Development of a Peristaltic Micropump for Bio-Medical Applications Based on Mini LIPCA

This paper presents the design, fabrication, and experimental characterization of a peristaltic micropump. The micropump is composed of two layers fabricated from Polydimethylsiloxane （PDMS） material. The first layer has a rectangular channel and two valve seals. Three rectangular mini lightweight piezo-composite actuators are integrated in the second layer, and used as actuation parts. Two layers are bonded, and covered by two Polymethyl Methacrylate （PMMA） plates, which help increase the stiffness of the micropump. A maximum flow rate of 900μL.min 1 and a maximum backpressure of 1.8 kPa are recorded when water is used as pump liquid. We measured the power consumption of the micropump. The micropump is found to be a promising candidate for bio-medical application due to its bio-compatibility, portability, bidirectionality, and simple effective design.

LIQUID-SOLID COUPLED SYSTEM OF MICROPUMP

This paper employs the integral-averaged method of thickness to approximate the periodical flows in a piezoelectric micropump, with a shallow water equation including nonlinearity and viscous damp presented to characterize the flows in micropump. The finite element method is used to obtain a matrix equation of fluid pressure. The fluid pressure equation is combined with the vibration equation of a silicon diaphragm to construct a liquid-solid coupled equation for reflecting the interaction between solid diaphragm and fluid motion in a micropump. Numerical results of a mode analysis of the coupled system indicate that the natural frequencies of the coupled system are much lower than those of the non-coupled system. The influence of additional mass and viscous damp of fluid on the natural frequencies of the coupled system is more significant as the pump thickness is small. It is found that the vibration shape functions of silicon diaphragm of the coupled system are almost the same as those of the non-coupled system. This paper also gives the first-order amplitude-frequency relationship of the silicon diaphragm, which is necessary for the flow-rate-frequency analysis of a micropump.

A Novel Integrated PZT-Driven Micropump and Microvalve

According to the'elastic buffer mechanism'and the'variable gap mechanism',a new device,which is both micropump and active microvalve actuated by PZT bimorph cantilever,was fabricated with polydimethyisiloxane (PDMS) and silicon chip.The thickness of the micropump membrance is about 180μm.The diameter and the depth of micropump chamber cavity are 6 mm and 40μm,respectively.The performances of the micropump,such as pump rate and backpressure,were characterized.As a flow-rectifying element,the diffusers and active valve were used instead of passive check valves.The flow rate and the backpressure of the micropump are about 420μL/min and 2 kPa when applying a 100 V square wave driving voltage at frequency of 35 Hz.

A NEW TYPE OF MICROPUMP DRIVEN BY A LOW ELECTRIC VOLTAGE

In this paper,we propose a new prototype model of a micro pump using ICPF(Ionic Conducting Polymer Film)actuator as the servo actuator.This micro pump consists of two active one- way valves that make use of the same ICPF actuator.The overall size of this micro pump prototype is 12mm in diameter and 20mm in length.The actuating mechanism is as follows:(1)The ICPF actuator as the diaphragm is bent into anode side by application of electricity.Then the volume of the pump chamber increases,resulting in the inflow of liquid from the inlet to the chamber.(2)By changing the current direction,the volume of the pump chamber decreases,resulting in the liquid flow from the chamber to the outlet.(3)The ICPF actuator is put on a sine voltage,the micro pump provides liquid flow from the inlet to the outlet continuously.Characteristic of the micro pump is measured.The experimental results indicate that the micro pump has the satisfactory responses.

Manipulating fluid with vibrating 3D-printed paddles for applications in micropump

This paper presents a novel working mechanism of a micropump using micropaddles(MPs)to actively manipulate fluid based on 3 D printing technology.The novel working principle is systematically discussed using analysis,computation and experiment methods.A theoretical model is established to research the working mechanism and crucial parameters for driving ability,such as MPs shape,size,vibration amplitude and frequency.Two different 3 D printing techniques that simplify the multi-step process into only one step are introduced to manufacture the prototype pump for investigating the principle experimentally.A testing system is designed to evaluate the flow rate of pumps with eight different vibrating paddles.A maximum flux of 127.9 mL/min is obtained at an applied voltage of 9 V.These experiments show that the active-type mechanical pump could not only freely control flow direction but also change flux by adopting different shapes or distribution ways.The advantage of the novel micropump is the application of the MP structure into the micropump system to actively manipulate fluid with flexibility and high driving ability at fairly low power.

