Xingfu Bao

Antioxidative therapy has been considered an efficient strategy for the treatment of a series of excessive reactive oxygen species (ROS)-triggered diseases, including oxidative-stress-induced periodontal disease. However, current natural enzymes and nanozymes often show their high specificity toward given ROS and have insufficient antioxidative effects against multiple ROS generated in the diseases process. Meanwhile, multienzyme-based antioxidant defense systems are usually confined by the complicated synthesis as well as potential unwanted residue and toxicity. Various supports are highly needed to immobilize natural enzymes and antioxidants during the biorelated usages due to their low operational stability and difficulty of reuse. To overcome these limitations, we develop a high-performance platform by using biodegradable polydopamine nanoparticles (PDA NPs) as smart ROS scavengers in oxidative stress-induced periodontal disease. Although PDA-based materials are well-known to eliminate ROS both in vitro and in vivo, their antioxidative performance in periodontal disease and relative mechanisms have yet to be well-explored. In this study, PDA NPs can act as ROS scavengers in dental specialties with ideal outcomes. Spectroscopic and in vitro experiments provide strong evidence for the roles of PDA NPs in scavenging multiple ROS and suppressing ROS-induced inflammation reactions. In addition to the above investigations, the results from a murine periodontitis model clearly demonstrate the feasibility of PDA NPs as robust antioxidants with which to remove ROS and decrease periodontal inflammation without any side effects. Taken together, the results from our present study will provide valuable insight into the development of safe and efficient antioxidant defense platforms for further biomedical uses.

Diethanolamine (DEA) has been extensively utilized as an alkaline buffer in current assays of alkaline phosphatase (ALP) activity in the past decades. While playing the role of a buffer, the chemical reactivity of DEA has been widely ignored in such assays. Herein, we report an interesting chromogenic interaction between DEA and 4-aminophenol (AP) in the presence of H2O for the first time, which inspires us to develop a novel DEA-participated ALP activity assay by using 4-aminophenyl phosphate (APP) as a substrate. This APP/DEA-based colorimetric approach has been proved to be comparable and even superior to the conventional p-nitrophenyl phosphate (pNPP)-based one, especially in the low ALP activity region, due to its higher sensitivity. The clear response mechanism and excellent sensing performance ensure that it can be further applied to determining ALP activity in real biological samples, screening potential ALP inhibitors in vitro, establishing ALP-enabled ELISA, and even fluorophore-assisted fluorescent ALP activity assay. It is demonstrated that this strategy not only possesses a good feasibility, but also exhibits a promising outlook for a series of ALP-related and -extended detections.

An enzyme cascade-triggered reaction with novel signal generation mechanism is beneficial for the development and insight of the enzyme cascade, which is extensively used for signal transduction in potential applications. Inspired by the fluorogenic and chromogenic reaction between dopamine and resorcinol, and the specific catalytic properties of alkaline phosphatase (ALP) and tyrosinase, we designed and synthesized an unconventional substrate of ALP, named p-aminoethyl-phenyl phosphate disodium salt (PAPP). As expected, the ALP and tyrosinase-incubated PAPP solution exhibited pale yellow with intense blue fluorescence upon addition of resorcinol, owing to the ALP-catalyzed transformation of PAPP into an intermediate tyramine, and the tyrosinase-catalyzed hydroxylation of tyramine to dopamine, as well as the specific reaction between dopamine and resorcinol. Therefore, an enzyme cascade system has been developed herein based on the ALP and tyrosinase coupled enzymes-triggered fluorogenic and chromogenic reaction. According to the direct relationship between the activity of ALP/tyrosinase and absorbance/fluorescence intensity of the resultant solution, the proposed enzyme cascade-triggered reaction was utilized for assaying ALP and tyrosinase activity with fluorometric and colorimetric dual-readout signals. Furthermore, such enzyme cascade catalysis process was integrated into the ALP-based cascade enzyme-linked immunosorbent assay with dual-readout signals, resulting in the sensitive detection of cardiac troponin I in diluted serum.

Due to its exceptional quality as a biomedical metal, stainless steel is often utilized to produce a broad range of medical tools. The resistance of stainless steel to corrosion is a key indicator of how long and how effective it will serve its intended purpose, and it is an important factor in determining the biocompatibility of the material. However, due to the complex physiological environment within the human body, the corrosion management of medical-grade stainless steel is facing several challenges. In this article, an overview of the factors that influence the corrosion performance of medical-grade stainless steel is provided, and new technologies and methods that have been developed in recent years to improve the corrosion resistance are discussed. These cutting-edge methods are expected to improve the corrosion resistance and longevity of medical-grade stainless steel, providing strong support for the increased applicability of the material in the medical industry.

, where the absorbance and fluorescence intensity are directly related to the concentration of added tyrosinase (i.e., the amount of conversion of tyramine to dopamine). The overall process of sensing tyrosinase activity takes less than 100 min at ambient temperature and pressure conditions with exceedingly simple operation procedure, explicit response mechanism, and formation of fluorophore with high quantum yield from scratch. Furthermore, such a convenient, rapid, cost-effective, and highly sensitive dual-readout assay exhibits promising prospect for the tyrosinase activity in extensive bioassays and clinic research as well as in screening potential tyrosinase inhibitors.