Bone remodeling or orthodontic treatment is usually a long-term process. It is highly desirable to speed up the process for effective medical treatment. In this work, a self-powered low-level laser cure system for osteogenesis is developed using the power generated by the triboelectric nanogenerator. It is found that the system significantly accelerated the mouse embryonic osteoblasts' proliferation and differentiation, which is essential for bone and tooth healing. The system is further demonstrated to be driven by a living creature's motions, such as human walking or a mouse's breathing, suggesting its practical use as a portable or implantable clinical cure for bone remodeling or orthodontic treatment.

• A triboelectric nanogenerator (TENG) and a glucose fuel cell (GFC) were separately designed to harvest biomechanical energy from body motion and biochemical energy from glucose molecules. • A hybrid energy-harvesting system (HEHS) which consisted of TENG and GFC was developed successfully, and it can simultaneously harvest biomechanical energy and biochemical energy. ABSTRACT Various types of energy exist everywhere around us, and these energies can be harvested from multiple sources to power micro-/nanoelectronic system and even personal electronic products. In this work, we proposed a hybrid energy-harvesting system (HEHS) for potential in vivo applications. The HEHS consisted of a triboelectric nanogenerator and a glucose fuel cell for simultaneously harvesting biomechanical energy and biochemical energy in simulated body fluid. These two energy-harvesting units can work individually as a single power source or work simultaneously as an integrated system. This design strengthened the flexibility of harvesting multiple energies and enhanced corresponding electric output. Compared with any individual device, the integrated HEHS outputs a superimposed current and has a faster charging rate. Using the harvested energy, HEHS can power a calculator or a green light-emitting diode pattern. Considering the widely existed biomechanical energy and glucose molecules in the body, the developed HEHS can be a promising candidate for building in vivo self-powered healthcare monitoring system.

Bone repair ability of microencapsulated chitosan, nanohydroxyapatite/collagen (nHAC), and poly(L-lactide) (PLLA)-based microsphere-scaffold delivery system was investigated in present research, with nHAC/PLLA composite scaffold as a control. Chitosan microspheres (CMs) encapsulated with bone morphogenetic protein-2-derived synthetic peptide were incorporated into nHAC and PLLA-based matrix via a thermally induced phase separation method, in which dioxane was used as the solvent for PLLA. Compared with the rapid release from CMs, the synthetic peptide was delivered from CMs/nHAC/PLLA microsphere-scaffold composite in a temporally controlled manner, depending on the degradation of both incorporated CMs and PLLA matrix. MC3T3-E1 osteoblastic cells were seeded into nHAC/PLLA and CMs/nHAC/PLLA scaffolds, respectively, and in vitro cytocompatibility was tested by scanning electron microscopy and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The results indicated that, with the appearance of CMs in microsphere-scaffold composite, the osteoblasts exhibit better morphology and proliferation ability. In vivo tissue compatibility was evaluated by transplanting the scaffolds into rabbit femoral condyles with a defect 6 mm in diameter. After implanting for 4, 8, and 12 weeks, respectively, radiographic and histological observation revealed that the CMs/nHAC/PLLA composite can accelerate the regeneration of cancellous bone defect as compared with the nHAC/PLLA scaffold. The results demonstrated that the CMs/nHAC/PLLA possesses better biocompatibility, which should be attributed to both the incorporated chitosan component and the encapsulated bioactive synthetic peptide. The promising CMs/nHAC/PLLA microsphere-scaffold composite can be used as delivery system for multiple bioactive factors or as inductive implant scaffold for bone regeneration.

The purpose of this study is to evaluate the overall toxicity of nasal instilled nanoscale copper particles (23.5 nm) in mice. Pathological examination, target organs identification, and blood biochemical assay of experimental mice were carried out in comparison with micro-sized copper particles (17 microm). However, only in the high-dose group of copper nanoparticles (40 mg/kg body weight instilled for three times in one week), the body weight of mice were retarded and significant pathological changes were observed. There were hydropic degeneration around the central vein and the spotty necrosis of hepatocytes in the liver and swelling in the renal glomerulus, while, severe lesion associated with the decreased number of olfactory cells and the dilapidated laminated structure were also observed in the olfactory bulb. The serum biochemical assay also indicated the sign of renal and hepatic lesion. However, there were no obvious pathological and physiological damages in the mice after instilling different-sized copper nanoparticles with low dose of 1 mg/kg body weight. The retention and distribution of copper in various tissues show that the liver, kidneys and olfactory bulb are the main accumulated tissues for copper particles, which were determined by high sensitive element-specific technique of ICP-MS. The copper contents of the liver, kidneys and the olfactory bulb increase significantly at the group of 40 mg/kg compared to the control group, which is in agreement with the histological changes. Therefore, the data indicate that nasal inhaled copper particles at very high dosage can translocate to other organs and tissues and further induce certain lesions. The present results are helpful to get better understanding of the risk assessment and evaluation for copper nanoparticles.

Nanoscale materials (such as TiO2, hydroxyapatite nanoparticles) have gained much concern in the coating of implants for cell adhesion and growth to improve the osteoconductivity. However, due to attrition and corrosion, the wear particles would be generated from the joint in living organism, and influence the physiological function of synovial membranes in joint cavity. In this study, the potential cytotoxicity of anatase TiO2 nanoparticles (TiO2 NPs) on rat synovial cell line 364 (RSC-364) was investigated. After treatment with different concentrations of TiO2 NPs (0, 3, 30, 300 microg/ml), the viability of RSC-364 cells were decreased in a dose-dependent manner. TiO2 NPs exposure could disrupt the integrity of cell plasma membrane, leading to the increased leakage of lactate dehydrogenase (LDH) into the culture medium. TiO2 NPs were uptaken by RSC-364 cells. The ultrastructure of RSC-364 cells was changed such as nuclear shrinkage and mitochondrial swelling. The reactive oxygen species (ROS) was over-produced especially in the cells exposed to 30 and 300 microg/ml TiO2 NPs. The activities of endogeneous antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT), were significantly decreased. The increased lipid peroxidation product (malondialdehyde, MDA) suggests the oxidative damage in cells. The flow cytometry detected that the cell cycle was blocked in G0/G1 phase, inhibiting the cell proliferation. These preliminary results indicate the oxidative stress injury and cytotoxicity of anatase TiO2 NPs on rat synovial cells. The reasonable and safe application of nanomaterials in artificial implants needs further study.