Gold Polyhedral Substrates for Enhanced β-Agonist Detection via Surface-Enhanced Raman Spectroscopy

Banned substances in sports are strictly enforced for the sake of keeping athletic competitions as fair as possible. However, for policies prohibiting specific substances to be effective, it requires the use of analytical techniques that can detect potential illicit substances in athletes’ bodies. In a recent study published in Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, researchers from Xihua University in Chengdu, China, led by Chuanfeng Wang, Yahui Zhang, and Xiaojun Luo, explored this topic by developing and testing a novel method for detecting β-agonists using surface-enhanced Raman spectroscopy (SERS) (1). This approach leverages gold polyhedral substrates synthesized through a seed-mediated technique, enabling highly sensitive and rapid detection of β-agonist compounds (1).

Doping for athletes. Golds, silver and bronze medal and doping syringe and pills with capsules on a gray background | Image Credit: © adragan - stock.adobe.com

β-Agonists, sometimes written as beta-agonists, are one type of banned substances that are included on the World Anti-Doping Agency's (WADA) list of prohibited substances (1). β-Agonists are bioactive catecholamine compounds naturally produced in the adrenal medulla glands of animals (1). They serve as medications to help treat specific lung conditions, such as asthma (2). They function by binding to beta-receptors in the body, and this causes certain functions to perform in the body, which include relaxing the muscles in several organs, such as the lungs (2).

However, the use of β-Agonists can result in several potentially severe side effects. Patients may experience hypertension, shakiness, and an irregular heart rate (2). Because of these deleterious side effects, using β-Agonists is disincentivized and discouraged (1).

In this study, the researchers used gold polyhedral substrates to improve the SERS signals associated with β-agonist compounds. Using SERS allowed the researchers to obtain low detection limits: 9.33 × 10⁻⁷ g/mL for salbutamol, 6.28 × 10⁻⁷ g/mL for clenbuterol, and 6.19 × 10−7 g/mL for higenamine (1). These results demonstrate the potential of SERS as a powerful tool for detecting trace amounts of β-agonists in biological samples.

To produce the gold polyhedral nanoparticles, the research team used a seed-mediated synthesis technique. Gold polyhedral nanoparticles are characterized by their shape, and their multiple corners helps amplify SERS signals (1). The enhancement factor for this system, evaluated using 4-aminothiophenol (4-ATP) as a beacon molecule, was determined to be 1.92 × 10⁵ (1).

Once the gold polyhedral nanoparticles were produced, the team conducted a series of experiments using urine samples to test the effectiveness of their method. The results were encouraging. The researchers observed great enhancement effects and a strong linear relationship between signal intensity and β-agonist concentration across a range of 10⁻³ to 10⁻⁶ g/mL (1). This approach allows for direct detection without the need for complex pretreatment processes, significantly simplifying the detection procedure.

As a result, this study can serve as another way to improve anti-doping protocols in sports. The researchers demonstrated that their method’s high sensitivity and rapid detection capabilities can effectively identify banned substances, ensuring fair and clean competition (1). The ability to quantify β-agonist concentrations with precision further enhances the integrity of anti-doping efforts (1).

By optimizing the gold polyhedral substrate and expanding its use to other banned substances, the team hopes to develop a robust and reliable tool for safeguarding the integrity of sports competitions (1). Their efforts will focus on translating these findings into actionable solutions that can be seamlessly integrated into existing anti-doping protocols (1).

Using SERS with gold polyhedral substrates represents a significant advancement in the field of molecular spectroscopy. This method not only provides a fast, simple, and effective means of detecting β-agonists but also paves the way for more comprehensive and reliable anti-doping strategies (1).

References

1. Chen, L.; Zeng, X.; Tan, R.; et al. Raman Spectroscopic Fingerprinting for the Identification and Quantitative Analysis of Sports Doping β−agonists Based on Gold Nanopolyhedra. Spectrochimica Acta Part A: Mol. Biomol. Spectrosc. 2025, 330, 125698. DOI: 10.1016/j.saa.2025.125698
2. Cleveland Clinic, Beta-agonist. Cleveland Clinic. Available at: https://my.clevelandclinic.org/health/treatments/24851-beta-agonist (accessed 2025-03-14)