Recent progress in aptamer-based microfluidics for the detection of circulating tumor cells and extracellular vesicles / 药物分析学报

Liquid biopsy is a technology that exhibits potential to detect cancer early,monitor therapies,and predict cancer prognosis due to its unique characteristics,including noninvasive sampling and real-time analysis.Circulating tumor cells(CTCs)and extracellular vesicles(EVs)are two important components of circu-lating targets,carrying substantial disease-related molecular information and playing a key role in liquid biopsy.Aptamers are single-stranded oligonucleotides with superior affinity and specificity,and they can bind to targets by folding into unique tertiary structures.Aptamer-based microfluidic platforms offer new ways to enhance the purity and capture efficiency of CTCs and EVs by combining the advantages of microfluidic chips as isolation platforms and aptamers as recognition tools.In this review,we first briefly introduce some new strategies for aptamer discovery based on traditional and aptamer-based micro-fluidic approaches.Then,we subsequently summarize the progress of aptamer-based microfluidics for CTC and EV detection.Finally,we offer an outlook on the future directional challenges of aptamer-based microfluidics for circulating targets in clinical applications.

Comparison of different approaches for direct coupling of solid-phase microextraction to mass spectrometry for drugs of abuse analysis in plasma / 药物分析学报

The direct coupling of solid-phase microextraction(SPME)to mass spectrometry(MS)(SPME-MS)has proven to be an effective method for the fast screening and quantitative analysis of compounds in complex matrices such as blood and plasma.In recent years,our lab has developed three novel SPME-MS techniques:SPME-microfluidic open interface-MS(SPME-MOI-MS),coated blade spray-MS(CBS-MS),and SPME-probe electrospray ionization-MS(SPME-PESI-MS).The fast and high-throughput nature of these SPME-MS technologies makes them attractive options for point-of-care analysis and anti-doping testing.However,all these three techniques utilize different SPME geometries and were tested with different MS instruments.Lack of comparative data makes it difficult to determine which of these methodologies is the best option for any given application.This work fills this gap by making a comprehensive comparison of these three technologies with different SPME devices including SPME fibers,CBS blades,and SPME-PESI probes and SPME-liquid chromatography-MS(SPME-LC-MS)for the analysis of drugs of abuse using the same MS instrument.Furthermore,for the first time,we developed different desorption chambers for MOI-MS for coupling with SPME fibers,CBS blades,and SPME-PESI probes,thus illustrating the universality of this approach.In total,eight analytical methods were developed,with the experimental data showing that all the SPME-based methods provided good analytical performance with R2 of linearities larger than 0.9925,accuracies between 81％and 118％,and good precision with an RSD％≤13％.

Neurotoxicity mechanism of aconitine in HT22 cells studied by microfluidic chip-mass spectrometry / 药物分析学报

Aconitine,a common and main toxic component of Aconitum,is toxic to the central nervous system.However,the mechanism of aconitine neurotoxicity is not yet clear.In this work,we had the hypothesis that excitatory amino acids can trigger excitotoxicity as a pointcut to explore the mechanism of neurotoxicity induced by aconitine.HT22 cells were simulated by aconitine and the changes of target cell metabolites were real-time online investigated based on a microfluidic chip-mass spectrometry system.Meanwhile,to confirm the metabolic mechanism of aconitine toxicity on HT22 cells,the levels of lactate dehydrogenase,intracellular Ca2+,reactive oxygen species,glutathione and superoxide dismutase,and ratio of Bax/Bcl-2 protein were detected by molecular biotechnology.Integration of the detected results revealed that neurotoxicity induced by aconitine was associated with the process of excitotoxicity caused by glutamic acid and aspartic acid,which was followed by the accumulation of lactic acid and reduction of glucose.The surge of extracellular glutamic acid could further lead to a series of cascade reactions including intracellular Ca2+overload and oxidative stress,and eventually result in cell apoptosis.In general,we illustrated a new mechanism of aconitine neurotoxicity and presented a novel analysis strategy that real-time online monitoring of cell metabolites can provide a new approach to mechanism analysis.

