Development of an Ultrasmall and Biocompatible Platinum Nanozyme Encapsulated by Zwitterionic Dendrimer for Highly Sensitive Detection of Glucose

• Published in: Langmuir Vol. 38; no. 18; pp. 5568 - 5578
• Main Authors: Cui, Yanshuai, Liu, Kai, Cui, Tianming, Liang, Bo, Sun, Haotian, Wang, Longgang
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 10.05.2022
• Subjects: Colorimetry - methods; Dendrimers; Fibrinogen; Glucose; HeLa Cells; Humans; Hydrogen Peroxide - chemistry; Metal Nanoparticles - chemistry; Peroxidase; Peroxidases; Platinum - chemistry
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/acs.langmuir.2c00168

Many kinds of noble metal nanoparticles can mimic the peroxidase-like function of horseradish peroxidase, which results in their wide applications in bio-related detection and drug delivery. However, those metal nanoparticles usually have low stability and reduced catalytic activity in biological complex medium. Herein, a zwitterionic peroxidase-like enzyme has been developed, which has high stability in fibrinogen solutions and high sensitivity for glucose detection. Maleic anhydride, cysteamine, and zwitterionic peptide EKEKC (EK-5) were used to modify generation 5 poly­(amido amine) dendrimers (G5 PAMAM) to prepare zwitterionic dendrimer G5MEKnC with nonfouling properties. Finally, the G5MEKnC-encapsulated platinum nanoparticles (Pt n -G5MEK50C) were prepared by entrapping the platinum nanoparticles (1.40 nm) in the catalytic centers in the interior of G5MEK50C. Pt55-G5MEK50C showed high stability in the buffer solution and the fibrinogen solution within 4 days. They also displayed high biocompatibility toward HeLa cells based on cytotoxicity results and morphological observations. Furthermore, the catalytic oxidation of 3,3′,5,5′-tetramethylbenzidine with H2O2 by Pt55-G5MEK50C followed the Michaelis–Menten equation, which confirmed their peroxidase-like properties. The catalytic mechanism was due to the generation of •OH from H2O2. More importantly, the peroxidase-like ability of Pt55-G5MEK50C was successfully used to establish a method for the determination of glucose concentration with a broad linear range of 1–2000 μM and a low detection limit of 0.1 μM. This method was highly accurate for the determination of glucose concentration in plasma. The zwitterionic dendrimer template enhanced the properties of Pt55-G5MEK50C. Taken together, a new kind of biocompatible nanozyme has been developed and successfully used for the sensitive detection of glucose in bio-related medium.