Flux is a dependent variable of:
(1) TIME : The longer the period,
the more to get to the other side.
(2) AREA : The larger the monolayer, the more paracellular channels.
(3) DRIVING FORCE : The bigger the
concentrations difference of ions/tracersbetween apical and basal sides, the faster the ions/tracers move.
Permeability (P) is Flux normalized to time, area, and driving force.
P = Flux/[time][Area][Driving Force]
P in [moles]/[hours][cm square][Molar]
To obtain Permeability of a monolayer:
(A) obtain flux measurements
by performing flux assays (Ion Flux Protocol or Radioactive Flux Protocol) and
(B) calculate permeabilities from flux measurements (Ion Quantitation
or Cpm-Flux Conversion -- Links in Flux Protocols).