Recent progress on detection techniques for human hormones / 药学学报

Human hormones at trace levels play a vital role in the regulation of a variety of functions and systems in the body, and an imbalance in hormone levels can lead to the emergence and development of diverse diseases. Therefore, the development of reliable sample pretreatment methods and sensitive and accurate analytical techniques for human hormone detection could contribute to the prevention, diagnosis and treatment of diseases, providing significant improvement for human health. Human samples which are usually used to detecting hormones, such as blood, saliva, urine and other matrix are more complex, so sample pretreatment is an important step to ensure the accuracy and reliability in the detection of hormones. In this review three common sample pretreatment methods including solid phase extraction (SPE), liquid-liquid extraction (LLE) and protein precipitation (PP) methods are discussed. Then, recent research progress in conventional techniques like liquid/gas chromatography and liquid/gas chromatography-mass spectrometry (LC/GC-MS/MS), as well as some novel strategies, such as immunoassay including chemiluminescence immunoassay (CLIA), lateral-flow immunoassay (LFIA) and time-resolved fluoroimmunoassay (TRFIA), and sensor technology including electrochemical (EC), fluorescent (FL) and surface-enhanced Raman scattering (SERS) sensors, and microfluidic chip analysis are discussed for human hormone detection. Finally, the future perspective on the use of these methods for hormone detection is considered. It is hoped to provide powerful insights to researchers for the relevant researches.

Application of Microfluidic Liver and Kidney Chips in Toxicology Research of Chinese Medicine / 中国实验方剂学杂志

Microfluidic liver and kidney chips have become preferred model carriers in recent years for new drug development， pharmacological and toxicological research， mechanism exploration， and disease model construction. In the context of the USA. Food and Drug Administration allowing the use of in vitro model data as a substitute for animal model data in new drug applications when animal disease models are difficult to construct， microfluidic chips have received widespread attention due to their high throughput， ability to highly mimic biological characteristics of living organisms， convenient evaluation of drug toxicity in normal or pathological states with repeated dosing， real-time induction and monitoring of culture processes， and real-time data acquisition and analysis. In toxicology research， liver and kidney chips can construct in vitro models suitable for the pharmacological and toxicological detection of different substances by combining 2D monocultures and co-cultures from different species sources， 3D cultures， spheroids/organoid cells， precision-cut liver and kidney slices， immortalized cell lines， or sandwich-cultured cell lines. This model maximally simulates or retains the organ function and in vivo microenvironment of the liver and kidney， including specific physiological tissue structures， multicellular interactions/crosstalk， and multi-organ coordination/feedback， to obtain results similar to or the same as in vivo experimental data， reducing interspecies differences. At the same time， it greatly reduces the use of experimental animals and lowers costs. Microfluidic technology provides necessary shear force microenvironments for the cultivation of contents and solves problems encountered in the cultivation process of liver and kidney chips， such as insufficient tissue oxygen supply， nutrient deficiencies， and accumulation of metabolites， leading to cell apoptosis and even tissue necrosis fibrosis， which make it difficult to maintain long-term structure and function. This article reviewed the application of microfluidic technology combined with liver and kidney chips in Chinese medicine toxicology research. By summarizing the development of microfluidic technology， liver chips， kidney chips， and providing application examples of microfluidic liver and kidney chips in Chinese medicine toxicology research， combined with the characteristics of Chinese medicine administration， the article explored the advantages and future development directions of their application in the field of Chinese medicine toxicology research.

Analysis of the Inhibitory Effect of Tirofiban on Shear-Induced Platelet Aggregation by Microfluidic Technique / 医用生物力学

