Rapid and sensitive detection of Staphylococcus aureus using a THz metamaterial biosensor based on aptamer-functionalized Fe3O4@Au nanocomposites

• Published in: Talanta (Oxford) 2024-05, Vol.272, p.125760-125760, Article 125760
• Main Authors: Yu, Wenjing, Li, Jining, Huang, Guorong, He, Zhe, Tian, Huiyan, Xie, Fengxin, Jin, Weidong, Huang, Qing, Fu, Weiling, Yang, Xiang
• Format: Article
• Language: English
• Subjects: Aptamer; biosensors; blood; detection limit; Fe3O4@Au nanocomposites; humans; magnetism; nanocomposites; public health; refractive index; Staphylococcus aureus; Terahertz metamaterials; urine
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2024.125760

Staphylococcus aureus (S. aureus) poses a serious threat to global public health, necessitating the establishment of rapid and simple tools for its accurate identification. Herein, we developed a terahertz (THz) metamaterial biosensor based on aptamer-functionalized Fe3O4@Au nanocomposites for quantitative S. aureus assays in different clinical samples. Fe3O4@Au@Cys@Apt has the dual advantages of magnetism and a high refractive index in the THz range and was used to rapidly separate and enrich target bacteria in a complex environmental solution. Furthermore, conjugation to the nanocomposites significantly increased the resonance frequency shift of the THz metamaterial after target loading. Our results showed that the shifts in the metamaterial resonance frequency were linearly related to S. aureus concentrations ranging from 1.0 × 103 to 1.0 × 107 CFU/mL, with a detection limit of 4.78 × 102 CFU/mL. The biosensor was further applied to S. aureus detection in spiked human urine and blood with satisfactory recoveries (82.4–109.6%). Our approach also demonstrated strong concordance with traditional plate counting (R2 = 0.99306) while significantly lowering the analysis time from 24 h to