Antibodies, disruptive potent therapeutic agents against
pharmacological
targets, face a barrier in crossing immune systems and cellular membranes.
To overcome these, various strategies have been explored including
shuttling via liposomes or biocamouflaged nanoparticles. Here, we
demonstrate the feasibility of loading antibodies into exosome-mimetic
nanovesicles derived from human red-blood-cell membranes, which can
act as nanocarriers for intracellular delivery. Goat-antichicken antibodies
are loaded into erythrocyte-derived nanovesicles, and their loading
yields are characterized and compared with smaller dUTP-cargo molecules.
Applying dual-color coincident fluorescence burst analyses, the loading
yield of nanocarriers is rigorously profiled at the single-vesicle
level, overcoming challenges due to size-heterogeneity and demonstrating
a maximum antibody-loading yield of 38–41% at the optimal vesicle
radius of 52 nm. The achieved average loading yields, amounting to
14% across the entire nanovesicle population, with more than two antibodies
per loaded vesicle, are fully comparable to those obtained for the
much smaller dUTP molecules loaded in the nanovesicles after additional
exosome-spin-column purification. The results suggest a promising
new avenue for therapeutic delivery of antibodies, potentially encompassing
also intracellular targets and suitable for large-scale pharmacological
applications, which relies on the exosome-mimetic properties, biocompatibility,
and low-immunogenicity of bioengineered nanocarriers synthesized from
human erythrocyte membranes.