“…Of the current methods available, optical imaging is perhaps the most relevant because of its high-sensitivity, the use of non-radioactive components, low cost and easy access 5–8. Therefore, it is not surprising that the past two decades have witnessed the disclosure of a large number of optical imaging probes aimed at evaluating the expression and activity of specific molecules or biological processes 9, 10. Furthermore, the conjugation of optical imaging probes with disease-specific ligands such as antibodies enables the targeted imaging of particular tissues which is of key relevance, for example, in cancer diagnosis 11.…”