Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 51
Filter
Add filters








Year range
1.
Chinese Journal of Biotechnology ; (12): 943-960, 2022.
Article in Chinese | WPRIM | ID: wpr-927756

ABSTRACT

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.


Subject(s)
COVID-19/diagnosis , Humans , Microfluidics , Nucleic Acid Amplification Techniques , Polymerase Chain Reaction , SARS-CoV-2/genetics
2.
Acta Pharmaceutica Sinica ; (12): 802-808, 2022.
Article in Chinese | WPRIM | ID: wpr-922904

ABSTRACT

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.

3.
Chinese Journal of Biotechnology ; (12): 3905-3914, 2021.
Article in Chinese | WPRIM | ID: wpr-921475

ABSTRACT

Microfluidic chip technology integrates the sample preparation, reaction, separation and detection on a chip. It consists a network of microchannels, which controls the whole system through fluid. With the advantages of portability, high throughput, and the ability to simulate the microenvironment in vivo, it has a broad application prospect in the research of disease diagnosis, pathogenesis and drug screening. Pulmonary inflammatory disease is a common disease usually caused by bacterial, viral and fungal infections. Early pneumonia is often difficult to diagnose due to lack of obvious respiratory symptoms or the symptoms are mostly atypical, but the disease progresses rapidly. Recently, microfluidic chip technology has been increasingly used to the study of pulmonary inflammatory diseases. In particular, it has been used to develop a "lung-on-a-chip" model, which can reproduce the key structure, function and mechanical properties of human alveolar capillary interface (i.e., the basic functional unit of a living lung), and well simulate the alveoli in vitro. Compared with the cell and animal models, this multifunctional micro experimental platform has great advantages. This article summarizes the advances of using microfluidic chips for the research and diagnosis of pulmonary inflammatory diseases, with the aim to provide new ideas for researchers in this area.


Subject(s)
Animals , Drug Evaluation, Preclinical , Humans , Lung , Microfluidic Analytical Techniques , Microfluidics
4.
Journal of Medical Biomechanics ; (6): E903-E909, 2021.
Article in Chinese | WPRIM | ID: wpr-920701

ABSTRACT

Objective To seperate fetal nucleated red blood cells (fNRBCs) from the whole maternal peripheral blood effectively by designing a circular channel microfluidic chip. Methods A microfluidic chip is designed by utilizing the margination in blood flow and the specific adhesion characteristics of immuno-agent anti-CD147. With the whole umbilical cord blood, the effects of different shear forces on the enrichment of fNRBCs was studied by immunofluorescence counting. Results Increasing shear rate in microfluidic chip could improve the number of captured fNRBCs compared with the static adhesion. With the increase of shear rate of blood flow, the number of the captured cells increased at first, and then decreased. Conclusions The use of microfluid chip can effectively seperate fNRBCs from the whole blood. The results provide an experimental reference for the non-invasive prenatal diagnosis research and the exploration on the mechanism of fetal cell migration.

5.
Chinese Journal of Biotechnology ; (12): 663-672, 2021.
Article in Chinese | WPRIM | ID: wpr-878591

ABSTRACT

We developed a high-efficiency microfluidic chip for extracting exosomes from human plasma. We collected peripheral blood from normal human, designed and fabricated a microfluidic chip based on nanoporous membrane and agarose gel electrophoresis to isolate exosomes. The extracted exosomes were characterized by transmission electron microscopy, nanosight and Western blotting, the morphology, concentration and particle size of exosomes were identified and analyzed. Meanwhile, we used ultracentrifugation and microfluidic chip to isolate exosomes separately. The particle size and concentration of the exosomes extracted by two methods were compared and analyzed, and their respective extraction efficiency was discussed. Finally, the expression level of miRNA-21 in exosomes was analyzed by RT-PCR. The microfluidic chip isolated (in 1 hour) high-purity exosomes with size ranging from 30-200 nm directly from human plasma, allowing downstream exosomal miRNA analysis. By comparing with ultracentrifugation, the isolation yield of microfluidic chip was 3.80 times higher than ultracentrifugation when the volume of plasma sample less than 100 μL. The optimized parameters for exosome isolation by gel electrophoresis microfluidic chip were: voltage: 100 V; concentration of agarose gel: 1.0%; flow rate of injection pump: 0.1 mL/h. The gel electrophoresis microfluidic chips could rapidly and efficiently isolate the exosomes, showing great potential in the research of exosomes and cancer biomarkers.


