Diffusion and calibration properties of microdialysis sampling membranes in biological media

Abstract

The diffusion and calibration properties for three commercially available microdialysis membranes (polycarbonate-polyether (PC), polyacrylonitrile (PAN), and cuprophan (CUP)) were evaluated. The analytes studied had molecular weights between 94 (phenol) and 1355 (vitamin B12). For each analyte-membrane pair, an effective membrane diffusion coefficient was calculated. Effective membrane diffusion coefficients varied considerably between the microdialysis membranes. For Vitamin B12, CUP and PAN membranes gave relative recovery values of greater than 20% at 0.5 microl min(-1), while the PC membrane had a 1% recovery. When backpressure was applied. PC and PAN membranes exhibited more ultrafiltration than CUP membranes. Ultrafiltration did not affect analyte relative recovery through either PC or PAN membranes. Effective membrane diffusion coefficients were not significantly altered for some membrane-analyte combinations when exposed to 4% bovine serum albumin or 0.3% fibrinogen. These data suggest that reductions in relative recovery during long-term microdialysis sampling experiments may be due to other physiologically relevant proteins or to tissue reactions near the dialysis membrane.

Influence of surface modification and static pressure on microdialysis protein extraction efficiency

“…Furthermore, the EE of the solute is significantly compromised and reduced as the molecular weight of the analyte begins to approach approximately 25% or greater of the MD membrane MWCO (Snyder et al 2001;Schutter et al 2004;Cynthia and Stenken 2014). Therefore, 3,000 kDa MWCO plasmapheresis type membranes are often used (Winter et al 2002;Clough et al 2007).…”

Microdialysis sampling techniques applied to studies of the foreign body reaction

“…The membrane MWCO is defined using kidney dialysis parameters rather than what the membrane can achieve as a MWCO with it incorporated into a microdialysis sampling device. The actual recovered molecular weights through dialysis membranes have been described and show that extraction efficiency is significantly compromised and reduced as the solute molecular weight begins to approach approximately 25% or greater of the membrane MWCO (Schutte et al, 2004; Snyder et al, 2001). This causes significant challenges with cytokines since many can be in the range of the MWCO.…”

Analytical Considerations for Microdialysis Sampling

“…The recoveries and apparent membrane diffusion coeffi cients for 10 different compounds spanning a molecular -weight range between 94 and 1355 Da and possessing different log P values were reported in a separate study [33] . For several compounds it was found that recovery was affected dramatically by the type of membrane used.…”