SPR precision, moved from the optics to the signal.
Inside every P4SPR 2.0 and P4PRO is a Kretschmann SPR instrument with the complex optics taken out.
Patented · Kretschmann · wavelength interrogation
HOW IT WORKS
How SPR measures binding
Binding on the gold moves a dip in the light. Following that dip over time gives the sensorgram.
THE DESIGN
Three design decisions
Keep the Kretschmann configuration
The same physics as conventional SPR, on purpose. Sensor surfaces, chemistries and published methods all carry over.
Streamline the optics
Every component the measurement didn't need is gone. The rest is fixed, machined geometry.
Offset with data and assay design
Peak tracking and reference channels, tuned for the larger shifts that larger targets give in complex samples.
Technical note: thin-film SPR and nanoparticle LSPR
Both use plasmons on gold. The difference is where the light travels and how far the sensing field reaches into the sample.
| Thin-film SPR (Lensless SPR) | Nanoparticle LSPR | |
|---|---|---|
| Light path | Reflects under the gold and never crosses the sample, so complex or opaque samples work. | Passes through the sample, so samples need to be clear. |
| Sensing depth | 200–300 nm: room for larger targets and sandwich assays. | 20–30 nm: very surface-sensitive, with fewer assay formats. |
| Sensitivity | About 1800 nm/RIU near water, rising at longer wavelength | A few hundred nm/RIU |
| Kinetics | Planar diffusion, consistent with most published SPR kinetics. | Radial diffusion, with fewer reference publications. |
Full comparison in TN-02: thin-film SPR and nanoparticle LSPR →
What replaced each part of a conventional bench
| Conventional SPR | Lensless SPR |
|---|---|
| Collimating and focusing lenses | Aperture tunnels machined into the light path shape the LED light |
| Rotating stage and angle scanning | Wavelength interrogation at a fixed angle: a broadband LED and a spectrometer read the resonance by colour |
| Hemispherical prism, source and detector on angled arms | Dove prism: light leaves on the same axis it enters, so the whole path is one straight line |
| Polarizer | Polarizer, kept |
| A full optical train for each channel | One LED and one sensing area per channel, with fibres feeding one shared spectrometer |
WHAT IT MEANS FOR YOU
The instrument is no longer the hard part.
When the light path is a machined part, an SPR instrument can be small, simple, and identical from one channel to the next.
SMALL
The lensless optical module fits within the footprint of an earbud case. Add the detector and the whole measurement is about the size of a pipette-tip box.
PORTABLE
A full instrument can travel in a carry-on and run on arrival.
YOUR BIOLOGY
The hard part moves to what you capture on the gold and how you design the assay.
INSIDE EVERY INSTRUMENT
One lensless core, three configurations.
The same four-channel optical block sits inside the P4SPR 2.0 and the P4PRO.
Core
P4SPR 2.0
+ Kinetics
P4PRO with AffiPump
+ Screening · New
Screening platform
PROOF
80+ peer-reviewed publications using Affinité SPR
Protein A binding human IgG, from the raw data
P4PRO, protein A surface, human IgG at 0.41, 11.1, 33 and 100 nM. Coloured lines are measured data; thin lines are a global 1:1 fit.
“High quality data, right out of the box. The best small SPR platform we’ve used.”University of Lille
Beyond SPR
SPR alongside other methods
SPR rarely works alone. Our team and our users combine it with other analytical methods, on the same sensor or in the same workflow.
Electrochemistry
SPR and electrochemistry on one gold surface
Our eSPR work reads both signals from the same sensor; the two methods gave comparable performance for DNA hybridization.
The eSPR note →Fluorescence
SPR and fluorescence on one chip
A single chip combining SPR with a fluorescent ELISA, shown for prostate-specific antigen.
The 2015 paper ↗Microfluidics
Sample preparation upstream
A microfluidic plasma-separation device feeds the P4SPR to measure biomarkers straight from whole blood.
The whole-blood note →Automation
Autosamplers and liquid handling
On the Screening platform an autosampler injects samples from well plates, run after run.
The Screening platform →Reference methods
Checked against HPLC and ELISA
Our application notes compare SPR results with established methods, such as the HPLC reference method for explosives in water.
The RDX note →Plasmonics
LSPR and SERS
Nanoparticle sensors read by LSPR and SERS, from the research publications of our team and users.
LSPR and SERS paper ↗Combining SPR with your method? Tell us about it →