Analysis of Vibrational Performance of A Piezoelectric Micropump with Diffuse/Nozzle Microchannel

Piezoelectric transducers of different external diameters are designed and fabricated and incorporated into micropumps. Through finite element analysis, it is shown that the volume efficiency of the micropump reaches its maximum value for the first mode of vibration. The variation of maximum displacement with frequency is determined under free and forced vibration. Results demonstrate that this variation shows the same trend for different driving waves at the same driving voltage. The maximum displacement under forced vibration is less than that under free vibration. The displacement increases with decreasing distance from the center of the transducer. The maximum displacement is inversely proportional to the diameter of the transducer and proportional to the driving voltage under both free and forced vibrations. Finally, the micropump flow rate and pressure are measured and are found to manifest the same trend as the maximum displacement under the same driving conditions. For a piezoelectric transducer of 12 mm external diameter, the maximum flow rate and pressure value are 150 μL/min and 346 Pa, respectively, under sine-wave driving at 100 Vpp driving voltage.

The dynamic characteristics of a valve-less micropump

The aim of this paper is to investigate the dynamic characteristics of a valve-less micropump. A dynamic mathe- matical model of the micropump based on a hydraulic analogue system and a simulation method using AMESim software are developed. By using the finite-element analysis method, the static analysis of the diaphragm is carried out to ob- tain the maximum deflection and volumetric displacement. Dynamic characteristics of the valve-less micropump under different excitation voltages and frequencies are simulated and tested. Because of the discrepancy between simulation results and experimental data at frequencies other than the natural frequency, the revised model for the diaphragm maximum volumetric displacement is presented. Comparison between the simulation results based on the revised model and experimental data shows that the dynamic mathematical model based on the hydraulic analogue system is capable of predicting dynamic characteristics of the valve-less micropump at any excitation voltage and frequency.

A Hybrid Silicon-PDMS Micropump Actuated by PZT Bimorph

The fabrication and characterization of a hybrid Silicon-PDMS micropump based on MEMS technology is presented. The micropump consists of one chamber,two passive valves and one PDMS diaphragm.A PZT bimorph working as the actuator is mounted on the PDMS diaphragm.The use of the PDMS diaphragm and the PZT bimorph can give rise to large displacements of the pump diaphragm,making the micropump more efficient and easier to be fabricated.The flow rate of the micropump is a function to the voltage and frequency of the applied square wave.When a square wave of 100V is applied,a maximum flow rate of 317μL/min and a back-pressure of 2 kPa are achieved at 20 Hz.

Design and fabrication process of electromagnetically actuated valveless micropump with two parallel flexible diaphragms

A parallel dynamic passive valveless micropump was designed, which consists of three layers-valve, diaphragm and electromagnetic coil. The valve was wetly etched in a silicon wafer, the diaphragm was a PDMS （polydimethyl siloxane） film spun on a silicon wafer with embedded permanent magnet posts, and the coil was electroplated on a silicon substrate. Under the actuation of the magnetic field generated by coils, the flexible diaphragm could be displaced upwards and downwards. After analyzing magnetic and mechanical characteristic of the flexible membrane and direction-dependence of the nozzle, a micropump was designed. And the relative length （L/d） of the micropump nozzle was taken 4. A 7 × 7 array of permanent magnetic posts was embedded in the PDMS film. Two diaphragms worked in an anti-step mode, which could relieve the liquid shock and increase the discharge of the micropump. The ANSYS and Matlab were adopted to analyze the actuation effect of the coil and the flow characteristic of the micropump. Results show that when actuated under a 0.3 A, 100 Hz current, the displacement of the diaphragm is more than 30 μm, and the discharge of the micropump is about 6 μL/s.

