Adjustment Of Flow Rate Research Articles

Kinetic Profiling of Homogeneous and Heterogeneous Biocatalysts in Continuous Flow by Online Mass Spectrometry.

Enzyme kinetics is normally assessed by performing individual kinetic measurements using batch-type reactors (test tubes, microtiter plates), in which enzymes are mixed with different substrates. Some drawbacks of conventional methods are the large amounts of experimental materials, long analysis times, and limitations of spectrophotometry. Therefore, we have developed a method for facile determination of enzyme kinetics using online flow-based mass spectrometry. A concentration ramp of substrate or product was created by dynamically adjusting flow rates of pumps delivering stock solution of substrate and diluent. Precise kinetic measurements were performed by reaction product quantification and initial rate calculation. In the presence of ascending substrate concentrations, the rate of a target enzyme (penicillinase)-catalyzed hydrolysis was varied. By measuring the reaction product continuously, Michaelis constants (KM) could be calculated. The enzyme kinetic measurements for hydrolysis of penicillins were conducted based on this simple, rapid, and low sample consumption online flow device. In the homogeneous reaction, the KM values for amoxicillin, ampicillin, penicillin G, and penicillin V were 254.9 ± 14.5, 29.2 ± 0.3, 2.6 ± 0.1, and 5.4 ± 0.1 μM, respectively. In the heterogeneous reaction, the KM values for amoxicillin, ampicillin, penicillin G, and penicillin V were 408.9 ± 75.1, 114.4 ± 8.0, 21.8 ± 0.7, and 83.3 ± 4.8 μM, respectively. Apart from enzyme assay, the showcased method for the generation of temporal concentration ramps can be utilized to perform rapid quantity calibrations for mass spectrometric analyses.

Convective enhancement of microalgae slurry in continuous tubular reactors for biocrude production during hydrothermal liquefaction

Continuous hydrothermal liquefaction (HTL) reactor is promising in the large-scale production of biocrude from microalgae biomass. To optimize the temperature distribution and biocrude yield of microalgae slurry, the convection of microalgae slurry is enhanced through adjusting flow rate (1 – 24 mL/min) and inserting twist tapes (twist ratio: 3 – 10) in the flow channel, respectively. A computational fluid dynamics (CFD) model integrated HTL kinetics of microalgae biomass is proposed to simulate the contour plots of temperature and biocrude yields at the heating temperature from 523 to 623 K. Comparing to increasing flow rate, the swirl flow induced by the twist tape can significantly increase the convective heat transfer coefficient from 669 to 1707 W·m−2·K−1, while the conversion rate of biocrude from 0.188 to 0.298 g·L-1·s−1 at 8 mL/min and 623 K. As the enhancement factor of convective heat transfer coefficient h /h0 is higher than 2, the biocrude yield YBC of microalgae slurry appears obvious increasing by the enhancing convective heat transfer. This investigation provides the insights to optimize the flow channel of tubular reactors for the optimization of HTL conversion of microalgae biomass.

The effect of newly designed dual-channel elastomeric pump for intravenous patient-controlled analgesia after total laparoscopic hysterectomy: a randomized, double-blind, prospective study

BackgroundA newly designed intravenous patient-controlled analgesia (PCA) device with a dual-channel elastomeric infusion pump has been recently introduced. One channel is a continuous line with a constant flow rate basal infusion, while the other channel has an adjustable flow rate and bolus function and is labeled as a selector-bolus channel. This study compared dual and single-channel intravenous PCA in terms of clinical effect and quality of recovery.MethodsEighty-four patients undergoing total laparoscopic hysterectomy were randomly allocated to a 1-channel group (n = 41) or a 2-channel group (n = 43). Only the selector-bolus channel was utilized, but the continuous channel was not utilized in the 1-channel group, but both channels were utilized in the 2-channel group. In the 1-channel group, 16 μg/kg of fentanyl, 2 mg/kg of ketorolac, and 12 mg of ondansetron with normal saline were administered to the selector-bolus channel and normal saline only in the continuous channel for blinding. In the 2-channel group, 16 μg/kg of fentanyl was administered to the selector-bolus channel, and ketorolac (2 mg/kg) and ondansetron (12 mg) were administered via the continuous channel.The quality of recovery was evaluated preoperatively and 24 h postoperatively using the Quality of Recovery-40 (QoR-40). Cumulative PCA consumption, postoperative pain rated using the numeric rating scale (NRS; during rest/cough), and postoperative nausea were evaluated 6, 12, 24, 36, and 48 h after surgery. Incidence of vomiting and use of antiemetics and rescue analgesics was measured.ResultsThe 24-h postoperative QoR-40 score was higher in the 2-channel group than in the 1-channel group (P=0.031). The incidence of nausea at 12 h and 36 h was significantly higher in the 1-channel group (P=0.043 and 0.040, respectively), and antiemetic use was more frequent in the 1-channel group (P=0.049). Patient satisfaction was higher in the 2-channel group (P=0.036). No significant differences were observed in pain scores during resting/cough or cumulative PCA consumption.ConclusionsThe 2-channel PCA showed better patient satisfaction with higher QoR-40 during the recovery compared with the 1-channel PCA. Better satisfaction was associated with lower nausea and reduced rescue antiemetics by maintaining the infusion of adjuvant analgesic agents and antiemetic agents constantly by utilizing dual channels.Trial registrationRegistered at ClinicalTrials.gov, NCT04082039 on 9 September 2019.

