Figures & data
Figure 1 Flowchart of performed experiments and analyses.
Abbreviations: Ti = titanium; HAPc = titanium implant coated with multisubstituted hydroxyapatites and collagen; PESW = pulsed electromagnetic short-waves; HF-PESW = high-frequency pulsed electromagnetic short-waves; ALP = alkaline phosphatase; OCN = osteocalcin; pps = pulses per second.
Figure 2 XRD pattern for ms-HAP/COL lyophilized powder (A) and for HAPc composite (ie, ms-HAP/COL@PLA/COL) coating on Ti surface (B); HR-TEM images (C, D) for ms-HAP/COL nanoparticles; SEM image (E) and EDX spectrum for same area (F) for ms-HAP/COL; SEM images (G, H) of the surface of HAPc coating on Ti; AFM images (I–K) of a COL fiber self-assembled in the COL layer of HAPc coating on Ti: 2D-topography (I), phase image (J) and amplitude image (K), for scanned area of 1 μm×1 μm; cross-section profile (L) on the white arrow in (I).
Abbreviations: XRD = X-ray diffraction; ms-HAP/COL = multisubstituted hydroxyapatite/collagen; ms-HAP/COL@PLA/COL = multisubstituted hydroxyapatite/collagen and poly-lactic acid/collagen; Ti = titanium; HAPc = titanium implant coated with multisubstituted hydroxyapatite and collagen; HR-TEM = high resolution transmission electron microscope; SEM = scanning electron microscope; EDX = energy-dispersive X-ray spectometer; AFM = atomic force microscope; COL = collagen.
Figure 3 Serum concentrations of bone formation markers: ALP (U/L, in panel A) and OCN (pg/mL, B). Error bars stand for SD. Data are given as mean ± SD. Statistically significant differences for P<0.05 are (*) marked.
Abbreviations: CG = control group; PESW = pulsed electromagnetic short-waves; HAPc = titanium implants coated with multisubstituted hydroxyapatite and collagen; HAPc+PESW = titanium implants coated with multisubstituted hydroxyapatite and collagen and pulsed electromagnetic short-waves.
Figure 4 Quantitative analysis of bone microstructure by micro-CT: total tissue volume (TV, A), bone volume (BV, B) and BV/TV ratio (C) in the region of interests of the fracture site of rats in CG, and in PESW, HAPc and HAPc+PESW groups at 2 and 8 weeks; significant differences for P<0.05 are (*) marked.
Abbreviations: CG = control group; PESW = pulsed electromagnetic short-waves; HAPc = titanium implants coated with multisubstituted hydroxyapatite and collagen; HAPc+PESW = titanium implants coated with multisubstituted hydroxyapatite and collagen and pulsed electromagnetic short-waves.
Table 1 Measured values of the breaking force and the corresponding displacement during the three points bending tests
Figure 5 Force vs displacement curves for the three points bending tests performed on the explanted femur of rats: (A) at 2 weeks post-implantation and (B) at 8 weeks post-implantation.
Abbreviations: CG = control group; PESW = pulsed electromagnetic short-waves; HAPc = titanium implants coated with multisubstituted hydroxyapatite and collagen; HAPc+PESW = titanium implants coated with multisubstituted hydroxyapatite and collagen and pulsed electromagnetic short-waves; N = newton; mm = milimeter.
Figure 6 H&E stained at 2 weeks post-surgery, 20× magnification: (A) Control group: persistence of post-fracture hematoma (h) and inflammatory exudation at fracture site (h-green arrow), and numerous large chondrocytes (*), without occurrence of newly synthesized collagen fibers; (B) PESW group: granulation tissue formation with slight inflammatory infiltrate, small chondrocytes gathered in minor clusters (*) and small amount of individual collagen fibers (f-black arrow) among chondrocytes; (C) HAPc group: complete resorption of post-traumatic hematoma and soft callus area formation is well defined by small clusters of grouped chondrocytes (*) separated by well-defined bundle of collagen fibers (f-black arrow) with irregular distribution among chondrocytes; (D) HAPc+PESW group: small islands of grouped chondrocytes (*) and the most advanced stage in synthesis of collagen fibers, assembled in dense, regular, abundant collagen bundles (f-black arrow), as a support for the future bone matrix. Abbreviations: H&E = hematoxylin and eosin; CG = control group; PESW = pulsed electromagnetic short-waves; HAPc = titanium implants coated with multisubstituted hydroxyapatite and collagen; HAPc+PESW = titanium implants coated with multisubstituted hydroxyapatite and collagen and pulsed electromagnetic short-waves.
Figure 7 H&E stained at 8 weeks post-surgery, 20× magnification; fracture site at the level of bone–implant interface: (A) Control group: incomplete newly formed spongy bone trabeculae (t-black arrow) delimiting areole (a) with bone marrow, and fibro-cartilaginous callus (*), clotted blood formed by inflammation, exudation and residual chondrocytes, partially still present at the fracture level; (B) PESW group: fibro-cartilaginous callus is completely resorbed, and a mixture of spongy bone, well-defined trabeculae (t-black arrow) delimiting areole (a), and compact bone (lamellar bone (l-blue arrows) around Haversian canals (Hc)); (C) HAPc group: there are less spongy bone trabeculae (t-black arrow), mainly areas of compact lamellar bone deposition (l-blue arrow), and Haversian canals (Hc) with a slightly irregular disposition of bone lamellae around them; (D) HAPc+PESW group: newly formed bone is compact lamellar bone (l) with regular, concentric disposition of bone lamellae (l-blue arrows) around Haversian canals (Hc), without areas of spongy bone trabeculae, indicating the more advanced stage of bone remodeling and the most complete bone fracture healing at this phase.
Abbreviations: H&E = hematoxylin and eosin; CG = control group; PESW = pulsed electromagnetic short-waves; HAPc = titanium implants coated with multisubstituted hydroxyapatite and collagen; HAPc+PESW = titanium implants coated with multisubstituted hydroxyapatite and collagen and pulsed electromagnetic short-waves.
