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1.
Materials (Basel) ; 17(6)2024 Mar 08.
Article in English | MEDLINE | ID: mdl-38541409

ABSTRACT

In metallurgical practice, the material is considered of adequate quality if it meets the customer's expectations. It is necessary to take representative samples and perform quality testing to avoid financial and intangible losses. Sample contamination and matrix and surface quality play a significant role in the accuracy of chemical analyses. The purpose of this paper is to point out the advantages of specific methods of taking samples, such as immersion and spoon sampling of molten metal, and, in the experimental part, to assess the impacts of factors affecting the quality of the sampling. The influence of time of final sampling on determining the true amount of magnesium during a single melt and the influence of duration of mixing of molten cast iron on the accuracy of chemical analysis of the control sample were investigated. It is important that the time between the modification and casting of the liquid cast iron from the casting ladle be as short as possible. This is because the magnesium burns out and thus the chemical analysis of the sample taken is not accurate. Another important factor is ensuring the melt before sampling is homogenized and has the minimum prescribed temperature (1420 °C). Increasing sample collection time will cause changes in its chemical composition.

2.
Biosensors (Basel) ; 13(6)2023 Jun 19.
Article in English | MEDLINE | ID: mdl-37367031

ABSTRACT

Recently, there has been an upsurge in the extent to which electrochemiluminescence (ECL) working in synergy with bipolar electrochemistry (BPE) is being applied in simple biosensing devices, especially in a clinical setup. The key objective of this particular write-up is to present a consolidated review of ECL-BPE, providing a three-dimensional perspective incorporating its strengths, weaknesses, limitations, and potential applications as a biosensing technique. The review encapsulates critical insights into the latest and novel developments in the field of ECL-BPE, including innovative electrode designs and newly developed, novel luminophores and co-reactants employed in ECL-BPE systems, along with challenges, such as optimization of the interelectrode distance, electrode miniaturization and electrode surface modification for enhancing sensitivity and selectivity. Moreover, this consolidated review will provide an overview of the latest, novel applications and advances made in this field with a bias toward multiplex biosensing based on the past five years of research. The studies reviewed herein, indicate that the technology is rapidly advancing at an outstanding purse and has an immense potential to revolutionize the general field of biosensing. This perspective aims to stimulate innovative ideas and inspire researchers alike to incorporate some elements of ECL-BPE into their studies, thereby steering this field into previously unexplored domains that may lead to unexpected, interesting discoveries. For instance, the application of ECL-BPE in other challenging and complex sample matrices such as hair for bioanalytical purposes is currently an unexplored area. Of great significance, a substantial fraction of the content in this review article is based on content from research articles published between the years 2018 and 2023.


Subject(s)
Biosensing Techniques , Luminescent Measurements , Electrochemistry/methods , Luminescent Measurements/methods , Photometry , Biosensing Techniques/methods , Electrodes , Electrochemical Techniques/methods
3.
Methods Mol Biol ; 2620: 15-20, 2023.
Article in English | MEDLINE | ID: mdl-37010743

ABSTRACT

Protein arginylation has been discovered in 1963 as a soluble activity in cell extracts that mediates the addition of amino acids to proteins. This discovery was nearly accidental, but due to the persistence of the research team, it has been followed through and led to the emergence of a new field of research. This chapter describes the original discovery of arginylation and the first methods used to demonstrate the existence of this important biological process.


