Organic small-molecule
photosensitizers are well-characterized and known for the light-responsive treatment modality including
photodynamic therapy. Compared with ultraviolet-visible (UV-vis) light used in conventional
photodynamic therapy with organic
photosensitizers, near-infrared (NIR) light from 700 to 900 nm is less absorbed and scattered by
biological tissue such as
hemoglobin,
lipids, and water, and thus, the use of NIR excitation can greatly increase the penetration depth and emission. Additionally, NIR light has lower energy than UV-vis that can be beneficial due to less activation of fluorophores present in tissues upon NIR irradiation. However, the low water stability, nonspecific distribution, and short circulation half-life of the organic
photosensitizers limit its broad
biological application. NIR responsive small-molecule
fluorescent agents are the focus of extensive research for combined molecular imaging and
hyperthermia. Recently a new class of NIR
dye,
IR-820 with excitation and emission wavelengths of 710 and 820 nm, has been developed and explored as an alternative platform to overcome some of the limitations of the most commonly used
gold nanoparticles for
photothermal therapy of
cancer. Herein, we synthesized a core-shell biocompatible nanocarrier envelope made up of a
phospholipid conjugated with poly(
ethylene glycol) as a shell, while poly(lactic
glycolic acid) (PLGA) was used as a core to encapsulate
IR-820 dye. The IR-820-loaded nanoparticles were prepared by nanoprecipitation and characterized for their physicochemical properties and photothermal efficiency. These nanoparticles were monodispersed and highly stable in physiological pH with the hydrodynamic size of 103 ± 8 nm and polydispersity index of 0.163 ± 0.031. The IR-820-loaded nanocarrier showed excellent biocompatibility in the dark, whereas remarkable
phototoxicity was observed with
breast cancer cells (MCF-7) upon NIR
laser excitation. Therefore, the IR-820-loaded
phospholipid mimicking biodegradable
lipid-
polymer composite nanoparticles could have great potential for
cancer theranostics.