10.1021/nn4018922.s001 Luisa Fiandra Luisa Fiandra Serena Mazzucchelli Serena Mazzucchelli Clara De Palma Clara De Palma Miriam Colombo Miriam Colombo Raffaele Allevi Raffaele Allevi Silvia Sommaruga Silvia Sommaruga Emilio Clementi Emilio Clementi Michela Bellini Michela Bellini Davide Prosperi Davide Prosperi Fabio Corsi Fabio Corsi Assessing the <i>In Vivo</i> Targeting Efficiency of Multifunctional Nanoconstructs Bearing Antibody-Derived Ligands American Chemical Society 2013 surface bioligand intracellular fate scFv fragments HC MNP HER 2 receptor efficiency model antibody breast cancer cells breast cancer detection MCF 7 cells target cells amphiphilic polymer shell nanoparticle core Vivo Targeting Efficiency breast cancer humanized monocolonal antibody trastuzumab nanoconstruct multifunctional nanoparticles antibody form vivo localization physicochemical properties multifunctional nanoprobes surface functionalization TZ vivo analyses iron oxide nanoparticle accumulation weight variants 2013-07-23 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Assessing_the_i_In_Vivo_i_Targeting_Efficiency_of_Multifunctional_Nanoconstructs_Bearing_Antibody_Derived_Ligands/2393950 A great challenge in nanodiagnostics is the identification of new strategies aimed to optimize the detection of primary breast cancer and metastases by the employment of target-specific nanodevices. At present, controversial proof has been provided on the actual importance of surface functionalization of nanoparticles to improve their <i>in vivo</i> localization at the tumor. In the present paper, we have designed and developed a set of multifunctional nanoprobes, modified with three different variants of a model antibody, that is, the humanized monocolonal antibody trastuzumab (TZ), able to selectively target the HER2 receptor in breast cancer cells. Assuming that nanoparticle accumulation in target cells is strictly related to their physicochemical properties, we performed a comparative study of internalization, trafficking, and metabolism in MCF7 cells of multifunctional nanoparticles (MNP) functionalized with TZ or with alternative lower molecular weight variants of the monoclonal antibody, such as the half-chain (HC) and scFv fragments (scFv). Hence, to estimate to what extent the structure of the surface bioligand affects the targeting efficiency of the nanoconjugate, three cognate nanoconstructs were designed, in which only the antibody form was differentiated while the nanoparticle core was maintained unvaried, consisting of an iron oxide spherical nanocrystal coated with an amphiphilic polymer shell. <i>In vitro</i>, <i>in vivo</i>, and <i>ex vivo</i> analyses of the targeting efficiency and of the intracellular fate of MNP-TZ, MNP-HC, and MNP-scFv suggested that the highly stable MNP-HC is the best candidate for application in breast cancer detection. Our results provided evidence that, in this case, active targeting plays an important role in determining the biological activity of the nanoconstruct.