Feedback effects of pesticides flow atomization on the operating characteristics of pulsed engines

Traditional pulse-jet fogger have problems such as poor atomization or unstable operation. A pulse-jet fogger test device with an adjustable liquid flow rate was designed. Four experimental settings were used, no spraying and spraying with three liquid flow rates (11 L/h, 14 L/h, and 20 L/h). Pressure waveform in the combustion chamber and smoke inhalation depth tests showed following results: under different chemical fluid flow conditions, influences of the thermal atomization of the chemical liquid were observed in the pulse engine. Feedback effects were mainly changes in parameters and during each pulsation period, the turning time of the airflow in the pulse engine had different effects. The fuel consumption rate and pressure peak-to-peak value under 20 L/h chemical fluid flow were higher than other working conditions, and the positive and negative pressure amplitude fluctuated the least and had the best pressure stability. The 14 L/h chemical liquid flow demonstrated the worst stability, with the most significant fluctuations in pressure amplitude and large cyclical changes and poor consistency of the maximum depth of smoke inhalation in each cycle in the atomization section, with a high maximum relative difference of 34.6%, causing significant turbulence in the airflow oscillation system.

Design and Experimental Testing of a Control System for a Solid-Fertilizer-Dissolving Device Based on Fuzzy PID

To overcome the problem of poor uniformity of solid-fertilizer-dissolving devices due to lag of fertilizer dissolution, a closed-loop control system based on fuzzy proportional-integral-derivative (PID) was designed and tested. A fertilizer concentration regulation model was then established according to the results. In this system, the control core was an STM32 used to feed back the fertilization concentration by detecting the electrical conductivity. For real-time adjustment of the fertilizer flow rate and water flow rate, a fuzzy PID control algorithm was utilized to compare the detected concentrations with the set concentrations. The linear relationships between quantities such as the fertilizer rate and PWM frequency, water flow rate and PWM duty ratio of the direct-current pump, and fertilizer concentration and electrical conductivity were all established to calibrate the system. The influence of the fertilizer flow rate and water flow rate on fertilizer concentration was determined by the control variable test method. The results showed a positive linear relationship between fertilizer concentration and fertilizer flow rate, while a reverse linear relationship was established between fertilizer concentration and water flow rate. After the introduction of the control system into the self-developed solid-fertilizer-dissolving device, the fertilizer concentration fluctuated near the set concentration in a range of no more than 1 g/L. After the disturbance of the fertilization device, the control system fine-tuned the device with a steady-state error of about 0.55 g/L after the system reached stability. The control system designed in this study was shown to run normally with good stability, speed, and accuracy, and with improved fertilization uniformity of the solid-fertilizer-dissolving device. This study lays the foundation for further study of fertilization control systems. It also provides a reference for the development of precise and intelligent fertigation.

Implantable double-layer pump chamber piezoelectric valveless micropump with adjustable flow rate function

The piezoelectric valveless micropump with the characteristics of precise liquid delivery is widely utilized in the field of biomedicine. However, the improvement of the flow rate of the piezoelectric micropump relies on the increase in size and driving voltage, which hinders its application in the implantable medical field. This article proposes a double-layer chamber valveless piezoelectric micropump, which has the obvious advantages of small size and adjustable flow rate, and is expected to be applied to the treatment of implantable hydrocephalus. The overall size of the micropump is 10 mm × 10 mm × 4 mm, which can be implanted in the cerebral cortex. Combined with polydimethylsiloxane-polyethylene glycol terephthalate bonding technology, the double-layer chamber micropump solves the contradiction between miniaturization and large flow range. The flow rate generated by micropump under low voltage can be adjusted according to the amount of hydrocephalus. In order to reveal the mechanism of increasing the flow rate, the working efficiencies of the microvalve and micropump are studied in this article. The electric-solid-fluid coupling simulation and experimental tests obtained the optimal structural parameters: the divergence angle is 30°, the throat width is 300 μm, and the upper chamber depth is 100 μm. The proposed micropump can achieve the tunable flow rate of 2.16–51.74 μl min−1.

