(766b) Coaxial Nanofibers with Aligned Gold Nanorods near the Fiber Surface for Surface Enhanced Raman Spectroscopy

Molecular sensors were made using Au or Ag and polymer composite fibers fabricated by electrospinning. Firstly, Surface-enhanced Raman Scattering (SERS) template was synthesized using electrospun Au nanorod/Poly vinly alcohol (PVA) nanofibers. The electromagnetic resonance from mutual orientation of Au nanorods in PVA fiber exhibited great enhancement of 3,3′-diethylthiatricarbocyanine iodide (DTTCI) signals under Raman scope. We then directed the placement of nanorods along the surface by coaxially electrospinning Au nanorod/PVA and pure PVA as shell and core, respectively, which showed even greater DTTCI signals than the monoaxially electrospun Au nanorod/PVA fiber with the same Au nanorod concentration. This finding suggests that the loading of costly Au nanorods can be reduced  up to three fold with the same sensitivity, resulting in more cost-effective free-standing SERS template. In addition, we have used coarse-grained molecular dynamics simulations to demonstrate that the extensive elongation from electrospinning attributes to the dispersion and alignment of nanorods in the cylindrical polymer matrix, and the selective placement of nanorods along the shell in coaxial electrospinning. Secondly, we will demonstrate that metal nanofibers from water-based electrospinning of highly loaded metal precursors can be served as a highly efficient SERS template.  Fabrication of such cost-effective and highly productive ultrasensitive SERS template shows great potentials in advanced biomedical imaging or single-molecule detection device.

Coaxial Nanofibers with Aligned Gold Nanorods near the Fiber Surface for Surface Enhanced Raman Spectroscopy