Fig. 1. The process of conical fiber surface functionalization.

Fig. 2. Surface raman spectroscopy diagram and SEM images of microfiber under different conditions

Fig. 3. Expression and purification of MPT64 and Ag85B proteins

Fig. 4. Secondary structure of the adapter protein and its molecular docking results with MPT64 and Ag85B proteins

Fig. 5. Binding studies of MPT64⁃AP and Ag85B⁃AP proteins to MPT64 and Ag85B proteins using fluorescence spectroscopy

Fig. 6. The transmission spectra of different concentrations of target proteins detected by MPT64⁃AP@GO and Ag85B⁃AP@GO modified ensors and the corresponding relationships between wavelengths and concentrations

Fig. 7. The optical response characteristics of different sensors were compared under undisturbed and disturbed conditions to evaluate their performance differences（n = 3）， ***p < 0.001

Fig. 8. The transmission spectrum and wavelength shift histogram of the micro⁃fiber sensor（n = 3）， ***p < 0.001

Fig. 9. The expression and purification of SARS⁃CoV⁃2 N protein and the screening of RNA / DNA aptamers

Fig. 10. The electrophoretic migration diagram of RNA⁃AP and DNA⁃AP

Fig. 11. The binding affinity measurement spectrum of RNA⁃AP and DNA⁃AP with the N protein

Fig. 12. Detection of N protein in FBS

Fig. 13. The optical response of the RNA⁃AP and DNA⁃AP to N proteins solution was compared under the potential interference of high concentrations of Asn, Cit, Urea and BSA （n = 3）， ***p < 0.001

Fig. 14. Transmission spectra and wavelength shift histograms of RNA⁃AP@GO and DNA⁃AP@GO modified sensors for detecting FBS solutions with and without N protein doping，（n = 3）， ***p < 0.001