Elevating Second Near-Infrared Photothermal Conversion Efficiency of Hollow Gold Nanorod for a Precise Theranostic of Orthotopic Bladder Cancer.

Abstract

The second near-infrared (NIR-II) window laser-activated agents have attracted broad interest in an orthotopic cancer theranostic. However, developing NIR-II photothermal agents (PTAs) with advanced photothermal conversion efficiency (PTCE) and tumor-specific response elevation remains a crucial challenge. Herein, a hollow gold nanorod (AuHNR) with a strong localized surface plasmon resonance (LSPR) peak in the NIR-II window was coated with MnO₂ and chitosan to obtain AuHNR@MnO₂@CS (termed AuMC) by a one-step method. Upon exposure to the tumor microenvironment (TME), the overexpressed GSH triggered degradation of the MnO₂ layer to release Mn²⁺ and resulted in the PTCE elevation owing to exposure of the AuHNR. Consequently, photoacoustic and magnetic resonance imaging for accurate diagnosis, Mn²⁺-mediated chemodynamic therapy, and AuHNR elevating PT therapy for precise treatment could be achieved. Both <i>in vitro</i> and <i>in vivo</i> experiments confirmed the good performance of the AuMC on an orthotopic bladder cancer precise theranostic. This study provided NIR-II activated, TME-response PT conversion efficiency enhanced PTAs and offered a tumor-selective theranostic agent for orthotopic bladder cancer in clinical application.