Template-Regulated Bimetallic Sulfide Nanozymes with High Specificity and Activity for Visual Colorimetric Detection of Cellular H₂O₂

Abstract

For the past several decades, most of the research studies on nanozymes have been aimed at improving their catalytic activity and diversity; however, developing nanozymes with strong catalytic activity and great specificity remains a challenge. Herein, a simple and efficient template synthesis method was used to synthesize bimetallic sulfide nanoparticles, NiCo 2 S 4 NPs, and prove that they have excellent peroxidase-like activity with good specificity. By regulating polyvinyl pyrrolidone (PVP) and hexadecyl trimethyl ammonium bromide as the templating agent, we have obtained the NiCo 2 S 4 (PVP) NPs with a high Ni/Co ratio, thus exhibiting superior peroxidase activity. In addition, the NiCo 2 S 4 NPs selectively catalyzed and oxidized colorless 3,3,5,5-tetramethylbenzidine (TMB). On being treated with H 2 O 2 , TMB turns blue while other substrates did not undergo the oxidation reaction under the same conditions, such as 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium (ABTS) and dopamine. The high specificity of NiCo 2 S 4 NPs is due to the strong electrostatic driving coordination between negatively charged NiCo 2 S 4 NPs and positively charged TMB. Due to the peroxidase activity of the developed NiCo 2 S 4 NPs, a simple, low-cost, and reliable colorimetric method was established. Simultaneously, this method for in situ quantitative monitoring of H 2 O 2 produced by MDA-MB-231 cells was also achieved. This study has provided a theoretical basis for the improvement of the activity and specificity of bimetallic sulfide nanozymes and may offer guidance for the further reasonable design of related materials.

Fe-Single-Atom Nanozyme Catalysts for Sensitive and Selective Detection of Nitrite via Colorimetry and Test Strips

“…15 The bimetallic sulfide NiCo 2 S 4 nanozyme was used for the colorimetric detection of intracellular hydrogen peroxide. 16 Although these new nanozyme-based strategies can overcome the limitations coming from temperature and pH on the catalytic activity of traditional natural nanozymes, they still have shortcomings such as lower catalytic activity, 17 poor catalytic selectivity, 17,18 insufficient metal utilization, and complex mechanism in the catalytic process. 19 The catalytic activity of traditional nanomaterials is limited due to their inhomogeneous catalytic active sites.…”

Peroxidase-Mimicking Hierarchically Organized Gold Particles for Glucose Detection

“…Natural enzymes are the most outstanding catalysts in biological processes in all living organisms . Since the preparation, purification, and storage of natural enzymes are difficult, usually time-consuming, and expensive, , and the inherent disadvantage that the catalytic activity of natural enzymes is easily inhibited, artificial enzyme mimics (nanozymes) have been promoted, becoming the focus of research. , The rise and development of nanoscience and technology have opened up new avenues for the application of nanozymes. , Compared with natural enzymes, nanozymes have the advantages of easy large-scale production, controllable activity, high environmental resistance, and lower cost. − …”

“…For example, H 2 O 2 is one of the main products of the glucose oxidation reaction obtained with the help of glucose oxidase (GOx), which plays an important role in many biological processes, , so it is particularly important to prepare excellent HRP mimics. In recent years, breakthroughs have been made in the research of nanomaterials as peroxidase mimics which have broad application prospects. − Among them, gold nanoparticles have become a research hotspot because of their excellent catalytic performance and wide application in many fields. − For example, Li et al designed defect-rich molybdenum disulfide nanosheets loaded with bovine serum albumin-modified gold nanoparticles (MoS 2 @Au@BSA NSs), which have a variety of enzyme activities including peroxidase and can significantly accelerate the healing of diabetic wounds through a cascade reaction; the gold–platinum nanoparticles (AuPt NDs) synthesized by Zhang et al not only have strong peroxidase activity but also can fight bacterial infection through a combination of chemical kinetics and photothermal therapy.…”

One-Pot Preparation of Imidazole-Ring-Modified Graphitic Carbon Nitride Nanozymes for Colorimetric Glucose Detection

“…Compared with natural enzymes, nanozymes exhibit significant advantages, such as low cost, adjustable catalytic activities and flexibility in structure design, which make them gradually become substitutes for natural enzymes and be gradually applied to lots of fields, especially in biosensing [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 ]. Because Fe 3 O 4 nanoparticles were first reported in 2007 to show intrinsic peroxidase-like activity by Yan’s group [ 9 ], lots of nanozymes, such as noble metal [ 10 , 11 , 12 , 13 , 14 ], metallic oxide [ 15 , 16 ], metal sulfide [ 17 , 18 ], graphene oxide [ 19 , 20 , 21 ], and carbon quantum dots [ 22 , 23 ], have been reported. Among them, two-dimensional (2D) materials, such as GO, have been widely explored as nanozymes, owing to its large specific surface area and high atomic utilization [ 24 , 25 ].…”