Journal of Analysis and Testing

ESR1 mutation is of great clinical significance and being promoted as a marker of resistance to endocrine therapy in breast cancers. However, it is a challenging task to detect ESR1 mutations from traditional biopsies and cell-free DNA (cfDNA), especially for polyclonal mutations. This is mainly attributed to massive wild-type background and the low-abundance of the mutations. Here, using one-step single-cell amplification coupling with pyrosequencing, we developed and validated an original strategy for simultaneous sensitive detection of adjacent ESR1 mutations in single circulating tumor cell (CTC) from breast cancers. Unlike expensive single-cell sequencing used in previous studies, the strategy does not require complicated two-step amplification or high-cost single-cell amplification kits. Three pivotal parts involved in the strategy are collection of CTCs from whole blood of breast cancer patients, one-step single-cell amplification and pyrosequencing of single-cell amplicons. To achieve better efficiency of one-step single-cell amplification for pyrosequencing, a set of experimental conditions were thoroughly trialed. The developed strategy enabled a highly specific detection of the ESR1 hotspot mutations from large wild-type background with the specificity as low as 1% and a high sensitivity of two copies of artificial samples or single-cell level and pretty good quantitative accuracy (R2 ≥ 0.9888). Using this strategy, 141 single CTCs from 11 cases of breast cancer patients were identified and collected, 126 of which were successfully analyzed with a high rate of 89.4%. These results indicate that the cost-effective and reliable strategy could be used for clinical management, showing promising application in the treatment decision-making of breast cancer patients.

Solvent free DNA–surfactant melts are receiving continuous attractions in recent years. Their physical properties could be regulated via changing the alkyl chain length of surfactants. As an ideal external stimulus, light has been used in the regulation of mechanical properties of DNA thermotropic liquid crystal (TLC) containing an azobenzene motif, while in this case, the UV light is the only effective excitation source. However, in comparison with visible light, UV light causes damage to DNA and has low tissue-penetration efficiency problem. In this work, a new type of DNA–didodecyldimethylammonium bromide (DNA–DDAB) TLCs fabricating with gold nanoparticles (AuNPs) was demonstrated. The visible light-induced photothermal effect of AuNPs could change the mechanical properties of AuNPs/DNA–DDAB TLCs, as shown by clearly boundary motion activity and viscoelasticity change. Furthermore, the ratio of AuNPs and charge stoichiometry of DNA:DDAB also affected photocurrent generation property of these DNA melts. The development of this visible light responsive DNA melt might facilitate the related studies in biomedicine and biomaterials.

Correction to: J. Anal. Test. (2017) 1:17 DOI 10.1007/s41664-017-0018-4.

Nanopores are nanofluidic channels formed through thin membranes that can deliver standout single-molecule and single-particle sensing capabilities. Analytical targets include small molecules and nanoparticles, and the DNA, protein, and glycan biopolymers underpinning genomics, proteomics, and glycomics. Detection—notably even in the simplest implementation, resistive-pulse sensing—does not inherently require sample labeling and, thus, offers the potential for general sensing utility combined with the prospective benefits of reduced sample processing requirements. A key pursuit for biopolymer sensing is the characterization of monomer sequence. This review article will provide an overview of the use of nanopores for general chemical sensing and –omics-related applications, writ-large. The broad analyte scope provides fertile ground for a discussion of principles governing nanopore sensing and considerations useful for guiding nanopore development. For nanopores to be effective in the face of broad analyte scope, stringent requirements on analytical performance must be met within the particular analyte class without sacrificing the operational flexibility necessary to be responsive across classes presenting very different physical and chemical challenges. These sample-driven challenges provide a unifying framework for discussing aspects of nanopore fabrication, properties, and integration; sensing paradigms, performance, and prospects; fundamental electrokinetic and interfacial phenomena; and practical challenges facing the use and further development of nanopore devices.

Due to the advantages of low background interference and high sensitivity, electrochemiluminescence (ECL)-based sensor has developed rapidly in recent years. The ECL sensors have shown the potential in the ultrasensitive and real-time analysis. Especially, the visual ECL analysis, including visual detection, cell imaging and single particle analysis, has offered many unique sensing platforms for analysis research and point-of-care testing. The high throughput ECL image analysis can not only provide ECL intensity but also reveal more information about the chemical reaction activity of particle and the physiological processes of cell operation. Therefore, we review the novel ECL luminophore, sensing systems, and successful applications in the visual ECL detection and imaging in this paper. First, the different ECL luminophore is summarized. Second, we discuss the ECL sensing mechanisms, focusing on the advantages and limitations of different sensing methods. Then, we highlight the recent advances in representative examples of visual ECL analysis, including aptasensing, multiplex immunoassays, cell imaging and single-particle analysis. At last, the outlook and prospects for the future visual ECL analysis are discussed based on the current development of ECL research.

