Sensitive detection of clenbuterol by hybrid iridium/silicon nanowire-enhanced laser desorption/ionization mass spectrometry

Bovine Omasum-Inspired Interfacial Carbon-Based Nanocomposite for Saliva Metabolic Screening of Gastric Cancer

Gastric cancer is one of the most common malignant digestive cancers, and its diagnostic has still faced challenges based on metabolic analysis due to complex sample pretreatment and low metabolite abundance. In this study, inspired by the structure of bovine omasum, we in situ synthesized a novel interfacial carbon-based nanocomposite of graphene supported nickel nanoparticles-encapsulated in the nitrogen-doped carbon nanotube (Ni/N-CNT/rGO), which was served as a novel matrix with enhanced ionization efficiency for the matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) saliva metabolic analysis of gastric cancer. Benefiting from its high sp² graphitic degree, large surface area, strong UV absorption, and rich active sites, Ni/N-CNT/rGO matrix exhibited excellent performances of reproducibility, coverage, salt-tolerance, sensitivity, and adsorption ability in MALDI-TOF MS. The differential scanning calorimetry (DSC) and thermal conversion behaviors explained the highly efficient LDI mechanism. Based on saliva metabolic fingerprints, Ni/N-CNT/rGO assisted LDI MS with cross-validation analysis could successfully distinguish gastric cancer patients from healthy controls through the screening of four potential biomarkers with an accuracy of 92.50%, specificity of 88.03%, and sensitivity of 97.12%. This work provided a fast and sensitive MS sensing platform for the metabolomics characterization of gastric cancer and might have potential value for precision medicine in the future.

Paper-Based Fluidic Sensing Platforms for β-Adrenergic Agonist Residue Point-of-Care Testing

The illegal use of β-adrenergic agonists during livestock growth poses a threat to public health; the long-term intake of this medication can cause serious physiological side effects and even death. Therefore, rapid detection methods for β-adrenergic agonist residues on-site are required. Traditional detection methods such as liquid chromatography have limitations in terms of expensive instruments and complex operations. In contrast, paper methods are low cost, ubiquitous, and portable, which has led to them becoming the preferred detection method in recent years. Various paper-based fluidic devices have been developed to detect β-adrenergic agonist residues, including lateral flow immunoassays (LFAs) and microfluidic paper-based analytical devices (μPADs). In this review, the application of LFAs for the detection of β-agonists is summarized comprehensively, focusing on the latest advances in novel labeling and detection strategies. The use of μPADs as an analytical platform has attracted interest over the past decade due to their unique advantages and application for detecting β-adrenergic agonists, which are introduced here. Vertical flow immunoassays are also discussed for their shorter assay time and stronger multiplexing capabilities compared with LFAs. Furthermore, the development direction and prospects for the commercialization of paper-based devices are considered, shedding light on the development of point-of-care testing devices for β-adrenergic agonist residue detection.

A label-free aptasensor for rapid detection of clenbuterol based on SYBR GREEN I

A label-free fluorescent biosensor based on clenbuterol binding aptamer and the fluorescent intercalator SYBR Green I (SGI) was established for the sensitive and selective detection of clenbuterol. In the absence...

Highly Sensitive Colorimetric/Surface-Enhanced Raman Spectroscopy Immunoassay Relying on a Metallic Core-Shell Au/Au Nanostar with Clenbuterol as a Target Analyte

Lateral flow immunoassay (LFIA) has emerged as an effective technique in the field of food safety and environmental monitoring. However, sensitive and quantitative detection is still challenging for LFIAs in complex environments. In this work, a dual-model colorimetric/SERS lateral flow immunoassay for ultrasensitive determination of clenbuterol was constructed based on a metallic core-shell Au/Au nanostar acting as a multifunction tag. Raman reporter molecules are located between the core (AuNP) and shell (Au nanostar) to form a sandwich structure, which contributes to eliminate the environmental interference and improve the detection stability. In addition, the Au/Au nanostar provides a much higher Raman enhancement due to the presence of sharp tips and larger surface roughness in comparison with gold nanoparticles (AuNPs). Thus, on the basis of the antibody-antigen interaction, the dual-model immunoassay can produce strong colorimetric and surface-enhanced Raman spectroscopy (SERS) signals for highly sensitive detection of the target analyte, clenbuterol. Under optimal conditions, clenbuterol could be detected by the colorimetric model with a visual detection limit of 5 ng/mL. Meanwhile, the SERS signal of the Au/Au nanostar was accumulated on the test line for the SERS model detection with a quantitative detection limit as low as 0.05 ng/mL, which is at least 200-fold lower than that of the traditional AuNPs-based immunoassay. Furthermore, recovery rates of the proposed method in food samples were 86-110%. This dual-model immunoassay provides an effective tool for antibiotic residues analysis and demonstrates a broad potential for future applications in food safety monitoring.