Cell Based Perfusion Assays

In vivo, several adherent cell types are exposed to mechanical shear stress in biofluidic systems like blood vessels. This mechanical stimulus has a great impact on the physiological behavior and adhesion properties of cells.

The µ-Slides were especially designed for conveniently performing flow assays. These consumables are tested for static and perfusion cell cultures. Being also compatible with any inverted microscopy technique they are ideally adapted to parallel perfusion assays directly on the microscope or inside the incubator.

Depending on the experimental requirements, peristaltic pumps, syringe pumps, or even simple gravity flow can be used. Click here for various pumping solutions or contact ibidi for personal consulting.

Experimental End Points Using µ-Slides

• real-time monitoring of morphological changes in living cells
  
• protein localization using fluorescence
  
• profiling secreted proteins in conditioned media
  
• cell adhesion
  
• gene expression profiling after cell detachment
  

Adhesion Assay

Cell Culture Under Shear Stress

Stop Flow Experiments

3D Cell Culture: Interstitial Flow

ECIS Flow Module

The ECIS technology allows measuring even small morphological changes with electrical signals, with a minimum of disturbance, and without any stainings. The measurements are automated and therefore highly reproducible with a minimum of work.

Shear Stress in General

... is the mechanical force induced by friction of liquid to the distal cell membrane. Cells might be able to countervail deformations caused by shear stress by rearranging their cytoskeleton. Other shear stress dependent effects are changes in metabolism, gene expression, and differentiation. Physiological shear stress values vary from 0.5dyne/cm² (small veins) to 20dyne/cm² (peaked flow in abdominal aorta).

Turbulent Flow

... near surfaces is characterized by changes in flow rate and direction. For simulating turbulent flow it is accepted to use laminar flow of oscillating direction within half a second. This is because turbulent flow can not be achieved in microchannels at physiological flow regimes for physical reasons.

 

Laminar Shear Stress

... is expected in most healthy biological vessel like arteries and veins. Experimentally it is achieved by per-fusing medium through microchannels of low heights. The observation area of homogeneous laminar shear stress includes the whole channel area without small stripes close to the side walls and near the reservoirs (both in the range of the channel heights). For homo-geneous laminar shear stress experiments µ-Slide I Luer, µ-Slide VI, and µ-Slide I are recommended.

Non-Uniform Laminar Shear Stress

... occurs at branching sites and other obstacles of vessel in vivo. Experimentally it can be achieved by spatially varying flow rates. It can be used for investigating cells at different shear stresses in one sample. More advanced it can be used for studying cells and their communication at positions with strongly varying shear stress. The µ-Slide y-shaped was designed for studies of non-uniform shear stress. In the branched region the prevalent shear stress is approximately half of the regions with only the single channel. At the branching point experimentators should refer to our numerical simulations for exact shear stress values. Please contact us for personal consulting.