Immediately after treatment, the activated polymer surface was grafted by immersion into water solution of BSA (concentration 2 wt.%, Sigma-Aldrich Corporation, St. Louis, MO, USA) for 24 h at room temperature (RT). The excess of non-bound molecules was removed by consequent immersion of the samples into distilled water for 24 h. The samples were dried at RT for 13 h. Diagnostic techniques The surface wettability was determined by water contact angle (WCA) measurement immediately after modification and after

17 days using selleck screening library distilled water (drop of volume 8 μl) at 20 different positions and surface energy selleck inhibitor evaluation system (Advex Instruments, Brno, Czech Republic). WCA of the plasma-treated samples strongly depends on the time from treatment.

The presence of the grafted protein molecules on the modified surface was detected by nano-LC-ESI-Q-TOF mass spectrometry. The samples Cediranib order were placed in Petri dish, and 10 μl of solutions (2 μl trypsin, concentration 20 μg μl−1 in 100 μl 50 mmol l−1 NH4HCO3) was applied on the sample surface. In the inside perimeter of Petri dishes, pieces of wet pulp were placed, in order to avoid drying of the solution on the surface of foils, and consequently the dish was closed. After 2 h of the molecule cleavage, new peptides were concentrated and desalted by reverse-phase zip-tip C18 (EMD Millipore Corporation, Billerica, MA, USA) at RT. The presence of the carbon, oxygen, and nitrogen atoms in the modified surface layer was detected by X-ray photoelectron spectroscopy (XPS). The spectra of samples were measured with Omicron Nanotechnology

Isotretinoin ESCAProbeP spectrometer (Omicron Nanotechnology GmbH, Taunusstein, Germany) (1,486.7 eV, step size 0.05 eV, area 2 × 3 mm2). This elemental analysis was performed 17 days after modification of the samples. The changes in surface morphology and roughness of samples were examined 17 days after modification by atomic force microscopy (AFM) using a Veeco CP II device (Bruker Corporation CP-II, Santa Barbara, CA, USA) (‘tapping’ mode, probe RTESPA-CP, spring constant 20 to 80 N∙m−1). The surface roughness value (R a) represents the arithmetic average of the deviation from the center plane of the samples. The electrokinetic analysis (zeta potential) of the samples was done using SurPASS instrument (Anton Paar, Graz, Austria), (adjustable gap cell, 0.001 mol∙dm−3 electrolyte KCl, pH = 6.3, RT). The values of the zeta potential were determined by two methods, a streaming current and a streaming potential and calculated by Helmholtz-Smoluchowski and Fairbrother-Mastins equations [18]. Each sample was measured four times with the experimental error of 10%. Biological test of adhesion and proliferation For evaluation of cell number and morphology in cell culture experiments, three pristine and modified HDPE and PLLA samples were used for analysis by randomly chosen fields.