Superparamagnetic Nanoparticles with Efficient Near-Infrared Photothermal Effect at the Second Biological Window

Area of Science:

• Biomedical Engineering
• Materials Science
• Nanotechnology

Background:

• Superparamagnetic iron oxide nanoparticles (IONs) are utilized for hyperthermia via radiofrequency radiation.
• IONs have limited absorption in the first near-infrared biological window (~800 nm), necessitating combination with other agents for laser ablation.
• IONs possess excellent water solubility, colloidal stability, and biocompatibility.

Purpose of the Study:

• To investigate the photothermal properties of IONs in the second biological window (1000-1350 nm).
• To evaluate the potential of IONs as standalone agents for laser-induced thermal ablation.
• To assess the photothermal conversion efficiency and thermogenic stability of IONs.

Main Methods:

• Irradiation of ION suspensions with infrared radiation in the second biological window.
• Measurement of temperature increase and photothermal conversion efficiency.
• Assessment of thermogenic stability during heating and cooling cycles.

Main Results:

• IONs effectively absorb and convert infrared radiation in the 1000-1350 nm range into heat.
• A significant temperature increase of 36 °C was achieved with IONs at 255 mg L^-1 under 8.7 W cm^-2 irradiation for 10 min.
• Photothermal conversion efficiency reached approximately 72%, with high thermogenic stability observed.

Conclusions:

• IONs are effective photothermal agents in the second biological window, overcoming limitations in the first.
• IONs demonstrate potential for laser-induced thermal ablation without requiring combination with other agents.
• The findings support the use of IONs for advanced therapeutic applications leveraging infrared radiation.