MOLECULES
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2022
·Vol. 27
·期 5
·1482
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IF 4.927
Yacong An,Xundou Li,Fengjiao Yao,Jinhong Duan,Xian-Da Yang
The PD-1/PD-L1 pathway blockade can generate a good clinical response by reducing immunosuppression and provoking durable antitumor immunity. In addition to antibodies, aptamers can also block the interaction between PD-1 and PD-L1. For the in vivo application, however, free aptamers are usually too small in size and quickly removed from blood via glomerular filtration. To avoid renal clearance of aptamer, we conjugated the PD-L1 aptamer to albumin to form a larger complex (BSA-Apt) and evaluated whether BSA-Apt would enhance the in vivo antitumor efficacy. The PD-L1 aptamer was thiol-modified and conjugated to the amino group of BSA via a SMCC linker. The average size of BSA-Apt was 11.65 nm, which was above the threshold for renal clearance. Functionally, BSA-Apt retained the capability of the PD-L1 aptamer to bind with PDL1-expressing tumor cells. Moreover, both the free aptamer and BSA-Apt augmented the PBMC-induced antitumor cytotoxicity in vitro. Furthermore, BSA-Apt generated a significantly stronger antitumor efficacy than the free PD-L1 aptamer in vivo without raising systemic toxicity. The results indicate that conjugating the PD-L1 aptamer to albumin may serve as a promising strategy to improve the in vivo functionality of the aptamer and that BSA-Apt may have application potential in cancer immunotherapy.Keywords:PD-L1;aptamer;albumin;BSA-Apt;cancer;immunotherapy
研究领域:
肿瘤学
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免疫学
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DOI
PubMed
高影响因子
Foods
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2022
·Vol. 11
·期 23
·3763
·
IF 5.561
Fan Zhang,Hongxia Du,Linsen Li,Tengfei Li,Jing Wang,Zilei Chen,Mengmeng Yan,Chao Zhu,Feng Qu
Lactoferrin (Lf), as a popular nutritional fortification in dairy products, has the ability regulate the body’s immune system and function as a broad-spectrum antibacterial, which is of great significance to the growth and development of infants and children. Herein, an indirect competitive enzyme-linked aptamer assay (ELAA) kit was established for rapid, sensitive, and visual determination of Lf in dairy products. In the construction, the Lf aptamer was conjugated with horseradish peroxidase (HRP) as the recognition probe and aptamer complementary strand (cDNA) were anchored onto the microplate as the capture probe. The recognition probes were first mixed with a sample solution and specifically bound with the contained Lf, then added into the microplate in which the free recognition probes in the mixture were captured by the capture probe. After washing, the remaining complex of cDNA/Aptamer/HRP in the microplate was conducted with a chromogenic reaction through HRP, efficiently catalyzing the substrate 3, 3′, 5, 5′-tetramethylbenzidine (TMB), therefore the color shade would directly reflect Lf concentration. Under the optimization conditions, a good linear relationship (R2, 0.9901) was obtained in the wide range of 25–500 nM with the detection limit of 14.01 nM and a good specificity, as well as the reliable recoveries. Furthermore, the ELAA kits achieved the Lf determination with an accuracy of 79.71~116.99% in eleven samples, which consisted of three kinds of dairy products: including goat milk powder, cow milk powder, and nutrition drop. Moreover, the results were also validated by the high-performance capillary electrophoresis (HPCE) method. The ELAA kit provides a simple and convenient determination for Lf in dairy products, and it is highly expected to be commercialized.Keywords:aptamer;lactoferrin determination;enzyme-linked aptamer assay;colorimetric;capillary electrophoresis
研究领域:
分析化学
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食品科学
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生物化学
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DOI
PubMed
高影响因子
Journal of Food Measurement and Characterization
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2022
·
IF 3.006
Ye Hua,Wan Tianxiang,Li Xinfu,Li Chao,He Kuo,Guo Yuanxin
Split aptamers are fragments of the parent aptamer which still possess binding ability to its target. They have shown great potential in the development of aptasensors. In this study, a fluorescence aptasensor was constructed employing the split aptamer as a cooperative recognition molecular probe and Graphene Oxide nanosheets (GO) as a quencher for rapid detection of kanamycin in chilled pork. Under optimal conditions,the proposed biosensor showed a good linear relationship in the range of 0.5–50 nM with the detection limit of 0.36 nM. The recoveries of the actual samples ranged from 97.6 to 103.5%. Furthermore, the test can be completed in 25 min. This study provides good reference for developing simple, economical, and rapid assay for other small molecular targets detection.
