Study on Biocompatibility of AuNPs and Theoretical Design of a Multi-CDR-Functional Nanobody

The investigation on proteinlike specific functions of nanoparticles (NPs) has been a huge challenge. Here, the biocompatibility of Au nanoparticles (AuNPs) to antigens hen egg white lysozyme and epidermal growth factor receptor was studied first by molecular dynamics (MD) simulations and the research results revealed that antigens could form quickly a stable binding with the AuNPs and kept the structural integrity of the protein, which demonstrated better biocompatibility of AuNPs. Then, two types of complementary-determining regions (CDRs) were grafted onto the AuNPs to design a novel multi-CDR-functional nanobody. By means of MD simulations under physiological conditions, we found that the bindings of the designed nanobody and the antigens were stable and safe. Compared with the results of antigens interacting with the natural antibody, the redundant CDRs on AuNPs bound with the nonactive site in the antigens to form a stable conformation, which leaded to the powerful binding capacity of the designed nanobody than that of the natural antibody. This study provided available insights into the biocompatibility of AuNPs and important theoretical proofs to the multi-CDR-functional nanobody applied in biological systems, which were expected to help in design of novel multifunctional nanobodies.