Adsorption of plasma proteins on polyethylene oxide-modified lipid bilayers studied by total internal reflection fluorescence

Xu, Zhong; Marchant, Roger

doi:10.1016/s0142-9612(00)00004-1

Cited by 41 publications

(30 citation statements)

References 23 publications

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“…The fluorescence signal varied less than 10% on individual measurements. This is in accordance with the reproducibility rate found by other authors using the same experimental setup (22).…”

Section: Methodssupporting

confidence: 93%

Displacement of Adsorbed Insulin by Tween 80 Monitored Using Total Internal Reflection Fluorescence and Ellipsometry

Mollmann

Elofsson²,

Bukrinsky

et al. 2005

Pharm Res

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“…The fluorescence signal varied less than 10% on individual measurements. This is in accordance with the reproducibility rate found by other authors using the same experimental setup (22).…”

Section: Methodssupporting

confidence: 93%

Displacement of Adsorbed Insulin by Tween 80 Monitored Using Total Internal Reflection Fluorescence and Ellipsometry

Mollmann

Elofsson²,

Bukrinsky

et al. 2005

Pharm Res

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“…In particular, as regards protein adsorption, one report suggested that PEGylation can reduce protein adsorption by liposomes, 8) whereas other reports indicated that the total protein adsorption from plasma was not changed or increased by PEG. 9,10) In another report, it was indicated that PEG-modification of negatively charged liposomes can inhibit the binding of fibrinogen to liposomes, but there were no effects of PEG on nearly neutral liposomes (PC : PG : PE : Chol= 69 : 4 : 4 : 23). 11) Negatively charged liposomes have often been used to show the inhibition of protein adsorption by PEG as described above, but the effect of PEG on nearly neutral or slightly negatively-charged liposomes remains unclear.…”

mentioning

confidence: 99%

Polyethylene Glycol Prevents <i>in Vitro</i> Aggregation of Slightly Negatively-Charged Liposomes Induced by Heparin in the Presence of Bivalent Ions

Shibata¹,

Yomota²,

Kawanishi³

et al. 2012

Biological & Pharmaceutical Bulletin

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Liposomes are of great interest as drug delivery vehicles, and studies have focused on understanding how the physical and chemical characteristics of liposomes can be modified to improve their in vivo behavior. In a previous study, we found that the slightly negatively-charged liposomes aggregate only in the culture medium of human umbilical vein endothelial cells, whereas the liposomes modified with polyethylene glycol (PEG) (PEGylated) did not aggregate. In the present study, we investigated the underlying mechanism of this phenomenon. Firstly, it was found that heparin in the culture medium is one of the factors that cause aggregation of the non-PEGylated liposomes. Since the addition of ethylenediaminetetraacetic acid (EDTA) prevented the aggregation, metal ions, such as Ca 2 and Mg 2 , in the culture medium could also be important in driving the aggregation. In the presence of heparin, higher concentrations of Ca 2 or Mg 2 increased the particle size of the non-PEGylated liposomes, although no change in the particle size of PEGylated liposomes was observed. Under conditions in which aggregation occurred, we measured the binding and uptake of liposomes by macrophages in vitro. The binding and uptake of non-PEGylated liposomes were significantly increased with increasing Ca 2 concentrations, whereas those of PEGylated liposomes were unchanged. While the formation of aggregations of cationic or anionic liposomes has been reported previously, there are few reports addressing the aggregation of slightly negatively-charged or neutral liposomes. Thus, our data provide useful insights on the effect of PEGylation on liposomal aggregation and in vivo behavior.Key words liposome; heparin; aggregation; polyethylene glycol; Ca 2+Various liposomal products have been developed and applied to clinical treatment. Since methods to control the size of liposome and to improve the in vitro and in vivo stability of liposome had been developed, liposomes have attracted more attention. Incorporation of polyethylene glycol (PEG)-conjugated lipids (PEGylated) into liposomes is known to improve the circulation time of liposomes and prevent their uptake by the reticuloendothelial system (RES).1-4) It was reported that PEGylation inhibits the adsorption of serum proteins in vitro, 5,6) and decreases the uptake of liposomes by cells such as macrophages.7) From these reports, the extension of the circulation time by PEGylation is widely considered to be caused by the formation of a hydration layer, and steric hindrance can also prevent protein (such as opsonin) adsorption following recognition by cells of the RES, such as macrophages. However, the mechanisms producing these effects of PEGylation remain controversial. In particular, as regards protein adsorption, one report suggested that PEGylation can reduce protein adsorption by liposomes, 8) whereas other reports indicated that the total protein adsorption from plasma was not changed or increased by PEG.9,10) In another report, it was indicated that PEG-modification of negatively char...

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“…The monolayer was held at constant pressure and the change in the area with time was recorded. A film was defined as stable when the change in area was less than 6% over 1 h. Once a film's stability was established, deposition of the DSPC monolayer onto a FPU-spin-coated film was performed by lowering the hydrophobic film through the air/water interface at a rate of 2 mm/min, while the film pressure was held at 45 mN/m [22].…”

Section: Preparation Of the Lb Monolayermentioning

confidence: 99%

“…Phospholipids are known to be a major component of a biomembrane surface, and exhibit unusually good platelet resistance. In addition, they are non-immunogenic and nonantigenic [20][21][22][23][24][25][26][27]. Chapman and co-workers [28][29][30] proposed several kinds of artificial surfaces with an aim to mimic the phospholipid structure formed on the endothelial cell membrane.…”

Section: Introductionmentioning

confidence: 99%

Properties of phospholipid monolayer deposited on a fluorinated polyurethane

Wang

Wei

Chen

et al. 2004

Journal of Biomaterials Science, Polymer Edition

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A simple procedure for surface modification of polyurethane by the Langmuir-Blodgett (LB) method using the amphiphile 1,2-distearoyl-sn-glycero-3-phosphocholine dihydrate (DSPC) was developed. The polyurethane containing the fluorinated moiety was prepared via the perfluoro-containing chain extender 2,2,3,3-tetrafluoro-1,4-butanediol. The fluorinated polyurethane (FPU) films were prepared by spin coating and dipping methods. The spin-coated FPU films exhibited hydrophobic characteristic and, thus, enhanced the transferability of DSPC. Held at constant pressure of 45 mN/m, the DSPC monolayer was transferred successfully to FPU films with a near-unity transfer ratio. The in vitro platelet adhesion assay revealed that the FPU modified with DSPC monolayer was more platelet compatible than the unmodified FPU substrates with no pseudopods and flattening of adherent platelets as well as lower platelet adhesion density. Moreover, the DSPC monolayer remained intact after platelet adhesion testing. In addition, the platelet compatibility of the unmodified FPU was affected by the film preparation methods. This might be attributed to the distinctive surface micromorphology formed. This simple DSPC deposition scheme by a LB technique would be very useful to further enhance the platelet compatibility of hydrophobic substrate and can be utilized for biomedical application in which the flow shear rate is not too high.

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Adsorption of plasma proteins on polyethylene oxide-modified lipid bilayers studied by total internal reflection fluorescence

Cited by 41 publications

References 23 publications

Displacement of Adsorbed Insulin by Tween 80 Monitored Using Total Internal Reflection Fluorescence and Ellipsometry

Displacement of Adsorbed Insulin by Tween 80 Monitored Using Total Internal Reflection Fluorescence and Ellipsometry

Polyethylene Glycol Prevents <i>in Vitro</i> Aggregation of Slightly Negatively-Charged Liposomes Induced by Heparin in the Presence of Bivalent Ions

Properties of phospholipid monolayer deposited on a fluorinated polyurethane

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