Pumpless Perfusion in Organ-on-Chip Devices Using Tesla Valves
In this interesting work, researchers from the University of Twente utilise Henniker’s HPT-200 plasma system in the development of a Tesla Valve-based pumpless flow system [1]. Pumpless perfusion is a method of moving fluids through a microfluidic or Organ-on-Chip system without using external pumps like syringe or peristaltic pumps.
Accurate modelling of human physiology using Organ-on-Chip (OOC) platforms depends on the ability to fabricate and condition microfluidic devices with precision. The Henniker HPT-200 plasma cleaner is used to prepare PDMS-glass microfluidic chips, enabling both strong surface bonding and hydrophilic channel treatment essential for fluid performance.
[2] The HPT-200 Model Image
The Application
The Tesla Valve-based system aimed to replicate physiological WSS levels found in liver sinusoidal endothelial cells (0.1–0.5 dyn/cm²) without requiring any mechanical pump. The method combined:
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A rocking platform to generate flow via gravity
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Passive Tesla Valves to restrict backflow
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PDMS/glass microfluidic chips to model Vessel-on-Chip (VOC) behaviour
A major requirement for successful implementation was the ability to fabricate bonded PDMS chips and render microchannels hydrophilic to maintain consistent fluid behaviour throughout testing.
[3] Figure 4: The principle of the pumpless unidirectional perfusion system utilising a combination of TV’s and a rocking platform. A) The system is at a equilibrium, the fluid levels in both reservoirs are equal and no flow is present. B) The fluid level in the left reservoir is higher, resulting in a forward flow mainly through the TV channel. C) The fluid level in the right reservoir is higher, resulting in a reverse flow mainly through the VOC channel. This figure is made using www.BioRender.com. Image Courtesy of https://essay.utwente.nl/107998/.
The Role of Henniker's HPT-200 Plasma Cleaner
Henniker’s HPT-200 plasma cleaner was used at two stages of device preparation:
1. PDMS-to-glass bonding
The PDMS Tesla Valve chip and glass substrate were exposed to plasma to activate the surfaces, enabling strong, permanent bonding. This ensured the integrity of the microchannels throughout repeated use.
2. Channel hydrophilisation
A second plasma treatment was applied prior to testing, modifying the surface energy of the channels. This rendered the PDMS channels hydrophilic, improving capillary action and ensuring uniform flow characteristics, a key factor in achieving accurate WSS modelling.
Keywords
- Hydropillic surface treatments
- Organ-on-chip
- Oumpless perfusion
- Tesla valve
- Microfluidics
- PDMS bonding
- PDMS glass bonding
- Plasma bonding
- HPT-200
References
Readers are referred to the original print, and details of the HPT-200 via the links below.