研究领域:
分析化学
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生物传感器
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食品科学
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产品关联
DOI
高影响因子
Food Analytical Methods
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2022
·Vol. 15
·期 8
·2202-2212
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IF 3.498
Feng Junli,Wu Yuanyuan,Shen Qing
In the present study, a sensitive and simple approach for colorimetric detecting microcystin-LR (MC-LR) in fish tissue was developed based on gold nanoparticles (AuNPs) and a truncated aptamer Apt-910–2, which was obtained by mutation and rational truncation from the previously selected 60-mer one. The 23-mer Apt-910–2 presented improved binding affinity to MC-LR and higher specificity. Under the optimum experimental conditions, the Apt-910–2 colorimetric aptasensor worked well in 10 to 150 ng/mL MC-LR concentration ranges, and the limit of detection (LOD) was 0.38 ng/mL. This Apt-910–2 colorimetric aptasensor was also applied to spiked fish tissue samples and gave recovery rates ranged from 75.18 to 87.72%, with the visual LOD 10 μg/kg in fish tissue judged by the naked eye. Thus, this study provides a rapid, reliable, and convenient approach for visual detection of MC-LR, which is of great significance for food safety control by assessing potential health risks related to seafood consumption.
研究领域:
环境科学
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分析化学
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食品安全
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产品关联
DOI
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
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2024
·
IF 8
Tianyu Huang,Xin Chen,Jinri Chen,Yuting Zhang,Xiaoli Wang,Zhimeng Wu,Nandi Zhou
Azithromycin can effectively inhibit bacterial protein synthesis and reduce biofilm formation and quorum sensing, and thus has been preferentially used in the treatment of various infections. However, azithromycin is also among the most highly concentrated antibiotics present in wastewater due to the inappropriate use and treatment. In order to sensitively and rapidly monitor the azithromycin residues, aptamers specific to azithromycin were selected through 12 rounds of screening by using magnetic beads-SELEX (MB-SELEX). The screened aptamers were assessed for their affinity and specificity using fluorescent assay. Apt3 emerged as the optimal candidate aptamer with the dissociation constant (K d ) of 235.07 nM. After secondary structure analysis and molecular docking, Apt3 was systematically truncated and subjected to single-base mutations. The optimal aptamer Apt3–27 T was identified, exhibiting the K d value of 215.84 nM and the improved specificity compared to the original aptamer. Then Apt3–27 T was utilized to construct a ratiometric fluorescent aptasensor, which exhibited the linear dynamic range of 25–400 nM and low detection limit of 9.78 nM. More importantly, the ratiometric fluorescence mechanism further improved the specificity of the biosensor, which finally can discriminate azithromycin from structurally similar erythromycin. Evaluation experiments using actual samples spiked with azithromycin showed the recovery ranging from 97.1% to 106% and the relative standard deviation ranging from 4.29% to 8.61%. The screened aptamer and constructed aptasensor offer the advantages of high affinity, high effectiveness and ease of use in actual sample detection, thereby displaying promising applications in the monitoring of azithromycin residues.
研究领域:
分析化学
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环境科学
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生物传感器
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药物分析
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DOI
高影响因子
ANALYST
·
2019
·Vol. 144
·期 12
·3826-3835
·
IF 4.019
Xinglin Wang,Xiaoyi Gao,Jiale He,Xiaochen Hu,Yunchao Li,Xiaohong Li,Louzhen Fan,Hua-Zhong Yu
Graphene oxide (GO)-based aptasensors are currently one of the most popular sensing platforms for the simple and rapid detection of various targets. Unfortunately, the GO-based aptasensors with long aptamer strands typically show unsatisfactory performance resulting from insignificant structural transformations upon target binding. We report herein the utilization of an aptamer-truncating strategy to combat such a challenge. Taking a pre-selected anti-aflatoxin B1 (AFB1) aptamer (P-AFB1-50) as a trial system, we sequentially remove the extraneous nucleotides within the aptamer by means of circular dichroism (CD) spectroscopy and binding affinity analysis. Particularly, the ratio of the quenching constants between the GO sheets and the truncated aptamers (labelled with fluorophores) in the absence and presence of the target was determined for each of the truncated aptamers to evaluate the optimal sequence. As a result, the truncated aptamer comprising 40 nucleotides was confirmed to show the highest FL output and the best detection limit upon conjugation with GO sheets. More importantly, we demonstrated that this truncating strategy is versatile, i.e., it can be easily extended to other aptamer systems (anti-ochratoxin A (OTA) aptamer, P-OTA-61, as an example) for extraneous nucleotide identification. Impressively, the two optimal truncated aptamers can work together on GO sheets to achieve a simultaneous detection of two different mycotoxins (i.e., AFB1 and OTA) in one single test. Essentially, this research opens a new avenue for the design and testing of aptamer-/GO-based-sensing platforms for rapid, low-cost and multiplex quantification of analytical targets of interest.
