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. Author manuscript; available in PMC: 2009 Dec 1.
Published in final edited form as: Bioconjug Chem. 2008 Dec;19(12):2577–2584. doi: 10.1021/bc8002937

Figure 4.

Figure 4

In vitro assay of 64Cu-labeled liposomes: a) Elution profiles of liposomes with 0.5 mol% BAT-PEG-lipid (HSPC:cholesterol:DSPE-PEG2000:BAT-PEG-lipid = 55.5:39:5.0:0.5, mol/mol/mol/mol, red diamond) and 0 mol% BAT-PEG-lipid (HSPC:cholesterol:DSPE-PEG2000 = 56:39:5.0:0.5, mol/mol/mol, blue square) after incubation with 64CuCl2 for 40 min and EDTA for 15 min at 35 °C in 0.1 M ammonium acetate buffer (pH 5.0). Liposomes were separated by a size exclusion column. With 0.5 mol% BAT-PEG-lipid, 64Cu was associated with liposomes; without BAT-PEG-lipid 64Cu was not detected in the liposomal fraction. b) Radio TLC on silica plate was developed with eluant (chloroform:methanol:H2O = 50:40:6, vol/vol/vol). Retention factor (Rf) of 64Cu-BAT-PEG-lipid was 0.8 and that of 64CuCl2 was 0. Lanes 1-6 were measured at 20 and 48 hours as indicated in figure 3b. c) Chromatogram of the mixture of 64Cu-liposomes and albumin (8 mg/mL) in PBS after 48 h incubation at 37 °C. The mixture was separated by a size exclusion column Elution of liposomes and serum proteins was measured by gamma-counter (diamonds) and UV absorbance at 280 nm (squares). d) Chromatogram of the mixture of 64Cu-liposomes and serum in PBS (PBS:serum = 1:1, vol/vol) after 48 h incubation at 37 °C. e) Radio TLC of fraction 18 performed as in b). The peak (Rf 0.8) represents 64Cu-BAT-PEG-lipid. Small peak near 0 indicates free 64Cu and middle peak has not been characterized.