Interference Pattern/Ripple Effect in SPRi Difference Image - Troubleshooting

Hello Arnoud,

I am wondering if you have any insight or suggestions for resolving a pernicious issue I have been experiencing in SPR imaging experiments. I am using the OpenPleX SPRi instrument from Horiba and utilizing gold coated slides immobilized to glass prisms using refractive index matching oil recommended and sold by Horiba.  

After sensor installation and region of interest definition, I observe to varying degrees of severity on different slides an interference pattern or "ripple" effect in the difference image that can increase in severity over time and which produces real signal in the live sensorgram recording (see attached images for more detail and example images). This creates an oscillation in the traces overtime that are distinct from other effects like drift.  The ripples do not appear to be a function of buffer flow and are not observed if a gold coated prism is used where oil is not necessary.

Have you every observed an effect like this? Where could they be coming from? Do you have any suggestions for what I could try to eliminate these ripples?  Have you observed anything like this before? Are there alternative refractive index matching reagents we could possible use if oil is the culprit?

Many thanks for your time and this wonderful online resource.

Kind Regards,
W

Hi,
and thanks for your kind words.
Unfortunately I am not familliar with the system you describe and the method of inserting the sensor chip into a spr instrument.
Pressure rings in the glass I have seen in the micorscope when the pressure is uneven but if this is possible in your instrument i don't know. I would check the oil if there is no moist in there. maybe a new bottle?
I will try to get some information but it will take some time.

kinds regards
Arnoud

Hi,

Did you ask Horriba?

and take a look at web.stanford.edu/group/Zarelab/publinks/782.pdf
Maybe you can get some clues what goes wrong.

Arnoud

Arnoud,

I have been in contact with Horiba and initially their suggestion was to reduce the pressure used to apply the Chip+Prism against the flowcell gasket however this did not resolve the issue unfortunately. I have informed them of this observation and also shared with them the article you posted as well. Thank you for that.

Thank you once more for your time and insight and if you happen to come across anything that may be applicable please share. I will be sure to update this forum as we continue troubleshooting, hopefully with news of a solution! 

Kind Regards