under the optimal conditions, the fluorescence method displayed excellent linear relationship between the fluorescence quenching efficiencies and the MG concentrations ranging from 0.02 μmol L −1 to 1.0 μmol L −1 . The detection limit of the method was 0.67 μg kg −1 (3 α / κ , n = 9) which is lower than the limit (1 μg kg −1 ) specified in the national standard of China (GB/T 19857–2005) and the limit (2 μg kg −1 ) specified by the European Food Safety Authority (EFSA, 2016). Excellent recoveries between 87.1% and 106.9% tested by spiking standards were achieved with RSD less than 6.4%. The data were confirmed by the method of HPLC, and the results proved that the established fluorescence method could be used for the rapid detection of MG in fish with high accuracy and sensitivity.
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NEW JOURNAL OF CHEMISTRY
·
2022
·Vol. 46
·期 33
·16177-16182
·
IF 3.925
Shuyan Xiao,Liang Sun,Jiping Lu,Zhongping Dong
A label-free fluorescent biosensor based on the clenbuterol binding aptamer and the fluorescent intercalator SYBR Green I (SGI) was established for the sensitive and selective detection of clenbuterol. In the absence of clenbuterol, a weak fluorescence signal of SGI was observed. In the presence of clenbuterol, the specific recognition and high-affinity binding of the aptamer with clenbuterol induced a conformational change of the aptamer, and a longer double-stranded DNA was formed. As a result, an enhancement in the fluorescence of SGI could be found. Under optimal conditions, the fluorescence change ratio increased linearly with clenbuterol concentration from 50 nM to 450 nM, with a detection limit of 18.8 nM. In addition, the proposed aptasensor showed good selectivity and was successfully applied for clenbuterol quantification in pork samples with recoveries of 90.37–104.98%.
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TALANTA
·
2025
·
IF 6.1
Luke Wei,Yuxin Hu,Jiamin Wu,Jing Mao,Tianqin Yin,Jieqiong Qiu
Doxorubicin (DOX), a widely utilized chemotherapeutic antibiotic, increasingly threatens environmental and public health due to its persistence in marine ecosystems, bioaccumulation in organisms, and contamination of agricultural systems. In response to the urgent demand for effective DOX detection, we have developed a label-free fluorescent aptamer biosensor (FAB) that employs SYBR Green I (SG I)-mediated signal amplification. A key innovation in this design is the strategic fragmentation of the 41-mer complementary strand (CP) of the DOX aptamer into three 11-mer fragments. It significantly mitigates nonspecific SG I binding interference caused by the longer ssDNA CP, enhancing the fluorescence signal ratio (F dsDNA /F ssDNA ) from 4.6-fold to 12.6-fold. Upon DOX introduction, competitive binding between DOX, SG I, and DNA further suppresses background noise, yielding an exceptional fluorescence quenching ratio (F 0 /F) of 52.8. The optimized FAB demonstrates ultra-sensitive DOX detection, with a detection limit of 1.41 nM and a linear response between 1.41 nM and 300 nM. The recoveries of DOX spiked into pond water and drinking water samples ranged from 95.1% to 101.8%, with relative standard deviations (RSDs) below 3.46%, demonstrating negligible matrix effects and confirming the FAB method’s robustness for environmental monitoring applications. This strategy synergistically enhances signal transduction efficiency, and strengthens detection reliability, all while maintaining operational simplicity. As a result, this FAB for DOX detection holds transformative potential, poised to revolutionize biosensor technology in the fields of food safety, environmental monitoring, and biosecurity.
