Xplora spectrometer

Raman spectroscopy was carried out using ACDs in aqueous droplets on the slide. The spectra were recorded on a Horiba Jobin Yvon XploRA spectrometer equipped with a 10× objective and a laser with a wavelength of 532 nm. Data were collected between 850 cm^–1 and 1700 cm^–1 using a grating of 600 grooves per mm. They were normalized using the LabSpec Version 5 software package.

UV–Vis absorption spectra of hematin (2 × 10⁻⁵ M) in the absence or presence of fibrinogen (5 mg/mL) were obtained by a UV–Vis spectrometer (SHIMADZH UV-2550) at ambient temperature. The scans were performed with quartz cuvettes with 1 mm optical path. For Raman measurements, a volume of 10 μL hematin solution (2 × 10⁻⁵ M) in the absence or presence of fibrinogen (5 mg/mL) was deposited onto quartz substrate and allowed to dry at 30 °C and the spectra were acquired with a HORIBA JOBIN YVON XploRA spectrometer which worked in the confocal mode. The spectra were collected on the edge of the “coffee-ring” arising from the outward flow of solvent36 . A 100× objective (Olympus, MPlanN, NA 0.9) was used to focus the laser onto the sample (with spot size ∼3 μm in diameter) and also collect the back-scattered Raman light into the detector. The laser power at the sample was reduced to approximately 5.0 mW. All the spectra represent the average from three cycles of 60 seconds Raman spectra acquired consecutively under the same conditions. For every sample, Raman measurements were conducted at 5 points at least, and at every point, the Raman spectra were collected with the parameters as described above.

Raman spectra were recorded with a Horiba Xplora spectrometer equipped with a 532 nm laser with a 0.79 mW power (Kyoto, Japan). 10 μL of DND in water were deposited on a silicon substrate and dried. Each spectrum is the average of 3 acquisitions realized at different positions on the substrate. The acquisition time is one minute, cumulated 10 times.