This instrument should fit your needs - www.p4spr.ca. It has 4 channels (3 samples; 1 reference); it is bench-top, very easy to use and affordable. It is currently used in academia in biomolecular assay development. The company is relatively close to you; in Montréal. Maybe you can send me more details about your study at [email protected] and we can discuss its feasability with the P4SPR.

Are you sure that you want to exclude SPR imaging (which is meant normally under high throughput)? The model you describe sounds complex to me, I think that you will have a lot of problems with decrypting SPR curves and determining what is really going on on the sensors surface. Imaging the sensor surface and being able to distinguish localised changes (seeing what is happening where) can be very helpful. With SPRi one can get qualitatively better results with less efforts and consumables.

I recommend that you use the Attana Cell 200 QCM Biosensor. On that you can charaterize antibody interaction with cells to get kinetics and affinity. Of course you can also run the standard biochemical assays in lipid vesicles, bacterias, viruse etc.See the publications below. Find more information at www.attana.com or contact me.

Best regards

Teodor

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Hi, if you have a lot of money: use Biacore. other good ones are devices from Sierra Sensors

I have been using BioNavis instruments. 

Thanks for all the good answers. I bought a used SPR to "play with". Once the capital budget allows, I'll probably buy new.