Embedding Atomically Dispersed Manganese/Gadolinium Dual Sites in Oxygen Vacancy‐Enriched Biodegradable Bimetallic Silicate Nanoplatform for Potentiating Catalytic Therapy

Abstract

Due to their atomically dispersed active centers, single‐atom nanozymes (SAzymes) have unparalleled advantages in cancer catalytic therapy. Here, loaded with chlorin e6 (Ce6), a hydrothermally mass‐produced bimetallic silicate‐based nanoplatforms with atomically dispersed manganese/gadolinium (Mn/Gd) dual sites and oxygen vacancies (OVs) (PMnSAGMSNs‐V@Ce6) is constructed for tumor glutathione (GSH)‐triggered chemodynamic therapy (CDT) and O2‐alleviated photodynamic therapy. The band gaps of silica are significantly reduced from 2.78 to 1.88 eV by doping with metal ions, which enables it to be excited by a 650 nm laser to produce electron‐hole pairs, thereby facilitating the generation of reactive oxygen species. The Gd sites can modulate the local electrons of the atom‐catalyzed Mn sites, which contribute to the generation of superoxide and hydroxyl radicals (•OH). Tumor GSH‐triggered Mn2+ release can convert endogenous H2O2 to •OH and realize GSH‐depletion‐enhanced CDT. Significantly, the hydrothermally generated OVs can not only capture Mn and Gd atoms to form atomic sites but also can elongate and weaken the O‐O bonds of H2O2, thereby improving the efficacy of Fenton reactions. The degraded Mn2+/Gd3+ ions can be used as tumor‐specific magnetic resonance imaging contrast agents. All the experimental results demonstrate the great potential of PMnSAGMSNs‐V@Ce6 as cancer theranostic agent.

Dual-Mode Lateral Flow Immunoassay Based on “Pompon Mum”-Like Fe3O4@MoS2@Pt Nanotags for Sensitive Detection of Viral Pathogens

“…According to the Nyquist plots, the semicircle diameter represents the charge transfer resistance (R ct ), and the linear portion is relevant to the diffusion process. 62 As shown in Figure S10, Fe 3 O 4 @MoS 2 @Pt possessed a smaller R ct value than Fe 3 O 4 @MoS 2 , indicating a higher electron transfer capability. The outstanding POD-like activity was favorable for the signal amplification on the test strips.…”

“…We also performed EIS experiments to confirm the enhanced electron transfer process. According to the Nyquist plots, the semicircle diameter represents the charge transfer resistance ( R ct ), and the linear portion is relevant to the diffusion process . As shown in Figure S10, Fe 3 O 4 @MoS 2 @Pt possessed a smaller R ct value than Fe 3 O 4 @MoS 2 , indicating a higher electron transfer capability.…”

Cobalt doped Prussian blue modified hollow polydopamine for enhanced antibacterial therapy

“…Subsequently, an ESR test using DMPO as a trapping agent for •OH was conducted (figure 2(i)). The result revealed a distinct 1:2:2:1 characteristic signal attributed to •OH in the resonance spectra [42] after 10 min of 808 nm laser irradiation in the DMPO + HPDA-PB NPs + H 2 O 2 system. These findings indicate that under pH 5.5 conditions, HPDA-PB can effectively catalyze the production of •OH from H 2 O 2 through a photo-enhanced Fenton-like effect induced by Co-PBA present within the HPDA-PB structure.…”

Single-Atom-Based Nanoenzyme in Tissue Repair

“…Understanding the toxic mechanisms of SAzymes is essential for their safe and effective application. The generation of ROS, especially under light exposure, , is commonly recognized as a contributor to SAzyme-associated toxicity. However, additional actions of SAzyme, such as the release of metal atoms and penetration of the cell envelope, also play a significant role in their toxicity.…”