Fabrication and antibacterial properties of cefuroxime-loaded TiO2 nanotubes.

The anodized titanium nanotubes (TiO2-NTs) are considered to be a potential material in clinical therapy. To enhance the antibacterial property of TiO2-NTs, cefuroxime is introduced into TiO2-NTs, and then, different chitosan layers are coated to control the release of cefuroxime. SEM and FTIR are adapted for the characterization of prepared TiO2-NTs. The effects of chitosan coating thickness on release of cefuroxime are also investigated, followed with the antibacterial property evaluation. The results show TiO2-NTs are fabricated by anodization method and cefuroxime is also successfully loaded into the nanotubes. The thickness of chitosan coating is an important factor to the release rate of cefuroxime. Antimicrobial detection and morphology observation of S. aureus show a sustained 7-day drug release and strong negative effect on bacteria. The approach in this study provides a broadly applicable method to fabricate titanium-based orthopedic implants with enhanced antibacterial properties.

A Hybrid Biofuel and Triboelectric Nanogenerator for Bioenergy Harvesting.

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.

Adverse Biological Effect of TiO2 and Hydroxyapatite Nanoparticles Used in Bone Repair and Replacement.

The adverse biological effect of nanoparticles is an unavoidable scientific problem because of their small size and high surface activity. In this review, we focus on nano-hydroxyapatite and TiO2 nanoparticles (NPs) to clarify the potential systemic toxicological effect and cytotoxic response of wear nanoparticles because they are attractive materials for bone implants and are widely investigated to promote the repair and reconstruction of bone. The wear nanoparticles would be prone to binding with proteins to form protein-particle complexes, to interacting with visible components in the blood including erythrocytes, leukocytes, and platelets, and to being phagocytosed by macrophages or fibroblasts to deposit in the local tissue, leading to the formation of fibrous local pseudocapsules. These particles would also be translocated to and disseminated into the main organs such as the lung, liver and spleen via blood circulation. The inflammatory response, oxidative stress, and signaling pathway are elaborated to analyze the potential toxicological mechanism. Inhibition of the oxidative stress response and signaling transduction may be a new therapeutic strategy for wear debris-mediated osteolysis. Developing biomimetic materials with better biocompatibility is our goal for orthopedic implants.

Implantable Self-Powered Low-Level Laser Cure System for Mouse Embryonic Osteoblasts' Proliferation and Differentiation.

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.

Lung injury induced by TiO2 nanoparticles depends on their structural features: size, shape, crystal phases, and surface coating.

With the rapid development of nanotechnology, a variety of engineered nanoparticles (NPs) are being produced. Nanotoxicology has become a hot topic in many fields, as researchers attempt to elucidate the potential adverse health effects of NPs. The biological activity of NPs strongly depends on physicochemical parameters but these are not routinely considered in toxicity screening, such as dose metrics. In this work, nanoscale titanium dioxide (TiO2), one of the most commonly produced and widely used NPs, is put forth as a representative. The correlation between the lung toxicity and pulmonary cell impairment related to TiO2 NPs and its unusual structural features, including size, shape, crystal phases, and surface coating, is reviewed in detail. The reactive oxygen species (ROS) production in pulmonary inflammation in response to the properties of TiO2 NPs is also briefly described. To fully understand the potential biological effects of NPs in toxicity screening, we highly recommend that the size, crystal phase, dispersion and agglomeration status, surface coating, and chemical composition should be most appropriately characterized.

Effect of anatase TiO2 nanoparticles on the growth of RSC-364 rat synovial cell.

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.

Repair of bone defect in femoral condyle using microencapsulated chitosan, nanohydroxyapatite/collagen and poly(L-lactide)-based microsphere-scaffold delivery 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.

Potential health impact on mice after nasal instillation of nano-sized copper particles and their translocation in mice.

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.

TiO2 nanoparticles translocation and potential toxicological effect in rats after intraarticular injection.

Recently, nanomaterials coating gained much concern in orthopedic implants such as bone, cartilage, joint, etc. The wear particles would generate from coating in living organism due to corrosion. In this study, we demonstrated that the intraarticular injected anatase TiO2 nanoparticles had a potential toxicological effect on major organs and knee joints of rats. The histopathological changes of heart, lung and liver indicated the dissemination of intraarticular TiO2 nanoparticles from joint cavity to system. In the knee joint, the aggregated TiO2 nanoparticles deposited and resulted in the synovium hypotrophy and lymphocytes and plasma cells infiltration, but had no effects on cartilage. In the TiO2-exposed synovium, the oxidative damage was induced because the glutathione peroxidase (GSH-Px), reduced glutathione (GSH), oxidized glutathione (GSSG), and superoxide dismutase (SOD) levels were highly regulated to counteract over-produced free radicals, i.e. hydrogen peroxide (H2O2). Further, the lipid peroxidation was detected in the synovium though the expression of proinflammatory cytokines such as tumor necrosis factor alpha (TNF-alpha) and interleukin (IL-1beta) was not much interfered. This research suggested that the amounts of nanocoating in the surface of implants should be controlled and standardized.

