Dv401 bv

Raman spectra were collected with a Raman microscope (BioParticle Explorer, rap.ID Particle Systems GmbH, Berlin, Germany). A solid-state frequency doubled Nd:Yag module (Cobolt Samba, 25 mW, Cobolt AB, Solna, Sweden) with an excitation wavelength of 532 nm was used. The laser light was focused through an 100x objective (Olympus MPlanFLN 100xBD) onto the sample. This result in a spot size <1 µm laterally so that approximately 7 mW hit the sample.The bacteria were measured from different regions of the specimens. The Rayleigh scattering was removed by two edge filters after collecting the 180°-backscattered light, while a thermoelectrically cooled CCD camera registered the light (Andor DV401-BV). A single-stage monochromator, consisting of a 920-line/mm grating, diffracted the backscattered light so that the spectral resolution accounted for about 8 cm⁻¹. The integration time per Raman spectrum (15 to 3275 cm⁻¹) was 5 seconds. Approximately 50 single-bacteria Raman spectra were measured per batch (biological replicate) and collected from four separately prepared batches for further analysis. The evaluation of the classification models was performed by using of about 20 spectra from other isolates (Table 2).

The topography of the CHO cells was evaluated by AFM imaging, and measurements of the cells’ surface roughness were performed using the NT-MDT Solver system from NT-MDT Inc. in semi-contact mode using commercial silicon cantilevers with a tip diameter of 10 nm and force constant of 1.5 N/m. Cell surface roughness analysis was performed on the topography images of cell surface areas (5 × 5 µm) using Nova software from NT-MDT Inc. Surface roughness factors (10-point height (Sz) and average) were determined.
Energy-dispersive X-ray spectroscopy (EDS) analysis was performed to determine the TiO₂-NPs content in CHO cells after exposure to the TiO₂-NP colloidal solution. The samples were examined using a Hitachi S-3400N Type II scanning electron microscope (Tokyo, Japan).
The Raman spectra of CHO cells were registered using a confocal Raman system ‘upright INTEGRA Spectra’ from NT-MDT, using a 100× objective, 20 mW 532 nm wavelength DPSS laser, and a spectrometer—Solar TII from NT-MDT, equipped with a TE-cooled (−60 °C) CCD camera—DV401-BV from Andor Technology (Oxford Instruments, Abingdon, UK). The power of the laser at the sample was 0.4 mW, and the acquisition time was 20 s.