Objective To observe the inhibitory effect of Tirofiban on different shear-induced platelet aggregation, and to provide medication suggestions for the treatment of thrombosis in different hemodynamic environment. Methods Polydimethylsiloxane ( PDMS)-glass microchannel chips were fabricated by soft lithography. The whole blood of healthy volunteers anticoagulated with sodium citrate was collected and incubated with different concentrations of Tirofiban in vitro. The blood flowed through the straight microchannel or channel with 80% narrow for 150 seconds at the speed of 11 μL/ min and 52 μL/ min, respectively. The wall shear stress rates in straight channel at 11 μL/ min and 52 μL/ min were 300 s-1 and 1 500 s-1, respectively. The maximum wall shear rates in the channel with 80% occlusion at 11 μL/ min and 52 μL/ min were 1 600 s-1 and 7 500 s-1, respectively. The adhesion and aggregation images of fluorescent labeled platelets on glass surface were photographed with the microscope, and the fluorescent images were analyzed with Image J. The platelet surface coverage ratio was used as a quantitative index of platelet aggregation behavior, and the IC50 of Tirofiban for platelet inhibition was calculated under different shear rates. Flow cytometry was used to detect the platelet activation index (CD62P, PAC-1) in the whole blood at 52 μL/ min in channel with 80% occlusion. Results Tirofiban inhibited platelet aggregation in a dose-dependent manner, and the inhibitory effect was related to the shear rate. Under the shear rates of 11 μL/ min and 52 μL/ min, the aggregation was almost completely inhibited when the concentration in straight channel reached 100 nmol / L. When the concentration in channels with 80% occlusion reached 1 μmol / L, the aggregation was almost completely inhibited. IC50 values at 11 μL/ min and 52 μL/ min in straight channel were 2. 3 nmol / L and 0. 5 nmol / L, respectively. IC50 values at 11 μL/ min and 52 μL/ min in channels with 80% occlusion were 20. 73 nmol / L and 4. 5 nmol / L. Pathologically high shearforce induced an increase in platelet activation, which could be inhibited by Tirofiban. Conclusions Tirofiban can effectively inhibit shear-induced platelet aggregation, and different concentrations of Tirofiban should be given according to the thrombus formed in different shear force environment in clinic practice

Detection of IgG protein in human urine based on vertical flow paper microfluidic chip / 生物工程学报

The kidney is the body's most important organ and the protein components in urine could be detected for diagnosing certain diseases. The amount of IgG protein in urine could be used to determine the degree of kidney function damage. IgG protein in human urine was detected by vertical flow paper-based microfluidic chip, double-antibody sandwich immunoreaction, and cell phone image processing. The results showed that using an IgG antibody concentration of 500 μg/mL and a gold standard antibody concentration of 100 μg/mL, the image signal showed a good linear relationship in the range of IgG concentration of 0.2-3.2 μg/mL, with R2=0.973 3 achieved. A complete set of detection devices were designed and the detection method showed good non-specificity.

Study on Platelet Adhesion and Aggregation Induced by Gradient Shear Stress Using Microfluidic Chip Technology / 中国实验血液学杂志

OBJECTIVE@#To study the effect of gradient shear stress on platelet aggregation by microfluidic chip Technology.@*METHODS@#Microfluidic chip was used to simulate 80% fixed stenotic microchannel, and the hydrodynamic behavior of the stenotic microchannel model was analyzed by the finite element analysis module of sollidwork software. Microfluidic chip was used to analyze the adhesion and aggregation behavior of platelets in patients with different diseases, and flow cytometry was used to detect expression of the platelet activation marker CD62p. Aspirin, Tirofiban and protocatechuic acid were used to treat the blood, and the adhesion and aggregation of platelets were observed by fluorescence microscope.@*RESULTS@#The gradient fluid shear rate produced by the stenosis model of microfluidic chip could induce platelet aggregation, and the degree of platelet adhesion and aggregation increased with the increase of shear rate within a certain range of shear rate. The effect of platelet aggregation in patients with arterial thrombotic diseases were significantly higher than normal group (P<0.05), and the effect of platelet aggregation in patients with myelodysplastic disease was lower than normal group (P<0.05).@*CONCLUSION@#The microfluidic chip analysis technology can accurately analyze and evaluate the platelet adhesion and aggregation effects of various thrombotic diseases unde the environment of the shear rate, and is helpful for auxiliary diagnosis of clinical thrombotic diseases.

Microfluidic Chip and Flow Cytometry for Examination of the Antiplatelet Effect of Ticagrelor / 中国医学科学院学报

Objective To examine the antiplatelet effect of ticagrelor by microfluidic chip and flow cytometry under shear stress in vitro. Methods Microfluidic chip was used to examine the effect of ticagrelor on platelet aggregation at the shear rates of 300/s and 1500/s.We adopted the surface coverage of platelet aggregation to calculate the half inhibition rate of ticagrelor.The inhibitory effect of ticagrelor on ADP-induced platelet aggregation was verified by optical turbidimetry.Microfluidic chip was used to construct an in vitro vascular stenosis model,with which the platelet reactivity under high shear rate was determined.Furthermore,the effect of ticagrelor on the expression of fibrinogen receptor (PAC-1) and P-selectin (CD62P) on platelet membrane activated by high shear rate was analyzed by flow cytometry. Results At the shear rates of 300/s and 1500/s,ticagrelor inhibited platelet aggregation in a concentration-dependent manner,and the inhibition at 300/s was stronger than that at 1500/s (both P<0.001).Ticagrelor at a concentration ≥4 μmol/L almost completely inhibited platelet aggregation.The inhibition of ADP-induced platelet aggregation by ticagrelor was similar to the results under flow conditions and also in a concentration-dependent manner.Ticagrelor inhibited the expression of PAC-1 and CD62P. Conclusion We employed microfluidic chip to analyze platelet aggregation and flow cytometry to detect platelet activation,which can reveal the responses of different patients to ticagrelor.

