Time-of-Flight Secondary
Ion Mass Spectrometry with
Principal Component Analysis of Titania–Blood Plasma Interfaces
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Abstract
Treatment of osseoimplant surfaces with autologous platelet-rich
plasma prepared according to the plasma rich in growth factors (PRGF-Endoret)
protocol prior to implantation yields promising results in the clinic.
Our objective is to understand the organization of complex interfaces
between blood plasma preparations of various compositions and model
titania surfaces. Here we present the results of the morphological
and chemical characterization of TiO<sub>2</sub> surfaces incubated
with four types of blood plasma preparations devoid of leukocytes
and red blood cells: either enriched in platelets (PRGF-Endoret) or
platelet-depleted, and either activated with CaCl<sub>2</sub> to induce
clotting, or not. Chemical characterization was done by time-of-flight
secondary ion mass spectrometry with principal component analysis
(ToF-SIMS/PCA). The interface morphology was studied with scanning
electron and atomic force microscopy. Immunofluorescence microscopy
was used to identify platelets and infer their activation state. We
observe clear differences among the four types of interfaces by ToF-SIMS/PCA.
Some of these could be straightforwardly related to the differences
in the sample morphology and known effects of platelet activation,
but others are more subtle. Strikingly, it was possible to differentiate
between these samples by ToF-SIMS/PCA of the protein species alone.
This clearly indicates that the composition, orientation, and/or conformation
of the proteins in these specimens depend both on the platelets' presence
and on their activation. The ToF-SIMS imaging functionality furthermore
provides unique insight into the distribution of phospholipid species
in these samples