Green Synthesis of Biocompatible Epigallocatechin Gallate-Derived Carbon Dots for Dual Fluorescent Detection of pH and Fe3

Juefei Wu; Yawei Ge; Qinying Tang; Kang Hu; Yi Wang; Ru Zhang; Yuxiao Mao; Bin Li

doi:10.1021/acsomega.5c11901

Green Synthesis of Biocompatible Epigallocatechin Gallate-Derived Carbon Dots for Dual Fluorescent Detection of pH and Fe³

ACS Omega. 2026 Jan 27;11(5):8637-8647. doi: 10.1021/acsomega.5c11901. eCollection 2026 Feb 10.

Authors

Juefei Wu^{1

2}, Yawei Ge^{1

2}, Qinying Tang^{1

2}, Kang Hu^{1

2}, Yi Wang^{1

2}, Ru Zhang^{1

2}, Yuxiao Mao³, Bin Li^{1

2}

Affiliations

¹ Institute of Smart Biomaterial Materials, School of Materials Science and Engineering, Zhejiang Sci-Tech University, Hangzhou 310018, P. R. China.
² Zhejiang-Mauritius Joint Research Center for Biomaterials and Tissue Engineering, Zhejiang Sci-Tech University, Hangzhou 310018, P. R. China.
³ Hangzhou Academy of Agricultural Sciences, Hangzhou 310000, P. R. China.

Abstract

Sensitive and biocompatible fluorescent probes capable of simultaneously detecting pH and Fe³⁺ are crucial for applications in environmental monitoring, biomedical diagnostics, and food safety. In this study, we present an environmentally friendly, one-step hydrothermal synthesis of multifunctional carbon dots (ECDs) utilizing epigallocatechin gallate (EGCG) as a natural carbon precursor. The synthesized ECDs exhibit pronounced pH-dependent fluorescence quenching over a broad pH spectrum (1.3-13.5), characterized by a sigmoidal response (R ² = 0.9918) and remarkable sensitivity within the physiological range (pH 6-8). The mechanism of pH-induced quenching of ECDs has been verified to be the aggregation of ECDs and surface deprotonation under high-pH conditions. Furthermore, the ECDs facilitate highly selective detection of Fe³⁺ through fluorescence quenching, a process attributed to electron transfer from EGCG-derived phenolic groups. Its fluorescence response shows a linear relationship within the Fe³⁺ concentration range of 1-125 μM with R ² = 0.995. Additionally, the ECDs demonstrate excellent biocompatibility (cell viability >90%, hemolysis <5%) and exhibit significant antibacterial activity against Escherichia coli and Staphylococcus aureus. This research illustrates a straightforward approach to developing eco-friendly, cost-effective, and multifunctional probes for integrated sensing and antimicrobial applications.