Additional file 8 of Advancing prion diagnostics: full-length human E200K RT-QuIC substrate facilitates prion detection in tear fluid and improves sensitivity in cerebrospinal fluid

Supplementary Figure 8: Procedure of tear fluid collection and strip extraction. A 5 × 35 mm strip was placed on the outer corner of the lower eyelid for 8–10 min, following the standard Schirmer test for tear production. Samples were frozen within 30 min and stored at − 80 °C without further treatment for storage. For protein isolation, samples were eluted by cutting at least 15 mm of the strip into 5 mm pieces, placing them in a 1.5 mL tube with 100 μL RT-QuIC buffer, vortexing for 1 min, and incubating for 30 min. Strips were then transferred to perforated 0.5 mL tubes placed above the 1.5 mL tubes and centrifuged at 14,000 rpm (Eppendorf centrifuge 5810 R), 4 °C for 30 min to collect the extract. Samples from both eyes were pooled for analysis.