Ultrasonically Prepared Sodium Heparin-Stabilized Indocyanine Green/Nano-Hydroxyapatite Suspension for Collaborative Photodynamic and Photothermal Tumor Therapy

Abstract

Indocyanine green (ICG) shows promise for diagnosing and treating tumors due to its good photothermal and fluorescent properties. In this study, sodium heparin (SH)-stabilized ICG/nano-hydroxyapatite (SH-ICG/nHAP) suspension was ultrasonically prepared to achieve photothermal and photodynamic collaborative therapy (PTT/PDT) for treating tumors. The nHAP had a short rod-like shape and a drug-loading capacity of 13.3% for ICG, corresponding to a drug-loading efficiency of 88.6%. In addition, the SH-ICG/nHAP suspension showed a very low release of ICG in PBS (7.4) and a slightly improved release in acidic buffers (6.5, 5.5), indicating an excellent binding ability of nHAP for ICG. The resulting SH-ICG/nHAP showed good suspension stability. Under an 808 nm near-infrared (NIR) laser, SH-ICG/nHAP showed good photothermal properties and could produce reactive oxygen species (ROS). Under the irradiation of an 808 nm NIR laser at 0.8 W/cm2 for 5 min, SH-ICG/nHAP was found to significantly inhibit HepG2 cells proliferation (78.58%), similar to free ICG. In vivo, SH-ICG/nHAP was found to exert an improved inhibitory effect on tumor growth compared to free ICG. Biocompatible and stable SH-ICG/nHAP suspension like this could be a promising system for the PTT/PDT of tumors.