Stability optimization of microbial surface-enhanced Raman spectroscopy detection with immunomagnetic separation beads

Sanna Uusitalo, Martin Kögler, Anna-Liisa Välimaa, Jarno Petäjä, Ville Kontturi, Samuli Siitonen, Riitta Laitinen, Matti Kinnunen, Tapani Viitala, Jussi Hiltunen

Research output: Contribution to journalArticleScientificpeer-review

5 Citations (Scopus)

Abstract

Immunomagnetic separation (IMS) beads with antibody coating are an interesting option for biosensing applications for the identification of biomolecules and biological cells, such as bacteria. The paramagnetic properties of the beads can be utilized with optical sensing by migrating and accumulating the beads and the bound analytes toward the focus depth of the detection system by an external magnetic field. The stability of microbial detection with IMS beads was studied by combining a flexible, inexpensive, and mass producible surface- enhanced Raman spectroscopy (SERS) platform with gold nanoparticle detection and antibody recognition by the IMS beads. Listeria innocua ATCC 33090 was used as a model sample and the effect of the IMS beads on the detected Raman signal was studied. The IMS beads were deposited into a hydrophobic sample well and accumulated toward the detection plane by a neodymium magnet. For the first time, it was shown that the spatial stability of the detection could be improved up to 35% by using IMS bead capture and sample well placing. The effect of a neodymium magnet under the SERS chip improved the temporal detection and significantly reduced the necessary time for sample stabilization for advanced laboratory testing.
Original languageEnglish
Article number037102
Number of pages8
JournalOptical Engineering
Volume56
Issue number3
DOIs
Publication statusPublished - 1 Mar 2017
MoE publication typeA1 Journal article-refereed

Keywords

  • biological cells
  • immunomagnetic separation beads
  • optical detection
  • surface-enhanced Raman spectroscopy

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