I appreciate your help and thank you again for the advices. The idea does not belong to me it's from a person that has a collaboration with the institute, they just came and left the alendronate, chip and said they wanted to see the interaction. the only article available on this type of interaction is for a home made SPR imaging (correct me if I am wrong buy they had a spectrophotometer and a sapphire instead of LED buit in) and the chip was made by them on a glass they first put Cr then silver after Ti and then HA ( Ti binds strong to HA) but this is beyond me to make another chip and redesign their experiment.Sorry if i retained you from your experiments.
Best regards
cristi
P.S. i'll be back with other questions:) if i get stuck somewhere.