Evaluation of the interaction between poly(methylidene malonate 2.1.2) nanoparticles and an anti-CD4 by surface plasmon resonance (SPR)

Surface plasmon resonance (SPR) measurements with BIAcore(TM) (Pharmacia Biosensor AB, Uppsala, Sweden) provides a label-free and real-time optical detection which was successfully used to assess interactions occurring between poly(methylidene malonate 2.1.2) (PMM 2.1.2) nanoparticles and proteins. Experiments using this methodology demonstrated that these colloidal polymeric carriers strongly adhered on immobilized proteins in an irreversible fashion, Present studies were especially focused on the co-adsorption of an anti-CD4 monoclonal antibody (IgG) and bovine serum albumin (BSA) onto PMM 2.1.2 nanoparticle surface. An adapted ELISA, a colorimetric protein assay as well as spectrofluorimetry allowed direct and/or indirect determination of nanoparticle-associated IgG and/or BSA. Confirming the SPR analysis, native and FITC-bearing anti-CD4 antibodies were shown to promptly interact with nanoparticle surface. In the current experimental conditions, about 1 mu g IgG was found associated per mg of polymer. Taken together, our results demonstrate that IgG binding on PMM 2.1.2 nanoparticles is very stable. Thus, poly(methylidene malonate 2.1.2) nanoparticles appear useful for the design of new antibody-mediated drug targeting devices.