Mirrored stainless steel substrate provides improved signal for Raman spectroscopy of tissue and cells.
Raman spectroscopy (RS) is a powerful technique that permits the non-destructive chemical analysis of cells and tissues without the need for expensive and complex sample preparation. To date, samples have been routinely mounted onto calcium fluoride (CaF2) as this material possesses the desired mechanical and optical properties for analysis, but CaF2is both expensive and brittle and this prevents the technique from being routinely adopted. Furthermore, Raman scattering is a weak phenomenon and CaF2provides no means of increasing signal. For RS to be widely adopted, particularly in the clinical field, it is crucial that spectroscopists identify an alternative, low-cost substrate capable of providing high spectral signal to noise ratios with good spatial resolution. Results show that these desired properties are attainable when using mirrored stainless steel as a Raman substrate. When compared with CaF2, data show that stainless steel has a low background signal and provides an average signal increase of 1.43 times during tissue analysis and 1.64 times when analyzing cells. This result is attributed to a double-pass of the laser beam through the sample where the photons from the source laser and the forward scattered Raman signal are backreflected and retroreflected from the mirrored steel surface and focused towards collection optics. The spatial resolution on stainless steel is at least comparable to that on CaF2and it is not compromised by the reflection of the laser. Steel is a fraction of the cost of CaF2and the reflection and focusing of photons improve signal to noise ratios permitting more rapid mapping. The low cost of steel coupled with its Raman signal increasing properties and robust durability indicates that steel is an ideal substrate for biological and clinical RS as it possesses key advantages over routinely used CaF2. © 2016 The Authors.Journal of Raman SpectroscopyPublished by John Wiley & Sons Ltd.
Department of Cell and Developmental Biology University College London London UK.
Aaran T
AT
Lewis
Department of Cell and Developmental Biology University College London London UK.
Riana
R
Gaifulina
Biophotonics Research Unit Gloucester Royal Hospitals NHS Foundation Trust Gloucestershire UK.
Martin
M
Isabelle
School of Physics and Astronomy, College of Engineering, Mathematics and Physical Sciences University of Exeter Exeter UK.
Jennifer
J
Dorney
Department of Cell and Developmental Biology University College London London UK.
Mae L
ML
Woods
Biophotonics Research Unit Gloucester Royal Hospitals NHS Foundation Trust Gloucestershire UK.
Gavin R
GR
Lloyd
Renishaw PLC New Mills Gloucestershire UK.
Katherine
K
Lau
Department of Cell and Developmental Biology University College London London UK.
Manuel
M
Rodriguez-Justo
Biophotonics Research Unit Gloucester Royal Hospitals NHS Foundation Trust Gloucestershire UK.
Catherine
C
Kendall
School of Physics and Astronomy, College of Engineering, Mathematics and Physical Sciences University of Exeter Exeter UK.
Nicholas
N
Stone
Department of Cell and Developmental Biology University College London London UK.
Geraint M
GM
Thomas
Raman spectroscopy; signal improvement; tissue