SENSORS AND ACTUATORS A-PHYSICAL
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2023
·
IF 4.6
Yuxin Mao,Xinyuan Tan,Yipeng Dou,Liangcun He,Songlin Li,Huchen Cao,Shengzhao Zhang
The increasing emphasis on portability and miniaturization in biomedical analysis and detection necessitates higher accuracy and applicability in handling sample reagents. In this study, we propose a high-precision portable programmable nanopipette based on pneumatic drop-on-demand and gas displacement pipetting techniques. The nanopipette employs programmable electropneumatic regulators and solenoid valves for precise control over air pressure, air pulse duration, and the number of air pulses, enabling accurate dispensing of specific liquid volumes. The nanopipette provides both discrete and continuous dispensing modes. In the discrete mode, it employs a single droplet as the minimum unit, allowing for precise dispensing of sub-microliter liquids (≤500 nL) by accumulating uniformly sized droplets. Conversely, the continuous mode enables the rapid dispensing of larger volume liquids (>500 nL) through continuous gas displacement. Thanks to the two dispensing modes, the nanopipette can handle a broad range of dispensing volumes, spanning six orders of magnitude (from 3 nL to 1 mL), with a minimum volume increment of 1 nL. Through validation using two characterization methods, the nanopipette demonstrates systematic errors (random errors) ranging from − 0.5% to − 3.6% ( ± 0.9% to ± 4.4%), surpassing the performance of existing commercial micropipettes . In proof-of-concept experiments involving extensive dilution and quantitative analysis of drug toxicity, the nanopipette efficiently simplified experimental procedures (from multiple dilutions to single-step dilution), minimized reagent consumption (from 22 mL to 500 μL), and produced highly accurate and reliable experimental results. These findings highlight the applicability and potential value of the nanopipette in the field of biomedical research.
研究领域:
生物医学工程
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分析化学
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DOI
高影响因子
INTERNATIONAL JOURNAL OF ENVIRONMENTAL ANALYTICAL CHEMISTRY
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2018
·
IF 1.372
Yanfang Zhao,Lubin Xu
In this work, a low-cost melamine-formaldehyde polymer with large-surface-area mesoporous structure was prepared and applied as an efficient solid sorbent for pre-concentration of five kinds of chlorinated herbicides including fomesafen, atrazine, pyrithiobac-sodium, benazolin and acifluorfene from water samples. Extraction parameters such as pH of the sample solution, amount of mesoporous melamine-formaldehyde polymer (mMFP), extraction time, type of desorption solv-ent and volume of the sample were systematically investigated. Combining dispersive solid-phase extraction with high-performance liquid chromatography (HPLC), the detection limits (S/N = 3) of the five herbicides were ranged from 0.04 to 0.18 μg L−1 with good linearity (R2 ≥ 0.9908). Then the tap water and river water samples were analysed by the developed method, and the obtained results indicated that this method provides acceptable recoveries and precisions. mMFP can be prepared through one-pot catalyst-free polymerisation from low-cost starting materials, so that they could be easily scaled up for the sample pre-treatment and have the powerful potentiality in purification of contaminated water.
研究领域:
环境科学
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分析化学
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水处理
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产品关联
DOI
高影响因子
JOURNAL OF BIOCHEMISTRY
·
2023
·Vol. 173
·期 5
·343-352
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IF 2.7
Cui Mingxin,Wong Okei,Li Qiang,Wang Wenya
T7 system is a commonly used in protein expression and the highest transcription activity of T7 RNAP usually caused the instability of T7 system. In order to apply T7 system extensively, it is essential to characterize T7 RNAP activity. In the present paper, an assay method for T7 RNAP activity was developed with a transcription–translation (TX-TL) system. After the optimization of TX-TL system, the operating parameters were determined as 34°C, 60 min with 20 ng/μl of plasmid DNA template. The standard curve of TX-TL assay method indicated an excellent correlation (r = 0.998), and the sensitivity was better than that of western blotting method. The precision investigation indicated a mean-relative error of 2.58% and a standard-relative error of 7.01%. Moreover, the cell lysate could be added directly to the optimized TX-TL system without affecting T7 RNAP activity assay. The feasibility of present method was further confirmed by characterizing T7 RNAP activity in cell lysate of five strains of Escherichia coli (E. coli) DH5α with different T7 RNAP activities and seven commercial strains of E. coli (DE3).
The present assay method for T7 RNAP activity would have a great application in synthetic biology, metabolic engineering, enzyme engineering and biomedicine.