Subject(s)
Exosomes , Humans , MicroRNAs/genetics , Microfluidics , Plasma , Ultracentrifugation
6.
Article in Chinese | WPRIM | ID: wpr-879212

ABSTRACT

A high throughput measurement method of human red blood cells (RBCs) deformability combined with optical tweezers technology and the microfluidic chip was proposed to accurately characterize the deformability of RBCs statistically. Firstly, the effective stretching deformation of RBCs was realized by the interaction of photo-trapping force and fluid viscous resistance. Secondly, the characteristic parameters before and after the deformation of the single cell were extracted through the image processing method to obtain the deformation index of area and circumference. Finally, statistical analysis was performed, and the average deformation index parameters (


Subject(s)
Erythrocyte Deformability , Erythrocytes , Humans , Microfluidics , Optical Tweezers , Viscosity
7.
Acta Pharmaceutica Sinica ; (12): 323-329, 2020.
Article in Chinese | WPRIM | ID: wpr-789033

ABSTRACT

Drug screening against Candida albicans has become more urgent due to the increasing incidence of infection and the development of drug-resistant strains. The microfluidic chip technique has shown great potential for high-throughput drug screening. In this study we developed a concentration gradient microfluidic chip platform for drug screening against Candida albicans. The generated concentration gradient on this platform was investigated qualitatively by monitoring the distribution of the fluorescent tracer fluorescein sodium and quantitatively by following the distribution of the model drug fluconazole as analyzed by HPLC; the effect of different flow conditions on the concentration gradient were determined. The ratio of the two aqueous phase flow rates was determined in the subsequent drug screening studies. Alamar Blue, an indicator of cell viability, was used in the susceptibility test for amphotericin B, fluconazole, itraconazole, voriconazole, posaconazole, terbinafine, 5-fluorocytosine and caspofungin as carried out on the established chip platform. The MIC range of the drugs, which was consistent with the MIC values of the CLSI-recommended standard, were obtained quickly and efficiently through the use of this platform, indicating that this new platform can quickly screen a series of antibacterial drugs in one run. In addition, the strain of Candida albicans we used showed resistance to terbinafine in our platform assay, consistent with the results of a 96-well plate assay, indicating that the platform can also be used for rapid screening of resistant strains.

8.
Article in Chinese | WPRIM | ID: wpr-848095

ABSTRACT

BACKGROUND: With the increasing proportion of infertility in the population, more and more attentions have been paid on assisted reproductive techniques. Fertilization and early embryo culture are the significant parts of assisted reproductive techniques; however, they remain unchanged in the last few decades. OBJECTIVE: To design a novel microfluidics-based fallopian tube model that can mimic the microenvironment of fertilization and early embryo culture in vivo. METHODS: Microfluidic device was manufactured by soft lithography method to mimic the anatomical characteristic of fallopian tube in vivo. Mouse oviduct primary epithelial cells were cultured and purified by explants culture method, and then the purified cells were identified by keratin immunofluorescence method. Epithelial cells were then loaded into the channel to mimic the biochemical environment of fallopian tube in vivo. The chip was connected to the automatic liquid changing device to mimic the liquid environment of fallopian tube in vivo. RESLUTS AND CONCLUSION: (1) The channel of this model is cylindrical with 2 cm of height and 1 cm of diameter, which were in accordance with the anatomical characteristic of the isthmus of fallopian tube in shape. (2) The keratin immunofluorescence was positive, which indicated that mouse oviduct primary epithelial cells can be obtained by explants culture method. (3) The cells were loaded into the channel to cover the wall of channel, which provided a biochemical microenvironment similar to that in vivo for fertilization and early embryo culture. After the chip was connected to the automatic liquid changing device, metabolic waste could be taken away and nutrient substance can be replenished in time, which mimics the real fluid environment in vivo. (4) This study combined microfluidics technology and assisted reproductive techniques to design a novel fallopian tube model, which mimics the micro-environment of fertilization and early embryo culture in vivo. This study has laid a foundation for further improvement of assisted reproductive techniques and the rate of fertilization and embryo optimization.

