A Non-Invasive Method for Monitoring Osteogenesis and Osseointegration Using Near-Infrared Fluorescent Imaging: A Model of Maxilla Implantation in Rats.

Currently, computed tomography and conventional X-ray radiography usually generate a micro-artifact around metal implants. This metal artifact frequently causes false positive or negative diagnoses of bone maturation or pathological peri-implantitis around implants. In an attempt to repair the artifacts, a highly specific nanoprobe, an osteogenic biomarker, and nano-Au-Pamidronate were designed to monitor the osteogenesis. In total, 12 Sprague Dawley rats were included in the study and could be chategorized in 3 groups: 4 rats in the X-ray and CT group, 4 rats in the NIRF group, and 4 rats in the sham group. A titanium alloy screw was implanted in the anterior hard palate. The X-ray, CT, and NIRF images were taken 28 days after implantation. The X-ray showed that the tissue surrounded the implant tightly; however, a gap of metal artifacts was noted around the interface between dental implants and palatal bone. Compared to the CT image, a fluorescence image was noted around the implant site in the NIRF group. Furthermore, the histological implant-bone tissue also exhibited a significant NIRF signal. In conclusion, this novel NIRF molecular imaging system precisely identifies the image loss caused by metal artifacts and can be applied to monitoring bone maturation around orthopedic implants. In addition, by observing the new bone formation, a new principle and timetable for an implant osseointegrated with bone can be established and a new type of implant fixture or surface treatment can be evaluated using this system.

From mono-PEGylation towards anti-nonspecific protein interaction: comparison of dihydrolipoic acid versus glutathione-capped fluorescent gold nanoclusters using gel electrophoresis.

Ultrafine fluorescent gold nanoclusters (AuNCs) have emerged as biocompatible nanoprobes for biomedical imaging in vivo, and the precision surface chemistry of AuNCs is the key for attaining their clinical application. Comparison of two promising candidates for future nanomedicine, i.e. dihydrolipoic acid- versus glutathione-capped AuNCs (AuNC@DHLA vs. AuNC@GSH), was conducted for the first time to clarify their polyethylene glycol-related bioconjugate chemistry (PEGylation) and protein interactions. Gel electrophoresis was performed to separate the number of AuNCs PEGylation, and the molecular weight of the PEG spacer dominated the resolution of the separation in the gel. We have engineered and isolated the mono-PEGylated AuNCs either from the indirect carbodiimide bioconjugate chemistry or the direct Au-S binding. One-pot synthesis showed great efficiency for isolating mono-PEGylated AuNC@GSH from the tailored controlled aggregation of Au(i)-thiolate complexes on in situ generated Au(0) cores. Post-PEGylation of AuNC@GSH was also feasible using monodendate thiol-terminated PEG, but bidendate ligands of AuNC@DHLA exhibited low PEGylated efficiency by Au-S binding. In addition, mono-PEGylated AuNC@GSH significantly enhanced the ability of anti-nonspecific protein adsorption, but mono-PEGylated AuNC@DHLA cannot avoid the nonspecific binding with serum albumin. In addition, specific nano-assembly involving mono-biotinylated AuNCs with streptavidin were also compared using gel electrophoresis. These results provide key insights into the selection, preparation and design of functional AuNCs as nanoprobes for versatile biomedical applications.

Publisher Correction: Non-Toxic Gold Nanoclusters for Solution-Processed White Light-Emitting Diodes.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.

Non-Toxic Gold Nanoclusters for Solution-Processed White Light-Emitting Diodes.

Solution-processed optoelectronic devices are attractive because of the potential low-cost fabrication and the compatibility with flexible substrate. However, the utilization of toxic elements such as lead and cadmium in current optoelectronic devices on the basis of colloidal quantum dots raises environmental concerns. Here we demonstrate that white-light-emitting diodes can be achieved by utilizing non-toxic and environment-friendly gold nanoclusters. Yellow-light-emitting gold nanoclusters were synthesized and capped with trioctylphosphine. These gold nanoclusters were then blended with the blue-light-emitting organic host materials to form the emissive layer. A current efficiency of 0.13 cd/A was achieved. The Commission Internationale de l'Eclairage chromaticity coordinates of (0.27, 0.33) were obtained from our experimental analysis, which is quite close to the ideal pure white emission coordinates (0.33, 0.33). Potential applications include innovative lighting devices and monitor backlight.

Impact of dihydrolipoic acid on mouse embryonic stem cells and related regulatory mechanisms.