Impacts of preferential vaporization on flashback behaviors of multi-component liquid fuels

Liquid transportation fuels are composed of a wide range of molecular structures and weights, therefore exhibiting a relatively large distillation temperature range. When fuel chemical properties change along with the distillation temperature curve, preferential vaporization effects could play a role in near-limit combustion behaviors. The objective of this study is to experimentally evaluate the role of preferential vaporization on flame flashback behaviors. A unique spray burner is developed to control the extent of fuel spray vaporization by adjusting flow rates and/or the spray injection location from the burner exit. Spray characteristics are comprehensively determined using Phase Doppler Particle Analyzer. Two binary component mixtures are formulated (n-octane/iso-cetane and iso-octane/n-hexadecane) to exhibit common combustion behaviors in the fully vaporized condition but have considerably different preferential vaporization characteristics. Identical flashback behaviors of two mixtures are observed for fully pre-vaporized conditions by setting the burner temperature at 700 K, including both propagation- and ignition-driven flashback behaviors. Partially vaporized conditions are investigated at two global equivalence ratios (1.0 and 1.4) by setting the burner temperature at 450 K. The flashback behaviors for both global equivalence ratio conditions are found to be affected by the preferential vaporization characteristics represented by laminar flame speeds of the vaporized fuel mixture composition. The relative significance of local flow perturbation induced by instantaneous fuel droplet evaporation near the flame surface has been also investigated by analyzing planar laser-induced fluorescence images, as well as considering the changes of Markstein length with the extent of fuel vaporization. Finally, the relative contributions of local laminar flame speed representing local fuel vapor deposit, local flow perturbation, and preferential vaporization are evaluated through feature sensitivity analyses.

Development of a Modular Tissue Phantom for Evaluating Vascular Access Devices.

Central vascular access (CVA) may be critical for trauma care and stabilizing the casualty. However, it requires skilled personnel, often unavailable during remote medical situations and combat casualty care scenarios. Automated CVA medical devices have the potential to make life-saving therapeutics available in these resource-limited scenarios, but they must be properly designed. Unfortunately, currently available tissue phantoms are inadequate for this use, resulting in delayed product development. Here, we present a tissue phantom that is modular in design, allowing for adjustable flow rate, circulating fluid pressure, vessel diameter, and vessel positions. The phantom consists of a gelatin cast using a 3D-printed mold with inserts representing vessels and bone locations. These removable inserts allow for tubing insertion which can mimic normal and hypovolemic flow, as well as pressure and vessel diameters. Trauma to the vessel wall is assessed using quantification of leak rates from the tubing after removal from the model. Lastly, the phantom can be adjusted to swine or human anatomy, including modeling the entire neurovascular bundle. Overall, this model can better recreate severe hypovolemic trauma cases and subject variability than commercial CVA trainers and may potentially accelerate automated CVA device development.

Retrograde intrarenal lithotripsy in completely bedridden children with severe physical disabilities

Pediatric urolithiasis is often associated with a metabolic disease or with a complication of steroid or antiepileptic agent use. Children who are on long-term bed rest or bedridden are also said to be at risk for urinary stone formation. Here we report two cases of compromised completely bedridden children with renal stones who achieved stone-free status without any complications through detailed intraoperative management. The patient in case 1 is an 8-year-old compromised bedridden boy with epilepsy, chromosomal abnormalities, and ulcerative colitis. In case 2, the patient is a 9-year-old compromised bedridden girl with hypoxic-ischemic encephalopathy and epilepsy. Both children had recurrent urinary tract infections (UTIs), and lithotripsy was planned for multiple renal stones. The patients were expected to be at high risk of developing a postoperative febrile UTI because they are compromised completely bedridden children. A 9.5/11.5-Fr ureteral access sheath was inserted, and lithotripsy was performed. The irrigation flow rate during lithotripsy was frequently adjusted and aspiration of intrarenal saline as necessary so as not to increase intrarenal pressure, with the aim of preventing postoperative febrile UTI. Stone-free status was achieved in both cases, without any intra and postoperative complications. • Long-term bed rest or Bedridden children are at high risk of urinary stone formation. • Bedridden children are high risk of developing febrile urinary tract infections. • Adjustment of irrigation flow rate is essential during retrograde intrarenal lithotripsy.

