UHMWPE carrying estradiol to treat the particle‐induced osteolysis—Processing and characterizing

Abstract

The objective of this study was to explore the possibility of UHMWPE implant used as the drug carrier to treat particle-induced osteolysis. 17beta-estradiol (E2), which had the potential application on osteolysis treatment and the high melting point, was added into UHMWPE powder to produce UHMWPE-E2 composites through hot press processing. The hydrophobicity, crystallinity, mechanical properties, and wear performance of the UHMWPE-E2 were characterized compared with the control UHMWPE. The thermal analysis and Fourier Transform Infrared Spectroscopy results demonstrated that the hot press processing would not alter the functional groups of E2 in this study. There were no significant differences in the hydrophobicity and crystallinity between the UHMWPE-E2 and UHMWPE. The UHMWPE-E2 showed satisfying mechanical properties, including ultimate tensile strength (47.2 +/- 3.6 MPa), yield strength (25.0 +/- 0.6 MPa) and elongation at break (320 +/- 25.5 %), which were similar with the control UHMWPE. The friction coefficients and worn scars were similar between the UHMWPE-E2 and the control UHMWPE. The wear mechanism of the UHMWPE-E2 and UHMWPE both were abrasive wear under dry friction. The UHMWPE-E2 possesses the approving mechanical properties and wear performance compared with the control UHMWPE, which might be used as the potential implanted drug carrier to prevent the particle-induced osteolysis in joint replacements.

Electrocrystallization of Calcium Phosphates

“…15 X-ray photoelectron spectroscopy (XPS) measurements were performed in order to determine unambiguously the CaP phase that formed during the EQCM experiment, so that the number of electrons transferred in the reaction could be determined. To this aim, the Ca/P and O/Ca atomic ratios were measured and the oxygen loss spectrum was analyzed, according to the procedure suggested by Lu et al 15,27 An innovative post-treatment was also applied, by exposing some coated samples to low-energy electron irradiation, thus modifying the surface energy on the nanoscale. 19,21,28 However, this will not be presented in this paper.…”

“…Plotting the data from Fig. 1 in the form of v versus 1/T, where v is the deposition rate (in units of g/(h⋅m 2 )) and T is the absolute temperature, the following relation was obtained: 15,16 Ln 14.74 4, 785 , 0.9742 T R…”

“…Future EQCM experiments, to be carried out with the same ion concentrations but adjusted to different pH values, are expected to show that with the increase of pH, the incubation time is shortened. 15 Several electrochemical and chemical reactions potentially involved in electrocrystallization of CaP on Ti are listed below. Under cathodic polarization, the following electrochemical reactions may take place: 14 14 The idea that much current is consumed during the process of electrocrystallization of CaP on electrolysis of water is supported by calculation of a very low equivalent weight (EW = 20.5 g/equiv).…”

“…The early stages of nucleation and growth are characterized. 14,15 The change in growth mode and the role of precursors to HAp are explained. The role of charge transfer and local increase in pH is discussed.…”

“…20,23 EXPERIMENTAL The experimental procedures have been described in detail elsewhere. 14,[15][16][17][18][19][20][21][22][23] In brief, electrodeposition was carried out in a standard three-electrode cell. Either a sheet made of commercially pure Ti grade 2 (10 × 10 × 5 mm) or a rod made of Ti-6Al-4V grade 5 was used as a cathode.…”