Research progress of microfluidic chips in age-related macular degeneration / 国际眼科杂志(Guoji Yanke Zazhi)

Age-related macular degeneration(ARMD)is the primary cause of severe visual impairment and blindness in people over 60 years old. With the aging of the global population, the incidence of the disease is also rising year by year. However, the pathogenesis and treatment strategy of ARMD need to be further explored. As a cutting-edge science and technology, microfluidic chips can build a comprehensive microsystem that simulates the condition and function of human tissues and organs, which has the advantages of less sample consumption and short analysis time. In recent years, many studies have confirmed that microfluidic chips can bring brand new technology solutions to the basic and clinical research of ARMD. This article will discuss and review the application progress of microfluidic chips in the areas of ARMD mechanism research, drug evaluation and clinical translation, providing a theoretical reference for further research on the diagnosis and treatment of ARMD.

Application progress of microfluidic chip in isolation and capture of circulating tumor cells / 中华检验医学杂志

The amount of circulating tumor cells(CTC) in peripheral blood is very small, which is difficult to isolate. Microfluidic chips are becoming a hot area in recent years because of their portability, high sensitivity, high capture,and low cost. Microfluidic devices have been shown to maintain optimal performance for CTC isolation capture, including flux, purity, recovery, and clinical relevance. However, microfluidic technology is still unable to recover CTC with high recovery and purity.

Expansion of cord blood stem cells in fibronectin-coated microfluidic bioreactor

ABSTRACT Background: Hematopoietic stem/progenitor cell transplantation is the main treatment option for hematological malignancies and disorders. One strategy to solve the problem of low stem cell doses used in transplantation is pre-transplant expansion. We hypothesized that using fibronectin-coated microfluidic channels would expand HSPCs and keep self-renewal potential in a three-dimensional environment, compared to the conventional method. We also compared stem cell homing factors expression in microfluidic to conventional cultures. Materials and methods: A microfluidic device was created and characterized by scanning electron microscopy. The CD133+ cells were collected from cord blood and purified. They were subsequently cultured in 24-well plates and microfluidic bioreactor systems using the StemSpan serum-free medium. Eventually, we analyzed cell surface expression levels of the CXCR4 molecule and CXCR4 mRNA expression in CD133+ cells cultured in different systems. Results: The expansion results showed significant improvement in CD133+ cell expansion in the microfluidic system than the conventional method. The median expression of the CXCR4 in the expanded cell was lower in the conventional system than in the microfluidic system. The CXCR4 gene expression up-regulated in the microfluidic system. Conclusion: Utilizing microfluidic systems to expand desired cells effectively is the next step in cell culture. Comparative gene expression profiling provides a glimpse of the effects of culture microenvironments on the genetic program of HSCs grown in different systems.

Sensitive detection of microRNAs using polyadenine-mediated fluorescent spherical nucleic acids and a microfluidic electrokinetic signal amplification chip / 药物分析学报

The identification of tumor-related microRNAs(miRNAs)exhibits excellent promise for the early diag-nosis of cancer and other bioanalytical applications.Therefore,we developed a sensitive and efficient biosensor using polyadenine(polyA)-mediated fluorescent spherical nucleic acid(FSNA)for miRNA analysis based on strand displacement reactions on gold nanoparticle(AuNP)surfaces and electrokinetic signal amplification(ESA)on a microfluidic chip.In this FSNA,polyA-DNA biosensor was anchored on AuNP surfaces via intrinsic affinity between adenine and Au.The upright conformational polyA-DNA recognition block hybridized with 6-carboxyfluorescein-labeled reporter-DNA,resulting in fluores-cence quenching of FSNA probes induced by AuNP-based resonance energy transfer.Reporter DNA was replaced in the presence of target miRNA,leading to the recovery of reporter-DNA fluorescence.Sub-sequently,reporter-DNAs were accumulated and detected in the front of with Nafion membrane in the microchannel by ESA.Our method showed high selectivity and sensitivity with a limit of detection of 1.3 pM.This method could also be used to detect miRNA-21 in human serum and urine samples,with re-coveries of 104.0％-113.3％and 104.9％-108.0％,respectively.Furthermore,we constructed a chip with three parallel channels for the simultaneous detection of multiple tumor-related miRNAs(miRNA-21,miRNA-141,and miRNA-375),which increased the detection efficiency.Our universal method can be applied to other DNA/RNA analyses by altering recognition sequences.