Feedback Linearization Based Flow Rate Control for Centrifugal Pump in Coupled-Tank Water Meter Testing System

A permanent magnet direct current (PMDC) motor centrifugal pump is intended to be used as the water supply unit in a feedback linearization based coupled-tank water meter testing system. Flow rate generated by the pump corresponds to the input variable for implementing the input-output feedback linearization to this single-input-single-output (SISO) system. The pump motor is driven by an Arm Cortex M7 based microcontroller applying the pulse-width modulation (PWM) strategy at various frequencies and pwm methods. It is aimed to determine a suitable PWM frequency and driving method in order to provide a stable flow rate at the desired duty cycle values. An H-Bridge driver integrated circuit (L298N) is used in both fast decay and slow decay modes for driving the pump motor. Flow rate measurements are carried out at 4 range of frequencies between 100 Hz and 20 kHz for each mode. Fast decay mode in low pwm frequency (100Hz) results in higher deviations at the steady-state flow rate. However, slow decay mode provides a faster reduction in motor speed despite the slower current decay, which improves the flow rate stability and minimize deviations at constant pwm duty cycle values. High pwm switching frequencies increase the energy losses resulting in a lower driving voltage range, which reduces the effective range of selection for pwm duty cycle setting of flow rate adjustment. 1 kHz PWM frequency combined with the slow-decay driving mode achieves good performance in terms of linear regression and wider range for pwm duty cycle to flow rate transformation.

Optical, thermal and thermo-mechanical model for a larger-aperture parabolic trough concentrator system consisting of a novel flat secondary reflector and an improved absorber tube

Using a larger-aperture parabolic trough concentrator can reduce cost and improve cycle efficiency. At present, the maximum output temperature of the typical parabolic trough concentrator systems is lower than the set 580 °C. Here a novel flat reflector was incorporated into the absorber tube to improve the intercept factor and optical efficiency and hence the overall performance. At the same time, the optimal diameter of the collector tube was also researched to meet the outlet temperature exceeding the set 580 °C and the absorber tube’s maximum temperature below 600 °C. A large-aperture parabolic trough concentrator (8 m aperture wide with 80° half rim-angle) is used as a case to demonstrate the effect of a flat reflector and advantages of the optimal absorber tube. Results obtained through simulations show that, in the large-aperture parabolic trough concentrator system with the flat reflector, the optimal diameter of the absorber tube was 70 mm for this design reaching 75% optical efficiency and 60.8% thermal efficiency at DNI = 1000 W/m2 and 53% daily average thermal efficiency for DNI = 400–1000 W/m2. Through adding a flat reflector, the optical efficiency and the uniformity were increased by 4–12% and 2–22% respectively, but the benefit gradually decreases with increasing the absorber tube diameter. To meet the requirement of outlet temperature more than 580 °C and absorber tube’s maximum temperature below 600 °C and reduce the thermal strain, a scheme of adjusting flow rate was incorporated.

Continuously Adjustable Micro Valve Based on a Piezoelectric Actuator for High-Precision Flow Rate Control

A MEMS-based micro valve fitted with a piezoelectric actuator is presented in order to achieve a continuously adjustable flow rate control. The micro valve is realized using a cost-effective fabrication scheme with simple polyimide (PI) bonding, which has an average shear strength of up to 39.8 MPa, indicating a relatively high reliability. The simulation results based on the finite element method (FEM) show that the valve membrane is able to seal the inlet and cut off the flow successfully with a piezoelectric force of 3N when the differential pressure is 200 kPa. The measurement of the flow rate through the outlets shows that the micro valve can control the flow rate effectively in a large range under different actuation voltages and differential pressures. When the actuation voltage is 140 V, the measured leak flow of the closed micro valve is smaller than 0.5 sccm with a differential pressure of 200 kPa.

