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Figure 4 | BMC Immunology

Figure 4

From: A novel assay for monitoring internalization of nanocarrier coupled antibodies

Figure 4

A. Chemical structures of DOGS-NTA-Ni and DSPE-PEG-NTA-Ni. DOGS-NTANi is an acidic lipid derivative with the functional moiety located immediately at the membrane surface where it can potentially interact with amphipathic drugs, such as doxorubicin, that may be situated in or be transversing the membrane. DSPE-PEG-NTA-Ni, on the other hand, has the NTA-Ni separated from the membrane by a poly(ethylene glycol) (PEG) spacer where interactions with drugs will likely be minimized. Doxorubicin (DOX) is commonly carried in the liposomal lumen in a precipitated form. However, it must transverse the membrane in order to be actively loaded into the liposomes. Highly water soluble drugs, including methotrexate (MTX), are encapsulated passively and reside almost exclusively in the liposomal interior. B. Doxorubicin-dependent cytotoxicity of anti-ErbB2-scFv-F5-(His)6 coupled to different liposomes. In each of these graphs, free doxorubicin (▲) is compared to anti-ErbB2-scFv-F5-(His)6-NTA-liposomal-DOX () and non-targeted NTAliposomal DOX with or without PEG spacer (). Cytotoxicity was determined using a calcein AM-cell viability assay as described in the methods section.

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