Reconstruction and Biomechanical Design of Microvascular Models / 医用生物力学

Neovascularization plays an important role in many physiological and pathological processes, but its mechanism is still unclear. Since vascular cells are subjected to a variety of biochemical and biomechanical stimulations in vivo and live in a complex microenvironment, it is necessary to construct the vascular model in vitro and simulate the in vivo microenvironment to explore the mechanism of neovascularization. Recently, owing to the advance of micromachining and microfluidic technology, various in vitro microvascular models have emerged. Variables such as shear stress, interstitial flow and biochemical gradient of angiogenic factors have been controlled in these models, which greatly promotes the research of neovascularization. The construction, development and biomechanical design of various microvascular models are reviewed in this paper.

Validation of microfluidic chip for detection of mutation hotspots associated with hereditary hearing loss / 中华检验医学杂志

Objective:To explore the application of microfluidic chip in detection of hereditary deafness-associated hotspot mutations.Methods:The dedicatedly designed and fabricated microfluidic chip was integrated with kompetitive allele-specific polymerase chain reaction amplification system, scanned via laser-excited confocal fluorescence scanner, and finally analyzed programmatically to acquire the typing results of the 23 mutation sites of the four common genes associated with hereditary hearing loss. Dried blood spots were collected from 276 neonates containing the 131 cases with hearing loss who were born in 2019 in Chengdu (deafness group) and the 145 cases with normal hearing who were born in 2020 in Chengdu (control group), and analyzed by the microfluidic chip to evaluate its clinical performance.Results:By cluster analysis, the microfluidic chip correctly analyzed the 23 positive reference samples and acquired the same typing results as their actual results, with a limit of detection of 1 mg/L. For the 276 newborn blood spots, the detection results of the microfluidic chips were confirmed to be correct by the contrasting methods. Among Deafness Group, 66 (50.4%) tested positive for the selected 23 mutation hotspots; among Control Group, 40(27.6%) were positive. Among these mutations, c.109G>A of the GJB2 gene was the most prevalent one, whose carrier rate in deafness group and control group were 46.6%(61/131) and 23.4% (34/145), respectively.Conclusions:The micro-fluidic chip system was succeeded in fulfilling the hereditary deafness-related mutation detection, and offered many advantages including high specificity, avoiding the amplicon carryover contamination, simplifying the entire experimental operation process and short detection time, so as to better meet the detection requirement of genetic testing for deafness in newborn screening and other fields.

Isothermal amplification technology based on microfluidic chip / 生物工程学报

Polymerase chain reaction (PCR) is the gold standard for nucleic acid amplification in molecular diagnostics. The PCR includes multiple reaction stages (denaturation, annealing, and extension), and a complicated thermalcycler is required to repetitively provide different temperatures for different stages for 30-40 cycles within at least 1-2 hours. Due to the complicated devices and the long amplification time, it is difficult to adopt conventional PCR in point-of-care testing (POCT). Comparing to conventional PCR, isothermal amplification is able to provide a much faster and more convenient nucleic acid detection because of highly efficient amplification at a constant reaction temperature provided by a simple heating device. When isothermal amplification is combined with microfluidics, a more competent platform for POCT can be established. For example, various diagnosis devices based on isothermal amplification have been used to rapidly and conveniently detect SARS-CoV-2 viruses. This review summarized the recent development and applications of the microfluidics-based isothermal amplification. First, different typical isothermal amplification methods and related detection methods have been introduced. Subsequently, different types of microfluidic systems with isothermal amplification were discussed based on their characteristics, for example, functionality, system structure, flow control, and operation principles. Furthermore, detection of pathogens (e.g. SARS-CoV-2 viruses) based on isothermal amplification was introduced. Finally, the combination of isothermal amplification with other new technologies, e.g. CRISPR, has been introduced as well.

