An Ultrasmall Fe₃O₄‐Decorated Polydopamine Hybrid Nanozyme Enables Continuous Conversion of Oxygen into Toxic Hydroxyl Radical via GSH‐Depleted Cascade Redox Reactions for Intensive Wound Disinfection

Abstract

Nanozyme‐based chemodynamic therapy (CDT) for fighting bacterial infections faces several major obstacles including low hydrogen peroxide (H2O2) level, over‐expressed glutathione (GSH) in infected sites, and inevitable damage to healthy tissue with abundant nonlocalized nanozymes. Herein, a smart ultrasmall Fe3O4‐decorated polydopamine (PDA/Fe3O4) hybrid nanozyme is demonstrated that continuously converts oxygen into highly toxic hydroxyl radical (•OH) via GSH‐depleted cascade redox reactions for CDT‐mediated bacterial elimination and intensive wound disinfection. In this system, photonic hyperthermia of PDA/Fe3O4 nanozymes can not only directly damage bacteria, but also improve the horseradish peroxidase‐like activity of Fe3O4 decorated for CDT. Surprisingly, through photothermal‐enhanced cascade catalytic reactions, PDA/Fe3O4 nanozymes can consume endogenous GSH for disrupting cellular redox homeostasis and simultaneously provide abundant H2O2 for improving •OH generation, ultimately enhancing the antibacterial performance of CDT. Such PDA/Fe3O4 can bind with bacterial cells, and reveals excellent antibacterial property against both Staphylococcus aureus and Escherichia coli. Most interestingly, PDA/Fe3O4 nanozymes can be strongly retained in infected sites by an external magnet for localized long‐term in vivo CDT and show minimal toxicity to healthy tissues and organs. This work presents an effective strategy to magnetically retain the therapeutic nanozymes in infected sites for highly efficient CDT with good biosafety.

A self-activated cascade nanoreactor based on Pd–Ru/GOx for bacterial infection treatment

“…In recent years, nanozymes, as antibiotic-free antibacterial agents, have gained attention. [7][8][9][10][11][12][13][14][15] Especially, peroxidase (POD)like nanozymes with the capability of catalyzing H 2 O 2 into toxic reactive oxygen species (ROS) had been utilized to fabricate various antibacterial systems. [16][17][18][19] However, these antibacterial systems generally require the assistance of external highly concentrated H 2 O 2 , which might not only bring about potential damage to normal tissues but also hinder the healing of wounds.…”

Efficient nanozyme engineering for antibacterial therapy

“…Au [19][20][21][22][23][24][25][26], Pt [27], Cu [28], Ir [29], Ag [30], Au-Pt [31,32], Pd-Cu [33], Pd-Pt [34], Au-Ag [35], etc), transition metal oxide or sulfide (e.g. Fe 3 O 4 [36][37][38], CuO [39], CeO 2 [40], V 2 O 5 [41], Co-V mixed metal oxide (MMO) [42], MoS 2 [43][44][45][46][47], NiS 2 [48], CuS [49][50][51][52], Co 4 S 3 [53], MnO 2 [54] etc), and nanocarbon (e.g. boron doped graphdiyne (B-GDY) [8], N-doped sponge-like carbon spheres (N-SCSs) [55], graphene quantum dots [56,57], etc)-based nanozymes, to recentlyadvanced metal organic framework (MOF) (e.g.…”

SERS monitoring of photoinduced-enhanced oxidative stress amplifier on Au@carbon dots for tumor catalytic therapy

“…However, depleting glutathione (GSH) in TME is a challenge because the overexpressed concentration level of GSH could prevent generating toxic levels of ROS 7 , 8 . Thus, in the past decade, photodynamic therapy (PDT) promoted by the photothermal effect based on nanotechnology 9 have captured comprehensive attention to target the broken of redox homeostasis in TME performed by synchronous elevating ROS levels and exhausting GSH 10 , 11 . However, the evidence of monitoring of oxidative stress processes based on PDT reaction promoted by photothermal effect in tumor is still lacking to insightful reveal the therapy mechanism.…”