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Oxide-dependent adsorption of a model membrane phospholipid, dipalmitoylphosphatidylcholine: bulk adsorption isotherms.
| Content Provider | Semantic Scholar |
|---|---|
| Author | Oleson, Timothy A. Sahai, Nita |
| Copyright Year | 2008 |
| Abstract | The importance of substrate chemistry and structure on supported phospholipid bilayer design and functionality is only recently being recognized. Our goal is to investigate systematically the substrate-dependence of phospholipid adsorption with an emphasis on oxide surface chemistry and to determine the dominant controlling forces. We obtained bulk adsorption isotherms at 55 degrees C for dipalmitoylphosphatidylcholine (DPPC) at pH values of 5.0, 7.2, and 9.0 and at two ionic strengths with and without Ca(2+), on quartz (alpha-SiO(2)), rutile (alpha-TiO(2)), and corundum (alpha-Al(2)O(3)), which represent a wide a range of points of zero charge (PZC). Adsorption was strongly oxide- and pH-dependent. At pH 5.0, adsorption increased as quartz < rutile approximately corundum, while at pH 7.2 and 9.0, the trend was quartz approximately rutile < corundum. Adsorption decreased with increasing pH (increasing negative surface charge), although adsorption occurred even at pH > or = PZC of the oxides. These trends indicate that adsorption is controlled by attractive van der Waals forces and further modified by electrostatic interactions of oxide surface sites with the negatively charged phosphate ester (-R(PO(4)-)R'-) portion of the DPPC headgroup. Also, the maximum observed adsorption on negatively charged oxide surfaces corresponded to roughly two bilayers, whereas significantly higher adsorption of up to four bilayers occurred on positively charged surfaces. Calcium ions promote adsorption beyond a second bilayer, regardless of the sign of oxide surface charge. We develop a conceptual model for the structure of the electric double layer to explain these observations. |
| Starting Page | 105 |
| Ending Page | 123 |
| Page Count | 19 |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://www.geology.wisc.edu/people/sahaiPDF/la703599g.pdf |
| PubMed reference number | 18348581v1 |
| Alternate Webpage(s) | https://doi.org/10.1021/la703599g |
| DOI | 10.1021/la703599g |
| Journal | Langmuir : the ACS journal of surfaces and colloids |
| Volume Number | 24 |
| Issue Number | 9 |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | 1,2-Dipalmitoylphosphatidylcholine Arabic numeral 0 Calcium Charge (electrical) Esters Ionic Strength Ions Oxides Phospholipids Quartz Tissue membrane Vesicle (morphologic abnormality) alpha-Mannosidosis phosphate ester regulation of sequestering of calcium ion |
| Content Type | Text |
| Resource Type | Article |
