PMID- 7918551
OWN - NLM
STAT- MEDLINE
DCOM- 19941121
LR  - 20190610
IS  - 0006-3002 (Print)
IS  - 0006-3002 (Linking)
VI  - 1195
IP  - 1
DP  - 1994 Oct 12
TI  - Poly(ethylene glycol) on the liposome surface: on the mechanism of polymer-coated 
      liposome longevity.
PG  - 11-20
AB  - The hypothetical model is built explaining the molecular mechanism of protective 
      action of poly(ethylene glycol) on liposomes in vivo. The protective layer of the 
      polymer on the liposome surface is considered as a statistical 'cloud' of polymer 
      possible conformations in solution. Computer simulation was used to demonstrate 
      that relatively a small number of liposome-grafted molecules of hydrophilic and 
      flexible polymer can create a dense protective conformational cloud over the 
      liposome surface preventing opsonizing protein molecules from contacting 
      liposome. A more rigid polymer fails to form this dense protective cloud, even 
      when hydrophilic. Computer simulation was also used to reveal possible 
      heterogeneity of reactive sites on a polymer-coated liposome surface, and to 
      estimate the optimal polymer-to-lipid ratio for efficient liposome protection. 
      Experiments have been performed with the quenching of liposome-associated 
      fluorescent label (nitrobenzoxadiazole or fluorescein) with protein 
      (rhodamine-ovalbumin or anti-fluorescein antibody) from solution. It was shown 
      that poly(ethylene glycol) grafting to liposomes hinders protein interaction with 
      the liposome surface, whereas liposome-grafted dextran (more rigid polymer) in 
      similar quantities does not affect protein-liposome interaction. Highly-reactive 
      and low-reactive populations of chemically identical reactive sites have been 
      found on polymer-coated liposomes. Experimental data satisfactory confirm the 
      suggested mechanism for the longevity of polymer-modified liposome.
FAU - Torchilin, V P
AU  - Torchilin VP
AD  - Center for Imaging and Pharmaceutical Research, Massachusetts General 
      Hospital-East, Charlestown 02129.
FAU - Omelyanenko, V G
AU  - Omelyanenko VG
FAU - Papisov, M I
AU  - Papisov MI
FAU - Bogdanov, A A Jr
AU  - Bogdanov AA Jr
FAU - Trubetskoy, V S
AU  - Trubetskoy VS
FAU - Herron, J N
AU  - Herron JN
FAU - Gentry, C A
AU  - Gentry CA
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - Netherlands
TA  - Biochim Biophys Acta
JT  - Biochimica et biophysica acta
JID - 0217513
RN  - 0 (Fluorescent Dyes)
RN  - 0 (Liposomes)
RN  - 0 (Polymers)
RN  - 3WJQ0SDW1A (Polyethylene Glycols)
SB  - IM
MH  - Binding Sites
MH  - Computer Simulation
MH  - Drug Stability
MH  - Fluorescent Dyes
MH  - Liposomes/*chemistry
MH  - Molecular Conformation
MH  - Polyethylene Glycols/*analysis
MH  - Polymers/*chemistry
MH  - Surface Properties
EDAT- 1994/10/12 00:00
MHDA- 2001/03/28 10:01
CRDT- 1994/10/12 00:00
PHST- 1994/10/12 00:00 [pubmed]
PHST- 2001/03/28 10:01 [medline]
PHST- 1994/10/12 00:00 [entrez]
AID - 0005-2736(94)90003-5 [pii]
AID - 10.1016/0005-2736(94)90003-5 [doi]
PST - ppublish
SO  - Biochim Biophys Acta. 1994 Oct 12;1195(1):11-20. doi: 
      10.1016/0005-2736(94)90003-5.