TiO2 nanotubes improve physico-mechanical properties of glass ionomer cement

ObjectivesThe aim of this study was to determine the physico-mechanical properties of a high viscosity glass ionomer cement (GIC) reinforced with TiO₂ nanotubes (TiO₂-nt).MethodsTiO₂-nt was incorporated into the GIC powder components (Ketac Molar EasyMix™) in concentrations of 0% (control group), 3%, 5%, 7% by weight. Compressive strength (n = 10/group), three point bending for flexural strength (n = 18/group), microshear bond strength to dentin and failure mode (n = 20/group), and surface roughness and weight loss before and after brushing simulation (30,000 cycles) (n = 8/group) were evaluated. Data were submitted to Shapiro-Wilk, ANOVA, Tukey and Chi-square tests (α ≤ 0.05).ResultsAddition of 5% of TiO₂-nt into GIC presented the highest values for compressive strength and differed from the control, 3% and 7% groups (p = 0.023). There were no significant differences in flexural strength (p = 0.107) and surface roughness before and after the dental brushing (p = 0.287) among the groups. GIC added with 5% TiO₂-nt showed the lowest weight loss values (p = 0.01), whereas the control, 3% or 5% TiO₂-nt groups presented similar microshear bond strength values (p ≥ 0.05). The 5% TiO₂-nt group featured higher microshear bond strength than the 7% TiO₂-nt group (p = 0.034). Cohesive in material was the most representative failure mode for all groups.SignificanceThe incorporation of TiO₂-nt did not affect GIC’s adhesiveness to dentin, but improved its compressive strength at 5%. Furthermore, TiO₂-nt decreased the percentage of weight loss after GIC’s surface wear.     

纳米药物递送系统在结核病治疗中的研究进展

目前,结核病防治形势仍十分严峻。然而,传统抗结核药物治疗方案存在疗程长、药物不良反应多以及患者依从性差等问题,常导致治疗失败,故亟需可以控制结核病的新药或新剂型。装载抗结核药物的纳米药物递送系统可以将抗结核药物主动或被动靶向到被感染的细胞或病灶部位内,杀菌的同时,还具有缓释给药、减少给药频率、减少剂量依赖性不良反应等优势。本文综述了纳米递药系统在结核病治疗方面的应用情况及前景。     

Silver Nanoparticle (AgNP) Technology applications in trauma and orthopaedics

Recently Nanotechnology advances continue to accelerate with development of incredible new materials and products in the field of science. The Nanotechnology has evolved in the domains of prevention, diagnosis and treatment in the field of trauma and orthopaedics. It provides a spectrum of new tools such as drug delivery (chemotherapy in orthopaedic oncology), diagnosis (bone diseases, osteoporosis, metastatic osteosarcoma), improving osteointegration of implant materials (implants & total joint replacements), combating infection (trauma implants and prosthesis), tissue engineering (hydroxyapatite scaffolds, cartilage defects, stem cell regeneration) and prevention of osteoporosis. The current article highlights the role of Silver Nanoparticle (AgNP) Technology applications in Trauma and Orthopaedics.     

Nanotechnology-based therapies for the prevention and treatment of Streptococcus mutans-derived dental caries

BackgroundDental caries results from long-term acid production when sugar is metabolized by a bacterial biofilm, resulting in a loss of calcium and phosphate from the enamel. Streptococcus mutans is a type of acid-producing bacteria and a virulent contributor to oral biofilms. Conventional treatment options, such as cefazolin and ampicillin, have significant levels of bacterial resistance. Other topical agents, such as fluoride, tend to be washed away by saliva, resulting in low therapeutic efficacy.HighlightThis review aims to highlight the solubility issues that plague poorly water-soluble therapeutic agents, various novel polymeric, and lipid-based nanotechnology systems that aim to improve the retention of therapeutic agents in the oral cavity.ConclusionIn this review, different formulation types demonstrated improved therapeutic outcomes by enhancing drug solubility, promoting penetration into the deep layers of the biofilm, facilitating prolonged residence time in the buccal cavity, and reducing the emergence of drug-resistant phenotypes. These formulations have a strong potential to give new life to therapeutic agents that have limited physicochemical characteristics.     

纳米骨组织材料用于骨质疏松治疗进展

目的旨在探究通过纳米骨组织材料治疗骨质疏松的进展,以促进其临床应用。方法由第一作者应用计算机检索PubMed、中国期刊全文数据库(CNKI)1997-05～2011-10相关文献。在标题、摘要、关键词中以"nano,osteoporosis,bone marrow mesenchymal stem cells(BMMSCs),treatment"或"纳米,骨质疏松,骨髓间充质干细胞,治疗"为检索词进行检索。选择文章内容与纳米技术治疗骨质疏松有关者,同一领域文献则选择近期发表在权威杂志文章。结果初检得到127篇文献,根据纳入标准选择36篇文献进行综述。结论纳米技术治疗骨质疏松已经成为骨质疏松治疗中的一项新兴技术。目前通过纳米技术治疗骨质疏松主要通过促进药物吸收,维持药物作用时间,增加药物靶向性,促进干细胞分化的机制来进行骨质疏松的治疗。目前常用的技术包括药物纳米化,纳米微载体,材料表面纳米化,纳米材料修饰干细胞等。但目前纳米技术治疗骨质疏松尚未成熟,仍有许多问题有待解决。     

Probabilistic approach for the risk assessment of nanomaterials: A case study for graphene nanoplatelets

