Description The above product listing is a group of compounds designed to
act as "membrane anchors" for ligands. A variety of functional
groups are available to covalently attach various ligands. Each group
of compounds is available with a saturated or unsaturated hydrophobic
group so the transition temperature of the "anchor" can
be defined. All of the compounds are in a pure form and ready to react
with your ligands.
Specifications
for Functionalized Phospholipids
Physical Examination
TLC:
One phosphorus positive spot
GC:
>99% (AUC) of appropriate fatty acid
HPLC:
>99% (AUC) of diacyl lipid
Solubility
Soluble:
Chloroform
Insoluble:
Acetone, Water
Stability
Storage:
-20°C
Shelf Life:
6 Months
Conjugation
of Proteins/Peptides/Drugs to Liposomes
Numerous lipids exist for the covalent or non-covalent attachment
of proteins, peptides, or drugs to the liposome surface. Most of
these lipids fall into 3 major classes of functionality: conjugation
through amide bond formation, disulfide or thioether formation,
or biotin/streptavidin binding.
Amide Conjugation Avanti offers phospholipids with either amine or carboxyl
functional groups for conjugation with proteins/peptides, or drugs
containing amine, carboxyl, or hydroxy groups. Carboxyacyl derivatives
of phosphatidylethanolamine (PE) have been used to achieve high
(up to 60%) coupling efficiency of antibodies to the surface of
preformed liposomes.1 Various acyl chain lengths ranging
from 4 to 22 carbons were utilized in the study, with optimum coupling
efficiency being achieved with a chain length of 12 carbons (1,12-dodecanedicarboxylate).
More recently it has been demonstrated that conjugation of an antibody
to N-glutaryl PE prior to mixing with dioleoyl PE (DOPE)/dioleoyl
phosphatidic acid (DOPA) successfully produced target-sensitive
immunoliposomes.2
Disulfide/Thioether Conjugation Avanti offers several lipids for disulfide (PDP-PE) or
thioether (MPB-PE or MCC-PE) conjugation of thio-containing proteins
or peptides. The maleimide-containing lipid, MPB-PE, has been used
to couple the homing device glu-plasminogen to liposomes without
loss of activity or interference with its fibrin-binding/homing
capacity.3 Also, this compound successfully formed antibody-conjugated
echogenic liposomes for ultrasonic image enhancement, specifically
for the detection and characterization of antherosclerosis.4
These lipid derivatives have also been used for delivery of prodrugs
with antitumoral activity,5 drug carriers with anti-HIV
activity,6 and gene delivery systems with increased transfection
efficiency.7, 8 A comparison of PDP and MPB conjugates
showed the MPB formed more stable complexes that survive in serum
longer.9 The MCC 10,11 contains a more stable
maleimide function group toward hydrolysis in aqueous reaction environments,
due to the proximity of an aliphatic cyclohexane ring rather than
the aromatic phenyl group of MPB.12
Biotin/Streptavidin Binding Avanti offers two forms of biotinylated lipid: one with
the biotin attached directly to PE (Biotin PE), and the other with
a 6-carbon spacer between the biotin and the PE (Biotin-Cap PE).
Biotin PE has been used for bilayer stabilization,13
temperature/pH sensitive liposomal drug delivery,14 tumor
imaging,15 two-dimensional crystallization on lipid bilayers,16,17,18
and immobilization of liposomes on gel beads for chromatographic
analysis of drug-membrane partitioning.19 Its use for
in vivo targeting applications utilizing liposomes containing
monosialoganglioside (GM1) or polyethylene glycol (PEG)
lipid derivatives has been demonstrated.20 However, it
was later shown that the Biotin-Cap PE derivative was superior in
these applications because the spacer arm extended the biotinyl
group out from the membrane surface.21 Steric hindrance
at the surface due to the inclusion of large bulky amphiphiles such
as GM1 or PEG-PE inhibits optimal vesicle binding to
streptavidin which could be alleviated by using Biotin-Cap PE.
References
Kung, V.T., and Redemann, C.T. (1986) Synthesis of carboxyacyl
derivatives of phosphatidylethanolamine and use as an efficient
method for conjugation of protein to liposomes. Biochim Biophys
Acta 862, 435-439.
Ng, K, Zhao, L, Meyer, J.D., Rittmann-Grauer, L., and Manning,
M.C. (1997) Use of circular dichroism spectroscopy in determining
the conformation of a monoclonal antibody prior to its incorporation
in an immunoliposome. J Pharm Biomed Anal 16, 507-513.
