Thermal-Responsive Gel-Based Overheat Limiter Enabled Intelligent Photothermal Therapy

Area of Science:

• Biomaterials Science
• Nanotechnology
• Medical Physics

Background:

• Photothermal therapy (PTT) faces limitations due to uncontrolled hyperthermia causing thermal damage to healthy tissues.
• Developing safe and effective PTT requires precise thermal regulation to prevent side effects.

Purpose of the Study:

• To develop an intelligent cooling thermal-responsive (ICTR) gel for controlled photothermal heating in PTT.
• To investigate the ICTR gel's ability to prevent thermal damage to surrounding tissues during PTT.

Main Methods:

• An ICTR gel incorporating poly(N-isopropylacrylamide-co-acrylamide) (P(NIPAM-AM)) microgel was synthesized.
• The gel's optical and thermal properties were evaluated, focusing on near-infrared (NIR) light transmittance and temperature-dependent refractive index changes.
• Animal studies were conducted to assess the efficacy and safety of ICTR gel-enabled PTT compared to conventional PTT.

Main Results:

• The ICTR gel exhibits high NIR transmittance (>95%) at low temperatures and increased light scattering above a specific threshold.
• Negative feedback regulation by the ICTR gel stabilized lesion temperatures around 45°C while keeping skin surface temperature below 35°C.
• Histological analysis showed no thermal damage to skin tissues treated with ICTR gel-enabled PTT, unlike conventional PTT.

Conclusions:

• The ICTR gel provides an intelligent thermal regulation mechanism for PTT, enhancing safety and efficacy.
• This approach establishes a universal paradigm for controlling temperature in PTT, minimizing accidental injury.
• ICTR gel-based PTT holds significant potential for safer and more effective therapeutic applications.