Highly Enhanced Enzymatic Activity of Mn-Induced Carbon Dots and Their Application as Colorimetric Sensor Probes.

Ahyun Lee,Wooseok Kang,Jin-Sil Choi

doi:10.3390/nano11113046

Abstract

Nanomaterial-based enzyme mimetics (nanozymes) have attracted significant interest because of their lower cost and higher stability compared to natural enzymes. In this study, we focused on improving the enzymatic properties of metal induced N-doped carbon dots (N-CDs), which are nanozymes of interest, and their applications for sensory systems. For this purpose, Mn(acetate)2 was introduced during the synthetic step of N-doped carbon dots, and its influence on the enzymatic properties of Mn-induced N-CDs (Mn:N-CDs) was investigated. Their chemical structure was analyzed through infrared spectroscopy and X-ray photoelectron spectrometry; the results suggest that Mn ions lead to the variation in the population of chemical bonding in Mn:N-CDs, whereas these ions were not incorporated into N-CD frameworks. This structural change improved the enzymatic properties of Mn:N-CDs with respect to those of N-CDs when the color change of a 3,3′,5,5′-tetramethylbenzidine/H2O2 solution was examined in the presence of Mn:N-CDs and N-CDs. Based on this enhanced enzymatic property, a simple colorimetric system with Mn:N-CDs was used for the detection of γ-aminobutyric acid, which is an indicator of brain-related disease. Therefore, we believe that Mn:N-CDs will be an excellent enzymatic probe for the colorimetric sensor system.

Highlights

IntroductionA chemical or physical transducer converts a chemical or biological signal into a recognizable signal (e.g., color or electrical signal)
In sensor systems, a chemical or physical transducer converts a chemical or biological signal into a recognizable signal
Mn-induced N-carbon dots (CDs) (Mn):N-doped carbon dots (N-CDs) with strong enzymatic effects can be applied as a colorimetric sensor probe for the detection of GABA

Summary

Introduction

A chemical or physical transducer converts a chemical or biological signal into a recognizable signal (e.g., color or electrical signal). Natural enzymes are effective chemical transducers, and they are widely used in sensor systems [1,2]. HRP accelerates H2 O2 -dependent one-electron oxidation, generating an electrical signal that allows for the sensitive detection of targets [6,7,8,9]. Regardless of their novel catalytic effectiveness, natural enzymes have limitations in industrial applications, such as low stability in harsh environmental conditions and relatively high costs of preparation, purification, and storage. Over the past few decades, researchers have made extensive efforts to develop replacements

Methods

Results

Conclusion