N, S-Doped Carbon Dots Prepared by Peanut Protein Isolates and Cysteamine as Highly Sensitive Fluorescent Sensors for Fe2+, Fe3+ and Lactoferrin

Xinxin Wang; Xinyu Zu; Ting Wang; Yanan Zhao; Yan Liang; Xiaochen Wang; Qian Chai; Yunjuan Zhang; Hongzhong Chen; Hua Wang

doi:10.3390/polym15010216

N, S-Doped Carbon Dots Prepared by Peanut Protein Isolates and Cysteamine as Highly Sensitive Fluorescent Sensors for Fe²⁺, Fe³⁺ and Lactoferrin

Polymers (Basel). 2022 Dec 31;15(1):216. doi: 10.3390/polym15010216.

Authors

Xinxin Wang¹, Xinyu Zu¹, Ting Wang², Yanan Zhao¹, Yan Liang¹, Xiaochen Wang³, Qian Chai³, Yunjuan Zhang³, Hongzhong Chen³, Hua Wang⁴

Affiliations

¹ State Key Laboratory of Biobased Material and Green Papermaking, School of Food Sciences and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, China.
² College of Biotechnology, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, China.
³ Shandong Center for Food and Drug Evaluation & Inspection, Jinan 250014, China.
⁴ School of Materials Science and Engineering, Shandong University, Jinan 250061, China.

Abstract

Lactoferrin (LF) is an iron-binding glycoprotein with various biological activities that has been extensively used in food and medical applications. Several methods for detecting LF have been reported, but they still face challenges in terms of sensitivity and simplicity of detection. To achieve an accurate and efficient detection of LF, we developed a method for the determination of LF in lactoferrin supplements using carbon dots (CDs) fluorescent probes. The N, S-doped PPI carbon dots (N, S-PPI-CDs) were prepared using a protein (peanut protein isolate) and cysteamine as precursors. The prepared N, S-PPI-CDs exhibited intense blue fluorescence and good biocompatibility, while the fluorescence intensity of the N, S-PPI-CDs showed a good linear relationship with Fe²⁺/Fe³⁺ concentration (0-2 μM). The N, S-PPI-CDs exhibited a high potential ability to rapidly detect Fe²⁺/Fe³⁺ within 30 s, with a limit of detection (LoD) of 0.21 μM/0.17 μM. Due to the reversible binding of LF to Fe, the N, S-PPI-CDs showed a high sensitivity and selectivity for LF, with a limit of detection (LoD) of 1.92 μg/mL. In addition, LF was quantified in real sample LF supplements and showed a fluctuation in recovery of less than 2.48%, further demonstrating the effectiveness of the fluorescent N, S-PPI-CDs sensor.

Keywords: Fe2+/Fe3+ detection; N, S-PPI-CDs; biocompatibility; fluorescence probe; lactoferrin supplement detection.

Abstract

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