Miniature Pump Research Articles

A simple system for staining protein and nucleic acid electrophoresis gels

Researchers in molecular biology spend a significant amount of time tending to the staining and destaining of electrophoresis gels. Here we describe a simple system, costing approximately $100 and taking approximately 1 h to assemble, that automates standard nucleic acid and protein gel staining protocols. Staining is done in a tray or, with DNA gels, in the electrophoresis chamber itself following automatic detection of the voltage drop. Miniature pumps controlled by a microcontroller chip exchange the necessary solutions at programmed time intervals. We demonstrate efficient and highly reproducible ethidium bromide and methylene blue staining of DNA in agarose gels and Coomassie blue and silver staining of proteins in polyacrylamide gels.

2904 圧電素子を用いた油圧式小型リニアアクチュエータの開発(J20-2 次世代アクチュエータシステム(2),J20 次世代アクチュエータシステム)

This paper describes the development of a new linear actuator which suits for gripper of industrial robot for millimeter-size parts. A hydraulic miniature linear actuator using a PZT that has relatively strong force, large stroke and small volume is proposed. Its possibility of realization is shown by design and prototype. The actuator is composed of a miniature pump and an output cylinder. A layered PZT is used to the miniature pump to make large discharging pressure. The miniature pump has been prototyped and driven on trial, but the fluid has not been transformed. From results of verification experiments, it has been confirmed that the pump displacement has been absorbed by deforming sealing materials used in the piston. On this account, a diaphragm is used instead of the piston, and its validity is verified by simulation.

The role of complement in biomaterial-induced inflammation

Biomaterials are regularly used in various types of artificial tissues and organs, such as oxygenators, plasmapheresis equipment, hemodialysers, catheters, prostheses, stents, vascular grafts, miniature pumps, sensors and heart aids. Although progress has been made regarding bioincompatibility, many materials and procedures are associated with side effects, in particular bioincompatibility-induced inflammation, infections and subsequent loss of function. After cardiopulmonary bypass, coagulopathies can occur and lead to cognitive disturbances, stroke and extended hospitalization. Hemodialysis is associated with anaphylatoid reactions that cause whole-body inflammation and may contribute to accelerated arteriosclerosis. Stents cause restenosis and, in severe cases, thrombotic reactions. This situation indicates that there is still a need to try to understand the mechanisms involved in these incompatibility reactions in order to be able to improve the biomaterials and to develop treatments that attenuate the reactions and thereby reduce patients’ discomfort, treatment time and cost. This overview deals with the role of complement in the incompatibility reactions that occur when biomaterials come in contact with blood and other body fluids.

XPS study of the deposited Ti layer in a magnetron-type sputter ion pump

X-ray photoelectron spectroscopy (XPS) was used to study the surface chemical composition of the anode deposits in a miniature magnetron ion pump. The pump was mounted on an UHV system with the ultimate pressure of 1 × 10 −9 mbar. A stable discharge was established in the nitrogen atmosphere with some traces of CO at about 10 −7 mbar. The cathode was made of pure titanium. The sputtered titanium atoms deposited on the anode, where they reacted with gases to form a film of titanium compounds. The thickness of the deposited titanium layer on the anode was about 100 nm. The results from XPS investigations indicate that active gases such as O 2 and N 2 react with Ti forming TiO 2 and TiN. While carbon containing molecules just adsorb on the surface and do not form carbide. In the bulk of the deposited layer almost pure TiN was found with some traces of oxygen and carbon. The part of carbon was bonded to TiC, which can be caused by ion sputtering during the depth profiling.

Miniature diaphragm pumps meet the performance challenge

System designers are being challenged to advance their product technology by specifying fluidic modules that can achieve increased performance capabilities while fitting in ever-smaller envelopes. Dan Schimelman from Hargraves Technology explains how the BTC IIS has been designed to outlast most of the systems it will be integrated into.

OPTIMAL DESIGN FOR THE MAGNETIC SUSPENDED CENTRIFUGAL BLOOD PUMP

An optimal design method for the maglev system is devised to develop a miniature and high performance maglev pump. There are trade-off problems on the maglev artificial heart design. For example, the device should be small enough for implantation. But, the small device has limited performance for force generation to suspend an impeller with the magnetic circuit. For another example, the gap between the levitated impeller and a pump casing is a main factor to determine the efficiency of the magnetic system. Narrow gap is suitable for the efficiency, but is not good for hemolysis property. For optimal design, a theoretical design model for a maglev centrifugal blood pump with a self-bearing motor is constructed based on the magnetic circuit theory. The self-bearing motor consists of the magnetic stator at the center of the pump, outer rotor ring with an impeller at the circumferential space of the stator. Relationships among model parameters are defined as restriction conditions. The thickness of magnets, the diameter of the stator and the turn number of electromagnet coils are optimized to achieve the small size and high efficient performance with pre-determined stiffness. As a result, the diameter of the stator could be reduced from 60 mm to 55 mm with no deterioration of the generated force. Also, the energy consumption was reduced from 16 W to 11 W against a head of 100 mm Hg with a flow rate of 5 L/min. Developed design method is useful to optimize the maglev pump and the optimized pump indicated sufficient performance as a ventricular assist device.