研究领域:
分子生物学
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生物技术
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合成生物学
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微生物学
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产品关联
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF LEGAL MEDICINE
·
2019
·Vol. 134
·期 1
·177-183
·
IF 2.094
Xie Mingkun,Song Feng,Li Jienan,Xie Bowen,Wang Shuangshuang,Wang Weizhi,Ma Hong,Luo Haibo
Genotyping by targeting short tandem repeats (STRs) has been widely used in forensic applications. However, most commercial kits detect autosomal STRs or Y-STRs alone, which waste both time and opportunity. The AGCU Expressmarker 16 + 22Y Kit includes 16 autosomal and 22 Y-chromosomal STR loci and is designed for the forensic science field and obtaining quicker results. Here, we conducted the validation study according to Scientific Working Group on DNA Analysis Methods (SWGDAM) guidelines. Validation of PCR-based studies, species specificity, sensitivity, DNA mixture studies, inhibitors, precision, and sizing accuracy were performed. Furthermore, this system was also tested in 346 random male samples from Han, Hui, Tibetan, and Zhuang populations in China, showing its high power for forensic discrimination in the Chinese population. In addition, this system was able to deal with AMELY deletion cases, which can correctly identify sex in forensic criminal investigations. Our results suggested that the AGCU Expressmarker 16 + 22Y Kit is a useful tool for rapid criminal investigation.
研究领域:
法医学
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分子生物学
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遗传学
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产品关联
DOI
PubMed
高影响因子
MICROCHEMICAL JOURNAL
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2024
·
IF 4.9
Lixia Luo,Jinglin Shui,Yingying Gu,Dandan Wang,Jiangyang Qin,Yanan Wang,Yong Mei
In order to detect the cervical cancer biomarker squamous cell carcinoma antigen (SCCA) in human serum, an electrochemical immunosensor was constructed. Zirconium 1,4-dicarboxybenzene MOF (UiO-66), with a high specific surface area, was coupled with gold nanoparticles (AuNPs), creating the UiO-66@AuNPs nanomaterial. This coupling increased the sensitivity of the electrochemical immunosensor by providing many biological binding sites for antibodies to bind to Au-S bonds. Then, mesoporous carbon (CMK-3) was added to the UiO-66@AuNPs nanomaterial to obtain a CMK-3@UiO-66@AuNPs nanocomposite. This further increased the electron transfer proficiency of the material and enhanced the electrochemical signal. Finally, the sensitive detection of squamous cell carcinoma antigen (SCCA) was made possible by unique immunological responses between antigens and antibodies. Transmission electron microscopy (TEM) analysis of CMK-3@UiO-66@AuNPs revealed embedded surfaces and voids; cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) confirmed the successful assembly of the electrochemical immunosensor. The developed electrochemical immunosensor demonstrated good linearity (R 1 2 = 0.999) from 0.01 pg/mL to 10,000 pg/mL, which is the concentration range of SCCA in human serum. The limit of detection was 0.0034 pg/mL (at an S/N ratio of 3). The immunosensor exhibited excellent precision, stability and selectivity, with a high rate of recovery (98.26–101.8 %). The experimental validation studies demonstrated that the electrochemical immunosensor was effective for the detection of SCCA in human serum, offering a novel method for the early diagnosis and dynamic surveillance of cervical cancer.
研究领域:
生物医学工程
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癌症研究
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电化学
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纳米技术
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分析化学
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产品关联
DOI
高影响因子
VIBRATIONAL SPECTROSCOPY
·
2021
·
IF 2.507
Lei Zhang,Yingshan Chen,Qin Zhu,Wenjin Ji,Suqing Zhao
Bisphenol A (BPA) is a typical endocrine-disrupting chemical (EDC), which has been banned for food packing and baby bottle material due to its potential endocrine harm to human body. In this paper, an easy and rapid immunochromatographic assay (ICA) combined with the technology of surface-enhanced Raman spectroscopy (SERS) was fabricated to improve the sensitivity and rapidity for quantitative determination of BPA. After 10 min of a quick chromatographic process, the specific Raman signal on T line of the test strip was measured. Compared with the traditional ICA, the SERS-ICA realized quantitative test and showed the limit of detection (LOD) was 0.1 ng/mL, getting approximately 300-fold lower. The method displayed high specificity and precision with RSD of 4.1%, and the test strip indicated favorable stability for two weeks without loss of activity. For river, tap and commercial drinking water sample, the SERS-ICA results were confirmed by HPLC, and the recoveries of spiked BPA were from 90.80-117.80%. It was shown that the proposed method takes advantages both of SERS and ICA, exhibiting high sensitivity, precision, stability, quantification and rapidity for field test, expecting a widely useful method for various small molecules in food safety, medical diagnosis and environmental samples.
研究领域:
分析化学
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环境科学
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食品安全
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医学诊断
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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）