9.
Article in Chinese | WPRIM | ID: wpr-847294

ABSTRACT

BACKGROUND: In vitro models are widely used in toxicology, pathology, and pharmaceutical research due to their short experimental cycles, low cost, and small species differences compared with animal models. Dynamic three-dimensional tissue culture mode is an important trend in the development of in vitro models. Dynamic three-dimensional culture in vitro models can be achieved by means of driving fluids in microfluidic systems. OBJECTIVE: To describe the microfluidic driving methods in the field of microfluidics, their respective advantages and disadvantages, and the application of different driving methods to different tissue culture requirements. METHODS: A computed-based retrieval of CNKI and Web of Science databases was performed for the articles concerning dynamic three-dimensional tissue culture and microfluidic driving methods to achieve dynamic culture of cells or tissues. The search terms were “microfluidic; micropump; organ-on-chip; three-dimensional tissue culture” in English and Chinese, respectively. RESULTS AND CONCLUSION: The microfluidic driving methods include passive driving and active driving. Whereas passive driving includes surface tension pump, osmotic pump and gravity pump. Active driving includes syringe pump and peristaltic pump. Each driving method has its advantages and disadvantages. To achieve accurate control of the medium flow rate in a dynamic three-dimensional tissue culture system, the best choice is to use syringe pumps or valve-type peristaltic pumps. To achieve closed-loop flow of culture medium in a dynamic three-dimensional tissue culture system, the best choice is to use gravity pumps or peristaltic pumps. To fulfill the need for a sterile environment in the experimental process in a dynamic three-dimensional tissue culture system, the best choices are surface tension pumps, gravity pumps, and pneumatic peristaltic pumps. To achieve high-throughput culture in dynamic three-dimensional tissue culture systems, the best choices are surface tension pumps, gravity pumps and pneumatic peristaltic pumps.

10.
Chinese Journal of Biotechnology ; (12): 1405-1413, 2020.
Article in Chinese | WPRIM | ID: wpr-826836

ABSTRACT

In vitro compartmentalization (IVC) links genotype and phenotype by compartmentalizing individual genes (including expression system) or cells into a micro-droplet reaction region. Combined with fluorescence-activated cell sorting (FACS), it can detect and separate single droplets in ultra-high throughput. IVC-FACS screening method has been widely used in protein engineering, enzyme directed evolution, etc. However, it is difficult to control the homogeneity of droplet size by mechanical dispersion method in previous studies, which seriously affects the quantitative detection of droplets and reduces the efficiency and accuracy of this screening method. With the rapid development of microfluidic chip manufacturing technology, the microfluidic chip-based methods for droplet generation are becoming more efficient and controllable. In this study, firstly, the water-in-oil (W/O) single-layer droplet generation chip was used to prepare single-layer monodisperse W1/O droplets at a high generation frequency, and then the W1/O droplets were reinjected into water-in-oil-in-water (W/O/W) double-layer droplet generation chip to prepare uniform W1/O/W2 double-layer emulsion droplets. By optimizing the flow rate and ratio of the oil and water phases, a single-layer micro-droplet can be generated with a diameter range from 15.4 to 23.2 μm and remain stable for several days under normal incubation. Then the single-layer droplets were reinjected into the double emulsion generation chip. By adjusting the flow rate of drop phase, oil phase and water phase, the double-layer emulsion droplets with a diameter range from 30 to 100 μm at a rate of 1 000 droplets/s could be obtained. Escherichia coli embedded in the double-layer emulsion droplets could be cultured and induced for protein expression. This study lays a foundation for the establishment of a high-throughput screening method based on the droplet and flow cytometry.