α-Lipoic acid (LA) is a thiol with antioxidant properties that protects against oxidative stress-induced apoptosis. LA is absorbed from the diet, taken up by cells and tissues, and subsequently reduced to dihydrolipoic acid (DHLA). Recently, DHLA has been used as the hydrophilic nanomaterial preparations, and therefore, determination of its bio-safety profile is essential. In this article, we show that DHLA (50-100 µM) induces apoptotic processes in mouse embryonic stem cells (ESC-B5), but exerts no injury effects at treatment dosages below 50 µM. Higher concentrations of DHLA (50-100 µM) directly increased the reactive oxygen species (ROS) content in ESC-B5 cells, along with a significant increase in cytoplasmic free calcium and nitric oxide (NO) levels, loss of mitochondrial membrane potential (MMP), activation of caspases-9 and -3, and cell death. Pretreatment with NO scavengers suppressed the apoptotic biochemical changes induced by 100 µM DHLA and promoted the gene expression levels of p53 and p21 involved in apoptotic signaling. Our results collectively indicate that DHLA at concentrations of 50-100 µM triggers apoptosis of ESC-B5 cells, which involves both ROS and NO. Importantly, at doses of less than 50 µM (0-25 µM), DHLA does not exert hazardous effects on ESC-B5 cell properties, including viability, development and differentiation. These results provide important information in terms of dosage safety and biocompatibility of DHLA to facilitate its further use as a precursor for biomaterial preparation.

Rapid transformation of protein-caged nanomaterials into microbubbles as bimodal imaging agents.

We present a general method for converting colloidal nanomaterials into microbubbles as ultrasound contrast agents. Protein-caged nanomaterials, made either by self-assembled nanoparticles' protein corona or by fluorescent gold nanoclusters, can be rapidly transformed into microbubbles via a sonochemical route, which promote disulfide cross-linking of cysteine residues between protein-caged nanomaterials and free albumin during acoustic cavitation. The proposed methods yielded microbubbles with multiple functions by adjusting the original nanoparticle/protein mixture. We also showed a new dual-modal imaging agent of fluorescent gold microbubbles in vitro and in vivo, which can hold many potential applications in medical diagnostics and therapy.

Dihydrolipoic acid induces cytotoxicity in mouse blastocysts through apoptosis processes.

α-Lipoic acid (LA) is a thiol with antioxidant properties that protects against oxidative stress-induced apoptosis. LA is absorbed from the diet, taken up by cells and tissues, and subsequently reduced to dihydrolipoic acid (DHLA). In view of the recent application of DHLA as a hydrophilic nanomaterial preparation, determination of its biosafety profile is essential. In the current study, we examined the cytotoxic effects of DHLA on mouse embryos at the blastocyst stage, subsequent embryonic attachment and outgrowth in vitro, in vivo implantation by embryo transfer, and early embryonic development in an animal model. Blastocysts treated with 50 µM DHLA exhibited significantly increased apoptosis and a corresponding decrease in total cell number. Notably, the implantation success rates of blastocysts pretreated with DHLA were lower than that of their control counterparts. Moreover, in vitro treatment with 50 µM DHLA was associated with increased resorption of post-implantation embryos and decreased fetal weight. Data obtained using an in vivo mouse model further disclosed that consumption of drinking water containing 100 µM DHLA led to decreased early embryo development, specifically, inhibition of development to the blastocyst stage. However, it appears that concentrations of DHLA lower than 50 µM do not exert a hazardous effect on embryonic development. Our results collectively indicate that in vitro and in vivo exposure to concentrations of DHLA higher than 50 µM DHLA induces apoptosis and retards early pre- and post-implantation development, and support the potential of DHLA to induce embryonic cytotoxicity.

Osteogenic differentiation is synergistically influenced by osteoinductive treatment and direct cell-cell contact between murine osteoblasts and mesenchymal stem cells.