Hybrid Optimization of a Valveless Diaphragm Micropump Using the Cut-Cell Method

This paper presents the optimization of 3D valveless diaphragm micropump for medical applications.The pump comprises an inlet and outlet diffuser connected to the main chamber equipped with a periodically moving diaphragm that generates the unsteady flow within the device.The optimization,which is related exclusively to the diaphragm motion,aims at maximizing the net flowrate and minimizing the backflow at the outlet diffuser.All CFD analyses are performed using an in-house cut-cell method,based on the finite volume approach,on a many-processor system.To reduce the optimization turn-around time,two optimization methods,a gradient-free evolutionary algorithm enhanced by surrogate evaluation models and a gradient-based(GB)method are synergistically used.To support the GB optimization,the continuous adjoint method that computes the gradient of the objectives with respect to the design variables has been developed and programmed.Using the hybrid optimization method,the Pareto front of non-dominated solutions,in the two-objective space,is computed.Finally,a couple of optimal solutions selected from the computed Pareto front are re-evaluated by considering uncertainties in the operating conditions;these are quantified using the polynomial chaos expansion method.

Performance of a serial-connection multi-chamber piezoelectric micropump

The concept and structure of serial-connection multi-chamber (SCMC) micropumps with cantilever valves is introduced. The SCMC micropump, which can be manufactured using conventional production techniques and materials, has a multi-layer circular planar structure. The border-upon piezoelectric actuators of a SCMC micropump work in anti-phase, as a result the pumping performance is similar to that of several single-chamber pumps running in series. The theoretical analysis shows that the pumping performance of a SCMC micropump depends not only on the characteristic and geometrical parameters of the piezoelectric actuators, but also on the number of pump chambers. Both flowrate and pressure of a SCMC pump can be enhanced to a certain extent. Four piezoelectric micropumps with different chambers were fabricated and tested. The testing results show that the enhancing extents of the flowrate and pressure of a SCMC piezoelectric micropump are different. The maximum flowrate and pressure of the four-chamber pump achieved are 2.5 times and 3.6 times those of the single-chamber pump achieved.

Simulation of the fluidic features for diffuser/nozzle involved in a PZT-based valveless micropump

PZT-based valveless micropump is a microactuator that can be used for controlling and delivering tiny amounts of fluids,and diffuser/nozzle plays an important role when this type of micropump drives the fluid flowing along a specific direction.In this paper,a numerical model of micropump has been proposed,and the fluidic properties of diffuser/nozzle have been simulated with ANSYS.With the method of finite-element analysis,the increased pressure drop between inlet and outlet of diffuser/nozzle induces the increment of flow rate in both diffuser and nozzle simultaneously,but the increasing rate of diffuser is faster than that of nozzle.The L/R,ratio of L(length of cone pipe) and R(radius of minimal cross section of cone pipe) plays an important role in fluidic performance of diffuser and nozzle as well,and the mean flow rate will decrease with increment of L/R.The mean flow rate reaches its peak value when L/R with the value of 10 regardless the divergence angle of diffuser or nozzle.The simulation results indicate that the fluidic properties of diffuser/nozzle can be defined by its geometric structure,and accordingly determine the efficiency of micropump.

A novel hydrodynamic suspension micropump using centrifugal pressurization and the wedge effect

The micropump is the heart of microfluidics systems.However,for mechanical micropumps,bearing wear failure has been a major obstacle to performance and reliability.Hydrodynamic suspension,which can make the rotating components levitate in liquid without any mechanical friction,is applied to break this bottleneck.In this paper,a novel kind of hydrodynamic suspension micropump(HSMP) without a grooved thrust bearing is proposed.Based on the centrifugal effect,the HSMP uses a rotating rotor to accelerate and pressurize adjacent fluid,and thus reacting forces are generated on the rotor surfaces to levitate it.The mechanisms of suspension forces formation,the centrifugal effect and the wedge effect in the liquid films near the rotor are identified using theoretical analysis and simulation.The variation in suspension forces with rotor position is investigated,revealing that the suspension bearings of the HSMP,similar to a spring damper,can self-adjust suspension forces along with a change in rotor position.Moreover,the suspension stiffness is positively correlated with the rotating speed.The HSMP prototype designed herein,whose overall size is only 34 mm × 34 mm × 31 mm,can provide a maximum output performance of3230 mL/min and 96.3 kPa at 20000 r/min,which is manyfold greater than other micropumps.The proposed HSMP is demonstrated to be more powerful with a simple structure,high power density,and high reliability.