Subject(s)
Emulsions , Flow Cytometry , High-Throughput Screening Assays , Microfluidics , Methods
11.
Article in Chinese | WPRIM | ID: wpr-856618

ABSTRACT

Objective: To preliminary study on the feasibility of constructing three-dimensional (3D) hippocampal neural network in vitro by using microfluidic technology. Methods: A network patterned microfluidic chip was designed and fabricated by standard wet etching process. The primary hippocampal neurons of neonatal Sprague Dawley rats were isolated and cultured, and then inoculated on microfluidic chip for culture. Immunofluorescence staining was used to observe the growth of hippocampal neurons at 3, 5, and 7 days of culture and electrophysiological detection of hippocampal neuron network at 7 days of culture. Results: The results showed that the number of hippocampal neurons increased gradually with the prolongation of culture time, and the neurite of neurons increased accordingly, and distributed uniformly and regularly in microfluidic chip channels, suggesting that the 3D hippocampal neuron network was successfully constructed in vitro. Single and multi-channel spontaneous firing signals of hippocampal neuronal networks could be detected at 7 days of culture, suggesting that neuronal networks had preliminary biological functions. Conclusion: Patterned microfluidic chips can make hippocampal neurons grow along limited paths and form 3D neuron networks with corresponding biological functions such as signal transduction, which lays a foundation for further exploring the function of neuron networks in vitro.

12.
Journal of Medical Biomechanics ; (6): E139-E144, 2019.
Article in Chinese | WPRIM | ID: wpr-802484

ABSTRACT

Objective To establish a new method to measure the elastic modulus of living circulating tumor cells (CTCs) by micropipette aspiration. Methods Living CTCs were enriched by commercial microfluidic chips and identified individually using EpCAM antibody under fluorescence microscope. The elastic modulus of CTCs was measured using micropipette aspiration and compared with cancer cell lines. Results For the elastic modulus of different cancer cell lines, heterogeneity was found not only between the different types of cancer cell lines but also inside the same cell line. The CTCs in breast cancer had a smaller elasticity modulus compared with MCF-7 cancer cell line. Conclusions This method can measure the elastic modulus of living CTCs, which provides cell mechanics data for studying the relationship between physical properties of CTCs and diagnosis of cancers, as well as developing the physical biomarkers of tumor cells.

13.
Article in Chinese | WPRIM | ID: wpr-798501

ABSTRACT

Objective:To study on the chemical constituents of total tannins from Spatholobi Caulis,and to analyze the pharmacodynamics and mechanism of total tannins from Spatholobi Caulis on cervical cancer HeLa cells. Method:UPLC-Q-TOF/MS was used to qualitatively analyze the composition of total tannins from Spatholobi Caulis.The appropriate concentration and time of administration were screened by 3 dimensional(3D) microfluidic chip.Flow cytometry was used to determine the effect of total tannins from Spatholobi Caulis on the cell cycle and apoptosis of cervical cancer HeLa cells and analyzed by FlowJo v10.0.7 and ModFit LT 3.2 software.Enzyme-linked immunosorbent assay(ELISA) was used to determine the changes of vascular endothelial growth factor(VEGF)-A and Caspase-3 factors in cervical cancer HeLa cells supernatant treated with total tannins from Spatholobi Caulis. Result:Total of 15 components in total tannins from Spatholobi Caulis were identified or inferred.The low,medium and high dosages of total tannins from Spatholobi Caulis were 0.5,1.0, 2.0 g·L-1 and the best time of administration was 36 h.The proportions of early and late apoptosis of cervical cancer HeLa cells increased significantly in the apoptosis analysis after being treated by total tannins from Spatholobi Caulis.The DNA synthesis early phase(G0/G1 phase) of cervical cancer HeLa cells significantly increased,and the DNA synthesis phase(S phase) and the DNA synthesis late phase(G2/M phase) reduced.After being treated with total tannins from Spatholobi Caulis,the expression of VEGF-A in cervical cancer HeLa cells supernatant was significantly decreased and the expression of Caspase-3 was significantly increased. Conclusion:Spatholobi Caulis is rich in tannins,which can significantly inhibit the proliferation of cervical cancer HeLa cells and promote its apoptosis.This paper can provide the basis for further research of total tannins from Spatholobi Caulis.

