Bioimaging based on antibody-conjugated amphiphilic polymer-core@shell quantum dots

Abstract

Quantum dots (QDs) are one of the most important achievements in the fast-growing nanotechnology field. Their unique optical properties make them superior to conventional fluorophores and essential in many applications. They have been successfully applied in various fields such as optics, electronics and biology. The ability to make QDs water soluble and use them to label specific biomolecules has led to promising applications such as high-resolution cellular imaging. Here, the authors present procedures for the synthesis and coating of cadmium selenide (CdSe) nanoparticles and their surface modification with an amphiphilic polymer for biological conjugation. The effectiveness of biological functionalization was assessed through cadmium selenide conjugation to an amine-reactive anti-human CD4 monoclonal antibody. The results showed that the fabricated QD cores had a size distribution of about 2·5–3 nm with the first exciton absorption peak and maximum emission wavelengths of 518 and 525 nm, respectively. Coating with zinc sulfide (ZnS) markedly increased the emission intensity of QDs. Fourier transform infrared analysis confirmed surface modification of core@shell QDs with the polymer. Intense specific fluorescent signals were observed when the QD-conjugated antibody was electrophoresed. Taken together, the procedure introduced here could be viewed as a platform for functional and efficient synthesis of QD nanoparticles.