2D PdCu Alloy Nanodendrites Manifest Effective Peroxidase-Like Activity Against Biofilms

Noble metal nanomaterials with peroxidase-like catalytic activity have received great interest lately for their potential applications in biomedicine and environmental protection; however, it is still challenging to achieve high catalytic efficiency despite enormous efforts. In this work, a novel but simple route was developed to synthesize 2D PdCu alloy nanodendrites (PdCu NDs) as a high-performance peroxidase mimic for biofilm elimination. Catalytic kinetics shows that the composition-dependent synergy between Pd and Cu in the PdCu NDs can strongly enhance the peroxidase-like activity. Density functional theory calculations further provide the underlying mechanisms at both atomic and electronic levels for the effective adsorption and dissociation of H2O2 molecules on PdCu NDs surfaces. Owing to their superior peroxidase-like activity, the PdCu NDs exhibit striking biofilm inhibition properties, which suggests that the controlled synthesis of 2D noble metal alloy may open up new opportunities for enhancing enzyme-like activities of noble metal nanomaterials.

Chiral FexCuySe nanoparticles as peroxidase mimics for colorimetric detection of 3, 4-dihydroxy-phenylalanine enantiomers

L-3,4-dihydroxy-phenylalanine (L-dopa) is the most widely used drug in Parkinson's disease treatment. However, development of cost-effective and high-throughput sensors to accurate enantioselective discrimination of L-dopa and D-dopa remains challenging to date. Herein, on the basis of the peroxidase-mimic activity of chiral FexCuySe nanoparticles, we demonstrated a novel colorimetric sensor for determination of chiral dopa. The surface chiral ligand, L/D-histidine (L/D-His), endowed the nanozymes with enantioselectivity in catalyzing the oxidation of dopa enantiomers. According to the values of kcat/Km, the efficiency of L-His modified nanoparticle (L-FexCuySe NPs) towards L-dopa was 1.56 times higher than that of D-dopa. While, D-His can facilely reverse the preference of the nanozyme to D-dopa. On the basis of high catalytic activity and enantioselectivity of L-FexCuySe NPs in oxidation of L-dopa, the L-FexCuySe NPs based system can be utilized for detection of L-dopa. The linear ranges for L-dopa determination were 5 µM to 0.125 mM and 0.125 mM to 1 mM with a detection limit of 1.02 µM. Critically, the developed sensor has been successfully applied in the quality control of clinical used L-dopa tablets. Our work sheds light on developing simple and sensitive chiral nanomaterials-based sensors for drug analysis.

Self-Assembly Cascade Reaction Platform for CD44 Positive Lung Cancer Therapy

Lung cancer, as one of the most fatal cancers around the world, is responsible for the death of millions every year. Among various types of lung cancers, the ones overexpressing CD44 is usually associated higher cell proliferation with poorer prognosis. Therefore, finding a way to effectively treat CD44 positive lung cancer is urgently needed. Here in this study, negatively charged ultrasmall prussian blue nanoparticles (UPBNPs) was firstly synthesized and adsorbed to polyethyleneimine (PEI) together with glucose oxidase (Gox). Afterwards, the PEI was further complexed with hyaluronic acid (HA) to give a cascade reaction platform (HP/UPB-Gox) for CD44 positive lung cancer therapy. The HP/UPB-Gox with HA shell was able to positively target CD44 overexpressed A549 cells. Upon arriving at the tumor tissue, the Gox catalyzed the glucose of tumor to create H2O2, which further served as the substrate of UPBNPs, a peroxidase mimic, to finally give highly toxic hydroxyl radical (OH) for cancer therapy. Therefore, the cascade reaction formed between UPBNPs and Gox was expected to realize effective treatment on CD44 overexpressed lung cancer.