Conductive hydrogels with photothermal effects: material design, mechanisms, and multifunctional applications

Conductive hydrogels with near-infrared (NIR) photothermal effects are a promising class of smart materials. They integrate the unique properties of hydrogels—such as flexibility and biocompatibility—with enhanced electrical conductivity and photothermal responsiveness. These materials use NIR light to induce localized heating through photothermal conversion, enabling precise control over physicochemical properties, including conductivity, mechanical strength, and antibacterial activity. However, comprehensive reviews in this field are limited. This article systematically classifies photothermal materials into four categories: conjugated polymers, carbon-based nanomaterials, inorganic nanomaterials, and metal-phenolic networks, and explains their mechanisms. We highlight recent advancements in applications such as smart wound dressings, soft actuators, and responsive sensors, while addressing challenges like optimizing photothermal efficiency, balancing biocompatibility with conductivity, and scaling up production. By providing a comprehensive analysis of material design strategies and applicationspecific innovations, this review aims to guide future research toward next-generation multifunctional hydrogels for advanced biomedical and technological applications.