Construction of a blood-brain barrier microfluidic chip model and evaluation of the permeability of active components in traditional Chinese medicine / 药学学报

A blood-brain barrier microfluidic chip platform for studying the permeability of active components in traditional Chinese medicine was developed. This model used primary human brain microvascular endothelial cells on a microfluidic chip consisting of two perpendicularly-crossing channels and a single layer porous polycarbonate membrane. The physiological shear stress in the human vasculature was also modeled in this device. Cell viability on the chip was monitored by cell staining and immunofluorescence staining. The cells spread well and the structure of an intercellular adhesion protein was satisfactory. The permeability of fluorescent tracers and three model drugs and the functional expression of P-glycoprotein (P-gp)on the blood-brain barrier were investigated. The results show that the apparent permeability coefficients (Papp) of the fluorescent tracers and three model drugs were consistent with those reported in the literature, and P-gp on the chip showed normal function, indicating that there was a complete structure and a functional BBB. The permeability of six active components of traditional Chinese medicine was investigated through this microfluidic chip and the drug concentration was determined by HPLC-MS/MS to obtain the Papp of each component. The Papp of corydaline was (4.51 ± 1.90)×10-7 cm·s-1, the Papp of tetrahydropalmatine was (9.10 ± 6.59)×10-7 cm·s-1, and the Papp of imperatorin was (9.38 ± 2.53)×10-7 cm·s-1; the concentration of isoimperatorin, baicalin and chlorogenic acid was below the limit of quantification, which suggested that isoimperatorin, baicalin and chlorogenic acid have poor permeability in this BBB chip. This blood-brain barrier microfluidic platform possesses a complete barrier function and near-physiological conditions and could be a valuable in vitro tool for drug permeability evaluation.

Current status and research progress of microfluidic immunochips in medical detection / 中华检验医学杂志

The traditional-immunological strategies for clinical laboratories often rely on large and expensive instruments and skilled operators, and the measurement time is also long. However, the sensitivity of these strategies is still unsatisfactory. It is urgent to research and develop the point-of-care testing (POCT) featured as a highly sensitive, accurate, and rapid/POCT diagnosis. The Microfluidic chips have multi-advantages that are suitable for the clinical POCT diagnosis: high sensitivity, throughput, and automation. Recently, the Microfluidic-immune chips developed based on the microfluidic technology combined with immune detection have considered not only hotspots in the related research but also benefit to the tumor marker detection, antigen and antibody detection of infectious diseases, autoantibody detection, hormone detection, and other fields. However, there are still many challenges to be overcome during the application of chips, such as more effective microfluidic manipulation, more sensitive collection, and analysis of reaction signals.

Preliminary application experience of disk microfluidic chip for detecting CALR gene mutation in patients with cerebral infarction / 中华检验医学杂志

Objective:To establish a disk (CD) microfluidic chip detection platform for the rapid detection of CALR-1 and CALR-2 mutations in patients with cerebral infarction, and summarize its clinical application value.Methods:Based on microfluidic technology and loop mediated isothermal amplification technology, a CD microfluidic chip detection platform for simultaneous detection of CALR-1 and CALR-2 gene mutations were established, and the sensitivity, specificity, repeatability and accuracy of the platform were verified. A total of 124 patients with cerebral infarction treated in Huashan Hospital, Shanghai Medical College, Fudan University from November 2019 to March 2021 were prospectively selected into the experimental group; and 80 healthy subjects were included in the control group. The CALR-1 and CALR-2 gene mutations in anticoagulant peripheral blood samples were detected by the CD microfluidic chip. Each chip could detect 4 samples at the same time and synchronously detect 3 indexes of each sample. The detection results could be obtained after isothermal amplification for 40 min. At the same time, sequencing method was used to verify the test results, and the consistency of the results of the two detection methods was compared.Results:Using this CD microfluidic chip platform, the synchronous amplification of 3 indexes in the sample could be completed within 40 min without the need of thermal circulation, and the whole detection process of the sample could be completed within 60 min. For samples with a high concentration of target nucleic acid, typical positive signals could be visualized after amplification for 10 min, and the test results would be available within 30 minutes after receiving the samples. The detection sensitivity of CD microfluidic chip method for CALR-1 and CALR-2 mutation load concentration was 1.0% and 0.5% respectively. Nonspecific amplification was not observed for the non-target nucleic acid samples, indicating the high specificity of this method. The coincidence rates of intra and inter batch repeatability were 100% (20/20) respectively. Two samples with CALR gene mutation were found in the cerebral infarction group, both of which were CALR-1 mutations (L367fs*46). There was no CALR-1 or CALR-2 mutation in the control group. The detection results of CD microfluidic chip method were completely consistent with the sequencing verification results (100% [204/204]).Conclusions:The CD microfluidic chip method could be used for the detection of CALR-1 and CALR-2 gene mutations in clinical samples of patients with cerebral infarction. This method has the advantages of high detection sensitivity, good detection specificity, fast detection speed and high detection flux, which is helpful to clarify the etiology of patients with cerebral infarction.

