text: Open flow microperfusion (OFM) is a sampling method for clinical and preclinical drug development studies and biomarker research. OFM is designed for continuous sampling of analytes from the interstitial fluid (ISF) of various tissues. It provides direct access to the ISF by insertion of a small, minimally invasive, membrane-free probe with macroscopic openings. Thus, the entire biochemical information of the ISF becomes accessible regardless of the analyte's molecular size, protein-binding property or lipophilicity.
  OFM is capable of sampling lipophilic and hydrophilic compounds, protein bound and unbound drugs, neurotransmitters, peptides and proteins, antibodies, nanoparticles and nanocarriers, enzymes and vesicles.