14.
Article in Chinese | WPRIM | ID: wpr-821718

ABSTRACT

Objective@#To establish and evaluate a microfluidic chip platform for the rapid diagnosis of post-neurosurgical bacterial infection. @*Methods@#The pathogens isolated from patients with post-neurosurgical bacterial infection in Beijing Tiantan Hospital Affiliated to Capital Medical University during 2007 and 2016 and the epidemiological data from China drug resistance monitoring network CHINET were analyzed retrospectively. Based on the retrospective data and the molecular epidemiological information of drug-resistant bacteria reported in the literature, target pathogens and drug resistance gene parameters were selected. The microbial identification parameters from 10 different bacteria, including Klebsiella pneumoniae, Acinetobacter baumannii, Staphylococcus epidermidis, Enterobacter cloacae, Staphylococcus aureus, Escherichia coli, Enterococcus faecium, Enterococcus faecalis, Stenotrophomonas maltophilia and Pseudomonas aeruginosa, and the parameters of 15 drug resistance genes, including mecA, vanA, vanB, aacC1, aadA1, bla CTX-M-1 , bla CTX-M-9 , bla GES-1 , bla OXA-23 , bla OXA-24 , bla OXA-58 , bla OXA-66 , bla KPC-2 , bla IMP-4 and bla VIM-2 , were selected for designing a microfluidic chip platform. Using MAIDI-TOF MS for bacterial identification, multiplex PCR for the detection of drug resistance genes, micro-broth dilution method for the detection of drug resistance phenotypes and ESBLs screening test as reference methods, 13 known bacteria were used to evaluate the preliminary performance of the established microfluidic chip platform, and 108 cerebrospinal fluid bacterial culture positive specimens were used to evaluate the clinical application value of the microfluidic chip platform. @*Results@#The identification rates of 13 known strains and the coincidence rate of drug resistance genes were 100%. The coincidence rate of identification results for 108 cerebrospinal fluid bacterial culture positive specimens between the microfluidic chip platform and the MALDI-TOF MS method was as high as 94.44%. The coincidence rates of drug resistance phenotype of carbapenems, oxacillin, vancomycin, ESBLs and genotype between the microfluidic chip platform and the micro-broth dilution method or ESBLs screening test were above 90%. @*Conclusion@#The established microfluidic chip platform is fast and accurate, and has application value in microbial identification and the prediction of drug resistance, which may be used as an important supplementary method in the diagnosis of post-neurosurgical bacterial infection.

15.
Article in Chinese | WPRIM | ID: wpr-815790

ABSTRACT

@# Abstract:Objective To establish a sensitive,rapid and convenient method for the detection of dengue antigen and assist clinical diagnosis of dengue. Methods In this paper,we developed a rapid detection method for dengue antigen based on microfluidic immune magnetic beads. Solidwork software was used to design microfluidic chip,which was prepared by mechanical processing and chemical sealing. Immunomagnetic beads of dengue antibody were prepared by chemical coupling reaction. Using HRP ⁃TMB ⁃H2O2 as color system,dengue NS1 antigen was detected on microfluidic chip carrier by double antibody sandwich method. Finally,57 clinical samples were tested by the novel method and traditional ELISA kit,and the accuracy of the method was analyzed,and the advantages and disadvantages of the two methods were compared. Results 20 minutes was needed to detect dengue NS1 antigen by using the novel ELISA method,and the reaction system only needed 10 μg beads and 10 μL samples. In the verification experiment,the method could distinguish the negative from the positive obviously. The positive sample had color rendering,while the negative and blank samples had no color rendering. In terms of detection performance,the coincidence rate between the new ELISA method and the traditional ELISA method reached 100%. Conclusion The novel ELISA detection platform had the advantages of simple,rapid,reagent and sample saving,high sensitivity,good stability and high accuracy,and could be used for the detection of dengue antigen.

16.
Acta Pharmaceutica Sinica ; (12): 269-280, 2019.
Article in Chinese | WPRIM | ID: wpr-780107

ABSTRACT

The blood-brain barrier (BBB) not only maintains the stability of the environment within the central nervous system by controlling the transport of substances on both sides of the blood and brain, but also plays an important role in the R&D of new drugs for neurological disorders. The establishment of an in vitro high-fidelity model to study BBB function is imperative for assessing barrier permeability of drugs and xenobiotics. However, the complexity of the BBB structure makes it difficult to replicate with an in vitro model. Compared to the traditional in vitro BBB model, the BBB-on-chip provides certain advantages in miniaturizing the system, reducing the amount of cells and medium required, and allowing simultaneously induction of shear stress. We review here the BBB-on-chip models from their establishment and characterization to applications in research of neuroinflammation, brain tumor and drug evaluation.