PURPOSE: The present study was designed to address whether osteoblasts play a synergistic role in promoting mesenchymal stem cell (MSC) osteogenesis in a direct cell-cell contact co-culture model. METHODS: Murine C3H10T1/2 and MC3T3-E1 cell lines were mixed and plated onto 12-well culture plates and co-cultured at various ratios of initial cell densities. To compare the possible improvement on osteogenic differentiation, co-culture cells were served with or without osteogenic supplements in culture medium. RESULTS: Weak osteogenesis was induced in MSCs co-cultured in an untreated medium with different ratios of osteoblasts. An osteoblast-dependent increase in osteogenic gene expression of Runx2, type I collagen, and osteocalcin was observed over time. Moreover, both alkaline phosphatase (ALP) activity and calcium deposition were distinctly enhanced at levels that were proportional to the quantity of osteoblasts in the culture. The increases in mRNA expression and ALP activity were greater in co-cultures treated with osteogenic supplements than in untreated cultures. However, the production of ALP activity followed by a distinct matrix mineralization was lower in osteogenic-treated cultures containing greater numbers of osteoblasts. This suggests that a higher density of osteoblasts may lead to weak osteogenesis of MSCs by direct cell-cell contact co-culture in an untreated environment. Furthermore, additional osteogenic supplements may act synergistically with osteoblasts to accelerate matrix mineralization by reducing the process of osteogenic differentiation in osteogenic treated co-cultures. CONCLUSIONS: The present work may improve the understanding of MSC osteogenesis and may provide benefits for regenerative medicine.

Nanoscale hepatoprotective herbal decoction attenuates hepatic stellate cell activity and chloroform-induced liver damage in mice.

BACKGROUND: San-Huang-Xie-Xin-Tang (SHXXT) decoction, a traditional Chinese medicine containing Rhei rhizome, Coptidis rhizome, and Scutellariae radix, is widely used in hepatoprotective therapy. However, preparation of the decoction requires addition of boiling water that causes loss of numerous effective components. METHODS: To improve the bioavailability of the decoction, nanoscale SHXXT was developed. Chloroform-induced liver injury and hepatic stellate cell activity in mice were used to demonstrate the hepatoprotective characteristics of nanoscale SHXXT decoction. RESULTS: Liver/body weight ratio and serum aspartate and alanine aminotranferase levels were recovered by the nanoscale SHXXT. TIMP-1 gene expression was inhibited and MMP-2 gene expression was accelerated in activated hepatic stellate cells. CONCLUSION: Nanoscale SHXXT decoction prepared in room temperature water could have preserved hepatoprotective ability. The results of this study indicate that nanoscale SHXXT could be extracted easily. The simple preparation of this herbal decoction is more convenient and energy-efficient.

Fluorescent gold nanoclusters as a biocompatible marker for in vitro and in vivo tracking of endothelial cells.

We have been investigating the fluorescent property and biocompatibility of novel fluorescent gold nanoclusters (FANC) in human aortic endothelial cells (HAEC) and endothelial progenitor cells (EPC). FANC (50-1000 nmol/L) was delivered into cells via the liposome complex. The fluorescence lasted for at least 28 days with a half-life of 9 days in vitro. Examination of 12 transcripts regulating the essential function of endothelial cells after a 72 h delivery showed that only the vascular cell adhesion molecule 1 and the vascular endothelial cadherin were down-regulated at high concentration (500 nmol/L). In addition, no activation of caspase 3 or proliferating cell nuclear antigens was detected. 3-[4,5-Dimethylthiazol-2-yl]-2,5- diphenyltetrazolium bromide (MTT) assay demonstrated that, unlike the markedly suppressed viability in cells treated with quantum dots, FANC had minimal effect on the viability, unless above 500 nmol/L, at which level a minor reduction of viability mainly caused by liposome was found. Tube formation assay showed no impaired angiogenesis in the EPC treated with FANC. In vivo study using hindlimb ischemic mice with an intramuscular injection of FANC-labeled human EPC showed that the cells preserved an angiogenic potential and exhibited traceable signals after 21 days. These findings demonstrated that FANC is a promising biocompatible fluorescent probe.

Ambulation study of a woman with paraplegia using a reciprocating gait orthosis with functional electrical stimulation in Taiwan: a case report.

PURPOSE: Many patients who suffer from spinal cord injuries with paraplegia cannot recover to walk independently. They need to use a special walking orthoses to support their body to walk properly. Traditionally, long leg braces (LLB) were fitted to patients for walking. Unfortunately, the results were not satisfactory as this device supplies adequate support with less than optimum mobility. This study used the latest reciprocating gait orthosis (RGO) combined with functional electrical stimulation (FES). This combination provides a greater support range while applying assistant mechanical walking structures. The FES co-ordination helps restore natural walking abilities that the paralysed patient has lost. METHOD: This study developed a walking orthosis with FES, using FES to stimulate specific muscles (quadriceps, hamstring) in the paralysed patients' lower limbs. The proposed method can achieve the benefits of physical therapeutics while paralysed patients can achieve the purpose of walking. The FES is designed with control buttons on the walking orthosis. A patient can control the left or right leg in walking and speed control via the control buttons. RESULTS: Several practical tests were conducted on the new walking orthosis. A 25-year-old female paralysed patient (L1 complete spinal cord injury) used traditional LLB, RGO and RGO with FES to proceed with walking rehabilitation and clinical assessment. Heart rate difference (HRdifference), mean blood pressure (MBPdifference), walking speed, length of steps, number of steps and oxygen consumption comparisons were made before and after walking. The results show that RGO and RGO with FES were both better than LLB. However, the differences between RGO and RGO with FES in HRdifference, MBPdifference, and walking speed were not significant. This is because the patient's right leg reaction to the electrical stimulation was relatively low. DISCUSSION AND CONCLUSIONS: In general, RGO can help the patient achieve quicker and more independent walking. The combination of RGO and FES can increase the effectiveness of RGO for more mobile aid. These two walking orthoses are better than traditional LLB. Both methods provide patients who suffer from paraplegia with better choices.