Experimental and numerical analysis on vortex cavitation morphological characteristics in u-shape notch spool valve and the vortex cavitation coupled choked flow conditions

The u-shape notch of spool valve is usually combined with the other typical throttling notches to achieve proportional flowrate adjustments in practical hydraulic control applications. Due to the vacuum-suction nozzle-structural effect, u-shape notch is more likely for cavitation arising. Traditionally, notch throttling is based on the continuity and Bernoulli equation to explain the Harvey nuclei bubble flow from development to collapse, which is not entirely agreed with present proliferated large vapor vortex cavitation researches. In this paper, experimental and numerical analysis discuss the morphological characteristics of u-shape notch vortex cavitation and the choked flow issues caused by vortex cavitation. The large vapor vortex cavitation morphological reproduced by the Large Eddy Simulation (LES) model associated with the multi-phase cavitation model is very close to experimental observations. Further, based on the clear cavity entity obtained by simulation, it could be found that, as notch opening increases, the cavity starting position moves back and the cavity moves upward. And as pressure difference increases, the cavity length increases smoothly until critical pressure value, after which the length increases sharply and maintains in long length level. In addition, it seems that the normalized measurement manner of cavitation length could be proposed, if using local cavitation number dividing incipient cavitation as abscissa to measure the cavity length. Moreover, the cavitating flowrate equation is proposed considering the cavitation-induced serious choked flow problem. The vortex cavitation, especially its length, is assumed to represent intense enough notch vortex flow friction loss. Based on the added flow loss term, the classical flowrate equation is revised, according to which the cavitating flowrate could be predicted within the accuracy of 0.5–2.0%.

Coupling of chiral and achiral stationary phases in supercritical fluid chromatography: Evaluating and improving retention prediction

Isomers and stereoisomers are always challenging to separate. Column coupling may provide improved chromatographic selectivity, necessary for the separation of the compounds with similar chemical and structural properties. The relatively low viscosity of supercritical fluids, used as mobile phases allows for the coupling of several columns in series in supercritical fluid chromatography (SFC), without exceeding the pressure limits of the system. The aim of this study is to propose reliable prediction of the retention behaviour of analytes on a coupled column system, based on a limited number of initial analyses. The chiral compounds atenolol, ephedrine, propranolol, mianserin, labetalol and nadolol, besides the diastereomers quinine and quinidine, and the structural isomers of aminophenol and aminocresol were used as model analytes. The retention behaviour of the analytes was determined on the individual chiral columns Lux Cellulose-1, Lux Cellulose-2, Lux Cellulose-3, Lux Cellulose-4, Lux Amylose-2 and the achiral columns Luna NH2, Luna Silica, Synergi RP and FluoroSep RP. The mobile phase was composed of CO2 mixed with 20% (v/v) MeOH, which contained 0.1% (v/v) trifluoroacetic acid and 0.1% (v/v) isopropylamine. The retention factors of the analytes on coupled stationary phases were predicted, and subsequently compared to the experimentally obtained ones. Relative deviations of predicted and experimental retention factors were in range from 0.00% to 51.91%. Flow rate and back pressure of the screening conditions were adjusted to improve prediction precision on four column combinations, with varying success rates. The average relative deviations of retention factors were reduced to 2.84% - 6.59% by adjusting flow rate, and to 2.30% - 8.57% by adjusting back pressure. The most successful approach, flow rate adjustment, was then applied to select a column combination providing improved resolution of the structurally similar components of silymarin extract.

Feasibility of continuous epidural analgesia in patients with failed back surgery syndrome and spinal stenosis

PurposeThe purpose of this study was to outline the feasibility of continuous epidural analgesia in the treatment of failed back surgery syndrome (FBSS) or spinal stenosis.MethodsWe queried our prospective collected institutional database to include all consecutive patients, who underwent continuous epidural analgesia with accompanying intensive physiotherapeutic exercise within a timeframe of 4 years. Patients suffered from FBSS or spinal stenosis; protocolled continuous epidural analgesia was planned for 4 days within the framework of an inpatient multimodal pain therapy concept. The instillation technique of the epidural catheter, the capability to attend in accompanying physiotherapy, and the peri-interventional complications were evaluated.Results153 patients with an average age of 57.4 years (± 11.9) were enrolled in this study. 105 patients suffered from FBSS and 48 patients had spinal stenosis. Overall, 148 patients (96.7%) reported the pain reduction and were able to perform daily intensified physiotherapeutic exercise. There were no serious adverse events, neither infection nor bleeding, no cardiopulmonary complication or permanent neurological deficits. The most common side effect was neurological impairment, such as numbness, dysesthesia, or weakness of the lower limbs with complete regression after flow rate adjustment. Patients with FBSS were more likely to develop dysesthesia (p = 0.007).ConclusionsContinuous epidural analgesia is feasible in patients with FBSS or spinal stenosis. This treatment enables extensive physiotherapeutic treatment even in patients with severe pain conditions and can be considered as an alternative to epidural injections. An increased complication rate in comparison to short-term perioperative or perinatal application was not observed.

