Heptamethine cyanine
dyes are categorized as a class of near infrared fluorescent (NIRF)
dyes which have been discovered to have
tumor targeting and accumulation capability. This unique feature of NIRF
dye makes it a promising candidate for imaging, targeted
therapy and also as a
drug delivery vehicle for various types of
cancers. The favored uptake of
dyes only in
cancer cells is facilitated by several factors which include organic
anion-transporting
polypeptides, high mitochondrial membrane potential and tumor hypoxia in
cancer cells. Currently nanotechnology has opened possibilities for multimodal or multifunctional strategies for
cancer treatment. Including heptamethine cyanine
dyes in nanoparticle based delivery systems have generally improved its
theranostic ability by several fold owing to the multiple functionalities and structural features of heptamethine
dyes. For this reason, nanocomplexes with NIRF
heptamethine cyanine dye probe are preferred over non-targeting
dyes such as indo cyanine green (ICG). This review sums up current trends and progress in NIRF
heptamethine cyanine dye, including
dye properties, multifunctional imaging and therapeutic applications in
cancer.