17.
Article in Chinese | WPRIM | ID: wpr-753368

ABSTRACT

The development of pharmaceutical analytical methods represents one of the most significant aspects of drug development. Recent advances in microfabrication and microfluidics could provide new approaches for drug analysis, including drug screening, active testing and the study of metabolism. Microfluidic chip technologies, such as lab-on-a-chip technology, three-dimensional (3D) cell culture, organs-on-chip and droplet techniques, have all been developed rapidly. Microfluidic chips coupled with various kinds of detection techniques are suitable for the high-throughput screening, detection and mechanistic study of drugs. This review highlights the latest (2010–2018) microfluidic technology for drug analysis and dis-cusses the potential future development in this field.

18.
Chinese Journal of Biotechnology ; (12): 396-403, 2019.
Article in Chinese | WPRIM | ID: wpr-771367

ABSTRACT

In recent years, many human central nervous systems (CNS) of microfluidic platforms and related disease models in vitro have been built with the continuous development of the microfluidic technology and biological microelectronics mechanical systems technology. Microplatforms have emerged to provide a better approximation of the in vivo scenario with better control of the structure, microenvironment and stimuli. This review summarized the basic technology of microfluidic chips in CNS and the application in CNS diseases. In addition, the research of microfluidic chip in CNS diseases has been also prospected. We also highlight challenges that can be addressed with interdisciplinary efforts to achieve more biomimicry.


Subject(s)
Central Nervous System Diseases , Humans , Microfluidic Analytical Techniques , Microfluidics
19.
Article in Chinese | WPRIM | ID: wpr-664807

ABSTRACT

An open-access microfluidic chip which enabled automatic cell distribution and complex multi-step operations was developed.The microfluidic chip featured a key structure in which a nanoporous membrane was sandwiched by a cell culture chamber array layer and a corresponding media reservoir array layer.The microfluidic approach took advantage of the characteristics of the nanoporous membrane.On one side, this membrane permitted the flow of air but not liquid, thus acting as a flow-stop valve to enable automatic cell distribution.On the other side, it allowed diffusion-based media exchange and thus, mimicked the endothelial layer.In synergy with a liquid transferring platform, the open-access microfluidic system enabled complex multi-step operations involving medium exchange, drug treatment, and cell viability testing.By using this microfluidic protocol, a 10 × 10 tissue arrays was constructed in 90 s, followed by schedule-dependent drug testing.Morphological and immunohistochemical assays results indicated that the resultant tumor tissue was faithful to that in vivo.Drug testing assays showed that the microfluidic tissue array promised multi-step cell assays under biomimetic microenvironment, thus providing an advantageous tool for cell research.

20.
Article in Chinese | WPRIM | ID: wpr-692357

ABSTRACT

A novel polydimethylsiloxane ( PDMS)-poly-L-lysine ( PLL) microfluidic chip, comprised of 24 reaction channels with 2. 5 μL volume of each reaction channel only, was proposed for quantitative analysis of methamphetamine ( MET) based on time-resolved immunoassay techniques. The chip utilized the adsorption characteristics of PDMS and PLL towards proteins to immobilize MET complete antigens ( MET-BSA) on the surface of reaction channel. Then the competition reaction could happen between MET-Ag in the sample solution and MET-BSA on the inner surfaces of the reaction channels with MET-Ab in the reagent. The surface of latex microspheres was labeled by lanthanide, which could emit red fluorescence under the exposure of ultraviolet ( UV ) . Based on the principle of competitive immunoassay, the more MET-Ag, the less the fluorescence intensity in the reaction channel. The detection results of this chip were acquired using UV-irradiation fluorescence imaging method. With this method, 24 samples could be detected and analyzed simultaneously on a chip by just taking the fluorescence image of the chip. The method allows the detection of MET antigens ranging from 100 ng/mL to 3000 ng/mL, with less sample consumption and high-throughput. This chip is suitable for the police preliminary screening work and has a good application prospects.

SELECTION OF CITATIONS
SEARCH DETAIL