Subject(s)
Amino Acids , Arginine , Amino Acids/metabolism , Arginine/chemistry , Proteins/metabolism , Protein Processing, Post-Translational , RNA, Transfer/metabolism
4.
Methods Mol Biol ; 2524: 409-432, 2022.
Article in English | MEDLINE | ID: mdl-35821490

ABSTRACT

Multiplex hextuple luciferase assaying allows monitoring the activity of five experimental pathways against one control at the same time. To perform multiplex hextuple luciferase assaying, six orthogonal luciferase reporter units are needed of which five are pathway-specific and one acts as a control for normalization. To ensure stoichiometric delivery of all six luciferase reporters in every transfected cell, synthetic assembly DNA cloning is used to stitch together all six luciferase reporter units into a single vector. Here, we provide a detailed three-step synthetic assembly DNA protocol to generate multiplex hextuple luciferase reporter plasmids for any five cellular signaling pathways of interest, against a control normalization pathway. A first protocol is provided on how to generate plasmids that contain novel transcription factor-binding motifs for specific transcription factors. A second protocol details on how to couple these novel transcription factor-binding motifs to one of five orthogonal luciferases to obtain specific luciferase reporters for cellular signaling pathways acting upstream of those transcription factor-binding motifs. Finally, a third protocol provides details on how to assemble orthogonal luciferase reporters for five cellular signaling pathways acting upstream of five unique transcription factor-binding motifs together with a control constitutive pathway luciferase reporter that will be used for normalization to obtain a final multiplex hextuple luciferase vector.


Subject(s)
DNA , Transcription Factors , Cloning, Molecular , DNA/genetics , Genes, Reporter , Luciferases/genetics , Plasmids/genetics , Transcription Factors/metabolism
5.
Front Immunol ; 13: 878226, 2022.
Article in English | MEDLINE | ID: mdl-35720370

ABSTRACT

Background: An increased risk of infection, malignancy, and cardiovascular diseases in maintenance hemodialysis patients is associated with hemodialysis-related immunity disturbances. Although defects in T-lymphocyte-dependent immune responses and preactivation of antigen-presenting cells have been documented in hemodialysis patients, the effects of long-term hemodialysis on the transcriptional program and chromosomal accessibility of circulating immune cell subpopulations remain poorly defined. Methods: We integrated single-cell RNA sequencing (scRNA-seq) and single-cell assay for transposase-accessible chromatin sequencing (scATAC-seq) to characterize the transcriptome profiles of peripheral mononuclear cells (PBMCs) from healthy controls and maintenance hemodialysis patients. Validation of differentially expressed genes in CD4+ T cells and monocytes were performed by magnetic bead separation and quantitative real-time PCR. Results: We identified 16 and 15 PBMC subgroups in scRNA-seq and scATAC-seq datasets, respectively. Hemodialysis significantly suppressed the expression levels of T cell receptor (TCR) genes in CD4+ T cell subsets (e.g., TRAV4, CD45, CD3G, CD3D, CD3E) and major histocompatibility complex II (MHC-II) pathway-related genes in monocytes (HLA-DRB1, HLA-DQA2, HLA-DQA1, HLA-DPB1). Downstream pathways of TCR signaling, including PI3K-Akt-mTOR, MAPK, TNF, and NF-κB pathways, were also inhibited in CD4+ T cell subpopulations during the hemodialysis procedure. Hemodialysis altered cellular communication patterns between PBMC subgroups, particularly TGF-TGFBR, HVEM-BTLA, and IL16-CD4 signalings between CD4+ T cells and monocytes. Additionally, we found that hemodialysis inhibited the expression of AP-1 family transcription factors (JUN, JUND, FOS, FOSB) by interfering with the chromatin accessibility profile. Conclusions: Our study provides a valuable framework for future investigations of hemodialysis-related immune dysregulation and identifies potential therapeutic targets for reconstituting the circulating immune system in maintenance hemodialysis patients.