Effects of nano calcium carbonate and nano calcium citrate on toxicity in ICR mice and on bone mineral density in an ovariectomized mice model.

Taking calcium supplements can reduce the risk of developing osteoporosis, but they are not readily absorbed in the gastrointestinal tract. Nanotechnology is expected to resolve this problem. In the present study, we examined whether the bioavailability of calcium carbonate and calcium citrate can be improved by reducing the particle size. The morphology of nano calcium carbonate and nano calcium citrate was characterized by dynamic laser-light scattering (DLS), field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The measurements obtained from DLS, FE-SEM and TEM were comparable. Acute and sub-chronic toxicity tests were performed to establish the safety of these products after oral administration. The no-observed-adverse-effect levels of nano calcium carbonate and nano calcium citrate were 1.3 and 2.3 g kg(-1) body weight, respectively. The results of our in vivo studies indicate that administering nano calcium carbonate and nano calcium citrate can enhance the serum calcium concentration and maintain the whole-body bone mineral density in ovariectomized mice. These data suggest that nano calcium carbonate and nano calcium citrate are more bioavailable than micro calcium carbonate and micro calcium citrate, respectively.

Tracking of cellular uptake of hydrophilic CdSe/ZnS quantum dots/hydroxyapatite composites nanoparticles in MC3T3-E1 osteoblast cells.

We report the fluorescent labeling of osteoblast cells using the biocompatible hydroxyapatite (HA) grown with nucleating seed of hydrophilic CdSe/ZnS quantum dots (QDs) allowing the real-time observation of cell under confocal microscope. We found that the MC3T3-E1 osteoblast cells can engulf HA with surface-tailored QDs showing fluorescent spots in the cytoplasm, while HA and QDs nanoparticles were not engulfed. It is interesting to see that the fluorescence was only displayed in the cytoplasm of MC3T3-E1 osteoblast cells. It can be envisioned that the nano-sized hydroxyapatite bearing fluorescent QD can only be internalized in the cytoplasm. Therefore, it is worth utilizing these composite particles to observe cellular physiology with minimal toxicity to the osteoblast cells.

Modulation of osteogenesis in human mesenchymal stem cells by specific pulsed electromagnetic field stimulation.

Human mesenchymal stem cells (hMSCs) are a promising candidate cell type for regenerative medicine and tissue engineering applications by virtue of their capacity for self-renewal and multipotent differentiation. Our intent was to characterize the effect of pulsed electromagnetic fields (PEMFs) on the proliferation and osteogenic differentiation of hMSCs in vitro. hMSCs isolated from the bone marrow of adult patients were cultured with osteogenic medium for up to 28 days and exposed to daily PEMF stimulation with single, narrow 300 micros quasi-rectangular pulses with a repetition rate of 7.5 Hz. Relatively greater cell numbers were observed at late stages of osteogenic culture with PEMF exposure. The production of alkaline phosphatase (ALP), an early marker of osteogenesis, was significantly enhanced at day 7 with PEMF treatment in both basal and osteogenic cultures as compared to untreated controls. Furthermore, the expressions of other early osteogenic genes, including Runx2/Cbfa1 and ALP, were also partially modulated by PEMF exposure, indicating that osteogenesis in hMSCs was associated with the specific PEMF stimulation. Based on ALP and alizarin red S staining, the accumulation of ALP protein produced by the hMSCs as well as calcium deposits reached their highest levels at day 28. Our results indicate that extremely low-frequency PEMF stimulation may play a modulating role in hMSC osteogenesis. Taken together, these findings provide insights on the development of PEMF as an effective technology for regenerative medicine.

Synthesis, characterization, and bioconjugation of fluorescent gold nanoclusters toward biological labeling applications.

