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[Display omitted] • A novel inorganic sonosensitizer (a-Mn-CoMo-LDH) was proposed for MRI-guided SDT. • Acid etching of Mn-CoMo-LDH successfully activated its ROS generation activity. • Doped Mn4+ decomposed H 2 O 2 into O 2 to alleviate the hypoxic tumor microenvironment. • Mn4+ consumed GSH to reduce its clearance of ROS and also generated Mn2+ for MRI. Sonodynamic therapy (SDT) has attracted increasing attention owing to its superior tissue penetration compared with other therapies. However, the development of multifunctional sonosensitizers with imaging capability and high production efficiency of reactive oxygen species (ROS) is still a challenge for current sonodynamic cancer therapy. Herein, we report the design and preparation of amorphous 2D Mn-doped CoMo-layered double hydroxide (a-Mn-CoMo-LDH) nanosheets (NSs) through acid etching-induced crystalline-to-amorphous phase transformation as a highly active nano-agent for magnetic resonance imaging (MRI)-guided SDT. The a-Mn-CoMo-LDH NSs exhibit superior ROS production capacity compared with amorphous CoMo-LDH NSs (∼1.3 times) and crystalline Mn-CoMo-LDH NSs (∼3.9 times) under ultrasound (US) irradiation, which is ∼ 9.9 times of the previously reported TiO 2 sonosensitizer. The doped Mn4+ in the a-Mn-CoMo-LDH NSs can not only decompose H 2 O 2 into O 2 to alleviate the hypoxia level in tumor microenvironment (TME), but also consume glutathione (GSH) to reduce its clearance of ROS, promoting the SDT performance synergistically. Importantly, the GSH consumption can partially reduce the Mn4+ to Mn2+ within the tumors, which can serve as an agent for T 1 -weighted MRI, thus endowing the a-Mn-CoMo-LDH NSs with excellent MRI capability. Therefore, the as-prepared a-Mn-CoMo-LDH NSs with polyethylene glycol modification can be used as an efficient nano-agent for MRI-guided SDT, which can effectively achieve apoptosis of cancer cells in vitro and eradication of tumors in vivo under US irradiation. [ABSTRACT FROM AUTHOR]

Recently, theranostic has drawn tremendous attention by virtue of the nanotechnology development and new material exploration. Herein, we reported a novel theranostic system by loading Au nanoclusters (AuNCs) and Chlorin e6 (photosensitizer, Ce6) onto the monolayer nanosheet surface of Gd-doped layered double hydroxide (Gd-LDH). The as-prepared Ce6&AuNCs/Gd-LDH exhibits a largely enhanced fluorescence quantum yield (QY) of 18.5% relative to pristine AuNCs (QY = 3.1%) as well as superior T 1 magnetic resonance imaging (MRI) performance ( r 1  = 17.57 mM −1 s −1 ) compared with commercial MRI contrast agent (Gd(III)-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (Gd-DOTA): r 1  ≈ 3.4 mM −1 s −1 ), resulting from a synergistic effect between AuNCs and Gd-LDH. In addition, both in vitro and in vivo therapeutic evaluations demonstrate an efficient dual-modality imaging guided anticancer performance, especially the synergetic enhanced magnetic resonance/fluorescence (MR/FL) visualization of tumor site. Therefore, this work demonstrates a successful paradigm for the design and preparation of LDHs monolayer-based theranostic material, which holds great promises in practical applications. [ABSTRACT FROM AUTHOR]