Varigatr

Ellipsometry measurements were performed
on a JA Woollam M-20000 DI ellipsometer using a Cauchy model for the
polymer layer. Infrared spectroscopy measurements were performed on
a Thermo-Fisher Nicolet iS50 FTIR equipped with a variable angle reflectance
accessory by Harrick VariGATR and a germanium crystal. X-ray photoelectron
spectroscopy (XPS) measurements were taken on a Thermo-Fisher K-Alpha
Plus XPS/UPS instrument with a monochromatic Al X-ray Source (1.486
eV). Survey spectra (1350 to −10 eV) were taken with 1 eV steps;
high resolution O 1s, N 1s, C 1s, and Si 2p spectra were taken with
0.1 eV steps.

The spectra of a bare Ti surface, as well as p-, PC-, and PCN-coated Ti surfaces was measured using a Nicolet 6700 FTIR spectrometer (Thermo Fisher Scientific, Waltham, MA, United States) with Ge-ATR arrangement (VariGATR, Harrick Scientific, Pleasantville, NY, United States). The experimental setup for all spectra included 3,000 scans, an applied force of 350 N, an incident angle of 65°, and 4 cm⁻¹ resolution.

Infrared spectra of MoS₂ nanosheets and functionalized MoS₂ nanosheets were recorded with a Thermo Scientific Nicole iS50 FT-IR using an Attenuated Total Reflectance (ATR) stage. The tool was equipped with a deuterated triglycine sulfate (DTGS) detector and KBr window. A Harrick VariGATR sampling stage with a 65° Germanium ATR crystal was used in this study. ATR-FTIR specimens were prepared by drop casting the solutions on silicon wafer with 300 nm SiO₂ as substrate. The contact area was about 1 cm². All spectra were recorded between 4000 and 600 cm⁻¹ with a resolution of 4 cm⁻¹ and 256 scans.

Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectrograms were performed to establish the binding of the EDC–NHS crosslinker to the Mo surface, and subsequent binding of IL-6 and CRP antibody to the EDC–NHS crosslinker. The tool was equipped with a deuterated triglycine sulfate detector and KBr window. A Harrick VariGATR sampling stage with a 65° germanium ATR crystal was used in this study. Measurements were taken as an average of 512 scans in the range of 4000–600 cm^-1 with 4 cm^-1 resolution. ATR-FTIR slides were prepared on cleaned glass slides with analogous metal deposition to the electrode fabrication process. The slides were incubated with 100 μl of the EDC–NHS mixture for 1 h. A 3 × PBS wash was performed to remove any unbound crosslinker. After washing and completely drying with nitrogen, the Mo EDC–NHS measurement was taken. After EDC–NHS functionalization, 100 μl of 10 μg/ml target antibody was incubated on the slide surface for an additional 30 min (one slide for IL-6 antibody and one slide for CRP). A 3× PBS wash was performed to remove unbound antibodies and the slides were dried with nitrogen and silica desiccant beads before the measurements were taken. All measurements represent individual slide preparations, with none being used more than once.