Hi, I am building a device. I need an in vivo procedure to perform the experiment. The experiment is based on shinning the red led light on to something just say finger. But I cant test it on any people or animals as of now. I need measure the measure drug concentration. So I need some kinda of model to perform this experiment So that I can inject some kind of drug in to something and when i shine the light I will have the photo detector that will absorb the left over light. please give me some suggestion on what type of models I can use.