Subject(s)
Leukocytes, Mononuclear , RNA , Chromatin , Humans , Phosphatidylinositol 3-Kinases , Receptors, Antigen, T-Cell , Renal Dialysis/adverse effects
6.
Front Immunol ; 12: 760381, 2021.
Article in English | MEDLINE | ID: mdl-34880858

ABSTRACT

Objective: Genetic studies on ankylosing spondylitis (AS) have identified more than 100 pathogenic genes. Building a bridge between these genes and biologically targeted therapies is the current research hotspot. Methods: We integrated single-cell assaying transposase-accessible chromatin sequencing (scATAC-seq) and single-cell RNA sequencing (scRNA-seq) to explore the key genes and related mechanisms associated with AS pathogenesis. Results: We identified 18 cell types in peripheral mononuclear cells from patients with AS and normal controls and summarized the cell-type-specific abnormal genes by scRNA-seq. Interestingly, we found that the pathogenic gene NFKB involved in AS progression originated from CD8+ T cells. Moreover, we observed an abnormal tumor TNF pathway mediated by abnormal expression of TNF, NFKB, FOS, JUN, and JUNB, and scATAC-seq results confirmed the abnormal accessible binding sites of transcriptional factors FOS, JUN, and JUNB. The final magnetic bead sorting and quantitative real-time PCR(RT-qPCR) confirmed that NFKB, FOS, JUN, and JUNB in CD8+ T cells differed in the AS group. Conclusions: Our results revealed a possible mechanism by which NFKB abnormally regulates FOS, JUN, and JUNB and drives AS progression, providing a novel perspective from a single cell point of view in AS.


Subject(s)
Spondylitis, Ankylosing/genetics , Transcription Factors/genetics , Adult , Chromatin Immunoprecipitation Sequencing , Female , Gene Expression , Humans , Leukocytes, Mononuclear/cytology , Male , RNA-Seq , Single-Cell Analysis , Spondylitis, Ankylosing/immunology , Young Adult
7.
ACS Appl Mater Interfaces ; 12(28): 31270-31281, 2020 Jul 15.
Article in English | MEDLINE | ID: mdl-32551533

ABSTRACT

Over the past few decades, colorimetric assays have been developed for cost-effective and rapid on-site urinalysis. Most of these assays were employed for detection of biomarkers such as glucose, uric acid, ions, and albumin that are abundant in urine at micromolar to millimolar levels. In contrast, direct assaying of urinary biomarkers such as glycated proteins, low-molecular-weight reactive oxygen species, and nucleic acids that are present at significantly lower levels (nanomolar to picomolar) remain challenging due to the interferences from the urine sample matrix. State-of-the-art assays for detection of trace amounts of urinary biomarkers typically utilize time-consuming and equipment-dependent sample pretreatment or clean-up protocols prior to assaying, which limits their applicability for on-site analysis. Herein, we report a colorimetric assay for on-site detection of trace amount of generic biomarkers in urine without involving tedious sample pretreatment protocols. The detection strategy is based on monitoring the changes in optical properties of poly(3-(4-methyl-3'-thienyloxy)propyltriethylammonium bromide) upon interacting with an aptamer or a peptide nucleic acid in the presence and absence of target biomarkers of relevance for the diagnosis of metabolic complications and diabetes. As a proof of concept, this study demonstrates facile assaying of advanced glycation end products, 8-hydroxy-2'-deoxyguanosine and hepatitis B virus DNA in urine samples at clinically relevant concentrations, with limits of detection of ∼850 pM, ∼650 pM, and ∼ 1 nM, respectively. These analytes represent three distinct classes of biomarkers: (i) glycated proteins, (ii) low-molecular-weight reactive oxygen species, and (iii) nucleic acids. Hence, the proposed methodology is applicable for rapid detection of generic biomarkers in urine, without involving sophisticated equipment and skilled personnel, thereby enabling on-site urinalysis. At the end of the contribution, we discuss the opportunity to translate the homogeneous assay into a paper-based format.


