Recently, the droplet microfluidic system attracts interests due to its high throughput and low cost to detect and screen. The picoliter micro-droplets from droplet microfluidics are uniform with respect to the size and shape, and could be used as monodispensed micro-reactors for encapsulation and detection of single cell or its metabolites. Therefore, it is indispensable to characterize micro-droplet and its application from droplet microfluidic system. We first constructed the custom-designed droplet microfluidic system for generating micro-droplets, and then used the micro-droplets to encapsulate important amino acids such as glutamic acid, phenylalanine, tryptophan or tyrosine to test the droplets' properties, including the stability, diffusivity and bio-compatibility for investigating its application for amino acid detection and sorting. The custom-designed droplet microfluidic system could generate the uniformed micro-droplets with a controllable size between 20 to 50 microm. The micro-droplets could be stable for more than 20 h without cross-contamination or fusion each other. The throughput of detection and sorting of the system is about 600 micro-droplets per minute. This study provides a high-throughput platform for the analysis and screening of amino acid-producing microorganisms.
Amino Acids ; isolation & purification ; Microfluidic Analytical Techniques ; Microfluidics ; instrumentation

As a novel analytical technology, the research of Micro total analysis systems (micro-TAS) has been spreading rapidly. micro-TAS has been widely used to perform chemical and biochemical analysis. Microfluidic-based analytical system as micro-TAS's manily direction develops very fast in terms of it's reaction speed, reagent consumption, miniaturization, cost, and automation. After having proven the value of microfluidics for genetic, proteomic and cytomics analysis, this article also anticipates the development tendency of this technology in the biology medicine domain. It has demonstrated that a truly, easy-to-handle Microfluidic-based analytical device will be emerged in the future.
Humans ; Microarray Analysis ; instrumentation ; methods ; Microfluidic Analytical Techniques ; trends ; Microfluidics ; trends ; Technology Assessment, Biomedical

Microfluidics deals with the manipulation of fluidics in the structure with dimensions of micrometers or nanometers. As an emerging field, microfluidics has numerous advantages, such as controllable fluid flow and reduced reagents consumption. Recently, microfluidic has been applied into the area of cell transfection, providing opportunities to investigate cell transfection process on microscale. This review summarizes recent technical development of cell transfection based on microfluidics, including transfeceted microarray, transfecetion established in miniaturization flowing space, microdrops, microinjection and microfluidic electroporation. The factors that affect the transfection efficiency and improvement approaches are also discussed.
Electroporation ; Microfluidic Analytical Techniques ; instrumentation ; Miniaturization ; Oligonucleotide Array Sequence Analysis ; Transfection

Point-of-care testing (POCT) is a test method performed on the sampling site or patient bedside. Accurate results can be achieved rapidly by the application of portable analytical instruments and compatible reagents. It has been widely used in the field of in vitro diagnosis (IVD). Paper-based microfluidics technology has great potential in developing POCT due to its advantages in low cost, simple operation, rapid detection, portable equipment, and unrestricted application conditions. In recent years, the development of paper-based microfluidic technology and its integration with various new technologies and methods have promoted the substantial development of POCT technology and methods. The classification and characteristic of the paper are summarized in this review. Paper-based microfluidic sample pretreatment methods, the flow control in the process of reaction and the signal detecting and analyzing methods for the testing results are introduced. The research progress of various kinds of microfluidic paper-based analytical devices (μPADs) toward POCT in recent years is reviewed. Finally, remaining problems and the future prospects in POCT application of paper-based microfluidics are discussed.
Diagnostic Tests, Routine ; methods ; Humans ; Microfluidic Analytical Techniques ; instrumentation ; Paper ; Point-of-Care Testing

We use direct-write laser micromachining technology to fabricate the microfluidic chip, and to establish a microfluidic chemiluminescence immunoassay system based on superparamagnetic microbeads, for detecting alpha- fetoprotein (AFP). The AFP analysis can be completed in 20 minutes with 5 microl sample and 5 microl reagent, and there is a good linear correlation in the range of 1-800 ng/ml.
Equipment Design ; Humans ; Immunoassay ; instrumentation ; methods ; Luminescent Measurements ; instrumentation ; methods ; Microfluidic Analytical Techniques ; instrumentation ; alpha-Fetoproteins ; analysis

Flexible print circuit (FPC) technology has been widely applied in variety of electric circuits with high precision due to its advantages, such as low-cost, high specific fabrication ability, and good flexibility, etc. Recently, this technology has also been used in biomedical engineering, especially in the development of microfluidic chip and microelectrode array. The high specific fabrication can help making microelectrode and other micro-structure equipment. And good flexibility allows the micro devices based on FPC technique to be easily packaged with other parts. In addition, it also reduces the damage of microelectrodes to the tissue. In this paper, the application of FPC technology in biomedical engineering is introduced. Moreover, the important parameters of FPC technique and the development trend of prosperous applications is also discussed.
Biomedical Engineering ; instrumentation ; methods ; Electricity ; Equipment Design ; Lab-On-A-Chip Devices ; trends ; Microelectrodes ; Microfluidic Analytical Techniques ; instrumentation ; Microfluidics ; instrumentation

We developed a novel microfluidic cell chip, which enabled drug delivery, fluid control and cell co-culture. The device consisted of an array of 6x6 cell culture chambers, a drug gradient generator and fluidic control valves. Micro-dam structures of the chambers were able to trap cells while loading and drug gradient network generated drug gradient of 6 different concentrations. Also we applied hydraulic valves to control the microfluid and simulate the microenvironment of cells. We had investigated the viability of co-culturing cells in the chip and the ability for drug screening. This microfluidic cell chip has the potential in cell-based research of high throughput drug screening.
Biosensing Techniques ; instrumentation ; methods ; Cells, Cultured ; Drug Evaluation, Preclinical ; methods ; Endothelial Cells ; cytology ; Hepatocytes ; cytology ; Humans ; Microfluidic Analytical Techniques ; instrumentation ; methods ; Microfluidics ; instrumentation ; methods ; Umbilical Veins ; cytology

