Near-infra-red fluorescent chitosan oligosaccharide lactate for targeted cancer imaging and photothermal therapy

Abstract

Photothermal therapy (PTT) is a promising approach for effective cancer treatment because of its noninvasive procedure, low toxicity to normal tissues, and high tumour ablation efficiency. Developing a PTT agent with precise tumour imaging capabilities is an essential prerequisite for effective PTT. In this study, we developed a bifunctional near-infra-red (NIR) fluorescent conjugate consisting of chitosan oligosaccharide lactate (COL) and the ZW800-1 NIR fluorophore (COL-ZW). We demonstrate that this conjugate is easy to use and that it is an effective theranostic agent for fluorescence-guided photothermal treatment. The temperature of COL-ZW increased by 62.3 C after NIR laser irradiation (1.1 W/cm 2) for 5 min in HT-29 tumour-bearing mice. The HT-29 tumours targeted by COL-ZW showed a remarkable decrease in tumour volume until a week after photothermal treatment. These in vivo results demonstrate that the bifunctional COL-ZW generates strong fluorescence and light-triggered PTT in tumour sites, indicating successful fluorescence-guided PTT. Importantly, no tumour recurrence or treatmentinduced toxicity was observed after a single dose of COL-ZW with laser irradiation. Therefore, a combinatorial treatment with COL-ZW and NIR laser irradiation could serve as a promising strategy for photothermal cancer therapy.

Molecular Tuning of IR-786 for Improved Tumor Imaging and Photothermal Therapy

“…Mice were intravenously administered with CA800Cl (10 nmol, 0.23 mg/kg) or PBS 24 h before laser irradiation and exposed to an 808 nm laser (1.1 W/cm 2 ) for 5 min. Previously, the power density of the 808 nm laser was optimally adjusted to prevent unnecessary damage in normal tissue owing to laser power alone, without any PTT agent [ 23 , 24 ]. The temperature of the tumors treated with CA800Cl markedly increased up to 54.9 °C after 5 min of laser irradiation, whereas tumor temperatures in the PBS-injected mice exhibited minimal change (39 °C) under the same condition ( Figure 5 d).…”

Tumor-Targeted ZW800-1 Analog for Enhanced Tumor Imaging and Photothermal Therapy

“…To confirm the photothermal properties of ZW800-AM, ZW800-AM (100 µM in PBS) and PBS solutions were individually exposed to 808 nm laser irradiation (1.1 W/cm 2 ) for 1 min. Previously, the power density of an 808 nm laser was determined optimal, capable of avoiding the unnecessary photothermal effect of only laser power, without any PTT agent [26,27]. Temperature changes during the laser irradiation were automatically recorded using an FLIR ® thermal imager as a function of the irradiation time.…”

The Microstructure, Antibacterial and Antitumor Activities of Chitosan Oligosaccharides and Derivatives

“…Photothermal therapy (PTT) has great potential in tumor therapy because of its low toxicity to normal tissues and high tumor ablation efficiency [81][82][83]. Sungsu Lee et al [84] reported a study on the tumor targeting property of COL and the advantages of PTT, combining COL with nearinfrared (NIR) fluorescent group ZW800-1 to form a COL-ZW800-1 (Figure 9a) conjugate for targeted cancer imaging and PTT in cancer treatment. The positive charge on COL binds the COL-ZW800-1 conjugate to the outer surface of the negatively charged tumor cell membrane.…”