Hierarchical assembly of gold nanorod stripe patterns for sensing and cells alignment

Hierarchical assemblies of nanomaterial superstructures with controlled orientation affords a multitude of novel properties of plasmonics and broad applications. Yet constructing multi-functional superstructures with nanoparticles positioned in desired locations remains challenging. Herein, gold nanorods (GNRs) assembled in stripe patterns with controlled orientation and structures in millimeter scale for versatile application have been achieved. Applications of patterned GNRs in sensing enhancement and engineering mammalian cells alignment are investigated experimentally. The performance of patterned GNRs in surface enhanced Raman scattering (SERS) and electrical sensing are found in orientational dependence. The SERS signals of vertically arranged GNR arrays exhibit double the folder intensity than those horizontally arranged. In contrast, the horizontally arranged GNRs exhibit twice as much electrical conductivity. The system is further explored to pattern mammalian cells. For the first time, we reveal the nanostructured topography of GNR confined cells to a specific region, and direct the adhesion and extension of living cells, which opens up broad applications in tissue engineering and biosensing.