**4.1. Methods based on labeling**

### *4.1.1. Conventional fluorescent labels-*

Among them are radioisotopes and conventional fluorochromes like fluorescein, BODIPY or cyanins. Cyanines are the most used in protein arrays due to its minimal interaction with other biomolecules and its high intensity. More than two fluorochromes can be combined to identify several biomarkers at the same time. It is used for cancer biomarkers.-