Synthesis of ultrasmall water-soluble fluorescent gold nanoclusters is reported. The clusters have a decent quantum yield, high colloidal stability, and can be readily conjugated with biological molecules. Specific staining of cells and nonspecific uptake by living cells is demonstrated.

Advantages of nanotechnology-based Chinese herb drugs on biological activities.

A number of new nanotechnology-based Chinese herb drugs have been developed that have efficient biopharmaceutical properties and desirable target characteristics. This offers several alternatives for medical applications. Nanoparticles of Chinese herb drugs possess many benefits, such as improving component solubility, enhancement of bioavailability, increasing absorbency of the organism, reducing medicinal herb doses, and achieving steady-state therapeutic levels of drugs over an extended period compared with traditional Chinese herb drug preparations. There are two basic techniques, 'bottom up' or 'top down', to prepare Chinese herb nanoparticles. Furthermore, specific surface modifications and new design strategies of Chinese herb drug nanoparticles are created to profit clinical applications. This review presents recent advances in nanotechnology-based Chinese herb drugs.

Relationships between physiological responses and presyncope symptoms during tilting up in patients with spinal cord injury.

This study attempted to use the eyesight range to quantify presyncope symptoms (PS), assess the relation between angle of head-up tilt, severity of injury on the American Spinal Injury Association (ASIA) scale, and PS on physiological signals, and determine the notable signals that represent PS in spinal cord injury (SCI) patients. Thirty-eight quadriplegic SCI subjects were recruited, in which the mean blood pressure (MBP), oxygen saturation (SpO(2)), heart rate (HR), and the low-frequency/high-frequency (LF/HF) ratio of the HR variability were measured during tilting up of the head. The SpO(2) and LF/HF differed significantly with the level of PS. These findings of the studied variables suggest that SpO(2) and LF/HF are the physiological signals that are most sensitive to detect in PS, and could be used for the optimal biofeedback design of tilt-table training systems aimed at overcoming posture hypotension in SCI patients.

Development of a biofeedback tilt-table for investigating orthostatic syncope in patients with spinal cord injury.

The purpose of this study was to develop a biofeedback tilt-table for automatic tilt-table training, helping patients with spinal cord injury (SCI) to recover more rapidly from orthostatic hypotension, and increasing safety to avoid syncope during training. This biofeedback tilt-table implemented automatic training maneuvers and included three closed feedback loops to monitor the acquisition of physiological signals from patients and the feedback of presyncope symptoms (PS) to regulate the angle of tilt. The results of clinical testing revealed that the mean blood pressure and oxygen saturation represented the most useful physiological signals for determining PS feedback and the quantitative criteria adopted were practicable and useful in describing the level of PS. This novel biofeedback tilt-table system offered higher patient throughput, faster training and safety in training of SCI patients to overcome their orthostatic hypotension than traditional tilt-table training, and could provide quantitative information of PS to assist medical staff in studying the mechanism of orthostatic syncope.

Dosage effects of curcumin on cell death types in a human osteoblast cell line.

Curcumin, the yellow pigment of Curcuma longa, is known to have antioxidant and anti-inflammatory properties, as well as their ability to either induce or prevent cell apoptosis. However, the precise molecular mechanisms of these effects are unknown. Here, we demonstrate that curcumin can induce apoptotic changes, including JNK activation, caspase-3 activation, and cleavage of PARP and PAK2, at treatment concentrations lower than 25 microM in human osteoblast cells. In contrast, treatment with 50-200 microM of curcumin does not induce apoptosis, but rather triggers necrotic cell death in human osteoblasts. Using the cell permeable dye 2',7'-dichlorofluorescin diacetate (DCF-DA) as an indicator of reactive oxygen species (ROS) generation, we found that while treatment with 12.5-25 microM curcumin directly increased intracellular oxidative stress, 50-200 microM curcumin had far less effect. Pretreatment of cells with N-acetyl cysteine or alpha-tocopherol, two well known ROS scavengers, attenuated the intracellular ROS levels increases and converted the apoptosis to necrosis induced by 12.5-25 microM curcumin. Moreover, we observed a dose-dependent decrease in intracellular ATP levels after treatment of osteoblast cells with curcumin and pretreatment of cells with antimycin or 2-deoxyglucose to cause ATP depletion significantly converted 12.5-25 microM curcumin-induced apoptosis to necrosis, indicating that ATP (a known mediator of apoptotic versus necrotic death) is most likely involved in the switching mechanism. Overall, our results signify that curcumin dosage treatment determines the possible effect on ROS generation, intracellular ATP levels, and cell apoptosis or necrosis in osteoblast cells.