Potential neurological lesion after nasal instillation of TiO(2) nanoparticles in the anatase and rutile crystal phases.

Nanoscale titanium dioxide (TiO(2)) is massively produced and widely used in living environment, which hence make the potential risk to human health. Central nervous system (CNS) is the potential susceptible target of inhaled nanoparticles, but the studies on this aspect are limited so far. We report the accumulation and toxicity results in vivo of two crystalline phases of TiO(2) nanoparticles (80nm, rutile and 155nm, anatase; purity >99%). The female mice were intranasally instilled with 500microg of TiO(2) nanoparticles suspension every other day for 30 days. Synchrotron radiation X-ray fluorescence analysis (SRXRF) and inductively coupled plasma mass spectrometry (ICP-MS) were used to determine the contents of titanium in murine brain. Then, the pathological examination of brain tissue, oxidative stress-mediated responses, and levels of neurochemicals in the brain of exposed mice were also analyzed. The obvious morphological changes of hippocampal neurons and increased GFAP-positive astrocytes in the CA4 region were observed, which were in good agreements with higher Ti contents in the hippocampus region. Oxidative stress occurred obviously in whole brain of exposed mice such as lipid peroxidation, protein oxidation and increased activities of catalase, as well as the excessive release of glutamic acid and nitric oxide. These findings indicate anatase TiO(2) nanoparticles exhibited higher concern on some tested biological effects. To summarize, results provided the preliminary evidence that nasal instilled TiO(2) nanoparticles could be translocated into the central nervous system and cause potential lesion of brain, and the hippocampus would be the main target within brain.

Time-dependent translocation and potential impairment on central nervous system by intranasally instilled TiO(2) nanoparticles.

Nanoparticles can be administered via nasal, oral, intraocular, intratracheal (pulmonary toxicity), tail vein and other routes. Here, we focus on the time-dependent translocation and potential damage of TiO(2) nanoparticles on central nervous system (CNS) through intranasal instillation. Size and structural properties are important to assess biological effects of TiO(2) nanoparticles. In present study, female mice were intranasally instilled with two types of well-characterized TiO(2) nanoparticles (i.e. 80 nm, rutile and 155 nm, anatase; purity>99%) every other day. Pure water instilled mice were served as controls. The brain tissues were collected and evaluated for accumulation and distribution of TiO(2), histopathology, oxidative stress, and inflammatory markers at post-instillation time points of 2, 10, 20 and 30 days. The titanium contents in the sub-brain regions including olfactory bulb, cerebral cortex, hippocampus, and cerebellum were determined by inductively coupled plasma mass spectrometry (ICP-MS). Results indicated that the instilled TiO(2) directly entered the brain through olfactory bulb in the whole exposure period, especially deposited in the hippocampus region. After exposure for 30 days, the pathological changes were observed in the hippocampus and olfactory bulb using Nissl staining and transmission electron microscope. The oxidative damage expressed as lipid peroxidation increased significantly, in particular in the exposed group of anatase TiO(2) particles at 30 days postexposure. Exposure to anatase TiO(2) particles also produced higher inflammation responses, in association with the significantly increased tumor necrosis factor alpha (TNF-alpha) and interleukin (IL-1 beta) levels. We conclude that subtle differences in responses to anatase TiO(2) particles versus the rutile ones could be related to crystal structure. Thus, based on these results, rutile ultrafine-TiO(2) particles are expected to have a little lower risk potential for producing adverse effects on central nervous system. Although understanding the mechanisms requires further investigation, the present results suggest that we should pay attention to potential risk of occupational exposure for large-scaled production of TiO(2) nanoparticles.

Identification of a common HLA-A*0201-restricted epitope among SSX family members by mimicking altered peptide ligands strategy.

