Au-Au/IrO₂@Cu(PABA) Reactor with Tandem Enzyme-Mimicking Catalytic Activity for Organic Dye Degradation and Antibacterial Application

Abstract

Herein, a Au-Au/IrO2 nanocomposite with tandem enzyme-mimicking activity was innovatively synthesized, which can show outstanding glucose oxidase (GOx)-like activity and peroxidase-like activity simultaneously under neutral conditions. Moreover, a Au-Au/IrO2@Cu­(PABA) reactor was prepared via encapsulation of the Au-Au/IrO2 nanocomposite in a Cu­(PABA) metal organic framework. The reactor not only exhibits excellent organic solvent stability, acid resistance, and reusability but also displays better cascade reaction catalytic efficiency (kcat /Km = 148.86 min–1 mM–1) than the natural free enzyme system (GOx/HRP) (kcat /Km = 98.20 min–1 mM–1) and Au-Au/IrO2 nanocomposite (kcat /Km = 135.24 min–1 mM–1). In addition, it is found that the reactor can catalyze glucose or dissolved oxygen to produce active oxygen species (ROS) including HO, 1O2, and O2 – · through its enzyme-mimicking activity. Finally, the novel reactor was successfully used in organic dye degradation and antibacterial application. The results show that it can effectively degrade methyl orange, methylene blue, and rhodamine B, which all can reach a degradation rate of nearly 100% after interacting with Au-Au/IrO2@Cu (PABA) for 3.5 h. Furthermore, the reactor also exhibits excellent antibacterial activity, so as to achieve a complete bactericidal effect to Staphylococcus aureus and Escherichia coli at a concentration of 12.5 μg mL–1.

In Situ Growth of a Metal–Organic Framework on Graphene Oxide for the Chemo-Photothermal Therapy of Bacterial Infection in Bone Repair

“…Bacterial infection is the major complication after bone transplantation, which seriously affects the process of bone repair and even leads to graft failure. − To solve these issues, chemotherapy and photothermal therapy have been used for antibacterial treatment; these therapies have high selectivity, minor resistance, and minimal toxicity. , Chemotherapy utilizes metal ions, such as zinc (Zn), silver, and copper, to destroy intrinsic components of the bacterial membrane through electrostatic action and then inactivates bacteria by generating reactive oxygen species (ROS). Nevertheless, bacteria, which erode bone implants, secrete polysaccharides, fibrin, and lipoprotein to form a dense biofilm that blocks the binding of the metal ions to the bacteria. , Photothermal therapy kills the bacterial biofilm with thermal damage, utilizing a near-infrared (NIR) light source and a photothermal agent as a heat-generating source. , Notably, the photothermal therapy generally requires a high local temperature (>70 °C), which undoubtedly damages the adjacent healthy tissue …”

In vitro degradation, photo-dynamic and thermal antibacterial activities of Cu-bearing chlorophyllin-induced Ca–P coating on magnesium alloy AZ31

“…According to previous reports, substances which can prduce Cu 2+ ions have been added to impart the antibacterial properties of the material, such as CuSO 4 [ 77 ], Cu monometallic [ 78 ], copper acetate [ 79 ], or CuO/Cu 2 O [ 80 ]. There are, nevertheless, scarce reports on the applications of porphyrin on biodegradable metals.…”

Recent advances in nanozymes for combating bacterial infection

“…At a certain concentration, the reactor had a thorough bactericidal effect on S. aureus and E. coli , showing good antibacterial activity. 72 Compared with native HRP, the Au@Co–Fe hybrid nanoparticles (Au@Co–Fe NPs) with peroxidase-mimicking activity were 50% of that of native horseradish peroxidase from gold nanoparticles, Co 2+ , and Fe 3+ . The experimental results indicate that Au@Co–Fe NPs exhibit antibacterial activity against P. aeruginosa, E. coli , S. aureus , and Bacillus cereus ( B. cereus ).…”