Preparation and characterization of universal Fe3O4@SiO2/CdTe nanocomposites for rapid and facile detection and separation of membrane proteins

Besides having many important physiological functions, cell membrane proteins have been recognized as major markers for many diseases in clinical examination. The discovery of new cell membrane proteins has attracted significant research interest. Herein, a multifunctional Fe3O4@SiO2/CdTe nanocomposite was designed for the detection and separation of cell membrane proteins, which was synthesized by a covalent coupling reaction between amino groups and carboxyl groups. It can serve as a universal tool for modifying antigens or other molecules that have amino groups. To verify the feasibility and practicability of this method, a folic acid (FA)-functionalized magnetic/fluorescent nanoprobe (Fe3O4@SiO2/CdTe-NH-FA) has been developed for recognizing and separating the FA receptor on HepG2 cells. FA was fixed to the shell of Fe3O4@SiO2/CdTe nanocomposites via 1,6-hexamethylenediamine. It obviously reduces the fluorescence quenching effect of FA on magnetic/fluorescent nanocomposites. The results demonstrate that the synthesized nanoprobe Fe3O4@SiO2/CdTe-NH-FA provides excellent optical characteristics for the reliable imaging of cancer cells and has good magnetic properties to enrich and isolate cell membrane proteins. Consequently, this biological nanoprobe can be used to find, obtain, and study unknown membrane proteins and predict the occurrence of some diseases. In addition, this nanoprobe will be a potential platform for accurate cancer diagnosis and therapy in the future.