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ANALYTICA CHIMICA ACTA
·
2020
·
IF 5.977
Dengwang Luo,Chaoyu Zhang,Yao Fang,Yiping Shen,Yuan Liang,Yaokun Xia,Fang Wu,Xiaosong Chen,Jingrong Liu,Jinghua Chen,Chunyan Li,Jianming Lan
Phospholipase A 2 (PLA 2 ) may be a vital biomarker for the prediction and diagnosis of some diseases. Consequently, it is of great significance to quantitatively detect PLA 2 in biologic samples. Herein, on the basis of the principle of luminescence resonance energy transfer (LRET) between upconversion nanoparticles (UCNPs) and SYBR Green I (SG), we proposed a technology for the highly sensitive detection of PLA 2 amount. Therein, as an energy receptor, SG will be quantitatively loaded into liposomes firstly. Then, due to the hydrolysis of liposomes under the catalysis of PLA 2 , SG will be released and inserted into the double-stranded DNA (dsDNA) on the surface of UCNPs, which triggers the LRET because of the shortening of effective spatial distance between UCNPs and SG. Under exciting of NIR light, UCNPs emit luminescence at 476 nm, which makes SG emit fluorescence at 522 nm through LRET. Under optimal conditions, the emission intensity ratio (I 522 nm /I 476 nm ) increased linearly with the PLA 2 amount in the range of 20 U/L to 400 U/L, and the limit of detection (LOD) reached 15 U/L. Here, after comparing with the clinical standard method, it is found that the biosensor is expected to provide a convenient and sensitive assay for the detection of PLA 2 in actual serum samples. Furthermore, such biosensor can also be used to test the inhibitor of PLA 2 .
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JOURNAL OF FLUORESCENCE
·
2024
·
IF 2.6
Li Ling,Li Zheng-Ling,Wang Wei,Long Xin-Xin,Liu Ping,Wang Guo-Tian,Sun Shi-Qing,Du Rong-Lian
The rapid and accurate detection of programmed death-ligand 1 (PD-L1) expression is of great value in the diagnosis and treatment of tumors. ELISA-based traditional method is the gold standard for protein detection, but there are still some shortcomings, especially the antigen-antibody dependence, greatly increased the detection time and cost. This work constructed a label-free fluorescent probe for rapid and sensitive detection of PD-L1 using a truncated aptamer as recognition molecules and double-stranded DNA specific dyes (SYBR Green I) as signal units. After a series of optimization conditions, this probe has good detection capability for PD-L1 in buffer solution with the detection limit as low as 0.68 ng/mL. Due to the specific recognition ability of aptamer and target, this method also has good selectivity for PD-L1 detection. The recovery of PD-L1 in human serum samples ranges from 86.20 to 96.36%. Compared with other methods, this strategy does not need to be marked, and does not need other complex design and purification process, but simple operation process and strong anti-interference ability. The whole detection process can be completed within 20 min and has good application prospect. This work will provide reference for drug dosage and prognosis evaluation of specific tumor therapy.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2024
·
IF 9.4
Hui Feng,Meng Luo,Guonian Zhu,Kerage Dorothy Mokeira,Yaoxin Yang,Yongxin Lv,Qing Tan,Xiangwen Lei,Hang Zeng,Hefa Cheng,Shuxia Xu
This study described the development of a photocatalytic electrochemical aptasensor for the purpose of detecting chloramphenicol (CAP) antibiotic residues in water by utilizing SYBR Green I (SG) and chemically exfoliated MoS 2 (ce-MoS 2 ) as synergistically signal-amplification platforms. The Au nanoparticles (AuNPs) were electrodeposited onto the surface of an indium tin oxide (ITO) electrode. After that, the thiolate-modified cDNA, also known as capture DNA, was combined with the aptamer. Subsequently, photosensitized SG molecules and ce-MoS 2 nanomaterial were inserted into the groove of the resultant double-stranded DNA (dsDNA). The activation of the photocatalytic process upon exposure to light resulted in the generation of singlet oxygen. This singlet oxygen effectively splits the double-stranded DNA, resulting in a significant enhancement in the current of [Fe(CN) 6 ] 3-/4- . When the CAP was present, both SG molecules and ce-MoS 2 broke away from the double-stranded DNA, which turned off the photosensitization response, leading to a significant decrease in the current of [Fe(CN) 6 ] 3-/4- . Under optimal conditions, the aptasensor exhibited a linear relationship between CAP and logarithmic concentrations from 20 to 1000 nM, with a detection limit (3 σ ) of 3.391 nM. The aptasensor also demonstrated good selectivity towards CAP in the presence of interfering antibiotics such as tetracycline, streptomycin, levofloxacin, ciprofloxacin, and sulfadimethoxine. Additionally, the results obtained from the analysis of natural water samples using the proposed aptasensor were consistent with the findings acquired through the use of a liquid chromatograph-mass spectrometer. Therefore, with its simplicity and high sensitivity, this biosensor can potentially detect alternative antibiotics in environmental water samples by replacing the aptamers based on photosensitization.
