Thinking Outside the Heart

Sarvazyan, Narine

doi:10.1177/1074248413520343

Cited by 3 publications

(1 citation statement)

References 67 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The assembled setup had all key parameters within the ranges expected to occur biologically, including the Young’s modulus and the linear dimensions of the compliant segment, the compression duration and frequency, and the fluid viscosity. These data warrant creation of similar pumping systems using excised vessels and/or tissue-engineered components 25 , 40 – 42 . These key components can be positioned outside the vessel of interest and can include a pair of low compliance cuffs and a band of periodically contracting muscle.…”

Section: Discussionmentioning

confidence: 96%

Output of a valveless Liebau pump with biologically relevant vessel properties and compression frequencies

Davtyan

Sarvazyan

2021

Sci Rep

View full text Add to dashboard Cite

Liebau pump is a tubular, non-peristaltic, pulsatile pump capable of creating unidirectional flow in the absence of valves. It requires asymmetrical positioning of the pincher relative to the attachment sites of its elastic segment to the rest of the circuit. Biological feasibility of such valveless pumps remains a hotly debated topic. To test the feasibility of the Liebau-based pumping in vessels with biologically relevant properties we quantified the output of Liebau pumps with their compliant segments made of a silicone rubber that mimicked the Young modulus of soft tissues. The lengths, the inner diameters, thicknesses of the tested compliant segments ranged from 1 to 5 cm, 3 to 8 mm and 0.3 to 1 mm, respectively. The compliant segment of the setup was compressed at 0.5–2.5 Hz frequencies using a 3.5-mm-wide rectangular piston. A nearest-neighbor tracking algorithm was used to track movements of 0.5-mm carbon particles within the system. The viscosity of the aqueous solution was varied by increased percentage of glycerin. Measurements yielded quantitative relationships between viscosity, frequency of compression and the net flowrate. The use of the Liebau principle of valveless pumping in conjunction with physiologically sized vessel and contraction frequencies yields flowrates comparable to peristaltic pumps of the same dimensions. We conclude that the data confirm physiological feasibility of Liebau-based pumping and warrant further testing of its mechanism using excised biological conduits or tissue engineered components. Such biomimetic pumps can serve as energy-efficient flow generators in microdevices or to study the function of embryonic heart during its normal development or in diseased states.

show abstract

Section: Discussionmentioning

confidence: 96%

Output of a valveless Liebau pump with biologically relevant vessel properties and compression frequencies

Davtyan

Sarvazyan

2021

Sci Rep

View full text Add to dashboard Cite

show abstract

Experimental characterization of an asymmetric valveless pump based on soft robotics technology

et al. 2023

View full text Add to dashboard Cite

Asymmetric pumping can be achieved by periodically compressing a flexible tube in its plane of symmetry using an actuator, as long as the rigid pipes connected to its ends are asymmetric. This mechanism, together with impedance pumping, composes the Liebau effect. While there have been numerous studies on impedance pumping, there is a lack of available research on asymmetric pumping. The aim of this study is to examine the influence of key parameters on the performance of this type of pump. In addition, this study implements an actuator based on soft robotics technology in asymmetric valveless pumping for the first time. The pump developed in this study can be applied in different areas involving the pumping of special fluids, including biomedical applications.

show abstract

Building Valveless Impedance Pumps From Biological Components: Progress and Challenges

Sarvazyan

2022

Front. Physiol.

Self Cite

View full text Add to dashboard Cite

Valveless pumping based on Liebau mechanism entails asymmetrical positioning of the compression site relative to the attachment sites of the pump’s elastic segment to the rest of the circuit. Liebau pumping is believed to play a key role during heart development and be involved in several other physiological processes. Until now studies of Liebau pump have been limited to numerical analyses, in silico modeling, experiments using non-biological elements, and a few indirect in vivo measurements. This review aims to stimulate experimental efforts to build Liebau pumps using biologically compatible materials in order to encourage further exploration of the fundamental mechanisms behind valveless pumping and its role in organ physiology. The covered topics include the biological occurrence of Liebau pumps, the main differences between them and the peristaltic flow, and the potential uses and body sites that can benefit from implantable valveless pumps based on Liebau principle. We then provide an overview of currently available tools to build such pumps and touch upon limitations imposed by the use of biological components. We also talk about the many variables that can impact Liebau pump performance, including the concept of resonant frequencies, the shape of the flowrate-frequency relationship, the flow velocity profiles, and the Womersley numbers. Lastly, the choices of materials to build valveless impedance pumps and possible modifications to increase their flow output are briefly discussed.

show abstract

Thinking Outside the Heart

Cited by 3 publications

References 67 publications

Output of a valveless Liebau pump with biologically relevant vessel properties and compression frequencies

Output of a valveless Liebau pump with biologically relevant vessel properties and compression frequencies

Experimental characterization of an asymmetric valveless pump based on soft robotics technology

Building Valveless Impedance Pumps From Biological Components: Progress and Challenges

Contact Info

Product

Resources

About