An experimental probabilistic approach for health risk assessment was applied for graphene nanoplatelets (GNPs). The hazard assessment indicated a low level of toxicity for the GNPs. The benchmark dose method, based on sub-chronic and chronic inhalation exposure studies, was used to quantify a guidance value (BMC_h) for occupational inhalation exposure to GNPs, expressed as a lognormal distribution with a geometric mean?±?geometric standard deviation of 0.212?±?7.79?mg/m³ and 9.37?×?10⁴?±?7.6 particle/cm³. Exposure scenarios (ES) were defined based on the scientific literature for large-scale production (ES1) and manufacturing (ES2) of GNPs; a third ES, concerning in-lab handling of GNPs (ES3) was based on results of experiments performed for this study. A probability distribution function was then assumed for each ES. The risk magnitude was calculated using a risk characterization ratio (RCR), defined as the ratio of the exposure distributions and the BMC_h distribution. All three ES resulted in RCR distributions ≥1 (i.e. risk present); however, none of the ES had a statistically significant level of risk at a 95% confidence interval. A sensitivity analysis indicated that ～75% of the variation in the RCR distributions was due to uncertainties in the BMC_h calculation.     

载三氧化二砷纳米微粒对胰腺癌腹水抑制效应的实验研究

目的探讨用纳米载体包裹的三氧化二砷(As2O3)在荷胰腺癌SCID小鼠体内的分布及对腹水生成和存活时间的影响。方法用超声乳化法制备载As2O3乳酸羟基乙酸共聚物纳米微粒(As2O3-NPs),用体外释药方法研究其释放特性。于小鼠右前腋下接种SW1990细胞12d后,静脉给As2O3-NPs5.0mg/kg体重,采用高压液相色谱法(HPLC)测定血浆、正常和肿瘤组织中As2O3含量。观察不同浓度As2O3-NPs对腹水生成的抑制作用。观察10.0mg/kg体重As2O3-NPs处理的胰腺癌小鼠的存活期、体重、腹腔渗透性及腹水中凋亡细胞的变化。结果As2O3-NPs直径为(210±23)nm,含药量为29%(重量比),体外释药速度明显慢于单纯的As2O3。As2O3-NPs在体内呈浓度依赖性抑制腹水形成,减少腹膜的通透性,增加腹水内凋亡细胞量,延长荷瘤小鼠的存活时间。结论As2O3-NPs具有明显的缓释药物功能,能有效积聚在肿瘤组织,并抑制癌性腹水生成,是一种有希望的抗肿瘤药物。     

A plug-and-play ratiometric pH-sensing nanoprobe for high-throughput investigation of endosomal escape

An important aspect in the design of nanomaterials for delivery is an understanding of its uptake and ultimate release to the cytosol of target cells. Real-time chemical sensing using a nanoparticle-based platform affords exquisite insight into the trafficking of materials and their cargo into cells. This versatile and tunable technology provides a powerful tool to probe the mechanism of cellular entry and cytosolic delivery of a variety of materials, allowing for a simple and convenient means to screen materials towards efficient delivery of therapeutics such as nucleic acids.     

Mitochondrial delivery of antisense RNA by MITO-Porter results in mitochondrial RNA knockdown,and has a functional impact on mitochondria

Mitochondrial genome-targeting nucleic acids are promising therapeutic candidates for treating mitochondrial diseases. To date, a number of systems for delivering genetic information to the cytosol and the nucleus have been reported, and several successful gene therapies involving gene delivery targeted to the cytosol and the nucleus have been reported. However, much less progress has been made concerning mitochondrial gene delivery systems, and mitochondrial gene therapy has never been achieved. Here, we report on the mitochondrial delivery of an antisense RNA oligonucleotide (ASO) to perform mitochondrial RNA knockdown to regulate mitochondrial function. Mitochondrial delivery of the ASO was achieved using a combination of a MITO-Porter system, which contains mitochondrial fusogenic lipid envelopes for mitochondrial delivery via membrane fusion and D-arm, a mitochondrial import signal of tRNA to the matrix. Mitochondrial delivery of the ASO induces the knockdown of the targeted mitochondria-encoded mRNA and protein, namely cytochrome c oxidase subunit II, a component of the mitochondrial respiratory chain. Furthermore, the mitochondrial membrane potential was depolarized by the down regulation of the respiratory chain as the result of the mitochondrial delivery of ASO. This finding constitutes the first report to demonstrate that the nanocarrier-mediated mitochondrial genome targeting of antisense RNA effects mitochondrial function.     

现行结核菌检测技术应用于泌尿系统结核诊断的研究进展

泌尿系统结核居于肺外结核第三位,其中最主要的是肾结核。肾结核是由结核分枝杆菌引起的慢性、进行性、破坏性病变,常因其结核症状不典型致使临床诊疗上易漏诊误诊,从而延误治疗时机,给患者泌尿系统带来很大损伤。目前泌尿系统结核的确诊主要依赖于临床表现结合实验室检查、影像学检查等。但是横跨在现有技术与泌尿系统结核临床诊断需要之间的鸿沟依旧为其早期诊断、病情评估和预后监测带来了不可避免的影响,这也阻碍了泌尿系统结核诊断方式更新的探索与发展。伴随着纳米技术和微流体技术的飞速发展,很多检测结核分枝杆菌的生物传感器应运而生。近年来纳米/微流体技术已经被广泛应用于发展现场检测多种疾病的诊断和监测技术方面,这预示着在结核病诊断方面应用纳米/微流体技术也是不可避免的趋势,更为诊断泌尿系统结核寻找更为可靠准确的依据和方法提供了新的契机。以下对泌尿系统结核的临床表现、诊断方法、横跨在现有技术与泌尿系统结核临床诊断之间的鸿沟、结核病诊断的纳米/微流体技术以及纳米/微流体技术能否为泌尿系统结核诊断与监测提供未来前景等方面进行综述。