Deep-Tissue Photothermal Therapy Using Laser Illumination at NIR-IIa Window

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Cancer Therapy

Background:

• Photothermal therapy (PTT) utilizes near-infrared (NIR) light for non-invasive tumor treatment.
• Current PTT predominantly uses the first NIR window (NIR-I; 700-900 nm), facing limitations in deep tissue penetration.
• The second NIR window (NIR-II; 1000-1700 nm), particularly NIR-IIa (1300-1400 nm), offers enhanced penetration depth and safety for PTT.

Purpose of the Study:

• To evaluate the efficacy of 1275 nm laser excitation in the NIR-IIa window for PTT.
• To compare the performance of 1275 nm NIR-IIa laser PTT against conventional 808 nm NIR-I laser PTT.
• To explore the potential of NIR-IIa PTT for improved deep-tissue tumor treatment.

Main Methods:

• Synthesis of copper sulfide-polyethylene glycol (CuS-PEG) nanoparticles as PTT agents with comparable absorption at 1275 nm and 808 nm.
• In vitro evaluation of cell ablation efficiency using both 1275 nm and 808 nm lasers.
• In vivo assessment of deep-tissue antitumor efficacy using the synthesized nanoparticles and both laser wavelengths.

Main Results:

• CuS-PEG nanoparticles demonstrated effective photothermal conversion at both 1275 nm and 808 nm.
• The 1275 nm laser exhibited significantly better cell ablation in vitro compared to the 808 nm laser.
• In vivo studies showed superior deep-tissue antitumor effects with the 1275 nm NIR-IIa laser compared to the 808 nm NIR-I laser.

Conclusions:

• 1275 nm laser excitation in the NIR-IIa window is a viable and effective modality for photothermal therapy.
• NIR-IIa laser illumination offers significant advantages over NIR-I for deep-tissue PTT.
• This approach holds high potential for advancing PTT outcomes in clinical cancer treatment.