Indocyanine green conjugated phototheranostic nanoparticle for photodiagnosis and photodynamic therapy.

ABSTRACT

BACKGROUND: Phototheranostics represents a highly promising paradigm for cancer therapy, although selecting an appropriate optical imager and sensitizer for clinical use remains challenging. METHODS: Liposomally formulated phospholipid-conjugated indocyanine green, denoted as LP-iDOPE, was developed as phototheranostic nanoparticle and its cancer imaging-mediated photodynamic reaction, defined as the immune response induced by photodynamic and photothermal effects, was evaluated with a near-infrared (NIR)-light emitting diode (LED) light irradiator. RESULTS: Using in vivo NIR fluorescence imaging, we demonstrated that LP-iDOPE was selectively delivered to tumor sites with high accumulation and a long half-life. Following low-intensity NIR-LED light irradiation on the tumor region of LP-iDOPE accumulated, effector CD8+ T cells were activated at the secondary lymphoid organs, migrated, and subsequently released cytokines including interferon-γ and tumor necrosis factor-α, resulting in effective tumor regression. CONCLUSIONS: Our anti-cancer strategy based on tumor-specific LP-iDOPE accumulation and low-intensity NIR-LED light irradiation to the tumor regions, i.e., photodynamic reaction, represents a promising approach to noninvasive cancer therapy.