The synovial sarcoma X breakpoint (SSX) gene family contains nine members. The SSX proteins are CT (cancer/testis) antigens and can be expressed in many tumor types. T cell immune response against SSX protein can be detected in tumor patients and mice expressing any SSX. Screening predominant protective epitopes might improve the low immunogenicity against these "self" CT antigens. Herein, we predicted HLA-A*0201-restricted epitopes for all nine SSX family members, followed by validation with epitope molecular modeling, peptide/HLA-A*0201 affinity, and binding stability assays. We obtained four highly homologous candidate epitopes with the high immunogenicity scores designated P1, P4, P5 and P6, from the nine SSX members. Each of the four candidates could elicit strong epitope-specific CTL immune responses, but P4 could evoke more interferon gamma (IFN-gamma)-producing T cells and more potent CTLs that could lyse more target cells. Importantly, almost all of the four epitopes induced CTLs could cross-lyse the mutual targets both in vitro in human PBMCs and HLA-A2.1/K(b) transgenic mice, but P4 showed superiority to other epitopes in term of cross-cytolysis. All of these results demonstrate that P4 can induce anti-tumor immunity in a fashion superior to other candidates, and may be the "common" CTL epitope among all SSX-expressing tumors. Due to its documented responses herein, P4 has potential application in peptide-mediated immunotherapy.

Scalp hair as a biomarker in environmental and occupational mercury exposed populations: suitable or not?

Hair is a well-established and widely used matrix for measuring mercury exposure of an individual. Although a variety of washing procedures to remove external mercury contamination have been proposed, no standardized procedures are available yet. In this study, different washing reagents like l-cysteine (Cys), 2-mercaptoethanol (ME), and disodium diaminoethanetetra acetate (EDTA) were used to find out if it is possible to remove mercury contamination from human scalp hair spiked with HgCl2 solutions at different concentrations. It was found that the external mercury contamination could not be fully washed off even using reagents with high affinity to mercury like l-cysteine and ME. However, for the well-pulverized CRM hair samples some of the endogenous mercury was washed off. It suggests that hair is not a suitable biomarker for evaluation of total mercury exposure especially in people like mercury miners or gold miners/burners associated with serious external Hg exposure. However, hair still can be used as an indicator for methyl mercury exposure because, generally, there is almost no exogenous contamination of methyl mercury in hair.

[Influence of intranasal instilled titanium dioxide nanoparticles on monoaminergic neurotransmitters of female mice at different exposure time].

OBJECTIVE: To investigate the influence of intranasal instilling titanium dioxide (TiO2) nanoparticles on monoaminergic neurotransmitters at different-time exposure. METHODS: CD female mice were intranasally instilled three different-sized (25 nm, 80 nm and 155 nm) TiO, suspension every other day in a dose of 50 mg/kg body weight. The control group was instilled the same volume of Milli-Q water. Inductively coupled plasma-mass spectrometry (ICP-MS) was used to analyze the titanium contents in murine brain after exposure to TiO2 particles 2 days, 10 days, 20 days and 30 days. The monoaminergic neurotransmitters such as norepinephrine (NE), dopamine (DA), 5-hydroxytryptamine (5-HT), 5-hydroxyindole acetic acid (5-HIAA), 3, 4-dihydroxyphenylacetic acid (DOPAC), and homovanillic (HVA), were determined by reversed-phase high performance liquid chromatography (RP-HPLC) with electrochemical detector. RESULTS: After exposure to TiO, nanoparticles 10 days, the titanium contents in murine brain were increased, the titanium content in the 25 nm group was up to (1059.3 +/- 293.5) ng/g. In 20 days, the titanium content decreased slowly with the metabolism of titanium in vivo, but it kept at a high level, the content decreased to (654.7 +/- 269.2) ng/g in the 25 nm group. After exposure to TiO2 nanoparticles 30 days, the titanium contents had no obviously change. Because of the accumulation of TiO, in the brain, the contents of NE and 5-HT increased significantly after exposure to 80 nm and 155 nm TiO, nanoparticles 20 days, while the decreased contents of DA, DOPAC, HVA and 5-HIAA were observed. CONCLUSION: The inhaled TiO2 nanoparticles could be translocated to and deposited in murine brain after absorbing by nasal mucosa, and further influence the releases and metabolisms of monoaminergic neurotransmitters in brain.

Acute toxicity and biodistribution of different sized titanium dioxide particles in mice after oral administration.

In order to evaluate the toxicity of TiO(2) particles, the acute toxicity of nano-sized TiO(2) particles (25 and 80nm) on adult mice was investigated compared with fine TiO(2) particles (155nm). Due to the low toxicity, a fixed large dose of 5g/kg body weight of TiO(2) suspensions was administrated by a single oral gavage according to the OECD procedure. In 2 weeks, TiO(2) particles showed no obvious acute toxicity. However, the female mice showed high coefficients of liver in the nano-sized (25 and 80nm) groups. The changes of serum biochemical parameters (ALT/AST, LDH) and pathology (hydropic degeneration around the central vein and the spotty necrosis of hepatocytes) of liver indicated that the hepatic injury was induced after exposure to mass different-sized TiO(2) particles. In addition, the nephrotoxicity like increased BUN level and pathology change of kidneys was also observed in the experimental groups. The significant change of serum LDH and alpha-HBDH in 25 and 80nm groups showed the myocardial damage compared with the control group. However, there are no abnormal pathology changes in the heart, lung, testicle (ovary), and spleen tissues. Biodistribution experiment showed that TiO(2) mainly retained in the liver, spleen, kidneys, and lung tissues, which indicated that TiO(2) particles could be transported to other tissues and organs after uptake by gastrointestinal tract.

