Tunable Plasmonic Hot-Spot Generation for Surface-Enhanced Raman Spectroscopy through Cilia Inspired Magnetic Actuators

Liman G., Yıldız E., Ergene E., Demirel G.

16th NANOSCIENCE & NANOTECHNOLOGY CONFERENCE, Ankara, Türkiye, 5 - 08 Eylül 2022, cilt.1, sa.1, ss.350

  • Yayın Türü: Bildiri / Özet Bildiri
  • Cilt numarası: 1
  • Basıldığı Şehir: Ankara
  • Basıldığı Ülke: Türkiye
  • Sayfa Sayıları: ss.350
  • Gazi Üniversitesi Adresli: Evet

Özet

Surface-enhanced Raman spectroscopy (SERS) is a powerful analytical technique providing sensitive, selective, and nondestructive bio-/chemical information. Raman signal enhancement in SERS is mainly originated from two theories; Electromagnetic and Chemical enhancements. Chemical enhancement (CE), which mainly relies on the charge-transfer processes between the chemisorbed analyte molecules and the SERS-active material, can provide unique enhancement and possibilities to design new SERS platforms. However, electromagnetic enhancement (EM), which is based on electric field magnification through excitation of localized surface plasmon resonances of the underlying SERS-active material, is still the dominant effect in SERS application. In EM, the electromagnetic field is enhanced at highly intense local electric field regions called as “hot-spots”. The generation of hot-spots in a SERS platform depends on the interparticle distance between plasmonic particles. Controlling the hot-spot formation is a hot topic not only in SERS field but in photonic, and diagnostic areas. Herein, we propose a simple yet versatile approach to manipulate hot-spot formation through soft actuators. Soft actuators with conical and cylindrical shapes are fabricated using a silicon rubber and magnetic micro particles in designed molds, which are created by a 3D printer. The fabricated platforms were then decorated with gold nanoparticles. Hot-spot generation performances of the platforms were evaluated by SERS using different Raman reporter molecules. Impressively, conical platforms demonstrate about 120 folds larger Raman signal enhancement in the presence of magnetic field compared to unactuated form. We also observed that hot-spot generation can be manipulated by controlling magnetic field force. Finally, inspired by a Turkish centipede, a proof-of-concept demonstration is performed to collect and analyze analyte molecules in a target point.