A method was developed for the determination of Aroclor 1254 in water samples using polystyrene–divinylbenzene (PS–DVB) solid-phase extraction (SPE) and gas chromatography (GC). The PS–DVB sorbent demonstrated good recoveries of Aroclor 1254 when sulfuric acid (1:1, v:v) was added to the samples. Sample quantification was performed using gas chromatography with a parallel column and dual electron capture detector. Factors in extraction method procedures were optimized, including sample pH, elution solvent, eluting volume and breakthrough volume. With the 1000 ml sample acidified to pH 1.0, a 6.0 ml n-hexane/ethyl acetate (1:1, v:v) elution solvent, and gas chromatographic determination, the recoveries of Aroclor 1254 in spiked water samples ranged from 90.6 to 104%. Across testing days, repeatability ranged from 4.7 to 7.6%. The method detection limit was 0.053 μg/L. PS–DVB exhibited a broader pH stability range, satisfactory recoveries, and good repeatability for Aroclor 1254 extraction. The results indicate that these methods can be used to analyze trace amounts of Aroclor 1254, and represent a new analytical approach for determining polychlorinated biphenyls in water samples.

A salting-out assisted liquid–liquid extraction method followed by high performance liquid chromatography with ultraviolet–visible detector (SALLE-HPLC–UV/Vis) has been proposed for determination of caffeine and nicotinic acid in raw and roasted coffee samples. Various parameters affecting chromatographic separations including mobile phase composition, injection volume, flow rate and column temperature were studied. Experimental parameters affecting the extraction efficiency of SALLE method such as type and volume of the organic solvent, type and amount of salt, pH of the sample, and concentration of the ion-pairing reagent were also studied and thereby optimum conditions were established. The calibration curves which were constructed at five different concentration levels using the optimum conditions exhibited good linearity, with the coefficient of determination (R2) 0.999 and 0.995 for caffeine and nicotinic acid, respectively. The limits of detection (LOD) and quantification (LOQ) which were determined at 3 and 10 times signal-to-noise ratio were 0.05 and 0.13 mg/L for nicotinic acid and 0.20 and 0.63 mg/L for caffeine, respectively. Intra- and inter-day precision studies were demonstrated satisfactory precision with RSD values below 10. Relative recoveries were also studied, and their results were ranging from 82–122% for both raw and roasted coffee samples. The findings demonstrated that the proposed method could be used as an effective and best alternative for the determination of caffeine and nicotinic acid in raw and roasted coffee samples. • SALLE was proposed for extraction caffeine and NA from raw and roasted coffee samples. • HPLC-UV/Vis was used for separation and determination of the target analytes. • The method has exhibited satisfactory analytical performance characteristics and good selectivity for both analytes. • The method uses classical laboratory apparatuses and small volume of less toxic organic solvent. • Compared to the other methods, the proposed method has similar or better LOD and LOQ than the earlier reported methods.

Liquid chromatography–mass spectrometry (LC–MS) has enabled the detection of thousands of metabolite features from a single biological sample that produces large and complex datasets. One of the key issues in LC–MS-based metabolomics is comprehensive and accurate analysis of enormous amount of data. Many free data preprocessing tools, such as XCMS, MZmine, MAVEN, and MetaboAnalyst, as well as commercial software, have been developed to facilitate data processing. However, researchers are challenged by the inevitable and unconquerable yields of numerous false-positive peaks, and human errors while manually removing such false peaks. Even with continuous improvements of data processing tools, there can still be many mistakes generated during data preprocessing. In addition, many data preprocessing software exist, and every tool has its own advantages and disadvantages. Thereby, a researcher needs to judge what kind of software or tools to choose that most suit their vendor proprietary formats and goal of downstream analysis. Here, we provided a brief introduction of the general steps of raw MS data processing, and properties of automated data processing tools. Then, characteristics of mainly free data preprocessing software were summarized for researchers’ consideration in conducting metabolomics study.

Chirality is one of the fundamental attributes of nature, which exists in different or even completely opposite metabolic, toxicological and pharmacological properties in organisms. Consequently, obtaining enantiomerically pure drugs or optically active intermediates is highly desired in many fields like medicine, food and biochemistry. Thereby, it also promoted the development of various enantiomer selective separation techniques. Among the many chiral separation methods, chiral mobile phase additives (CMPAs) are widely used in various chromatographic techniques due to their simple operation, good versatility and low price. There have been a number of reviews on the research progress of CMPAs in last 2 decades, but they only reviewed the application of CMPAs in one specific chromatographic technique. Therefore, to provide a more comprehensive illustration of CMPAs in separation technology, their applications in high-performance liquid chromatography, capillary electrophoresis, countercurrent chromatography, nano-liquid chromatography were summarized and their advantages and disadvantages were briefly introduced in this critical review. The application of molecular simulation in the study of chiral separation mechanism was briefly summarized. We expect that it will provide researchers with the latest developments in this field and potential inspirations.