Ventricular unloading with a miniature axial flow pump in combination with extracorporeal membrane oxygenation

ECMO for acute cardiorespiratory failure is an established therapeutic option. Persistent insufficient unloading of the left ventricle (LV) can compromise recovery of ventricular function. We decided to insert a miniature rotary blood pump (Impella) for decompression of the LV. In contrast to previous experience with this new device, where it was generally used for postcardiotomy heart failure or cardiogenic shock and inserted in the operating room or the catheter laboratory, this is the first report describing the potential of this technology in the intensive care unit, in a patient on ECMO and the value of echocardiography guidance. A 13-year-old boy with a history of congenital heart disease was admitted to the ICU with acute cardio-respiratory failure. On day 2 venoarterial ECMO was instituted because of worsening cardiorespiratory insufficiency refractory to conventional treatment. On day 5 a percutaneous rotary blood pump was inserted to decompress the LV. A percutaneous miniature rotary blood pump can be an alternative to decompress a failing LV in the setting of VA-ECMO. Echocardiography can avoid the use of fluoroscopy and the transport to a catheter laboratory to insert the rotary pump.

OS1-11 携帯型燃料電池用マイクロターボポンプ(OS1 マイクロエネルギー変換,分散と集中の共存)

We have developed a process to fabricate micro-to-millimeter-sized plastic parts with multilayer microstructures using new low-stress ultrathick photoresist (XP SU-8 3000 series, Kayaku Microchem). Using this process, a 2-dimensional shrouded impeller with 16mm diameter and 400μm blade height was fabricated for a miniature turbo pump supplying air to portable fuel cells. The impeller was glued onto a high-speed magnetic motor, and rotation speed, flow rate and pressure rise was measured. The impeller generated 6.51/min air flow and 0.16kPa pressure rise at 80000rpm.

The PediaFlow™ Pediatric Ventricular Assist Device

The very limited options available to treat ventricular failure in patients with congenital and acquired heart diseases have motivated the development of a pediatric ventricular assist device (VAD). Our effort involves a consortium consisting of the University of Pittsburgh, Carnegie Mellon University, Children's Hospital of Pittsburgh, World Heart Corporation, and LaunchPoint Technologies, LLC. The overall aim of our program is to develop a highly reliable, biocompatible VAD for chronic support (6 months) of the unique and high-risk population of children between 3 kg and 15 kg (patients from birth to 2 years of age). The innovative pediatric VAD we are developing (PediaFlow) is based on a miniature mixed-flow turbodynamic pump featuring magnetic levitation, with the design goal being to assure minimal blood trauma and risk of thrombosis. This article discusses the limitations of current pediatric cardiac assist treatment options and the work to date by our consortium toward the development of a pediatric VAD.

Towards the Development of a Pediatric Ventricular Assist Device

The very limited options available to treat ventricular failure in children with congenital and acquired heart diseases have motivated the development of a pediatric ventricular assist device at the University of Pittsburgh (UoP) and University of Pittsburgh Medical Center (UPMC). Our effort involves a consortium consisting of UoP, Children's Hospital of Pittsburgh (CHP), Carnegie Mellon University, World Heart Corporation, and LaunchPoint Technologies, Inc. The overall aim of our program is to develop a highly reliable, biocompatible ventricular assist device (VAD) for chronic support (6 months) of the unique and high-risk population of children between 3 and 15 kg (patients from birth to 2 years of age). The innovative pediatric ventricular assist device we are developing is based on a miniature mixed flow turbodynamic pump featuring magnetic levitation, to assure minimal blood trauma and risk of thrombosis. This review article discusses the limitations of current pediatric cardiac assist treatment options and the work to date by our consortium toward the development of a pediatric VAD.

Miniature pumps for use in analytical instrumentation and devices

Herbert Hansel from German company Rietschle Thomas Puchheim GmbH provides an overview of pumps that are used in analytical instrumentation and devices by looking at their underlying designs and working principles.

