The chemical distribution maps of oxygen (a), carbon (b) and titanium (c) obtained for the RAPID implant.

<p>The distribution of the elements is grain type with carbon spread all over the surface while titanium is almost homogenous.</p

The C1s (a) and O1s (b) core lines recorded for as received and after photofunctionalization samples.

<p>The lines in red show the decontamination effect of the UVC irradiation decreasing the hydrocarbons peak and increasing the Oxygen peak.</p

Atomic concentration calculations obtained from the AES and XPS spectra for the surfaces of RAPID implant as received and after UVC irradiation.

<p>Atomic concentration calculations obtained from the AES and XPS spectra for the surfaces of RAPID implant as received and after UVC irradiation.</p

Atomic concentration of carbon, nitrogen, oxygen and titanium calculated from C1s, N1s, O1s, Al2p, Ti2p and F1s core lines for BASE and RAPID implants.

<p>Atomic concentration of carbon, nitrogen, oxygen and titanium calculated from C1s, N1s, O1s, Al2p, Ti2p and F1s core lines for BASE and RAPID implants.</p

Line shape analysis of C1s and O1s spectra for the implant as received (a and c) and after photofunctionalization (b and d).

<p>Comparing (a and b) the intensity of the peak at 285 eV corresponding to the carbon contamination is highly reduced. The oxygen lines (c and d) show an increase in oxygen peak.</p

Scheme representing the interactions of carboxyl and amine groups with TiO2 surface when exposed to the atmosphere.

<p>The surface shown is TiO2 (110), with Ti (light blue) and O (orange). See text for details.</p

Electron microscope images obtained from magnification x500 recorded for BASE (a) and RAPID (b) implants as received.

<p>The contrast from light to dark areas suggest a considerable degree of roughness of the analysed areas. Comparing (a and b) the surfaces of both type implants are quite similar.</p

Atomic concentration of carbon, nitrogen, oxygen and titanium calculated from C1s, N1s, O1s, Al2p, Ti2p and F1s core lines for BASE and RAPID implants.

<p>Atomic concentration of carbon, nitrogen, oxygen and titanium calculated from C1s, N1s, O1s, Al2p, Ti2p and F1s core lines for BASE and RAPID implants.</p

Relevance of the Poly(ethylene glycol) Linkers in Peptide Surfaces for Proteases Assays

Poly­(ethylene glycol)­s (PEGs) with different lengths were used as linkers during the preparation of peptide surfaces for protease detection. In the first approach, the PEG monolayers were prepared using a “grafting to” method on 3-aminopropyltrietoxysilane (APTES)-modified silicon wafers. Protected peptides with a fluorescent marker were synthesized by Fmoc solid phase synthesis. The protected peptide structures enabled their site-specific immobilization onto the PEG surfaces. Alternatively, the PEG-peptide surface was obtained by immobilizing a PEG-peptide conjugate directly onto the modified silicon wafer. The surfaces (composition, grafting density, hydrophilicity, and roughness) were characterized by time-of-flight-secondary ion mass spectrometry (ToF-SIMS), X-ray photoelectron spectroscopy (XPS), contact angle (CA), and atomic force microscopy (AFM). Introducing the PEG linker between the peptide and surface increased their resistance toward nonspecific protein adsorption. The peptide surfaces were examined as analytical platforms to study the action of trypsin as a representative protease. The products of the enzymatic hydrolysis were analyzed by fluorescence spectroscopy, electrospray ionization–mass spectrometry (ESI-MS), and ToF-SIMS. Conclusions about the optimal length of the PEG linker for the analytical application of PEG-peptide surfaces were drawn. This work demonstrates an effective synthetic procedure to obtain PEG-peptide surfaces as attractive platforms for the development of peptide microarrays