1,721,032 research outputs found
Building droplet-based microfluidic systems for biological analysis
No full textIn the present paper, we review and discuss current developments and challenges in the field of droplet-based microfluidics. This discussion includes an assessment of the basic fluid dynamics of segmented flows, material requirements, fundamental unit operations and how integration of functional components can be applied to specific biological problems
Droplet-based microfluidics: Formation, detection and analytical characterization
No full textMicrofluidics has become attractive in the recent decade due to its ability to offer low-cost, robust and miniaturized assays at a small cost as compared to the bulk tests. The credit mainly goes to the advancement in miniaturization technologies allowing cheaper and faster fabrications of microfluidics devices. Continuous microfluidics has been developed for the study of chemical and biochemical reactions inside microchannels, but the Taylor dispersion, sample contamination on the channel walls and less mixing efficiency has offset the benefits of microfluidics. Droplet-based microfluidics, on the other hand, has emerged as a powerful tool to encapsulate chemical and biological samples in discrete droplets and has generated a diverse array of applications including biochemical reactions, chemical synthesis, drug delivery, and point-of-care diagnostics. This review will outline the droplet generation, mixing, merging and detection methods, and characterization of droplet contents
Droplet-interfaced separations as an emerging tool for high-throughput microchip electrophoresis
No full textElectrophoresis is a powerful analytical separation technique to analyses biological sample fragments such as nucleic acids, biomarkers, proteins, enzymes etc. Microchip electrophoresis (MCE) is a miniaturised form of electrophoresis and offers fast, robust and low-cost analyses and portability. However, the current format of MCE operates only in the single channel, which limits the throughput of the separations. Droplet-based microfluidics, on the other hand, offers simplicity, robustness and multiplicity in microchannels. Therefore, it has a great potential for droplet-based high throughput electrophoretic separations of DNA fragments, proteins and biomarkers from biofluids such as saliva, blood, dialysate etc. and the ease of operational procedures could further lead this for the Point-of-Care (POC) diagnostics in healthcar
Micro peristaltic pump system for the generation of arbitrary droplet sequence and multiple-step biochemical assays
No full textSensitive absorbance measurement in droplet microfluidics via multipass flow cells
No full textAbsorbance measurement is a useful analytical tool that can be used along with colorimetric assays to measure a wide range of analytes. However, since sensitivity is directly proportional to path length, sensitive measurements in microfluidic channels are inherently challenging. This is especially true for droplet microfluidics where the lensing at the droplet/carrier interface further constrains path length. In this study, we developed multipass flow cells assembled with squared PTFE tube with parallel mirrors on both sides, laser diode and detector. The devices featured affordable low power components, and was made using simple fabrication techniques making it accessible to a wide range of researchers. In testing it allowed multiple reflection of light in the detection chamber, which significantly increased the optical path length by 8 times. The flow cell was used to quantify the phosphate levels in water samples from a tidal chalk river which could not be measured with a simple single-pass flow cell
Generation and manipulation of “smart” droplets
No full textWe report the generation and manipulation of electrorheological (ER) droplets that exhibit the giant ER effect. The experiments were carried out on specially designed microfluidic chips, in which the ER droplets were generated by using the microfluidic flow-focusing approach. Both the size and formation rate of these droplets can be controlled through digitally applied electrical signals. The principle of droplet manipulation is based on the electrical responsiveness of ER droplets and hence the denotation of “smart” when the electrical signals can be triggered by sensing/control devices. Due to the unique characteristics of the GER effect, the smart droplets can deform and even stop the microfluidic channel flow under an applied electric field. The pressure difference induced by the smart droplets inside the micro-channel is controllable by varying the field strengths, droplet sizes and particle concentrations in the GER suspension. By trapping and timed release of smart droplets in different micro-branch channels, we demonstrate that the smart droplets generated upstream cannot only be stored or displayed in the desired downstream channel(s) and thereby offer the potential of micro-droplet display, but also be useful in counting, flow directing and sorting the desired number of passive droplets sandwiched between two smart droplets. Such capabilities of smart droplets will enable the programmable control of discrete processes in bio-analysis, chemical reactions, digital microfluidics, and digital droplet display
Manipulations of microfluidic droplets using electrorheological carrier fluid
No full textElectrorheological (ER) fluids are a type of ‘‘smart’’ colloid capable of reversible viscosity variations, or even solidification, in response to an applied electric field. The response time can be as short as a few milliseconds. By using the ER fluid as the carrier fluid in microfluidic chips, we report the generation and manipulation of microdroplets and bubbles via integrated, digitally controlled micro-electrodes equipped with a feedback system. By utilizing the strong electric response of the ER fluid, the flow rate can be easily controlled digitally, thereby making tunable the size of the droplets generated and their separations. In particular, ordering change in a chain of droplets is demonstrated. The maneuverability presented in this paper may have potential applications in a variety of lab chips for chemical reactions, bioassays, as well as microfluidic logic computation
Novel technologies for the formation of 2-D and 3-D droplet interface bilayer networks
No full textDroplet Interface Bilayer (DIB) networks have vast potential in the field of membrane biophysics, synthetic biology, and functional bio-electronics. However a technological bottleneck exists in network fabrication: existing methods are limited in terms of their automation, throughput, versatility, and ability to form well defined 3-D networks. We have developed a series of novel and low-cost methodologies which address these limitations. The first involves building DIB networks around the contours of a microfluidic chip. The second uses flow rate and droplet size control to influence droplet packing geometries within a microfluidic chamber. The latter method enables controlled formation of various 3-D network arrays consisting of thousands of interconnected symmetric and asymmetric lipid bilayers for the first time. Both approaches allow individual droplet position and composition to be controlled, paving the way for complex on-chip functional network synthesis.<br/
Microdialysis/ultrafiltration-integrated droplet microfluidic sensors for decoding nitrate dynamics in soil
No full textDataset in support of the thesis 'A droplet microfluidic redox sensor'
No full textA dataset to accompany the thesis 'A Droplet Microfluidic Redox Sensor'. Contains CSV files and the necessary processing code to extract the data forming the key results presented in the thesis. </span
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