Introduction to SERS applications Sense ‘13, VTT, Espoo

© Renishaw Diagnostics LtdSlide 1

Introduction to SERS applicationsSense ‘13, VTT, Espoo

Dr. David EustaceCommercial Business Manager

Renishaw Diagnostics LtdNova Technology ParkGlasgowUK

www.RenishawDiagnostics.com

EU FP-7 PHOTOSENS Project

Slide 2 © 2011 Renishaw Diagnostics Ltd.Confidential

• 3 year project looking at SERS and photonic crystal sensing

• Project closing 31st January 2014

• Novel high volume manufacturing methods for SERS andPC sensors based on roll-to-roll nanoimprinting on advancedplastics

Industrial User Group Meeting31st October, Espoo, 2pm

All welcome (NDA permitting)

© Renishaw Diagnostics Ltd.

Contents

• Intro to Renishaw Diagnostics

• Surface enhanced Raman scattering (SERS)

• Klarite SERS substrates, applications

• RenDx™ DNA detection using SERRS

• RenDx RUO Product

Introduction to Renishaw Diagnostics Ltd

• Formed in July 2007 as D3 Technologies Ltd

• Spin out from University of Strathclyde, with seed funding fromScottish Enterprise

• Acquired analytical business unit of Mesophotonics (July 07)

• Expanded facility in June 2010 to ~6000 sq.ft

• 25 full time multidisciplinary staff, expanding

• Renishaw plc – majority shareholder

• Molecular diagnostics focus with research in adjacent sectors

©Renishaw Diagnostics Ltd

Core Competence & IP

• World-leading centre for the exploitation of SurfaceEnhanced Resonance Raman Spectroscopy (SERRS)for clinical research and molecular diagnosticsapplications

• Unique combination of IP and expertise

• Proprietary Raman substrates

• Advanced biology, chemistry and biochemistry

• Fully regulatory compliant organisation; ISO13485accredited.


What is SERS? (simple version!)

• SERS is a laser based optical spectroscopy which creates enhancedscattering from a molecule absorbed onto a ‘roughened’ metal surface

Laser induces vibration andcauses light to scatter

Molecule on active surface givesmuch stronger scattering

Each vibration generates aunique peak in the spectra.

Corrugatedmetal surface

Laser1

2 34

SERS signal5



What is SERS?

• Corrugated metal surfaces dramatically increase efficiency of light coupling into andout of molecules (>106)

• Enhancement of Raman scattering due a combination of:– Electromagnetic effect (largest contribution)

• Molecule vibrations are much stronger in strong plasmon electromagnetic fields• Enhancement factor >104

• Well proven

– Chemical effect (minor contribution)• Molecule-metal bond (adsorption) favour direct transfer of energy into the molecule• Enhancement factor ~102

• Still unclear and debated

inin

First experimental observation: pyridine on roughened Ag electrodes Chem. Phys. Lett. 26 163 (1974)


Correct inter-particle distance“Hot spot” SERS!

NO “hot spot”: NO SERS!

• Great for studying fundamental science– “Single” molecule detection– Molecule interactions– Binding dynamics– Tuning system to experiments

A TEM and electron energy loss spectroscopy (EELS) investigationof active and inactive silver particles for surface enhancedresonance Raman spectroscopy (SERRS)

Imran Khan, Dale Cunningham, Sorin Lazar, Duncan Graham, W.Ewen Smith and David W. McComb

Faraday discussions 132, 171 (2006)

Colloidal SERS


‘Solid State’ SERS

• Details of nano-void morphology

– A micron scale pyramid etch of asilicon wafer coated with a conformalgold layer

• Plasmon electric field distribution atsurface

– Depends on geometrical factors (holesize, pitch, shape) and excitationwavelength

• SERS intensity is also dependent onmolecule affinity and proximity to metal


Nano voids = Plasmon cavities = Periodic nanostructures = Klarite

Aperture

Pitch

Depth

54.7°

“Enhancement Factor” – Ambiguous term (what is the zero value?)

Better descriptions of performance: Limit of detectionNormalised peak intensity using a standard molecule

So SERS performance is measurable and comparable and can be dependent upon:

• Pit geometry • Surface roughness • Molecular affinity for surface

• Instrumental effects

Klarite surface


Typical Renishaw Diagnostics manufacturing run: 3 x 6-inch wafers200-400 chips per waferUp to 1200 chips in a single batch

Arraystructured

surface

1 m

Etched features

SERSactive area

2µm

Electric fieldlocalization

FlatAu

Klarite substrate

Key Advantages

• Increased multiplex capability - the unique molecular fingerprintgenerated by SERRS means true multiple analyte detection can becarried out in a single experiment

• High sensitivity & specificity - SERRS has been shown to be 3 ordersof magnitude more sensitive than fluorescence

• Ease of adaptation to existing routine experiments in terms ofspectral interpretation and reagents


Multiple Analyte Detection


Dylight649

50:50 mix

Dylight680


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Run 1 average peak height



Accurate quantification with RSD <15% opens up a range of new applications.

IMPORTANT: Multivariate analysis using chemometrics is much more accurate than this univariatemethod.

Quantification possibilities


SERS Applications

Recent years have seen Raman Spectroscopy gain widespread acceptance as a fast and robustmaterials identification tool.

This has been prompted by low cost, portable instrumentation and advances in software datahandling.

As a technique, Raman spectroscopy is moving out of the lab and into the field/productionsite.

Delta Nu ReporteRB&W Tek MiniRam II Ahura Truscan

Examples:


1500 1000 500

L-Alanine

L-Phenylalanine

Wavenumber (cm-1)

160 012 0080 04 00R am a n sh if t (cm -1)

Cytochrome C

Lysozyme

Bacillus spore

Increasingcomplexity

What can you detect?


• Industry requirement for reduced plant turnaround time throughimproved CV time.

• HPLC CV protocols can involve long sample measurement times (up to ~30mins).

• When a large number of measurements are required, long measurementtimes can lead to extended delays.

• SERS based protocols have the potential to rapidly decrease measurementtimes, while providing additional molecule specific information.

• Klarite® SERS substrates can be used to deliver a robust and reproduciblequantification protocol.

Application example: Cleaning verification


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• Typical datasets show steady decreasein peak intensity with concentration.

• Data shown here has been backgroundsubtracted but is otherwise unprocessed.

• Analysis can optimise data format foruse in standard protocols (chemometricsprocessing).

• Analysis methods include 1st/2nd

order derivation, peak height/areanormalisation, mean centring.

Run 1

Run 2 SE1000 data

SE1000 data

Cleaning verification: sample datasets


PHOTOSENS project

• Cheaper mass-produced substrates using plastic based roll-to-roll manufacturing

• Enhanced chemical sensing using MIP and surface chemistry

• Use both of the above to overcome key hurdles to marketentry within pharmaceutical environment: cost, reproducibility,sensitivity, experiment set-up


Summary

• Renishaw Diagnostics are commercialising state-of-the-artSERS applications

• These offer high sensitivity and specificity whilesignificantly reducing measurement times

• Multiplex detection offers real advantages in diagnostics

• Portability of instrumentation is key to wide range ofapplication environments

EU FP-7 PHOTOSENS Project

Slide 21 © 2011 Renishaw Diagnostics Ltd.Confidential

• 3 year project looking at SERS and photonic crystal sensing

• Project closing 31st January 2014

• Novel high volume manufacturing methods for SERS andPC sensors based on roll-to-roll nanoimprinting on advancedplastics

Industrial User Group Meeting31st October, Espoo, 2pm

All welcome (NDA permitting)

Introduction to SERS applications Sense ‘13, VTT, Espoo

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