Continuous low volume delivery of intravenous treprostinil via a central venous catheter with a miniature pump in a conscious dog model

Two animal studies were conducted to determine the feasibility of infusing treprostinil via a central venous catheter at an infusion rate of 0.1 mL/hour. Currently treprostinil is administered intravenously at infusion rates of approximately 1.0 to 2.0 mL/hour to patients with pulmonary arterial hypertension, which reflects standard clinical practice to ensure line patency with continuous intravenous administration via a central venous catheter. In a pilot study three male beagle dogs were administered 50 ng/kg/min of treprostinil continuously at an infusion rate of 0.1 mL/hr via the MiniMed 407C infusion pump for 21 days. In a definitive study, six male beagle dogs were administered 50 ng/kg/min of treprostinil continuously at an infusion rate of 0.1 mL/hr via the MiniMed 407C infusion pump for 60 days. In both studies 'no delivery' pump alarms were documented throughout the study in addition to pharmacokinetic data at specified time points. There were no documented occlusions in the 21-day pilot study. In the 60-day study one animal had a documented catheter occlusion after 16 days of therapy. Following reimplantation with a new catheter this animal did not have any additional occlusions for 40 days. No other animals in this study had any significant problems. In both studies, pharmacokinetic data were similar to that observed in previous animal studies evaluating treprostinil administration at the same dose and at higher infusion rates. These animal data support the evaluation of administering treprostinil at a low infusion rate via the MiniMed 407C infusion pump in patients with pulmonary arterial hypertension.

Miniature self-priming pump available

Miniature self-priming pump available

Performance and Development of a Miniature Rotary Shaft Pump

The development and performance of a novel miniature pump called the rotary shaft pump (RSP) is described. The impeller is made by boring a 1.168 mm hole in one end of a 2.38 mm dia shaft and cutting slots in the side of the shaft at the bottom of the bored hole such that the metal between the slots defines the impeller blades. The impeller blades and slots are 0.38 mm tall. Several impeller designs are tested over a range of operating conditions. Pump performance characteristics, including pressure rise, hydraulic efficiency, slip factor, and flow rate, are presented for several different pump configurations, with maximum flow rate and pressure rise of 64.9ml∕min and 2.1 kPa, respectively, when the working fluid is water. Potential applications include transport of biomedical fluids, drug delivery, total analysis systems, and electronics cooling.

ELIMINATION OF REVERSAL FLOW IN BACK CLEARANCE GAPS OF A MINIATURE PEDIATRIC CENTRIFUGALBLOOD PUMP BY CFD

The configuration of a centrifugal pump has been widely used as a ventricular assist device (VAD) for adults and recently for infants and small children with failing ventricles. For such a centrifugal pump, the back clearance gap together with the central core and outer annular clearance gap jointly form a washout flow path. However, within the washout path, the flow demonstrates a complex 3-dimensional structure, whcih potentially causes cellular trauma and/or thrombosis and also affects hydrodynamic performance. The objective of this study was to eliminate the reversal flow in the back clearance gaps of a miniature pediatric centrifugal blood pump by CFD analyses and design optimization. A commercial CFD code, Star-CD, was utilized to simulate the 3-D blood flow within a miniature centrifugal pump. An implicit method based on multiple reference frames was used for the coupling between the rotational and stationary elements. A power law function was integrated into the code to evaluate hemolysis with the shear history being recorded by the Lagrangian particle tracking method. By CFD analyses and optimization design, it was found that secondary blades, located along the lower and side surfaces of the rotor, can generate antegrade blood flow in the clearance gaps. Through optimizing the secondary blades number and their geometry by CFD, we were able to achieve net antegrade flow with minimal zones of retrograde flow.

702 磁気浮上型小型ターボポンプの開発(関東支部 茨城講演会)

We have developed the magnetically suspended miniature turbo pump with five-DOF control for artificial. The pump system consists of two magnetic bearings, a motor and a levitated impeller. The magnetic bearings are set at each side of the impeller. The axial position, the radial position and the tilt of the impeller are controlled by using the magnetic bearings. The motor mechanism is set between both magnetic bearings. The maximum oscillation amplitude of the levitated impeller in the axial direction was 0.02 [mm] and that in the radial direction was 0.11 [mm] during pumping. Maximum rotation speed, maximum pump head and maximum flow rate were 10,500 [rpm], 67 [mmHg] and 1.5 [L/min], respectively. The developed magnetic suspension system displayed sufficient suspension performance for artificial heart.

