Fluorescence imaging of macromolecule transport in high molecular weight cut-off microdialysis
- 254 Downloads
When microdialysis (MD) membrane exceeds molecular weight cut-off (MWCO) of 100 kDa, the fluid mechanics are in the ultrafiltration regime. Consequently, fluidic mass transport of macromolecules in the perfusate over the membrane may reduce the biological relevance of the sampling and cause an inflammatory response in the test subject. Therefore, a method to investigate the molecular transport of high MWCO MD is presented. An in vitro test chamber was fabricated to facilitate the fluorescent imaging of the MD sampling process, using fluoresceinylisothiocyanate (FITC) dextran and fluorescence microscopy. Qualitative studies on dextran behavior inside and outside the membrane were performed. Semiquantitative results showed clear dextran leakage from both 40 and 250 kDa dextran when 100 kDa MWCO membranes were used. Dextran 40 kDa leaked out with an order of magnitude higher concentration and the leakage pattern resembled more of a convective flow pattern compared with dextran 250 kDa, where the leakage pattern was more diffusion based. No leakage was observed when dextran 500 kDa was used as a colloid osmotic agent. The results in this study suggest that fluorescence imaging could be used as a method for qualitative and semiquantitative molecular transport and fluid dynamics studies of MD membranes and other hollow fiber catheter membranes.
KeywordsMicrodialysis High molecular weight cut-off Membrane Fluorescence Imaging FITC Dextran
This research was in part supported by the Uppsala Berzelii Technology Centre for Neurodiagnostics, funded by the Swedish Governmental Agency for Innovation Systems and the Swedish Research Council Grant number P29797-1. The authors acknowledge mDialysis and Pharmacosomos AS for sharing their knowledge and for material support and Visualize your Science for graphical assistance.
- 9.Clough GF, Jackson CF, Lee JJP, Jamal SC, Church MK (2007) What can microdialysis tell us about the temporal and spatial generation of cytokines in allergen-induced responses in human skin in vivo? J Invest Dermatol 127:2799–2806Google Scholar
- 17.Keeler GD, Durdik JM, Stenken JA (2013) Comparison of microdialysis sampling perfusion fluid components on the foreign body reaction in rat subcutaneous tissue. Eur J Pharm Sci, in press. [Epub ahead of print; PMID: 24239995]Google Scholar
- 22.Dahlin AP, Wetterhall M, Liljegren G, Bergström SK, Andrén P, Nyholm L, Markides KE, Bergquist J (2005) Capillary electrophoresis coupled to mass spectrometry from a polymer modified poly(dimethylsiloxane) microchip with an integrated graphite electrospray tip. Analyst 130:193–199CrossRefGoogle Scholar
- 26.Pharmacosmos GPC standards (2014) Pharmacosmos. Available at: http://www.dextran.net. Accessed 28 Mar 2014. (Online document)
- 27.Pharmacosmos A/S batch release certificate, Dextran 60 EP, Batch no: 40013 (2006) Pharmacosmos. Available at: http://www.dextran.net. Accessed 6 Jan 2006. (Online document)