Subject(s)
Biomarkers/urine , Biosensing Techniques/methods , Colorimetry/methods , Humans , Limit of Detection , Polymers , Thiophenes/urine , Urinalysis
8.
Acta Pharm ; 70(3): 373-385, 2020 Sep 01.
Article in English | MEDLINE | ID: mdl-32074063

ABSTRACT

Green and sensitive spectrofluorometric methods have been developed and validated for the determination of timolol maleate (TML)/hydrochlorothiazide (HCT) and amiloride hydrochloride (AMH)/hydrochlorothiazide in tablets. The proposed spectrofluorometric procedures were found to be linear in the range of 4-12, 5-35 and 0.025-0.2 mg L-1 for HCT, TML and AMH, resp. The excitation and emission wavelengths for HCT, TML and AMH at room temperature were 270 and 375, 295 and 435, 330 and 415 nm, resp. The methods were validated with respect to ICH guidelines. The AMH showed higher sensitivity with lower values of LOD and LOQ values compared to HCT and TML. The proposed methods were applied to two pharmaceutical formulations; the method for HCT and AMH has proven as reliable assaying method, whereas the method for TML, when combined with HCT, is applicable to screening semi-quantitative analyses.


Subject(s)
Amiloride/analysis , Hydrochlorothiazide/analysis , Spectrometry, Fluorescence/methods , Timolol/analysis , Drug Combinations , Limit of Detection , Reproducibility of Results , Tablets , Temperature
9.
Biosens Bioelectron ; 151: 111972, 2020 Mar 01.
Article in English | MEDLINE | ID: mdl-31999580

ABSTRACT

Dengue non-structural protein 1 (NS1 DENV) is considered a biomarker for dengue fever in an early stage. A sensitive and rapid assay for distinguishing positive from negative dengue infection samples is imperative for epidemic control and public health in tropical regions because it enables the development of instantaneous updatable databases and effective surveillance systems. Presently, we successfully report, for the first time, the use of the electrochemical capacitive method for the detection of NS1 DENV biomarker in human serum samples. By using a ferrocene-tagged peptide modified surface containing anti-NS1 as the receptor, it was possible to differentiate positive from negative samples with a p < 0.01 in a reagentless and label-free capacitive format. This capacitive assay had a cut-off of 1.36% (confidence interval of 99.99%); it therefore opens new avenues for developing miniature label-free electrochemical devices for infectious diseases.


Subject(s)
Biosensing Techniques , Dengue Virus/isolation & purification , Dengue/blood , Viral Nonstructural Proteins/blood , Antibodies, Viral/blood , Antibodies, Viral/immunology , Antigens, Viral/blood , Antigens, Viral/immunology , Dengue/immunology , Dengue/virology , Dengue Virus/immunology , Dengue Virus/pathogenicity , Humans , Point-of-Care Systems , Viral Nonstructural Proteins/immunology
10.
ACS Sens ; 4(9): 2216-2227, 2019 09 27.
Article in English | MEDLINE | ID: mdl-31394901

ABSTRACT

Label-free approaches for molecular diagnostic applications are appealing because of their inherent point-of-care advantages. Nonetheless, technical challenges impose a limit on the use of these methods as will be discussed in this paper. Electrochemical spectroscopic methods, such as impedance and impedance-derived methods, are highly effective in the development of label-free diagnostic assays, but they require careful control of the dynamics of the sensing interface. We herein report the strength and challenges of the current methodologies associated with the applications of impedance and impedance-derived methods by focusing on their principles of operation. We demonstrate that the uses of their potentialities are not based on the know-how of these methods, but on how to combine the spectroscopic features with the required chemical design for the associated sensing interfaces. Predominantly, we illustrate how to use the resistive and capacitive terms of the interface to improve its sensitivity to the target. For instance, with the proper signal amplification strategy, limitations related to target-to-receptor size ratio can be overcome. The target-to-receptor ratio is one of the difficulties that we use as an example to illustrate how the sensing of an electric signal can be improved by controlling the properties of the interface on the nanometer scale.


