Figure 1
From: Amine modification of calcium phosphate by low-pressure plasma for bone regeneration
Plasma polymerization system and characterization of plasma-polymerized films. (A) Schematic diagram of the pulsed-plasma deposition system used in this study. Samples were placed on the bottom metal electrode, which was powered by high-voltage bipolar pulse voltages with a peak-to-peak voltage of 2.2 kV. The power, repetition frequency, and duty cycle were 15 W, 5 kHz, and 1%, respectively. The plasma was generated from a gas mixture of CH4, N2, and He with flow rates of 10, 20, and 10 sccm, respectively, and a gas pressure of 70 Pa. (B) The atomic concentration ratios on a plasma-treated dense β-TCP disk surface (top) and those on an untreated dense β-TCP disk surface (bottom). More precise values are given in the main text. (C) The relative number of primary amines (–NH2) among all atoms excluding hydrogen (left) and the number ratios of primary amines to C or N atoms (right) on the surface of the plasma-polymerized film deposited on a dense β-TCP disk. In (B,C), all measurements were triplicate. (D) The profiles of relative atomic concentrations along the center axis of a plasma-treated porous β-TCP disk, indicating plasma polymerization of the inner pore surfaces due to the penetration of plasma-generated deposition precursors through the interconnected pores from the plasma-treated disk surface. After a single side of a porous β-TCP disk was plasma-treated, it was cut in half through its center and the relative atomic concentrations were measured at 25 points along the center axis. The horizontal axis of the figure represents the position along the center axis measured from the plasma-exposed top surface of the disk. In each case above, the plasma treatment time was 30 min. Schematic diagrams (A and the top part of D) were drawn using Microsoft PowerPoint 2016.