After years of development, biosensors based on imaging ellipsometry and biosensors based on total internal reflection imaging ellipsometry have been successfully implemented in various engineering systems. Their experimental setups, detection principles, and biological and clinical applications are briefly reviewed.
Antibodies ; analysis ; immunology ; Antigens, CD ; analysis ; immunology ; Bacteria ; chemistry ; isolation & purification ; Biomarkers ; analysis ; Biosensing Techniques ; instrumentation ; methods ; Humans ; Ligands ; Microfluidic Analytical Techniques ; instrumentation ; methods ; Microfluidics ; instrumentation ; methods ; Molecular Imaging ; instrumentation ; methods ; Protein Array Analysis ; instrumentation ; methods ; Viruses ; chemistry ; isolation & purification

OBJECTIVETo establish a new method for sperm sorting by imitating the physiological process of sperm-cervical mucus interaction on the microfluidic chip.

METHODSWe designed a microfluidic chip to imitate the physiological process of natural sperm sorting in the microchannel based on the interaction between sperm and cervical mucus, and obtained motile sperm after the interaction. Meanwhile, we established an integrated real-time sperm detection reservoir on this chip to determine sperm parameters using the computer-assisted sperm analysis system. We analyzed 30 samples using both microfluidic and swim-up methods, and compared the results with those obtained before sorting.

RESULTSThe rate of grade a + b sperm, the rate of morphologically normal sperm, straight-line velocity (VSL), average path velocity (VAP) and straightness (STR) were (29.78 +/- 11.24)%, (8.00 +/- 5.19)%, (18.89 +/- 4.90) microm/s, (26.84 +/- 5.13) microm/s and (70.15 +/- 7.61)%, respectively, before sorting, (71.65 +/- 11.18)%, (14.95 +/- 6.79)%, (24.14 +/- 5.95) microm/s, (32.61 +/- 6.36) microm/s and (73.87 +/- 9.34)%, respectively, after swim-up sorting, and (92.37 +/- 6.33)%, (23.33 +/- 7.67)%, (34.03 +/- 16.78) microm/s, (38.73 +/- 16.40) microm/s and (84.91 +/- 12.56)%, respectively, after sorting on the microfluidic chip. The sperm parameters obtained before sorting showed statistically significant differences from those obtained on the chip (P < 0.01) and by the swim-up method (P < 0.05).

CONCLUSIONImitation of the physiological interaction between sperm and cervical mucus on the microfluidic chip helped the realization of both the natural sorting and real-time analysis of sperm. The quality of the sperm sorted on the microfluidic chip is significantly better than that of the sperm before sorting and sorted by the swim-up method. This has prepared the ground for imitating the fertilization process under the physiological condition on the microfluidic chip.

Cell Movement ; Cell Separation ; Cervix Mucus ; Humans ; Male ; Microfluidic Analytical Techniques ; instrumentation ; Microfluidics ; methods ; Oligonucleotide Array Sequence Analysis ; Semen Analysis ; Sperm Motility ; physiology ; Spermatozoa ; physiology

BACKGROUND: Normal erythrocyte is deformable and this facilitates blood flow in the capillaries. Oxidative stress reduces the deformability of erythrocytes, and influences on blood flow in microcirculation. The objective of this study was to investigate the deformability of erythrocytes exposed to oxidative stress, the protective effects of verapamil and ascorbic acid against oxidative damages in erythrocytes, and the value of the microfluidic ektacytometer, RheoScan-D (RheoMeditech, Korea) in clinical application. METHODS: Effects of oxidative stress on erythrocytes were investigated using tert-butyl hydroperoxide (tBHP). Before exposure to tBHP, the erythrocytes were pretreated with verapamil and ascorbic acid to examine their protective effect against oxidative damages. The deformability of erythrocytes was measured by the microfluidic ektacytometer, RheoScan-D. RESULTS: When treated with tBHP, the deformability of erythrocytes was decreased (P<0.01) and methemoglobin (metHb) formation and mean corpuscular volume (MCV) of erythrocytes were increased (P<0.01, P<0.05) compared to those of the untreated control cells. Compared to the tBHP treated cells, pretreatment with verapamil increased the deformability of erythrocytes (P<0.01) and decreased metHb formation (P<0.01) and MCV (P<0.05). Likewise, pretreatment with ascorbic acid increased the deformability of erythrocytes (P<0.01) and decreased metHb formation (P<0.01). CONCLUSIONS: Oxidative stress reduces the deformability of erythrocytes and the deformability could be one of markers for oxidative damage. Verapamil and ascorbic acid have protective role against tBHP induced oxidative stress. The ektacytometer, RheoScan-D used in this study is convenient for clinical measurement and could be used in various fields of clinical medicine.
Adult ; Antioxidants/pharmacology ; Ascorbic Acid/*pharmacology ; Calcium Channel Blockers/pharmacology ; Erythrocyte Deformability/*drug effects ; Erythrocytes/drug effects/physiology ; Humans ; Male ; Microfluidic Analytical Techniques/*instrumentation ; Oxidative Stress ; Statistics, Nonparametric ; Verapamil/*pharmacology ; tert-Butylhydroperoxide/*pharmacology