Self-assembly method for the preparation of near-infrared fluorescent spider silk coatedwith CdTe nanocrystals

Abstract

Spider silks have great potential in many fields due to their high strength and superbtoughness. In this work, fluorescent spider silks were fabricated by consecutivelyassembling CdTe nanocrystals and polyelectrolyte (PE) macromolecules ontospider dragline silks. Scanning electron microscopy and fluorescence microscopyimages showed that a large number of CdTe nanocrystals and PE molecules weresuccessfully deposited on the surface of the spider silks, and the silk compositesobtained exhibited core–shell structure characteristics. The energy dispersionx-ray spectrum (EDS) showed that the silk composites contained about 2.68%(w/w) of CdTe nanocrystals when the spider silks were coated with just one layer ofPE/CdTe/PE. The resulting fluorescent spider silks exhibited very bright fluorescence, andtheir emission spectrum was located in the near-infrared (NIR) band. The mechanicalproperties of these modified spider silks, such as the maximum pull force and theelastic limit elongation when a single spider silk strand breaks, showed a slightdecrease after coating with CdTe nanocrystals and PE. This fluorescent spider silk isenvisioned to have applications in materials science, microelectronics, and even biology.