Cyanine dyes in optical imaging of tumours

Abstract

Near-infrared imaging holds promise for in-vivo cancer detection because of flow tissue autofluorescence and high tissue penetration depth. Cyanine dyes have shown much potential as non-targeting contrast agents for optical imaging; in particular, indocyanine green has long been implemented in clinical use. To improve targeting selectivity and delivery efficiency, common strategies with activatable technology need the chemical conjugation of suitable near-infrared emission range agents with tumour-specific ligands such as antibodies. 1 Kobayashi H Longmire MR Ogawa M Choyke PL Kawamato S Multiplexed imaging in cancer diagnosis: applications and future advances. Lancet Oncol. 2010; 11: 589-595 Summary Full Text Full Text PDF PubMed Scopus (66) Google Scholar Although these conjugated agents with tumour-specific antibodies or other ligands have shown promising efficacy in preclinical and clinical trials compared with conventional chemotherapy drugs, limitations in their delivery and specificity remain. For example, in-vivo studies have shown that only one to ten parts per 100 000 of intravenously administered monoclonal antibodies, of therapeutic or imaging agents, can reach their parenchymal targets, and only to specific tumour types. 2 Wang X Yang L Chen ZG Shin DM Application of nanotechnology in cancer therapy and imaging. CA Cancer J Clin. 2008; 58: 97-110 Crossref PubMed Scopus (537) Google Scholar Furthermore, the chemical conjugation might affect the specificity, affinity, and distribution of the agents in cells and tissues.