Development of Nickel Selenide@polydopamine Nanocomposites for Magnetic Resonance Imaging Guided NIR‐II Photothermal Therapy

The penetration depth of near-infrared laser has greatly restricted the development of most photothermal agents. Recently, photothermal agents in the second near-infrared (NIR-II) window have drawn great attention as they can overcome above barrier. Herein, a novel "all in one" NIR-II responsive nanoplatform (nickel selenide @polydopamine nanocomposites, NiSe@PDA NCs) based on in situ coating the polydopamine (PDA) on the surface of biomineralized nickel selenide nanoparticles (NiSe NPs) for dual-model imaging-guided photothermal therapy is reported. Under the illumination of NIR-II laser (1064 nm), the photothermal conversion efficiency of NiSe@PDA NCs can reach 48.4%, which is higher than that of single NiSe NPs due to the enhanced molar extinction coefficient. In addition, because of the paramagnetic effect of NiSe NPs, the constructed NiSe@PDA NCs can be acted as T1 contrast agent for magnetic resonance imaging (MRI). Most importantly, the MRI contrast effect is enhanced with the coating of PDA layer due to the loose structure of PDA. Ultimately, both in vitro and in vivo experiments demonstrate that the developed NCs can achieve efficient MRI-guided photothermal therapy for treating malignant tumor. Therefore, the designed NiSe@PDA NCs with excellent features show great potential for clinical MRI-guided cancer therapy.