Artificial intelligence powered glucose monitoring and controlling system:Pumping module

BACKGROUND Diabetes,a globally escalating health concern,necessitates innovative solutions for efficient detection and management.Blood glucose control is an essential aspect of managing diabetes and finding the most effective ways to control it.The latest findings suggest that a basal insulin administration rate and a single,highconcentration injection before a meal may not be sufficient to maintain healthy blood glucose levels.While the basal insulin rate treatment can stabilize blood glucose levels over the long term,it may not be enough to bring the levels below the post-meal limit after 60 min.The short-term impacts of meals can be greatly reduced by high-concentration injections,which can help stabilize blood glucose levels.Unfortunately,they cannot provide long-term stability to satisfy the postmeal or pre-meal restrictions.However,proportional-integral-derivative(PID)control with basal dose maintains the blood glucose levels within the range for a longer period.AIM To develop a closed-loop electronic system to pump required insulin into the patient's body automatically in synchronization with glucose sensor readings.METHODS The proposed system integrates a glucose sensor,decision unit,and pumping module to specifically address the pumping of insulin and enhance system effectiveness.Serving as the intelligence hub,the decision unit analyzes data from the glucose sensor to determine the optimal insulin dosage,guided by a pre-existing glucose and insulin level table.The artificial intelligence detection block processes this information,providing decision instructions to the pumping module.Equipped with communication antennas,the glucose sensor and micropump operate in a feedback loop,creating a closed-loop system that eliminates the need for manual intervention.RESULTS The incorporation of a PID controller to assess and regulate blood glucose and insulin levels in individuals with diabetes introduces a sophisticated and dynamic element to diabetes management.The simulation not only allows visualization of how the body responds to different inputs but also offers a valuable tool for predicting and testing the effects of various interventions over time.The PID controller's role in adjusting insulin dosage based on the discrepancy between desired setpoints and actual measurements showcases a proactive strategy for maintaining blood glucose levels within a healthy range.This dynamic feedback loop not only delays the onset of steady-state conditions but also effectively counteracts post-meal spikes in blood glucose.CONCLUSION The WiFi-controlled voltage controller and the PID controller simulation collectively underscore the ongoing efforts to enhance efficiency,safety,and personalized care within the realm of diabetes management.These technological advancements not only contribute to the optimization of insulin delivery systems but also have the potential to reshape our understanding of glucose and insulin dynamics,fostering a new era of precision medicine in the treatment of diabetes.

离心式铁磁流体微泵的设计及流动特性分析

铁磁流体微泵由于其自润滑性和自密封性,使其更加符合微流控技术应用在生物医学、生命科学、化学分析、航空航天等领域的需求,而在目前的结构设计中无法同时满足加工简单、可靠性高、流动稳定等优势,因此限制其应用及发展。为提高铁磁流体微泵的可靠性和稳定性,促进其发展和应用,本研究基于铁磁流体的外场控制原理、磁流变效应及介质流体的流体力学行为设计了一种离心式的新型铁磁流体微泵,并应用数值计算分析了介质流体流动特性。结果表明:该微泵可以有效实现泵送过程,当转速为10 r/min时,一个周期内的泵送净流量可达0.07 kg/T,且在两股铁磁流体的交替作用下可以阻断泵腔进口与出口的介质流体质量交换;由于铁磁流体与泵腔结构的动静干涉作用,导致出口流量存在轻微脉动(数量级为10^(-5)),但仍处于层流状态(Re<1),并且由于惯性力与特征尺寸相关而黏滞力与特征尺寸无关等力学因素,导致泵送动力对出口尺寸长度非常敏感,在转速4 r/min、出口段长度9 mm时无法实现有效泵送。同时对铁磁流体与泵送介质流体之间的相界面压力波动和自密封性能进行分析,得到相界面上的压力波动峰值远小于铁磁流体自密封性能,相差3个数量级,从铁磁流体的密封稳定性和界面稳定性角度验证了离心式铁磁流体微泵的可行性。

微流控系统中微泵和微阀的研究与挑战

微流控芯片是由微流体系统中的驱动元件——微流体泵和控制元件——微流阀来实现微流体准确操纵。随着微流控芯片集成程度的不断提高,液体流道变得更加复杂且体积更加微小,如何在微小尺度上实现流体驱动和控制就成了芯片设计中的一个重点。文章针对微泵与微阀的国内外研究现状、关键技术及发展趋势进行阐述,旨在为相关产业的发展及技术研究等方面提供借鉴与参考。

