Two‐dimensional transition metal carbides and nitrides (MXenes) nanosheets with high photothermal conversion efficiency as well as photothermal stability can efficiently generate remarkable hyperthermia for photothermal therapy (PTT) of cancer. However, mono‐MXenes cannot exhibit precise diagnosis and treatment to complete ablation of cancer cells in the PTT process. To overcome this dilemma, an “all‐in‐one” nanoplatform of titanium carbide (Ti ₃ C ₂ ) MXene‐based composite nanosheets is developed for magnetic resonance imaging (MRI)‐guided multi‐modal hyperthermia and chemodynamic tumor ablation, which was achieved by bonding of manganese ion on the surface of Ti ₃ C ₂ , and then was the functionalized nanosheets was modified by biocompatible PEG (Mn‐Ti ₃ C ₂ @PEG). Due to magnetic and Fenton‐like catalytic properties of Mn components, Mn‐Ti ₃ C ₂ @PEG not only acted as the contrast agents for T ₁ ‐weighted MRI (relaxivity value of 1.05 mM ⁻¹ s ⁻¹ ), but also converted cellular H ₂ O ₂ into highly toxic hydroxyl radicals (·OH) mediated chemodynamic therapy (CDT). Moreover, Furthermore, Mn‐Ti ₃ C ₂ @PEG can efficiently suppressed tumor‐growth by PTT, due to the high photothermal conversion capability and photothermal stability. As a proof‐of‐concept model, the as‐designed Mn‐Ti ₃ C ₂ @PEG nanoplatform shows simultaneous MRI and dual‐modal treatment for effective suppression of tumor with minimized side effects both in vitro and in vivo , indicating the great potential for clinical cancer theranostics.

Introduction: Targeting, imaging, and treating tumors represent major clinical challenges. Developing effective theranostic agents to address these issues is an urgent need. Methods: We introduce an “all-in-one” tumor-targeted theranostic platform using CuFeSe₂-based composite nanoparticles (CuFeSe₂@PA) for magnetic resonance (MR) and computed tomography (CT) dual model imaging-guided hyperthermia tumor ablation. Plerixafor (AMD3100) is bonded to the surface of CuFeSe₂ as a targeting unit. Due to the robust interaction between AMD3100 and the overexpressed Chemokine CXC type receptor 4 (CXCR4) on the membrane of 4T1 cancer cells, CuFeSe₂@PA specifically recognizes 4T1 cancer cells, enriching the tumor region. Results: CuFeSe₂@PA serves as a contrast agent for T₂-weighted MR imaging (relaxivity value of 1.61 mM^{− 1} s^{− 1}) and CT imaging. Moreover, it effectively suppresses tumor growth through photothermal therapy (PTT) owing to its high photothermal conversion capability and stability, with minimized side effects demonstrated both in vitro and in vivo. Discussion: CuFeSe₂@PA nanoparticles show potential as dual-mode imaging contrast agents for MR and CT and provide an effective means of tumor treatment through photothermal therapy. The surface modification with Plerixafor enhances the targeting ability of the nanoparticles, performing more significant efficacy and biocompatibility in the 4T1 cancer cell model. The study demonstrates that CuFeSe₂@PA is a promising multifunctional theranostic platform with clinical application potential.

A novel H ₂ S-activated cancer-specific fluorescent probe COX2-H ₂ S was rationally developed, with naphthalimide as the fluorophore and indomethacin as the targeting unit, for the imaging determination of H ₂ S in living cells, C. elegans , and zebrafish.