Peptide nanozymes: An emerging direction for functional enzyme mimics.

The abundance of molecules on early Earth likely enabled a wide range of prebiotic chemistry, with peptides playing a key role in the development of early life forms and the evolution of metabolic pathways. Among peptides, those with enzyme-like activities occupy a unique position between peptides and enzymes, combining both structural flexibility and catalytic functionality. However, their full potential remains largely untapped. Further exploration of these enzyme-like peptides at the nanoscale could provide valuable insights into modern nanotechnology, biomedicine, and even the origins of life. Hence, this review introduces the groundbreaking concept of "peptide nanozymes (PepNzymes)", which includes single peptides exhibiting enzyme-like activities, peptide-based nanostructures with enzyme-like activities, and peptide-based nanozymes, thus enabling the investigation of biological phenomena at nanoscale dimensions. Through the rational design of enzyme-like peptides or their assembly with nanostructures and nanozymes, researchers have found or created PepNzymes capable of catalyzing a wide range of reactions. By scrutinizing the interactions between the structures and enzyme-like activities of PepNzymes, we have gained valuable insights into the underlying mechanisms governing enzyme-like activities. Generally, PepNzymes play a crucial role in biological processes by facilitating small-scale enzyme-like reactions, speeding up molecular oxidation-reduction, cleavage, and synthesis reactions, leveraging the functional properties of peptides, and creating a stable microenvironment, among other functions. These discoveries make PepNzymes useful for diagnostics, cellular imaging, antimicrobial therapy, tissue engineering, anti-tumor treatments, and more while pointing out opportunities. Overall, this research provides a significant journey of PepNzymes' potential in various biomedical applications, pushing them towards new advancements.

Laminarin-modulated osmium nanozymes with high substrate-affinity and selective peroxidase-like behavior engineered colorimetric assay for hydroxyl radical scavenging capacity estimation.

Hydroxyl radical (·OH) scavenging capacity (HOSC) estimation is essential for evaluating antioxidants, natural extracts, or drugs against clinical diseases. While nanozymes offer advantages in related applications, they still face limitations in activity and selectivity. In response, this work showcases the fabrication of laminarin-modulated osmium (laminarin-Os) nanoclusters (1.45 ± 0.05 nm), functioning as peroxidase-like nanozymes within a colorimetric assay tailored for rational HOSC estimation. This study validates both the characterization and remarkable stability of laminarin-Os. By leveraging the abundant surface negative charges of laminarin-Os and the surface hydroxyls of laminarin, oxidation reactions are facilitated, augmenting laminarin-Os's affinity for 3,3',5,5'-tetramethylbenzidine (TMB) (KM = 0.04 mM). This enables the laminarin-Os-based colorimetric assay to respond to ·OH more effectively than citrate-, albumin-, or other polysaccharides-based Os. In addition, experimental results also validate the selective peroxidase-like behavior of laminarin-Os under acidic conditions. Antioxidants like ascorbic acid, glutathione, tannic acid, and cysteine inhibit absorbance at 652 nm in the colorimetric platform using laminarin-Os's peroxidase-like activity. Compared with commercial kits, this assay demonstrates superior sensitivity (e.g., responds to ascorbic acid 0.01-0.075 mM, glutathione 1-15 µg/mL, tannic acid 0.5-5 µM, and monoammonium glycyrrhizinate cysteine 1.06-10.63 µM) and HOSC testing for glutathione, tannic acid, and monoammonium glycyrrhizinate cysteine. Overall, this study introduces a novel Os nanozyme with exceptional TMB affinity and ·OH selectivity, paving the way for HOSC estimation in biomedical research, pharmaceutical analysis, drug quality control, and beyond.

Glucose Oxidase Energized Osmium with Dual-Active Centers and Triple Enzyme Activities for Infected Diabetic Wound Management.

Diabetic wounds are susceptible to bacterial infections, largely linked to high blood glucose levels (hyperglycemia). To treat such wounds, enzymes like glucose oxidase (GOx) can be combined with nanozymes (nanomaterials mimic enzymes) to use glucose effectively for purposes. However, there is still room for improvement in these systems, particularly in terms of process simplification, enzyme activity regulation, and treatment effects. Herein, the approach utilizes GOx to directly facilitate the biomineralized growth of osmium (Os) nanozyme (GOx-OsNCs), leading to dual-active centers and remarkable triple enzyme activities. Initially, GOx-OsNCs use vicinal dual-active centers, enabling a self-cascaded mechanism that significantly enhances glucose sensing performance compared to step-by-step reactions, surpassing the capabilities of other metal sources such as gold and platinum. In addition, GOx-OsNCs are integrated into a glucose-sensing gel, enabling instantaneous visual feedback. In the treatment of infected diabetic wounds, GOx-OsNCs exhibit multifaceted benefits by lowering blood glucose levels and exhibiting antibacterial properties through the generation of hydroxyl free radicals, thereby expediting healing by fostering a favorable microenvironment. Furthermore, the catalase-like activity of GOx-OsNCs aids in reducing oxidative stress, inflammation, and hypoxia, culminating in improved healing outcomes. Overall, this synergistic enzyme-nanozyme blend is user-friendly and holds considerable promise for diverse applications.

Advances and perspectives of nanozymes in respiratory diseases.

Respiratory diseases, some of the most common human diseases, have become a prominent public health and medical problem. Feasible treatment and prevention strategies are still required to prepare for respiratory emergencies. Nanotechnology has provided new technological conceptions in respiratory disease-related applications and inspired the exploration of various multifunctional nanomaterials. Among them, "nanozymes" with enzyme-like activities and nanomaterials' physicochemical properties may propel the development in this field. Over the past few decades, nanozymes have distinguished themselves in the fields of biosensing, biomedicine, imaging, and environmental protection due to their outstanding enzymatic properties, reactive oxygen species-regulating mechanism, high stability, modifiability, mass production, and others. Herein, this article reviews the research progress of nanozymes in diagnosing, treating, and preventing respiratory diseases, hoping to bring new ideas for promoting nanozymes and their beneficial applications in respiratory diseases.

[Postoperative anxiety and its relationship with life quality in patients with Ménière's diseases].

OBJECTIVE: To investigate the postoperative anxiety and its relationship with life quality in patients with Ménière's diseases.
 Methods: A total of 68 patients with Ménière's disease, who received the treatment of endolymphatic sac decompression from 2010 to 2016, were enrolled. They finished two scales (the self-rating anxiety scale and the quality of life questionnaire for endolymphatic sac decompression of Ménière's disease) by snail mail. The patients were divided into different groups based on their preoperative course, postoperative follow-up time, clinic stage and quality of life after endolymphatic sac decompression surgery, and their anxiety was analyzed. In addition, 109 gender and age-matched patients with other diseases of otorhinolaryngology served as the control group, and their anxiety was also analyzed.
 Results: There was no statistical difference in the postoperative anxiety among the patients with preoperative course for less than 1 year, 1 to 5 years or more than 5 years (all P>0.05). There was no statistical difference in the patients with different duration of follow-up (P>0.05). There was no statistical difference in the patients with the different clinic stages (all P>0.05). There was no statistical difference in the patients with the improved life or non-improved life after surgery (P>0.05). The degree of the anxiety in the Ménière's group was more severe than that in the control group (P<0.01).
 Conclusion: It needs to keep in mind that a certain degree of postoperative anxiety still keeps in patients with Ménière's disease.