Design,fabrication and experimental research for an electrohydrodynamic micropump

This paper presented a novel electrohydrodynamic (EHD) micropump based on MEMS technology. The working mechanisms and classification of EHD micropump were introduced. The fabrication process of EHD micropump was presented with the material selection,optimal design of microelectrode and assembly process. Static pressure experiments and flow experiments were carried out using different fluid and the channel depth. The results indicated that the micropump could achieve a maximum static pressure head of 268 Pa at an applied voltage of 90 V. The maximum flow rate of the micropump-driven fluid could reach 106 μL/min. This paper analyzed the future of combining micropump with heat pipe to deal with heat dissipation of high power electronic chips. The maximum heat dissipation capacity of 87 W/cm2 can be realized by vaporizing the micropump-driven liquid on vaporizing section of the heat pipe.

无脉冲微流控片上蠕动微泵研制及其性能研究

为解决微流体连续输送过程中存在的流动脉冲、精度低等问题,研制一种基于微流控技术的片上蠕动微泵。该微泵由微流控芯片和电机驱动系统组成,利用驱动系统中的滚子轴承连续挤压微流控芯片中的微流道,以实现微流体的精确泵送。为研究微泵的流量特性,设计具有气腔稳流功能的微流道,采用光固化3D打印技术与模塑法制作微流控芯片样件;开发电机驱动系统,测试微泵在不同电机转速下的平均流量、总流量和瞬时流量,并将其流量特性与商业蠕动泵的流量特性进行对比。研究结果表明:随着电机转速增加,微泵的平均流量逐渐增大,瞬时流量误差逐渐减小;当电机转速大于60 r/min时,瞬时流量误差可控制在5%以内,其流量精度显著高于商业蠕动泵的流量精度;片上蠕动微泵可有效抑制微流体脉冲,提升微流体控制精度,在精密微流体输送中具有广阔的工程应用前景。

微量泵持续泵入胰岛素对重症糖尿病酮症酸中毒患者糖代谢的影响

目的探究重症糖尿病酮症酸中毒(Diabetic Ketoacidosis,DKA)患者治疗中微量泵持续泵入胰岛素对糖代谢的影响。方法回顾性选取2023年2月-2024年1月泉州市第一医院收治的110例重症DKA患者的临床资料,所有患者均接受常规对症治疗及胰岛素治疗,根据胰岛素给药方式不同,分为常规组(n=55,静脉缓慢滴注胰岛素)、观察组(n=55,微量泵持续泵入胰岛素),比较两组临床指标、糖代谢水平及不良反应发生情况。结果两组临床指标比较,观察组尿酮体转阴时间(20.32±7.38)h、血pH值恢复时间(10.37±3.45)h及血糖达标时间(4.43±1.25)h时间均短于常规组,差异有统计学意义(t=11.358,8.467,13.407,P均<0.05)。治疗15 d后,观察组血糖水平低于常规组,差异有统计学意义(P<0.05)。观察组不良反应总发生率(3.64%)低于常规组(14.55%),差异有统计学意义(χ^(2)=3.960,P<0.05)。结论重症DKA患者常规对症治疗基础上加入微量泵持续泵入胰岛素方式,临床指标及糖代谢水平改善情况更佳,不良反应发生随之减少。

Experimental investigation on phase transformation type micropump

The phase transformation type micropump without moving parts was experimentally studied in this note. To analyze the pumping mechanism of the micropump, a simplified physical model was presented. The experimental results indicate that the pump characteristic is mainly dependent on the heating and cooling conditions. For a given system, there exist an optimal combination of heating current and switch time with which the flow rate reaches maximum. Comparing with the natural cooling, the forced con-vective cooling needs larger heating current to obtain the same flow rate. In our experiments, the maximum flow rate is 33μL/min when the inner diameter of the micropump is 200μm, and the maximum pumping pressure reaches over 20 kPa. The theoretical analysis shows that the pumping mechanism of the micropump mainly lies in the large density difference between liquid and gas phases and the effect of gas chocking.