Fig 2: a) Scheme of the SPR-POF probe fabrication procedure; b) Scheme of the SPR-POF functionalization process with anti-MAVS antibody; c) Experimental setup used to test the MAVS biosensor.

Fig 3: Selectivity tests. (a) Resonance wavelength variation (Δλ) obtained by testing the MAVS biosensor with four interfering human proteins (EGF, FGF, TGF-α, and TNF-α) (100 nM in PBS) and with a mixture of them (in PBS) containing also the target analyte (MAVS 1 nM). (b) SPR spectra recorded in FBS at various dilutions (1:10,000 to 1:50) and in a clinical sample from a NR patient (Case #2) diluted 1:50. (c) SPR spectra recorded in HS at various dilutions (from 1:10,000 to 1:50) and in a clinical sample from a BR patient (Case #5) diluted 1:250.

Fig 4: a) SPR spectra recorded in the presence of negative control first, and then the positive control, diluted with different dilution factors. b) Western blotting of total protein lysates for H1688 SCLC cell line with and without MAVS silencing. GAPDH was used to ensure equal loading. Original uncropped gels are reported in Figure S2.

Fig 5: Average estimated MAVS concentration in real samples. SCLC patients’ sera were collected from patients with PFS > 6 months (n = 5) and PFS < 6 months (n = 5). BR: Best Responders. LIR: Long Immuno Responders. NR: Non Responders.