Indocyanine green assembled free oxygen-nanobubbles towards enhanced near-infrared induced photodynamic therapy

Abstract

Photodynamic therapy (PDT) has shown a promising capability for cancer treatment with minimal side effects. Indocyanine green (ICG), the only clinically approved near-infrared (NIR) fluorophore, has been used as a photosensitizer for PDT in clinical application. However, the main obstacle of directly utilizing ICG in the clinic lies in its low singlet oxygen ( 1 O 2 ) quantum yield (QY) and instability in aqueous solution. To improve the PDT efficacy of ICG, free ICG molecules were assembled with free oxygen nanobubbles (NBs-O 2 ) to fabricate ICG-NBs-O 2 by hydrophilic-hydrophobe interactions on the gas—liquid interface. Interestingly, 1 O 2 QY of ICG-NBs-O 2 solution was significantly increased to 1.6%, which was estimated to be 8 times as high as that of free ICG solution. Meanwhile, ICG-NBs-O 2 exhibited better aqueous solution stability compared with free ICG. Furthermore, through establishing tumor models in nude mice, the therapeutic efficacy of ICG-NBs-O 2 was also assessed in the PDT treatment of oral cancer. The tumor volume in ICG-NBs-O 2 treated group on day 14 decreased to 0.56 of the initial tumor size on day 1, while the tumor volume in free ICG treated group increased to 2.4 times. The results demonstrated that ICG-NBs-O 2 showed excellent tumor ablation in vivo . Therefore, this facile method provided an effective strategy for enhanced PDT treatment of ICG and showed great potential in clinical application. Electronic Supplementary Material Supplementary material (measurements of the singlet oxygen quantum yield of ICG-NBs-O 2 , time-dependent temperature changes during the laser irradiation, photographs of Cal27 tumor-bearing nude mice and complete blood count of health male balb/c mice analysis) is available in the online version of this article at 10.1007/s12274-022-4085-0.

β-Lactamase-Responsive Probe for Efficient Photodynamic Therapy of Drug-Resistant Bacterial Infection

“…The 1 O 2 QY of CySG-2 solution was investigated by an indirect method. According to previous reports in the literature, the 1 O 2 QY of ICG is 0.2%. , The ROS calculation formula is specified as where K CySG‑2 and K ICG represent the decomposition rate constants of DPBF by CySG-2 and ICG solution, respectively. A ICG and A CySG‑2 are the integral areas of the optical absorption bands between 750 and 850 nm by CySG-2 and free ICG solution, respectively.…”

“…According to previous reports in the literature, the 1 O 2 QY of ICG is 0.2%. 44,45 The ROS calculation formula is specified as…”

Drug delivery system based on nanobubbles

“…The production of reactive oxygen species (ROS) depends on oxygen, and the increase in oxygen level can enhance ROS production, and therefore the effectiveness of PDT. Yang et al [ 96 ] presented the indocyanine green oxygen‐NBs (ICG‐NBs‐O 2 ), which were fabricated by assembling indocyanine green molecules with free oxygen NBs. The ICG‐NBs‐O 2 exhibited better aqueous solution stability and eight times singlet oxygen quantum yield compared with free indocyanine green.…”

“…[ 137,138 ] Due to the nanoscopic gaseous cavities, drug delivery capacity, and acoustic performance, NBs have shown enhanced near‐infrared‐induced photodynamic therapy. [ 96 ]…”

“…To improve the PDT effect of ICG, ICG‐NBs‐O 2 aqueous solution was prepared by self‐assembly of free ICG molecules on the gas–liquid interface of free nano‐oxygen bubbles (NBs‐O 2 ). [ 96 ] The results show that the quantum yield of singlet oxygen ( 1 O 2 ) of ICG‐NBs‐O 2 is significantly increased, which is eight times higher than that of free ICG aqueous solution. In vivo and in vitro experiments show that ICG‐NBs‐O 2 aqueous solution has significantly improved the PDT effect of tumors compared with free ICG aqueous solution.…”