Subject(s)
Biosensing Techniques/methods , Spectrum Analysis , Animals , Electrochemistry , Humans
11.
Zhongguo Zhong Yao Za Zhi ; 43(22): 4457-4461, 2018 Nov.
Article in Chinese | MEDLINE | ID: mdl-30593238

ABSTRACT

The aim of this study is to analyze the compositions of main bile acids in fermented and mixed processing products of arisame cum bile from pig bile, and to establish a method for content determination of bile acids in fermented Arisaema Cum Bile. Fermented and mixed processing products were prepared from arisaematis rhizome and arisaematis rhizoma preparatum with pig bile respectively. Then the differences in bile acids compositions between such two kinds of products were compared by high performance liquid chromatography and evaporative light-scattering detector (HPLC-ELSD). With three kinds of free bile acid compositions as the indicators, HPLC-ELSD method was adopted to determine the content of bile acid compositions in fermented product,on Agilent Eclipse XDB C18(4.6 mm×250 mm, 5 µm) chromatographic column, with acetonitrile and 0.1% glacial acetic acid solution (55:45) as mobile phase, at a flow rate of 1 mL·min⁻¹, column temperature of 30 °C, drift tube temperature of 90 °C, and a nitrogen flow rate of 2.2 mL·min⁻¹. The results showed that the bile acids in fermented bile Arisaema were mainly in a free form, while in mixed processing product, the compositions were mainly in a conjugated form. Three kinds of free bile acids, namely porcine cholic acid (HCA), porcine deoxycholic acid (HDCA) and chenodeoxycholic acid (CDCA) in fermented product, showed a good linear relationship in the range of quantification. The average recovery rate was 95.99%-104.3%, complying with the requirements. The results showed that the conjugated bile acids could be transformed into free bile acids during the fermentation of arisaema cum bile. This established method can effectively control the content of bile acids compositions in fermenting arisaema cum bile.


Subject(s)
Arisaema , Animals , Bile , Bile Acids and Salts , Chromatography, High Pressure Liquid , Fermentation , Swine
12.
Article in Chinese | WPRIM (Western Pacific) | ID: wpr-775321

ABSTRACT

The aim of this study is to analyze the compositions of main bile acids in fermented and mixed processing products of arisame cum bile from pig bile, and to establish a method for content determination of bile acids in fermented Arisaema Cum Bile. Fermented and mixed processing products were prepared from arisaematis rhizome and arisaematis rhizoma preparatum with pig bile respectively. Then the differences in bile acids compositions between such two kinds of products were compared by high performance liquid chromatography and evaporative light-scattering detector (HPLC-ELSD). With three kinds of free bile acid compositions as the indicators, HPLC-ELSD method was adopted to determine the content of bile acid compositions in fermented product,on Agilent Eclipse XDB C₁₈(4.6 mm×250 mm, 5 μm) chromatographic column, with acetonitrile and 0.1% glacial acetic acid solution (55:45) as mobile phase, at a flow rate of 1 mL·min⁻¹, column temperature of 30 °C, drift tube temperature of 90 °C, and a nitrogen flow rate of 2.2 mL·min⁻¹. The results showed that the bile acids in fermented bile Arisaema were mainly in a free form, while in mixed processing product, the compositions were mainly in a conjugated form. Three kinds of free bile acids, namely porcine cholic acid (HCA), porcine deoxycholic acid (HDCA) and chenodeoxycholic acid (CDCA) in fermented product, showed a good linear relationship in the range of quantification. The average recovery rate was 95.99%-104.3%, complying with the requirements. The results showed that the conjugated bile acids could be transformed into free bile acids during the fermentation of arisaema cum bile. This established method can effectively control the content of bile acids compositions in fermenting arisaema cum bile.