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ANALYTICAL CHEMISTRY
·
2024
·
IF 6.7
Qianru Zhang,Anqi Liu,Xin Song,Shihao Xu,Liangguo Da,Dan Lin,Changlong Jiang
Organophosphate pesticides (OPs) are widely utilized in agricultural production, and the residues threaten public health and environmental safety due to their toxicity. Herein, a novel and simple DNA aptamer-based sensor has been fabricated for the rapid, visual, and quantitative detection of profenofos and isocarbophos. The proposed DNA aptamers with a G-quadruplex spatial structure could be recognized by SYBR Green I (SG-I), resulting in strong green fluorescence emitted by SG-I. The DNA aptamers exhibit a higher specific binding ability to target OP molecules through aromatic ring stacking, disrupting the interaction between SG-I and DNA aptamers to induce green fluorescence quenching. Meanwhile, the fluorescence wavelength of G-quadruplex fluorescence emission peaks changes, accompanied by an obvious fluorescence variation from green to blue. SG-I-modified aptasensor without any additive reference fluorescence units for use in multicolor fluorescence assay for selective monitoring of OPs was first developed. The developed aptasensor provides a favorable linear range from 0 to 200 nM, with a low detection limit of 2.48 and 3.01 nM for profenofos and isocarbophos, respectively. Moreover, it offers high selectivity and stability in real sample detection with high recoveries. Then, a self-designed portable smartphone sensing platform was successfully used for quantitative result outputs, demonstrating experience in designing a neotype sensing strategy for point-of-care pesticide monitoring.
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International Journal of Nanomedicine
·
2023
·
IF 8
Huazhang Qiu,Namei Wu,Yanjie Zheng,Min Chen,Shaohuang Weng,Yuanzhong Chen,Xinhua Lin
A robust and versatile signal-on fluorescence sensing strategy was developed to provide label-free detection of various target analytes. The strategy used SYBR Green I dye and graphene oxide as signal reporter and signal-to-background ratio enhancer, respectively. Multidrug resistance protein 1 (MDR1) gene and mercury ion (Hg2+) were selected as target analytes to investigate the generality of the method. The linear relationship and specificity of the detections showed that the sensitive and selective analyses of target analytes could be achieved by the proposed strategy with low detection limits of 0.5 and 2.2 nM for MDR1 gene and Hg2+, respectively. Moreover, the strategy was used to detect real samples. Analytical results of MDR1 gene in the serum indicated that the developed method is a promising alternative approach for real applications in complex systems. Furthermore, the recovery of the proposed method for Hg2+ detection was acceptable. Thus, the developed label-free signal-on fluorescence sensing strategy exhibited excellent universality, sensitivity, and handling convenience.
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ANALYTICAL CHEMISTRY
·
2019
·
IF 6.35
Xinfeng Zhang,Xiaoya Fan,Yanying Wang,Fengjie Lei,Lin Li,Juewen Liu,Peng Wu
Aggregation of plasmonic gold nanoparticles (AuNPs) has been widely used for label-free colorimetric sensing. Adding salt is a commonly used method to induce a color change, but salt-induced aggregation by charge screening is a slow kinetic process, making quantitative and reproducible measurement difficult. Herein, we explored an alternative method by charge neutralization using positively charged molecules, such as a DNA-staining dye, SYBR Green I (SG), for efficient and stable assembly of AuNPs. Even submicromolar SG effectively triggered the aggregation of AuNPs in less than 1 min, and the resulting intense blue color was stable for over 10 h. The charge neutralization effect of SG was confirmed with zeta potential measurements. Besides, pH-dependent aggregation of AuNPs by SG agreed well with the pKa of the nitrogen atoms responsible for the positive charges in the SG structure. Moreover, the charge neutralization effect was also observed from polycations such as polyamines. The SG-induced assembly of AuNPs was developed into a label-free colorimetric sensing platform. Benefiting from the intense blue color, this new sensing strategy allowed visual detection of as low as 0.1 nM DNA, 50-fold lower than that by salt. Such a charge neutralization strategy may inspire further thinking on fundamental colloidal science and its applications in analytical chemistry. This work itself significantly improved AuNP-based colorimetric sensors in terms of detection time, signal stability, and sensitivity.
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