Purpose Bone consolidation after severe trauma is the most challenging task in orthopedic surgery. This study aimed to develop biomimetic composite for coating Ti implants. Afterwards, these implants were tested in vivo to assess bone consolidation in the absence or the presence of high-frequency pulsed electromagnetic short-waves (HF-PESW). Materials Biomimetic coating was successfully developed using multi-substituted hydroxyapatite (ms-HAP) functionalized with collagen (ms-HAP/COL), embedded into poly-lactic acid (PLA) matrix (ms-HAP/COL@PLA), and subsequently covered with self-assembled COL layer (ms-HAP/COL@PLA/COL, named HAPc). Methods For in vivo evaluation, 32 Wistar albino rats were used in four groups: control group (CG) with Ti implant; PESW group with Ti implant+HF-PESW; HAPc group with Ti implant coated with HAPc; HAPc+PESW group with Ti implant coated with HAPc+HF-PESW. Left femoral diaphysis was fractured and fixed intramedullary. From the first post-operative day, PESW and HAPc+PESW groups underwent HF-PESW stimulation for 14 consecutive days. Biomimetic coating was characterized by XRD, HR-TEM, SEM, EDX and AFM. Results Osteogenic markers (ALP and osteocalcin) and micro-computed tomography (CT) analysis (especially bone volume/tissue volume ratio results) indicated at 2 weeks the following group order: HAPc+PESW>HAPc≈PESW ( P >0.05) and HAPc+PESW>control ( P <0.05), indicating the higher values in HAPc+PESW group compared to CG. The fracture-site bone strength showed, at 2 weeks, the highest average value in HAPc+PESW group. Moreover, histological analysis revealed the most abundant COL fibers assembled in dense bundles in HAPc-PESW group. At 8 weeks, micro-CT indicated higher values only in HAPc+PESW group vs CG ( P <0.05), and histological results showed a complete-healed fracture in groups: HAPc+PESW, HAPc and PESW, but with more advanced bone remodeling in HAPc+PESW group. Conclusion Using Ti implants coated by HAPc jointly with HF-PESW stimulation positively influenced the bone consolidation process, especially in its early phase, thus potentially providing a superior strategy for clinical applications.

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In urban areas, the diesel-fuelled and bio-fuelled vehicles represent the major sources of nanoparticles complemented by nanotechnology with different types of particles, in addition to natural and to other anthropogenic sources. The atmospheric nanoparticles differ in composition, size, shape or oxidant capacity, presenting a large variability that causes difficulties in their measurements and health impact identification. The oxidative stress can be initiated by atmospheric nanoparticles through different mechanisms: interaction between nanoparticles and tissue cells, cellular internalisation of nanoparticles, activation of signalling pathways, decrease of the cellular antioxidants, activation of the pro-inflammatory cascade, lipid peroxidation, activation of cellular signalling pathway that leads to apoptosis, etc. Ultrafine particles (<100 nm) represent ~80% of the total atmospheric particles and produce inflammation through oxidative stress mechanisms. The atmospheric nanoparticles can penetrate the skin and can be inhaled or ingested affecting different organs and leading to different diseases: neurodegeneration, thrombogenesis, atherosclerosis, asthma, lung cancer, heart arrest, etc.