NITRATE REMOVAL IN WOODCHIP DENITRIFICATION BIOREACTOR – AN APPROACH COMBINING MATHEMATICAL MODELLING AND PI CONTROL

A mathematical model of nitrate removal in woodchip denitrification bioreactor based on field experiment measurements was developed in this study. The approach of solving inverse problem for nonlinear system of differential convection-reaction equations was applied to optimize the efficiency of nitrate removal depending on bioreactor’s length and flow rate. The approach was realized through the developed algorithm containing a nonlocal condition with an incorporated PI controller. This allowed to adjust flow rate for varying inflow nitrate concentrations by using PI controller. The proposed model can serve as a useful tool for bioreactor design. The main outcome of the model is a mathematical relationship intended for bioreactor length selection when nitrate concentration at the inlet and the flow rate are known. Custom software was developed to solve the system of differential equations aiming to ensure the required nitrate removal efficiency.

Tuneable polarity and enhanced piezoelectric response of ZnO thin films grown by metal–organic chemical vapour deposition through the flow rate adjustment

The formation process of ZnO thin films grown by pulsed-liquid injection metal–organic chemical vapour deposition (PLI-MOCVD) has a major impact on its morphological, structural, electrical and piezoelectric properties, but their correlation has not been elucidated yet nor decoupled from the thickness effects.

Analysis of Flow Factor Control Strategy in Vanadium Redox Flow Batteries

Optimization of the performance of vanadium redox flow batteries (VRFBs) is closely related to flow rate control: a proper flow rate adjustment reduces the losses and extends the battery lifetime. In this regard, the so-called flow factor control strategy of VRFBs has been recently proposed in the literature and some numerical/experimental validations have been performed. The strategy is a generalization of Faraday's frst law of electrolysis as it uses a special scaling parameter referred to as the flow factor. In our paper, we show how this factor is related to the conversion rate (fraction conversion per pass) and geometrical properties of the battery. Finally, we investigate the flow factor as a function of the fraction conversion per pass and stack/tank volumes, and perform numerical simulations to confrm the theoretical results.

Design of a gas-system for testing the phosphine protection of canisters in respirators

The canister is a critical component of non-powered air-purifying respirators that protects operators from fumigation environments but which typically lacks equipment for the detection of harmful agents. Based on research of the common fumigant phosphine, a device is herein designed to test the phosphine filtering ability of different canisters, and methods of device operation are discussed. The experimental device comprises systems for phosphine input control, canister protection test, phosphine tail gas disposal, and nitrogen purging. Adjustable system pressure and gas flow rate allow testing of a series of parameters under phosphine environments. The device is used to continuously test the protection times of different canisters against different concentrations of phosphine at different temperature and humidity conditions. Three sets of experiments were performed to investigate the testing capabilities of the proposed device and to characterize the protective capacity of canisters at different ambient conditions. The testing threshold of the device, protection times for canisters, and influences of moisture were studied to verify device reliability. Results indicate that the device can effectively test different combinations of parameters and distinguish between different canister performances in a selected threshold range (phosphine concentration ≤5000 ppm and flow rate ≤30 L min−1). Humidity is found to negligibly impact the protection ability of canisters against phosphine.

Plug-and-play microfluidic production of monodisperse giant unilamellar vesicles using droplet transfer across Water–Oil interface

Giant unilamellar vesicles (GUVs) are cell-sized compartments widely used in biological and chemical applications. The monodispersity of GUVs is essential for quantitative analysis and experimental reproducibility in biomimetic microreactor studies. In this study, we established a highly reproducible plug-and-play microfluidics-based method to generate monodisperse GUVs without surface treatment of the channel or precise flow-rate adjustment. In the microfluidic channel, we generated water-in-oil (W/O) droplets through hydrodynamic flow focusing and transferred across the W–O interface to form thin-shelled water-in-oil-in-water (W/O/W) droplets as precursors to GUVs. The success rate of the W/O droplet transfer reached nearly 100% by stabilizing the co-flow of oil and water and adjusting the curvature of the W–O interface. Owing to interfacial energy minimization, the thin oil layer of the W/O/W droplets dewetted and detached to form GUVs. We performed a membrane-protein insertion assay to confirm the unilamellarity of the GUVs and their shrinkage caused by osmotic action.