Protective Effect of Ginsenosides Rg1 and Rb1 Against Intestinal Epithelial Barrier Injury Induced by Lipopolysaccharide in Vitro / 中国实验方剂学杂志

ObjectiveTo investigate the effects of ginsenoside Rg1 and ginsenoside Rb1 on the release of inflammatory factors of human myeloid leukemia monocytes （THP-1） induced by lipopolysaccharide （LPS） and their protective effects on the inflammatory injury of intestinal epithelial cells （Caco-2） induced by THP-1 cell activation based on the co-culture system of THP-1 and Caco-2. MethodFirstly，the microfluidic chip of co-culture of THP-1 and Caco-2 cells was prepared. In the experiment， a blank group， an LPS group， and drug intervention groups were set up.The cells in the blank group were cultured conventionally. In the LPS group，LPS （1 mg·L-1） was added to the lower THP-1 cells after the upper Caco-2 cells formed a monolayer barrier. On the basis of the LPS group， 33 mg·L-1 ginsenoside Rg1 and 33 mg·L-1 ginsenoside Rb1 were added to THP-1 cells respectively. After the co-culture of THP-1 cells and Caco-2 cells for 24 hours， the fluorescein isothiocyanate （FITC）-Dextran fluorescence value in the lower chip channel was detected by FITC-Dextran tracer method. A blank group， an LPS group，and drug intervention groups were set up in the THP-1 cell experiment. THP-1 cells in the blank group were cultured conventionally. In the LPS group， LPS （1 mg·L-1） was added to THP-1 cells.Ginsenoside Rg1 and ginsenoside Rb1 of the corresponding doses （11，33，100 mg·L-1） were added to the drug intervention groups respectively on the basis of the LSP group. After 24 hours of cell culture， the activity of THP-1 cells was detected by cell counting kit-8 （CCK-8）. Real-time quantitative polymerase chain reaction （Real-time PCR） was used to detect the expression of inflammatory cytokines such as interleukin-6 （IL-6）， interleukin-1β （IL-1β）， and tumor necrosis factor （TNF）-α of THP-1 cells. A blank group， an LPS group， and drug intervention groups were set up in the Caco-2 cell experiment. Caco-2 cells in the blank group were cultured conventionally， and in other groups， the corresponding cell supernatant in the second part of the THP-1 cell experiment was employed in Caco-2 cells. After 24 hours of cell culture，the activity of Caco-2 cells was detected by CCK-8. Real-time PCR was used to detect the expression of IL-6，interleukin-8 （IL-8）， TNF-α， and Occludin of Caco-2 cells. The expression of tight junction protein Occludin in Caco-2 cells was detected by Western blot. ResultBoth ginsenoside Rg1 and ginsenoside Rb1 could effectively protect LPS-induced intestinal epithelial barrier permeability in the co-culture system of THP-1 and Caco-2 cells （P<0.01）. Ginsenosides Rg1 and Rb1 antagonized LPS-induced increased expression of IL-6，IL-1β， and TNF-α in THP-1 cells （P<0.05）. When the supernatant of THP-1 cells treated with ginsenosides Rg1 and Rb1 was co-cultured with Caco-2 cells， the expression of IL-6，IL-8， and TNF-α in Caco-2 cells was significantly reduced （P<0.01）， and the expression of tight junction protein Occludin was up-regulated. ConclusionIn the co-culture system of THP-1 and Caco-2 cells simulating the intestinal epithelial barrier function in vitro，ginsenosides Rg1 and Rb1 play a protective role against LPS-induced intestinal epithelial barrier injury by regulating the release of inflammatory cytokines by THP-1 cells， thereby regulating the inflammatory response and cell barrier integrity of Caco-2 cells.