研究领域:
分析化学
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生物传感器
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毒理学
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DOI
PubMed
高影响因子
Toxins
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2019
·Vol. 11
·期 8
·447
·
IF 3.895
Li Liu,Zafar Iqbal Tanveer,Keqiu Jiang,Qingwen Huang,Jinghui Zhang,Yongjiang Wu,Zheng Han
With the widespread contamination of ochratoxin A (OTA), it is of significant importance for detecting OTA in foods and traditional Chinese medicine (TCM). In this study, a novel label-free fluorescent aptasensor utilizing the interaction between OTA-triggered antiparallel G-quadruplex and (N-methyl-4-pyridy) porphyrin (TMPyP) for the rapid and sensitive determination of OTA was established. The fluorescence of CdTe quantum dots (QDs) could be quenched by TMPyP. In the presence of analyte (OTA), the aptamer could recognize OTA and transform from a random coil to the antiparallel G-quadruplex. The interaction between G-quadruplex and TMPyP could release CdTe QDs from TMPyP, and thus recover the fluorescence of CdTe QDs. Under optimized conditions, the detection limit of the designed aptasensor was 0.16 ng mL−1, with a linear range of 0.2 to 20 ng mL−1. Furthermore, this aptasensor showed high selectivity toward OTA against other structural analogs and other mycotoxins, and was successfully applied inAstragalus membranaceussamples. The presented aptasensor for OTA detection could be a promising tool for the field monitoring of food and TCM.Keywords:ochratoxin A;porphyrin;quantum dots;G-quadruplex aptamerKey Contribution:A label-free fluorescent aptasensor for the sensitive determination of ochratoxin A utilizing the interaction between OTA-triggered G-quadruplex and TMPyP is reported.
研究领域:
食品安全
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分析化学
·
生物技术
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DOI
PubMed
高影响因子
Small
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2024
·
IF 13
Hongyuan Cui,Tianfang Zheng,Nana Qian,Xueqi Fu,Aijun Li,Shu Xing,Xiao-Feng Wang
Exosomes are nanovesicles secreted by cells, which play a crucial role in various pathological processes. Exosomes have shown great promise as tumor biomarkers because of the abundant secretion during tumor formation. The development of a convenient, efficient, and cost-effective method for simultaneously enriching and detecting exosomes is of utmost importance for both basic research and clinical applications. In this study, an aptamer-functionalized magnetic Ti 3 C 2 composite material (Fe 3 O 4 @Ti 3 C 2 @PEI@DSP@aptamer@FAM-ssDNA) is prepared for the simultaneous enrichment and detection of exosomes. CD63 aptamers are utilized to recognize and capture the exosomes, followed by magnetic separation. The exosomes are then released by cleaving the disulfide bonds of DSP. Compared to traditional methods, Fe 3 O 4 @Ti 3 C 2 @PEI@DSP@aptamer@FAM-ssDNA exhibited superior efficiency in enriching exosomes while preserving their structural and functional integrity. Detection of exosome concentration is achieved through the fluorescence quenching of Ti 3 C 2 and the competitive binding between the exosomes and a fluorescently labeled probe. This method exhibited a low detection limit of 4.21 × 10 4 particles mL −1 , a number that is comparable to the state-of-the-art method in the detection of exosomes. The present study demonstrates a method of simultaneous enrichment and detection of exosomes with a high sensitivity, accuracy, specificity, and cost-effectiveness providing significant potential for clinical research and diagnosis.
研究领域:
纳米技术
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生物标志物研究
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癌症诊断
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分子生物学
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产品关联
DOI
PubMed
高影响因子
TALANTA
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2020
·
IF 5.339
Shimeles Addisu Kitte,Terefe Tafese,Chen Xu,Muhammad Saqib,Haijuan Li,Yongdong Jin
The development of highly sensitive electrochemiluminescence (ECL) immunosensors by using functional nanoparticles as signal amplifiers is a solution towards sensitive determination of many low concentration disease biomarkers. Herein, a sensitive aptamer-based, sandwich-type surface plasmon enhanced electrochemiluminescence (SPEECL) immunosensor was demonstrated for the detection of cardiac troponin I (cTnI), by means of aptamer conjugated CdS QDs and AuNPs as ECL luminophores and plasmon sources, respectively, in which Tro4 aptamer was used as a capture probe for cTnI and Tro6 aptamer as a detecting probe. The signal of the developed SPEECL system showed ~ 5-fold increment as compared to that of without AuNPs. Using this ECL platform for the detection of cTnI, a linear range and the limit of detection (LOD) were found to be 1 fg/mL - 10 ng/mL and 0.75 fg/mL, respectively.