Subject(s)
Animals , Arisaema , Bile , Bile Acids and Salts , Chromatography, High Pressure Liquid , Fermentation , Swine
13.
Article in Chinese | WPRIM (Western Pacific) | ID: wpr-851945

ABSTRACT

Objective To establish a rapid and nondestructive method for the determination of multi-components in Salvia miltiorrhiza to improve the quality control of S. miltiorrhiza based on Near infrared spectroscopy combined with partial least squares (PLS) method. Methods A total of 106 batches of S. miltiorrhiza samples from different origins were collected. The content of 11 components (tanshinol sodium, protocatechuic aldehyde, caffeic acid, rosmarinic acid, alkannic acid, salvianolic acid B, salvianolic acid A, dihydrotanshinone, tanshinone I, cryptotanshinone, and tanshinone IIA) in all of the samples which was conducted as the reference value were determined by a UPLC method established in the previous research. And the NIRS spectrum were obtained under the integrating sphere diffuse reflection mode. The different processes of modeling were optimized by partial least squares (PLS) and other chemometrics methods, including the selection of calibration set and validation set, different pretreatment method, different spectral section, and the determination of factors. A linear quantitative calibration model between the near infrared spectrum and the content of the components to be measured was tried to be established so that the content of the components could be measured by NIRS rapidly. Results The predicted value of NIRS and the measured value of UPLC of five components in S. miltiorrhiza, including salvianolic acid B, dihydrotanshinone, tanshinone I, cryptotanshinone, and tanshinone IIA, presented a good linearity, indicating the calibration models had a preferable forecast results. The correlation coefficient were 0.981 1, 0.936 3, 0.960 5, 0.910 9, 0.978 0 respectively, and the mean and square deviation of the prediction set (RMSEP) were 0.957 0, 0.037 7, 0.041 6, 0.114, 0.063 9, respectively; But the model of the other constituents failed to reach the quantitative level. Conclusion The content of salvianolic acid B, dihydrotanshinone, tanshinone I, cryptotanshinone, tanshinone IIA in S. miltiorrhiza can be determined rapidly and nondestructive by the NIRS combined with PLS method, which lays a foundation for the rapid and field determination method for the medicinal materials and decoction pieces of S. miltiorrhiza.

14.
Talanta ; 175: 217-223, 2017 Dec 01.
Article in English | MEDLINE | ID: mdl-28841982

ABSTRACT

By employing the attractive performance of fluorescent carbon dots and the assistant of hairpin structure, an innovative dual-channel biosensor on the basis of gold nanoparticles (AuNPs) for detecting multiple nucleotide sequences has been successfully proposed. In brief, the fluorescence of carbon dots (CDs) was quenched in the absence of the targets, and the hairpin structure was hybridized with the AuNPs-DNA and resulted in recovering the fluorescence. Instead, the presence of breast cancer (BRCA1) RNA/DNA could specifically bind with its contrary sequence to release the CDs from AuNPs, hence leading to the fluorescence recovery as a positive signal. Again, the hairpin structure can be released in the presence of thymidine kinase (TK1) RNA/DNA, thus induced a fluorescence quenching accordingly. Subsequently, the prepared sensing model was applied to detect BRCA1 RNA/DNA respectively accompanied with a linear range of 4-120nM as well as a detection limit of 1.5nM and 2.1nM, and 10-120nM as well as a detection limit of 3.6nM and 4.5nM for TK1 RNA/DNA respectively. More importantly, this sensing model could assay any possible gene sequence or aptamer-substrate complexes by appropriately programming.


Subject(s)
Biosensing Techniques/methods , Carbon/chemistry , DNA/analysis , Nucleic Acid Hybridization/methods , Quantum Dots/chemistry , RNA/analysis , Aptamers, Nucleotide/chemistry , Aptamers, Nucleotide/genetics , Biosensing Techniques/instrumentation , DNA/genetics , Equipment Design , Fluorescence , Genes, BRCA1 , Gold/chemistry , Humans , Limit of Detection , Metal Nanoparticles/chemistry , RNA/genetics
15.
Biosens Bioelectron ; 86: 996-1002, 2016 Dec 15.
Article in English | MEDLINE | ID: mdl-27498327

