Ultrasensitive platform for the determination of biothiols using aggregation-induced emission of gold-cysteine nanosheets

Mohamed Ibrahim Halawa; Fathalla Belal; Alaa A Salem; Lei Su; Xueji Zhang

doi:10.1016/j.bios.2025.117131

Ultrasensitive platform for the determination of biothiols using aggregation-induced emission of gold-cysteine nanosheets

Biosens Bioelectron. 2025 Jan 3:272:117131. doi: 10.1016/j.bios.2025.117131. Online ahead of print.

Authors

Mohamed Ibrahim Halawa¹, Fathalla Belal², Alaa A Salem³, Lei Su⁴, Xueji Zhang⁵

Affiliations

¹ Guangdong Laboratory of Artificial Intelligence and Digital Economy (SZ), Shenzhen University, Shenzhen, 518060, China; Marshall Laboratory of Biomedical Engineering, Shenzhen Key Laboratory of Nano-Biosensing Technology, School of Biomedical Engineering, Shenzhen University Medical School, Shenzhen University, Shenzhen, 518060, China; Department of Pharmaceutical Analytical Chemistry, Faculty of Pharmacy, Mansoura University, Mansoura, 35516, Egypt; Department of Chemistry, College of Science, United Arab Emirates University, Al Ain, 15551, United Arab Emirates. Electronic address: mohamedhalawa@uaeu.ac.ae.
² Department of Pharmaceutical Analytical Chemistry, Faculty of Pharmacy, Mansoura University, Mansoura, 35516, Egypt.
³ Department of Chemistry, College of Science, United Arab Emirates University, Al Ain, 15551, United Arab Emirates. Electronic address: Asalem@uaeu.ac.ae.
⁴ Marshall Laboratory of Biomedical Engineering, Shenzhen Key Laboratory of Nano-Biosensing Technology, School of Biomedical Engineering, Shenzhen University Medical School, Shenzhen University, Shenzhen, 518060, China. Electronic address: sulei@szu.edu.cn.
⁵ Guangdong Laboratory of Artificial Intelligence and Digital Economy (SZ), Shenzhen University, Shenzhen, 518060, China; Marshall Laboratory of Biomedical Engineering, Shenzhen Key Laboratory of Nano-Biosensing Technology, School of Biomedical Engineering, Shenzhen University Medical School, Shenzhen University, Shenzhen, 518060, China. Electronic address: zhangxueji@szu.edu.cn.

PMID: 39764980
DOI: 10.1016/j.bios.2025.117131

Abstract

Highly ordered ultrathin nanosheets (NSs) of Au(I)-Cys were fabricated through aggregation-induced supramolecular self-assembly triggered by an extended agitation in an alkaline environment. The synthesized Au(I)-Cys NSs exhibited intense luminescence and exceptional chirality. Remarkably, additions of biothiols to Au(I)-Cys NSs have significantly enhanced their luminescence emission, and circular dichroism properties coupled with morphological modulations into nanoflowers, nanodendrites, or closely packed aggregates. These new findings of Aggregation-Induced Luminescence Enhancement (AIEE) and Aggregation-Induced Circular Dichroism Enhancement (AICE) were attributed to multiple interactions involved such as Au-S bonding, stacked H-bonding, and strong aurophilic Au(I)···Au(I), ligand-metal-charge-transfer (LMCT) and ligand-metal-metal-charge-transfer (LMMCT). The AIEE phenomenon of the fabricated Au(I)-Cys NSs was utilized for developing a highly sensitive luminescent platform for determining homocysteine (Hcy), cysteine (Cys), and glutathione (GSH) biothiols in human serum. The developed platform is simple, fast, sensitive, and highly selective for the determination of biothiols through the concentration ranges of (0.25-100.0 μM), (0.625-40.0 μM), and (5.00-600.0 μM), with a lower detection limit (S/N = 3:1) of 0.15, 0.10 and 1.20 μM for Hcy, Cys, and GSH; respectively. Interestingly, irradiation of Au(I)-Cys NSs with a high-energy electron beam during TEM analysis led to an in-situ transformation of the Au(I)-Cys NSs into gold nanoclusters (AuNCs). This phenomenon provided an innovative bottom-up strategy for the synthesis of AuNCs that could be employed in various biological and therapeutic applications. Optimization of the applied voltage and electron beam's exposure time has been found effective in synthesizing precisely designed and size-controlled AuNCs.

Keywords: Aggregation-induced emission; Au(I)-cysteine complexes; Biothiols; Chiralty enhancement; Gold nanoclusters.