Open flow microperfusion (OFM) is a membrane-free, time-resolved, minimally-invasive, in-vivo sampling technology

OFM uses probes with macroscopic openings to exchange substances in a liquid pathway that is based on convection rather than diffusion so that the exchange can occur non-selectively in either direction.

The direct liquid pathway between the probe’s perfusate and the surrounding interstitial fluid (ISF) provides a diluted but otherwise unchanged ISF sample, since no dialysis or filtering occurs. OFM provides unfiltered, merely diluted interstitial fluid from the investigated target tissues (skin, adipose, brain tissue). Endogenous and exogenous substances present in the interstitial fluid of targeted tissues can thus be quantified without the risk of investigating an altered sample.


Skin Tissue

Dermal OFM (dOFM) measures PK/PD of drugs in the dermis after topical or systemic application.
e.g. antibodies, protein-bound drugs.


Brain Tissue

Cerebral OFM (cOFM) monitors BBB function and drug transport across the intact blood-brain-barrier (BBB).
e. g. nanoformulations, antibodies.


Adipose Tissue

Adipose OFM (aOFM) assesses transport routes, drug dispersion and drug effects in adipose tissue,
e.g. insulins, GLP-1 receptor agonists.  

Membrane-free sampling

The distinct advantage of OFM lies in the direct access to the interstitial fluid of different tissues by using membrane-free probes. Membrane-based sampling is often limited to sampling low molecular weight or hydrophilic substances. Membrane-free OFM probes feature an exchange area with no diffusion barrier, hence sampling is not restricted by the size or lipophilicity of substances or protein binding effects.

Investigate diseases and treatments

OFM enables the investigation of disease biomarkers directly in the affected tissue and can be used to continuously monitor therapeutic effects on tissue level. Resulting OFM data are barely influenced by other metabolic processes in the body contrary to standard blood sampling. Time-resolved profiles over longer time periods allow the assessment of treatment effects and can be performed at multiple test sites in one subject.  


Materials and Methods




Study materials

  • CE-marked probes, pumps and accessories for preclinical and clinical studies
  • minimally invasive, membrane-free probes (fluoropolymer) with a 0.55 x 15 mm exchange area
  • portable pump (0.1-10 µl/min) with delta push-pull modes
  • 3 OFM probes per pump

Complementary methods

  • ultrasound to verify probe location and measure dermal thickness
  • tape stripping
  • skin biopsies and suction blister
  • TEWL (transepidermal water loss)
  • skin impedance




Study materials

  • cOFM material available for preclinical use only
  • minimally invasive, membrane-free probes (fluoropolymer) with 0.5 mm diameter
  • high precision stereotactic implantation
  • removable healing dummy allows tissue regeneration after implantation

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