2, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei, Anhui, China
3, Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas, United States
It is highly desirable, while extremely difficult to actively control the release dynamics of molecules from nanoparticle-carriers and to monitor the release process in real time. In this work, we report the design, fabrication, and manipulation of a superstructural Raman nanosensor, offering integrated dual functions in ultra-sensitive biodetection and dynamic control in molecule release. The device has a designed porous superstructure, consisting of gold (Au) nanorod cores and silica shells embedded with arrays of nanocavities arranged in concentric layers in three-dimensions (3D), where high-density plasmonic silver (Ag) nanoparticles are grown both in the nanocavities and on the outer surfaces. The Ag nanoparticles provide substantially enhanced Raman sensitivity for detection of molecules, owing to the large number of hotspots, as well as the near-field coupling of Ag nanoparticles due to their 3D concentric arrangement. Furthermore, by controlling the external electric field, the release of molecules can be facilely controlled at tunable rates owing to the induced electrokinetics at the junctions of Ag nanoparticles. Finally, the biosensing-release-unibody devices can be readily motorized, including transport and rotation, which opens new opportunities for single-cell bioresearch and precision medicine.