Antioxidative function and biodistribution of [Gd@C82(OH)22]n nanoparticles in tumor-bearing mice.

Oxidative stress is considered to be one of the important mechanisms involved in carcinogenesis. In our previous study, gadolinium endohedral metallofullerenol ([Gd@C82(OH)22]n nanoparticles) have shown high inhibitory activity on hepatoma cell (H22) growth in mice. To explore the antioxidative functions of nanoparticles, we investigated the biodistribution of [Gd@C82(OH)22]n nanoparticles, the changes of blood coagulation profiles, the metabolism of reactive oxygen species (ROS) in the tumor-bearing mice as well as the possible relationships between nanoparticles treatment and ROS production in this paper. The activities of hepatic superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), glutathione S-transferase (GST) and catalase (CAT) as well as the levels of reduced glutathione (GSH), protein-bound thiols and malondialdehyde (MDA) were compared between the tumor-bearing mice and normal mice. Transplanted tumors were grown in mice by subcutaneous injection of murine hepatoma cells in the mice. The comparison of the above parameters between nanoparticles and cyclophosphamide (CTX) therapy were also investigated. [Gd@C82(OH)22]n administration can efficiently restore the damaged liver and kidney of the tumor-bearing mice. All the activities of enzymes and other parameters related to oxidative stress were reduced after [Gd@C82(OH)22]n treatment and tended closely to the normal levels. The results suggest that [Gd@C82(OH)22]n nanoparticle treatment could regulate ROS production in vivo.

[Analysis of total mercury and methylmercury concentrations in four commercially important freshwater fish species obtained from Beijing markets].

OBJECTIVE: The present paper makes an attempt to evaluate the risk of mercury exposure to human by analyzing the total mercury and methylmercury concentrations of four commercially important freshwater fish species in Beijing market. METHODS: Fish samples of common carp, grass carp, bighead carp, and snakehead were purchased from Beijing market. Then their muscle, liver and gills were taken out. The total mercury and methylmercury concentrations were determined using ultrasonic-assisted solvent extraction coupled with inductively coupled plasma-mass spectrometry. Samples were digested with 6mol/L HCl and sonicated for 2 hours. Subsequently, some aliquots were directly diluted for determination of total mercury concentrations; the remained extracts were extracted with CH2 C12 , and then back extracted with H20 for determination of methylmercury concentrations. To evaluate the validity of the method, the standard materials of DORM-2 and DOLT-3 were also measured. RESULTS: According to the concentrations oof total mercury and methylmercury in the muscles, an order was obtained as: snakehead > bighead carp > grass carp > common carp, which showed that the accumulation of mercury in fish was closely related to food chain. Methylmercury were about 80% of the total mercury, whereas there was a positive relationship between total mercury and methylmercury. The mercury distributions in the bighead carp and snakehead fish showed that the order of mercury concentrations was: muscle > liver > gill, the ratio of methylmercury to total mercury was: muscle > gill > liver. Methylmercury was mainly accumulated in the muscle of fish. CONCLUSION: mercury concentrations of the four fishes in Beijing markets were all below the standard level according to the National Standard of China, therefore, it is safe to human health.

Multihydroxylated [Gd@C82(OH)22]n nanoparticles: antineoplastic activity of high efficiency and low toxicity.

[Gd@C82(OH)22]n particles (22 nm in a saline solution) of a dose level as low as 10(-7) mol/kg exhibit a very high antineoplastic efficiency ( approximately 60%) in mice. A dose increment of 1 x 10(-7) mol/kg increases the tumor inhibition rate 26%. [Gd@C82(OH)22]n particles have a strong capacity to improve immunity and interfere with tumor invasion in normal muscle cells, nearly without toxicity in vivo and in vitro. Unlike conventional antineoplastic chemicals, the high antitumor efficiency of nanoparticles is not due to toxic effects to cells because they do not kill the tumor cells directly and only about 0.05% of the used dose is found in the tumor tissues. Results suggest that fullerene derivatives with proper surface modifications and sizes may help realize the dream of tumor chemotherapeutics of high-efficacy and low-toxicity.