Showing papers by "Harbin Engineering University published in 2022"

Guiding Transition Metal‐Doped Hollow Cerium Tandem Nanozymes with Elaborately Regulated Multi‐Enzymatic Activities for Intensive Chemodynamic Therapy

Abstract: Clinical applications of nanozyme-initiated chemodynamic therapy (NCDT) have been severely limited by the poor catalytic efficiency of nanozymes, insufficient endogenous hydrogen peroxide (H2 O2 ) content, and its off-target consumption. Herein, the authors developed a hollow mesoporous Mn/Zr-co-doped CeO2 tandem nanozyme (PHMZCO-AT) with regulated multi-enzymatic activities, that is, the enhancement of superoxide dismutase (SOD)-like and peroxidase (POD)-like activities and inhibition of catalase (CAT)-like activity. PHMZCO-AT as a H2 O2 homeostasis disruptor promotes H2 O2 evolution and restrains off-target elimination of H2 O2 to achieve intensive NCDT. PHMZCO-AT with SOD-like activity catalyzes endogenous superoxide anion (O2•- ) into H2 O2 in the tumor region. The suppression of CAT activity and depletion of glutathione by PHMZCO-AT largely weaken the off-target decomposition of H2 O2 to H2 O. Elevated H2 O2 is then catalyzed by the downstream POD-like activity of PHMZCO-AT to generate toxic hydroxyl radicals, further inducing tumor apoptosis and death. T1 -weighted magnetic resonance imaging and X-ray computed tomography imaging are also achieved using PHMZCO-AT due to the existence of paramagnetic Mn2+ and the high X-ray attenuation ability of elemental Zr, permitting in vivo tracking of the therapeutic process. This work presents a typical paradigm to achieve intensive NCDT efficacy by regulating multi-enzymatic activities of nanozymes to perturb the H2 O2 homeostasis.

Coordinating the Mechanisms of Action of Ferroptosis and the Photothermal Effect for Cancer Theranostics

Abstract: Combination therapy based on different mechanisms of cell death has shown promise in tumor therapy. However, when different modalities are integrated, the maximum synergy of the therapeutic effects is often lacking in the design. Herein, we report a cancer theranostic nanomedicine formula developed by considering the mechanisms of action of ferroptosis and the photothermal effect in combination therapy. The croconaine molecule was encapsulated as both a photothermal converter and an iron-chelating agent with BSA, thus leading to biocompatible and stable Cro-Fe@BSA nanoparticles (NPs). The Cro-Fe@BSA NPs in the tumor milieu showed an activated photothermal effect leading to enhanced radical formation owing to the temperature-dependent Fenton reaction kinetics, while radical formation during ferroptosis in turn prevented the heat-induced formation of heat shock proteins and thus the self-protection mechanism of cancer cells in response to heat. The activatable photoacoustic and magnetic resonance imaging performance of the Cro-Fe@BSA NPs also enabled safe and reliable cancer theranostics.

Metagenomic analysis on resistance genes in water and microplastics from a mariculture system

Abstract: Microplastics existing widely in different matrices have been regarded as a reservoir for emerging contaminants. Mariculture systems have been observed to host microplastics and antibiotic resistance genes (ARGs). However, more information on proliferation of ARGs and metal resistance genes (MRGs) in mariculture system at the presence of microplastics is needed. This study used metagenomic analysis to investigate the distribution of ARGs and MRGs in water and microplastics of a typical mariculture pond. Total 18 types including 174 subtypes of ARGs were detected with the total relative abundances of 1.22/1.25 copies per 16S rRNA copy for microplastics/water. Chloramphenicol resistance genes were the dominant ARGs with the abundance of 0.35/0.42 copies per 16S rRNA copy for microplastics/water. Intergron intI1 was dominant gene among 6 detected mobile genetic elements (MGEs) with the abundance of 75.46/68.70 copies per 16S rRNA copy for water/microplastics. Total 9 types including 46 subtypes of MRGs were detected with total abundance of 5.02 × 102/6.39 × 102 copies per 16S rRNA copy for water/ microplastics while genes resistant to copper and iron served as the dominant MRGs. Proteobacteria, Bacteroidetes, and Actinobacteria accounted for 84.2%/89.5% of total microbial community in microplastics/water. ARGs with relatively high abundance were significantly positively related to major genera, MGEs, and MRGs. Microplastics in mariculture system could enrich most of MRGs and some ARGs to serve as potential reservoir for these pollutants. The findings of this study will provide important information on resistance gene pollution at presence of microplastics in the mariculture system for further proposing suitable strategy of environmental management.