Development of a dynamic delivery method for in vitro bioassays

Kwon, Jung-Hwan, Mayer, Philipp, Wüthrich, Thomas and Escher, Beate I. (2009) Development of a dynamic delivery method for in vitro bioassays. Chemosphere, 76 1: 83-90. doi:10.1016/j.chemosphere.2009.02.023

Author Kwon, Jung-Hwan
Mayer, Philipp
Wüthrich, Thomas
Escher, Beate I.
Title Development of a dynamic delivery method for in vitro bioassays
Journal name Chemosphere   Check publisher's open access policy
ISSN 0045-6535
Publication date 2009-03-25
Year available 2009
Sub-type Article (original research)
DOI 10.1016/j.chemosphere.2009.02.023
Open Access Status
Volume 76
Issue 1
Start page 83
End page 90
Total pages 8
Editor M. Oehme, K. Kannan, A. Sabljic
Place of publication Oxford
Publisher Pergamon Press/Elsevier
Language eng
Subject 05 Environmental Sciences
0502 Environmental Science and Management
Abstract Measuring the biological activity of hydrophobic chemicals using in vitro assays is challenging because their aqueous solubility is low and the high density of bio-suspensions strongly decreases the bioavailability of hydrophobic pollutants. Dynamic dosing by partitioning from a stable polymer has a potential to overcome these limitations. Poly(dimethylsiloxane) (PDMS) was chosen due to its documented bio-compatibility and excellent partitioning properties. PDMS sheets were loaded with five polycyclic aromatic hydrocarbons (PAHs) and then immersed in model bio-suspensions composed of membrane vesicles (“chromatophores”, composed of 30% lipids and 70% proteins) isolated from the photosynthetic bacterium Rhodobacter sphaeroides or phospholipid bilayer vesicles (liposomes) composed of palmitoyl-oleoyl phosphatidylcholine (POPC). Method development included the determination of partition coefficients between chromatophores or liposomes and water, desorption rate constants from PDMS to bio-suspensions, and diffusion resistances in both PDMS and bio-suspensions. The release of the PAHs from the PDMS into the bio-suspensions was measured and modeled as a combination of diffusion in pure water and diffusion in a completely mixed solvent composed of water and bio-suspensions. The mass transfer resistance for the release was lower in the PDMS than in the tested solutions, which demonstrates that PDMS can efficiently deliver PAHs even to dense biosuspensions. The contribution of aqueous diffusion to the mass transfer decreased with increasing hydrophobicity of the PAHs indicating that hydrophobic chemicals are efficiently transported with suspended biomaterial. The passive dosing system is versatile and offers a number of applications. Promising are tests with instantaneous response, where the time-dependent effect can be translated to concentration-effect curves but the system is also applicable for assuring constant dosing for longer-term testing.
Keyword Passive dosing
Aqueous boundary layer
Poly(dimethylsiloxane) (PDMS)
Membrane vesicles
Polycyclic aromatic hydrocarbons (PAHs)
Q-Index Code C1
Q-Index Status Confirmed Code
Grant ID 20081100
Institutional Status UQ

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Created: Fri, 26 Jun 2009, 22:13:34 EST by Professor Beate Escher on behalf of National Res Centre For Environmental Toxicology