ABSTRACT

A rapid and multiplexed immunosensor was developed based on a quantum dot (QD)-reverse assaying strategy (RAS) and immuno-magnetic beads (IMBs) for one-step and simultaneous detection of Escherichia coli O157: H7 and Salmonella. In a conventional QD-based immunosensor, the fluorescence signal of the "IMBs-target-QD" immunoconjugate is directly used as the assaying readout. However, the fluorescence signal is affected by IMBs due to light scattering and the "IMBs-target-QD" immunoconjugate needs multiple washing and re-suspension steps. To address these problems, we use the surplus QD-antibody conjugate as signal readout in the RAS, which prevents interference from the IMBs, increases the fluorescence signal, and avoids complex operations. Compared with conventional QD-based immunosensor, the sensitivity of QD-RSA immunosensor for detection of Escherichia coli O157: H7 has been improved fifty-fold, and whole analysis procedure can be finished within 1h. Therefore, this RSA strategy is promising for improving the performance of QD-based immunosensors and could greatly broaden their applications.


Subject(s)
Food Analysis/instrumentation , Food Contamination/analysis , Immunomagnetic Separation/instrumentation , Listeria/isolation & purification , Quantum Dots , Bacterial Typing Techniques/instrumentation , Complex Mixtures/analysis , Equipment Design , Equipment Failure Analysis , Food Microbiology/instrumentation , Reproducibility of Results , Sensitivity and Specificity , Spectrometry, Fluorescence/instrumentation
16.
Biosens Bioelectron ; 86: 83-89, 2016 Dec 15.
Article in English | MEDLINE | ID: mdl-27336615

ABSTRACT

A facile-green strategy to synthesize carbon dots (CDs) with a quantum yield (QY) of nearly 13.9% has been built up, while tomato juice served as the carbon source. Interestingly, not only the precursor of CDs and the whole synthesis procedure were environmental-friendly, but this type of CDs also exhibited multiple advantages including high fluorescent QY, excellent photostability, non-toxicity and satisfactory stability. Significantly, a label-free sensitive assay for detecting carcinoembryonic antigen (CEA) in a continuous and recyclable way has been proposed on the basis of adsorption and desorption of aptamers by the surface of CDs through a competitive mechanism. To be specific, the richness of carboxyl groups of the CDs enabled strong adsorption of ssDNA to the surface of CDs through π-π stacking interactions, resulting in the effective fluorescence quenching by forming CDs-aptamer complexes. The stronger binding affinity between CEA and CEA-aptamer than the π-π stacking interactions has been taken advantage to achieve immediate recovery of the fluorescence of CDs once CEA was introduced. Thereby, quantitative evaluation of CEA concentration in a broad range from 1ngmL(-1) to 0.5ngmL(-1) with the detection limit of 0.3ngmL(-1) was realized in this way. This strategy can be applied in a recyclable way, broadening the sensing application of CDs with biocompatibility. Besides, the CDs were used for cell imaging, potentiating them towards diverse purposes.


Subject(s)
Carbon/chemistry , Carcinoembryonic Antigen/analysis , Fruit and Vegetable Juices , Nanoparticles/chemistry , Solanum lycopersicum/chemistry , Spectrometry, Fluorescence/methods , Absorption, Physicochemical , Fluorescent Dyes/chemical synthesis , Staining and Labeling
17.
Article in Chinese | WPRIM (Western Pacific) | ID: wpr-790561

ABSTRACT

Objective To improve the quality control standard of lidocaine hydrochloride injection .Methods A method for determination of related substances in lidocaine hydrochloride injection was established .Lidocaine hydrochloride was as‐sayed by HPLC .The chromatographic conditions :C18 chromatographic column was used .The mobile phase was phosphate buffer and acetonitrile (50∶50 ,adjusted to pH 8 with phosphoric acid) .The detection wavelength was 254 nm .Results Ac‐cording to the result of method verification ,related substances could be examined by HPLC .Lidocaine hydrochloride was as‐sayed by HPLC ,which showed excellent linearity at the range of 373 .62‐3 736 .19 μg/ml .The average recoveries were 102 .1% (RSD=0 .9% ) .Conclusion The improved standard could be used to control the quality of lidocaine hydrochloride injection .