First-generation hybrid MEMS gas chromatograph

The fabrication, assembly, and initial testing of a hybrid microfabricated gas chromatograph (microGC) is described. The microGC incorporates capabilities for on-board calibration, sample preconcentration and focused thermal desorption, temperature-programmed separations, and "spectral" detection with an integrated array of microsensors, and is designed for rapid determinations of complex mixtures of environmental contaminants at trace concentrations. Ambient air is used as the carrier gas to avoid the need for on-board gas supplies. The microsystem is plumbed through an etched-Si/glass microfluidic interconnection substrate with fused silica capillaries and employs a miniature commercial pump and valve subsystem for directing sample flow. The latest performance data on each system component are presented followed by first analytical results from the working microsystem. Tradeoffs in system performance as a function of volumetric flow rate are explored. The determination of an 11-vapor mixture of typical indoor air contaminants in less than 90 s is demonstrated with projected detection limits in the low part-per-billion concentration range for a preconcentrated air-sample volume of 0.25 L.

ELECTROMAGNETIC MINIATURE PUMP USING PERISTALTIC MOTION OF INTERCHANGEABLE FLEXIBLE TUBE

This paper presents an electromagnetic miniature pump using peristaltic motion of an interchangeable flexible tube. Four hinge-type electromagnetic actuators arranged serially in one line pinch a flexible tube and generate peristaltic motion on the tube. In order to reduce electric power consumption, the magnetic latch mechanism using permanent magnets is applied to the actuator drive. As the actuator pinches the outside wall of the interchangeable tube, this pump can deal with any liquids inside the tube. The prototype pump has the flow rate range of 0.1~1cm 3 /min and the maximum pressure of 13kPa by a battery drive. This paper shows the electromagnetic design of the actuator using the FEM magnetic field analysis. The optimum drive sequence of the pinching actuators and the experimental result of pump characteristics are reported. Furthermore, feasibility consideration of application to the portable intravenous drip system for medical treatments is carried out.

Preliminary results of fetal cardiac bypass in nonhuman primates

Fetal cardiac surgery has potential benefits for treatment of some congenital heart defects. However, placental dysfunction as a result of fetal bypass, fetal stress, and fetal exposure to external milieu needs to be overcome to optimize the outcomes of fetal cardiac bypass. In this study we evaluated the technical feasibility of cardiac bypass in the nonhuman primate fetus and the efficacy of different anesthetic approaches. Twelve baboon fetuses, average gestation 146 +/- 8 days and weight 696 +/- 184 g, were used. Three fetuses were excluded from the study because of nuchal cord presentations. The animals were separated into two anesthesia groups: isoflurane (n = 6) and fentanyl and midazolam (n = 3). A miniature roller pump circuit without oxygenator was used for fetal bypass for 30 minutes. No blood transfusion was performed. Fetal blood gas samples were collected before bypass, during bypass, and at 15 and 60 minutes after bypass. All fetuses in the isoflurane group were successfully placed on the cardiac bypass circuit. However, 2 animals in the fentanyl and midazolam group were not placed on the bypass circuit because of sustained elevation in maternal uterine tone. All maternal baboons survived. Of the 6 fetuses in the isoflurane group, 5 survived for 60 minutes; however, placental function continued to deteriorate after bypass (Pa o 2 33 +/- 3 mm Hg before bypass, 23 +/- 6 mm Hg 15 minutes after, and 18 +/- 9 mm Hg 60 minutes after). The technical feasibility of cardiac bypass in nonhuman primate fetuses weighing less than 1000 g was confirmed. Isoflurane anesthesia appears to be superior to fentanyl and midazolam anesthesia for fetal cardiac surgery because of adequate uterine relaxation.

Concept for a new hydrodynamic blood bearing for miniature blood pumps.

The most crucial element of a long-term implantable rotary blood pump is the rotor bearing. Because of heat generation and power loss resulting from friction, seals within the devices have to be avoided. Actively controlled magnetic bearings, although maintenance-free, increase the degree of complexity. Hydrodynamic bearings for magnetically coupled rotors may offer an alternative solution to this problem. Additionally, for miniature pumps, the load capacity of hydrodynamic bearings scales slower than that of, for example, magnetic bearings because of the cube-square-law. A special kind of hydrodynamic bearing is a spiral groove bearing (SGB), which features an excellent load capacity. Mock-loop tests showed that SGBs do not influence the hydraulic performance of the tested pumps. Although, as of now, the power consumption of the SBG is higher than for a mechanical pivot bearing, it is absolutely contact-free and has an unlimited lifetime. The liftoff of the rotor occurs already at 10% of design speed. Further tests and flow visualization studies on scaled-up models must demonstrate its overall blood compatibility.