Development of a Dual-Epitope Nanobody-Based Immunosensor with MXenes@CNTs@AuNPs for Ultrasensitive Detection of Rotavirus

• Published in: Analytical chemistry (Washington) 2024-12, Vol.96 (49), p.19678-19686
• Main Authors: Hu, Wenjin, Yang, Shixiang, Wang, Xiaolong, Li, Xi, Lei, Liusheng, Lin, Huai, Yuan, Qingbin, Mao, Daqing, Luo, Yi
• Format: Article
• Language: English
• Subjects: Antigens, Viral - analysis; Antigens, Viral - immunology; Biosensing Techniques - methods; Epitopes - chemistry; Epitopes - immunology; Gold - chemistry; Humans; Immunoassay - methods; Limit of Detection; Metal Nanoparticles - chemistry; Rotavirus - immunology; Rotavirus - isolation & purification; Single-Domain Antibodies - chemistry; Single-Domain Antibodies - immunology
• ISSN: 0003-2700; 1520-6882; 1520-6882
• DOI: 10.1021/acs.analchem.4c04826

Immunoassays have become essential tools for detecting infectious viruses. However, traditional monoclonal antibody-dependent immunoassays are costly, fragile, and unstable, especially in complex media. To overcome these challenges, we have developed cost-effective, robust, and high-affinity nanobodies as alternatives to monoclonal antibodies for rapid detection applications. We engineered dual-epitope nanobody (NB) pairs and incorporated them into a sandwich immunosensor design to detect transmitted rotaviruses in rectal swabs and wastewater samples. To further enhance sensitivity, we synthesized an advanced two-dimensional material, MXenes@CNTs@AuNPs, which offers an extensive specific surface area that supports the enrichment and immobilization of NBs. This integration with catalase-modified magnetic probes facilitates signal generation. Subsequently, our sensor achieved a detection limit of 0.0207 pg/mL for the rotavirus VP6 antigen, significantly outperforming commercial antigen kits with a sensitivity enhancement of 3.77 × 105-fold. The exceptional sensor performance extended to specificity, repeatability, stability, and accuracy across various sample types, establishing it as a promising tool for rotavirus detection. This research outlines a viable strategy for creating a robust and ultrasensitive analytical nanoprobe, thereby addressing the critical need for efficient and reliable viral detection methods in various environments.