18.
Biosens Bioelectron ; 74: 546-53, 2015 Dec 15.
Article in English | MEDLINE | ID: mdl-26188677

ABSTRACT

By employing attractive performance of fluorescent carbon dots, we herein successfully established an assay for analyzing bacteria firstly. Specifically, carbon dots with blue fluorescence were initially synthesized according to a previous report, and modified with vancomycin on their surfaces. Subsequently, the prepared carbon dots were applied to detect Staphylococcus aureus accompanied with a linear range of 3.18×10(5)-1.59×10(8) cfu/mL as well as a detection limit of 9.40×10(4) cfu/mL. Compared with other regular methods, our method is more rapid and convenient in term of methodology. Meanwhile, the current strategy was applied for detection of other bacteria including Bacillus subtilis, Listeria monocytogenes, Salmonella, Pseudomonas aeruginosa and Escherichia coli, and the modified carbon dots showed obvious affinity with Gram-positive bacteria owing to the ligand-receptor interactions between vancomycin and the cell walls, suggesting its value for detecting Gram-positive bacteria. Additionally, the practicability of this sensing approach was validated by recovery experiments conducted in orange juice, confirming its potential to broaden avenues for detection of Gram-positive bacteria.


Subject(s)
Carbon/chemistry , Colony Count, Microbial/methods , Staphylococcus aureus/drug effects , Staphylococcus aureus/isolation & purification , Vancomycin/chemistry , Vancomycin/pharmacology , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Coated Materials, Biocompatible/chemical synthesis , Nanoparticles/chemistry , Nanoparticles/ultrastructure , Particle Size
19.
Article in Chinese | WPRIM (Western Pacific) | ID: wpr-840658

ABSTRACT

Objective: To develop a new method for the simultaneous determination of two hydrophilic components and two lipophilic components of Radix et Rhizoma Salviae Miltiorrhizae. Methods: The HPLC-DAD method was employed using a column of Agilent Zorbax TC C18 (4.6 mm × 250 mm, 5 μm) with a mobile phase of methanol -2% acetic acid. The gradient elution program was as follow:0-15 min, 30% B-40% B; 15-20 min, 40% B-60% B; 20-25 min, 60% B-90% B; 25-40 min, 90% B. The detection wavelength was set at 281 nm and the temperature was 35°C. Results: The linearity was obtained over 3.76-120.20 μg · ml-1 (r=0.999 9) for rosmarinic acid, 34.20-109 4.5 μg · ml-1 (r=0.999 9) for salviamolic acid B, 0.64-20.32 μg · ml-1 (r=0.999 9) for clyptotanshinon, and 1.02-32.72 μg · ml-1 (r=0.999 6) for tanshinone II A. The RSDs of precision and stability of the sample were both less than 1% in 48 hours. The average recovery was between 99.72%-100.63%. Conclusion: The present method is simple and has satisfactory efficacy; it can simultaneously determine multiple hydrophilic and lipophilic bioactive components in Salvia miltiorrhiza from different areas.

20.
Article in Chinese | WPRIM (Western Pacific) | ID: wpr-434169

ABSTRACT

Objective: To study and determine the Water-soluble substances of Salvia chinensis. Methods: The constituents of the n-Butanol-soluble portion of the water extractive were isolated and purified by means of Sephadex LH20 column chromatographic methods. HPLC was used to determine the contents. Results: Two compounds were isolated and identified as danshensu and rosmarinic acid. The linear range of danshensu was 1.48~7.40 μg. The average recovery was 102.8% and RSD was 1.04% ; The linear range of protocatechualdehyde was 0.05~0.26μg. The average recovery was 101.5% and RSD was 0.72%. Conclusion: The method can provide useful references to quality control of Herba Salvia chinensis. Danshensu was firstly isolated from Herba Salvia chinensis.

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