Heeremans, J.L., Kraaijenga, J.J., Los, P., Kluft, C., and Crommelin,
D.J. (1992) Development of a procedure for coupling the homing
device glu-plasminogen to liposomes. Biochim Biophys Acta
1117, 258-264.
Demos, S.M., Onyuksel, H, Gilbert, J., Roth, S.I., Kane, B.,
Jungblut, P., Pinto, J.V., McPherson, D.D., and Klegerman, M.E.
(1997) In vitro targeting of antibody-conjugated echogenic liposomes
for site-specific ultrasonic image enhancement. J Pharm Sci
86, 167-171.
Crosasso, P., Brusa, P., Dosio, F., Arpicco, S., Pacchioni,
D., Schuber, F., and Cattel, L. (1997) Antitumoral activity of
liposomes and immunoliposomes containing 5-fluorouridine prodrugs.
J. Pharm Sci 86, 832-839.
Kamps, J.A., Swart, P.J., Morselt, H.W., Pauwels, R., De Bethune,
M.P., De Clercq, E., Meijer, D.K., and Scherphof, G.L. (1996)
Preparation and characterization of conjugates of (modified) human
serum albumin and Liposomes: drug carriers with an intrinsic anti-HIV
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with neutral complexes of lipospermine and thiol-reactive phospholipids.
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Hashida, S., and Ishikowa, E. (1985) Use of normal IgG and its
fragments to lower the non-specific binding of Fab5-enzyme conjugates
in sandwich enzymes immunoassay. Anal. Lett. 18(b9), 1143-1155
Dewey, R. E., Timothy, D. H., and Levings III, C.S. (1987) A
mitochondrial protein associated with cytoplasmic male sterility
in the T cytoplasm of maize. Proc. Natl. Acad. Sci. U.S.A.
84, 5374-5378
Hermanson, G. T. (1996) Bioconjugate Techniques. Academic
Press, Inc.
Wright, S.E., and Huang, L. (1992) Bilayer stabilization of
phosphatidylethanolamine by N-biotinylphosphatidylethanolamine.
Biochim Biophys Acta 1103, 172-178.
Ferraretto, A., Sonnino, S., Soria, M.R., and Masserini, M.
(1996) Characterization of biotinylated liposomes sensitive to
temperature and pH: new tools for anti-cancer drug delivery. Chem
Phys Lipids 82, 133-139.
Ogihara-Umeda, I., Sasaki, T., Toyama, H., Oda, K., Senda, M.,
and Nishigori, H. (1994) Rapid tumor imaging by active background
reduction using biotin-bearing liposomes and avidin. Cancer
Res 54, 463-467.
Darst, S.A., Ahlers, M., Meller, P.H., Kubalek, E.W., Blankenburg,
R., Ribi, H.O., Ringsdorf, H., and Kornberg, R.D. (1991) Two-dimensional
crystals of streptavidin on biotinylated lipid layers and their
interactions with biotinylated macromolecules. Biophys J
59, 387-396.
Hemming, S.A., Bochkarev, A., Darst, S.A., Kornberg, R.D., Ala,
P., Yang, D.S., and Edwards, A.M. (1995) The mechanism of protein
crystal growth from lipid layers. J Mol Biol 246, 308-316.
Qin, H., Liu, Z., and Sui, S.F. (1995) Two-dimensional crystallization
of avidin on biotinylated lipid monolayers. Biophys J 68,
2493-2496.
Yang, Q., Liu, X.Y., Ajiki, S., Hara, M., Lundahl, P., and Miyake,
J. (1998) Avidin-biotin immobilization of unilamellar liposomes
in gel beads for chromatographic analysis of drug-membrane partitioning.
J Chromatogr B Biomed Sci Appl 707, 131-141.
Loughrey, H.C., Ferraretto, A., Cannon, A.M., Acerbis, G., Sudati,
F., Bottiroli, G., Masserini, M., and Soria, M.R. (1993) Characterization
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FEBS Lett 332, 183-188.
Corley, P., and Loughrey, H.C. (1994) Binding of biotinated-liposomes
to streptavidin is influenced by liposomes composition. Biochim
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Lesermam, L. & Machy, P., (1987), "Ligand Targeting
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Channel activity of a viral transmembrane peptide in micro-BLMs: Vpu(1-32) from HIV-1. J Am Chem Soc. 2004 Dec 15;126(49):16267-74.
PMID: 15584764 [PubMed - indexed for MEDLINE]
A. G. Bittermann, S. Jacobi, L. F. Chi, H. Fuchs, and R. Reichelt
Contrast Studies on Organic Monolayers of Different Molecular Packing in FESEM and Their Correlation with SFM Data
