Injectable NIR-II Photothermal Hydrogels for Image-Guided Adipose Remodeling and Antiobesity Therapy

Area of Science:

• Biomaterials Science
• Nanomedicine
• Metabolic Disorders

Background:

• Obesity is a complex metabolic disorder with limited effective treatments.
• Photothermal therapy (PTT) presents a noninvasive approach, but requires advanced materials for combined therapy and imaging.
• Existing treatments lack precision and can have systemic side effects.

Purpose of the Study:

• To develop an injectable photothermal hydrogel for image-guided, localized antiobesity therapy.
• To engineer a material with second near-infrared window (NIR-II) fluorescence for real-time monitoring.
• To evaluate the efficacy and safety of mild PTT for adipose tissue remodeling.

Main Methods:

• Engineered a pyrazine-based molecule (PPT-TPA8) for NIR absorption and NIR-II emission.
• Incorporated PPT-TPA8 into a PLGA-PEG-PLGA thermoresponsive matrix to form an injectable hydrogel.
• Conducted in vitro and in vivo studies using mild, image-guided PTT to assess adipose tissue response and hydrogel behavior.

Main Results:

• The hydrogel demonstrated controllable mild heating and local retention under low-power irradiation.
• NIR irradiation induced adipocyte apoptosis and white-to-beige fat conversion, reducing fat accumulation.
• NIR-II fluorescence allowed noninvasive, real-time tracking of hydrogel degradation and distribution without systemic toxicity.

Conclusions:

• The developed biocompatible hydrogel enables precise, image-guided, and minimally invasive antiobesity therapy.
• This platform shows potential for localized adipose tissue remodeling and metabolic improvement.
• The dual therapeutic and imaging capabilities offer a significant advancement in obesity treatment strategies.