研究领域:
分析化学
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生物化学
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纳米技术
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生物医学工程
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心脏病学
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DOI
PubMed
高影响因子
BIOSENSORS & BIOELECTRONICS
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2019
·
IF 9.518
Jiangle Yi,Zhen Liu,Jianhui Liu,Hanbiao Liu,Fangquan Xia,Dong Tian,Changli Zhou
A novel label-free electrochemical aptasensor was fabricated based on a three-dimensional porous electrode (3D-CS/rGO/GCE) for the detection of acetamiprid residues. The sensing signal was generated by the DNA itself. The porous electrode was prepared by electrodeposition in situ and characterized by scanning electron microscope (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). These results indicated that the porous electrode has a uniform nanoporous structure, high active area, and excellent conductivity , leading to improve the transmission efficiency of current signals. The 3D-CS/rGO/GCE was used to increase a load of acetamiprid aptamer on the electrode. Meanwhile, DNA self-assembly strategy was used to further increase the DNA amounts. Thus the electrochemical current was amplified significantly due to increased phosphate group amounts by the above synergistic effect . The determination of acetamiprid residues using square wave voltammetry (SWV) showed good sensitivity, with the linear range from 0.1 pM to 0.1 μM and the detection limit was 71.2 fM. The label-free electrochemical aptasensor was also used to detect acetamiprid residues in tea samples with satisfactory results.
研究领域:
分析化学
·
环境科学
·
食品科学
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DOI
高影响因子
Food Analytical Methods
·
2018
·Vol. 11
·期 6
·1668-1676
·
IF 2.245
Jia Jie,Yan Shang,Lai Xiaoxia,Xu Yongzhen,Liu Tong,Xiang Yuhong
A facile colorimetric aptasensor based on unmodified gold nanoparticles (AuNPs) for rapid, highly sensitive and selective detection of malachite green (MG), one of triphenylmethane dyes and antibiotics, was successfully developed. Malachite green RNA aptamer having the binding ability with high affinity and specificity would be the ideal recognition receptor for MG. RNA aptamer can adsorb on the AuNPs and protect AuNPs against salt-induced aggregation. When malachite green were added in a solution, aggregation of AuNPs was specifically induced by desorption of aptamer from the surface of gold nanoparticles as the formation of aptamer-target complex. Therefore, the salt could trigger AuNP aggregate and the solution color changed from red to blue. The solution colors and absorbance were related with the concentrations of MG, and a well linear relationship in the wide range was obtained. The detection limit of MG was down to 15.95 nM. This colorimetric method was better than other traditional methods in terms of its reduced detection time, simple signal generation, high selectivity, lower detection limit, and observation with the naked eye. The proposed one-step, label-free method was successfully used to determine MG in actual fish samples. The high recoveries of MG in fish sample detection were satisfied.
研究领域:
分析化学
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环境科学
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纳米技术
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食品安全
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产品关联
DOI
高影响因子
JOURNAL OF FOOD COMPOSITION AND ANALYSIS
·
2022
·
IF 4.52
Yue Tang,Hongyan Yu,Xiaojuan Niu,Qiaodie Wang,Yuanyuan Liu,Yuangen Wu
Pesticide residues like carbendazim have always been a great threat to agricultural production and food safety. Herein, a fluorescent aptasensor for carbendazim detection was established based on aptamer-mediated quenching of gold nanoparticles (AuNPs) toward carbon dots (CDs). CZ-13 aptamer can wrap AuNPs and make them dispersed in salt solution, thus quench the fluorescence of CDs. On adding carbendazim, the aptamer is firstly consumed to preferentially combine with pesticides, resulting in the fluorescence recovery of CDs from quenching status. The degree of fluorescence recovery is positively correlated with pesticide concentration, which enables us to establish a fluorescence aptasensor for carbendazim detection. Under optimal conditions, the limit of detection of the fluorescent aptasensor is determined as low as 2.3 μg·L −1 . Moreover, the average recovery range of carbendazim in several vegetables and fruits is from 86 % to 99 %, indicating that such aptasensor may have bright application prospects for carbendazim detection in foods .
研究领域:
食品安全
·
分析化学
·
环境科学
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）