Genetically Modified Ferritin Nanoparticles with Bone-Targeting Peptides for Bone Imaging

Bone homeostasis plays a major role in supporting and protecting various organs as well as a body structure by maintaining the balance of activities of the osteoblasts and osteoclasts. Unbalanced differentiation and functions of these cells result in various skeletal diseases, such as osteoporosis, osteopetrosis, and Paget’s disease. Although various synthetic nanomaterials have been developed for bone imaging and therapy through the chemical conjugation, they are associated with serious drawbacks, including heterogeneity and random orientation, in turn resulting in low efficiency. Here, we report the synthesis of bone-targeting ferritin nanoparticles for bone imaging. Ferritin, which is a globular protein composed of 24 subunits, was employed as a carrier molecule. Bone-targeting peptides that have been reported to specifically bind to osteoblast and hydroxyapatite were genetically fused to the N-terminus of the heavy subunit of human ferritin in such a way that the peptides faced outwards. Ferritin nanoparticles with fused bone-targeting peptides were also conjugated with fluorescent dyes to assess their binding ability using osteoblast imaging and a hydroxyapatite binding assay; the results showed their specific binding with osteoblasts and hydroxyapatite. Using in vivo analysis, a specific fluorescent signal from the lower limb was observed, demonstrating a highly selective affinity of the modified nanoparticles for the bone tissue. These promising results indicate a specific binding ability of the nanoscale targeting system to the bone tissue, which might potentially be used for bone disease therapy in future clinical applications.     

A kind of injectable Angelica sinensis polysaccharide(ASP)/hydroxyapatite (HAp) material for bone tissue engineering promoting vascularization,hematopoiesis, and osteogenesis in mice

Scaffolds made from single hydroxyapatite (HAp) possess neither biological properties of bone nor functions of promoting vascularization and inhibiting immune rejection. To overcome these drawbacks of HAp, Angelica sinensis polysaccharide (ASP)/HAp composite scaffolds were prepared and its application possibility in bone tissue engineering was studied. The scaffolds were examined by mechanical test, releasing test, degradation test, and histological evaluation. The results showed that the scaffolds had good degradation and ASP releasing. The histological examination indicated that ASP/HAp material could effectively promote vascularization, hematopoiesis, and osteogenesis in mice. In conclusion, the composite material could be used for bone tissue engineering with good prospect.     

Design of three-dimensional interconnected porous hydroxyapatite ceramic-based composite phase change materials for thermal energy storage

In this article, three-dimensional connected porous hydroxyapatite ceramics (PHCs) were prepared by using the Pickering emulsion template, which possessing controlled pore structure simply by adjusting the solid content from 35 to 55 wt%. The polyethylene glycol (PEG) and PHCs were compounded by vacuum impregnation to acquire composite phase change materials (CPCMs) with admirable shape stability. The SEM and EDS images showed that PEG was successfully adsorbed in the pore, and the results of FT-IR, XRD, TGA, and thermal cycles test, demonstrated the CPCMs possessed satisfactory chemical stability, favorable thermal stability, and wonderful thermal reliability. The maximum package ratio obtained was 66 wt%, which was supported by the PHC sample prepared with a solid content of 40 wt%. Moreover, the phase transition temperature and latent heat during melting and solidification were 53.41°C and 117.5 J/g, 36.49°C and 111.1 J/g, respectively. Therefore, the prepared PCM composites had a controlled pore structure, stable chemical properties, high latent heat, and excellent thermal reliability, making it a reliable application of thermal energy storage.     

奶粉中羟基磷灰石成分的检测

将奶粉溶于超纯水中,经超声、离心、真空冷冻干燥提取奶粉中无机成分富含物,再经X射线粉末衍射(Xray powder diffraction,XRD)和傅里叶红外光谱法对其进行定性鉴别分析;于空白奶粉样品中加入不同浓度的针状纳米羟基磷灰石标准品,经与样品相同处理后进行XRD分析,利用扫描电子显微镜(Scanning electrons microscopy, SEM)、透射电子显微镜—能谱仪(Transmission electron microscopy-energy spectrometer,TEM-EDS)对样品及加标样品中提取成分进行了形貌和纳米尺寸表征。结果表明,加标样品XRD检测中确定含有羟基磷灰石成分,电镜下能观察到纳米尺寸的针状羟基磷灰石,因此验证了此方法检测纳米羟基磷灰石的可行性;5种样品中1种样品含有羟基磷灰石,并含有未知结构的类似于球状的纳米成分(元素组成为碳、氧、磷、氯),3种样品含有晶体状的方解石,1种样品不含有晶体状羟基磷灰石。     

Biological activity of hydroxyapatite/poly(methylmethacrylate) bone cement with different surface morphologies and modifications for induced osteogenesis

Although having advantages such as good mechanical property and rapid curing, the poor absorption and biological activity of hydroxyapatite (HA)/poly(methylmethacrylate) (PMMA) bone cement limits its clinical application. Therefore, it is of vital importance to improve the integration and the biological activity of HA/PMMA bone cement. In this study, spherical and rod-like HA/PMMA bone cement with different content of P(MMA-co-MPS) were chosen to enhance its interface bioactivity. The content of P(MMA-co-MPS) on the surface of HA was 12, 30, 15, and 28%, respectively, corresponding to 0.3 r-HA, 1.5 r-HA, 0.3 s-HA, and 1.5 s-HA, whose calcium-to-phosphorus (Ca/P) ratios were 1.62, 1.5, 1.65, and 1.53, respectively, and were confirmed by energy dispersive spectroscopy. From scanning electron microscope, we found that the spherical HA (s-HA) promotes the biomineralization on the surface of PMMA than rod-like HA (r-HA). In addition, cell experiments in vitro showed that s-HA/PMMA with lower modification degree (0.3) of P(MMA-co-MPS) results in more cell adhesion and more evenly distributed on surface spreading while observed under laser confocal microscope. Meanwhile, in vitro, cell proliferation and alkaline phosphatase activity indicated that s-HA/PMMA bone cement promotes early osteogenic differentiation of rBMSCs in a deeper extent than r-HA/PMMA, demonstrating that 0.3 s-HA/PMMA provides a favorable theoretical basis for the further clinical application of HA/PMMA bone cement as an optimized bone repair material. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48188.     

The bioactivity of titanium-cuttlefish bone-derived hydroxyapatite composites sintered at low temperature

ABSTRACT

The most limiting features of titanium as a bone substituent are lack of bioactivity and high Young’s modulus. We have prepared titanium-hydroxyapatite (Ti-HAp) composites using titanium hydride as sintering agent to provide titanium sintering at lower temperature and preserve the stability of apatite phase. After low temperature sintering, no hydroxyapatite decomposition was detected. Pure titanium samples sintered in the presence of hydride showed smooth surface indicating good densification at 800°C. Higher HAp content resulted in decreased density and higher porosity due to the formation of micro- and macro-pores caused by the integration of HAp particles into titanium matrix and titanium hydride decomposition. However, Vickers microhardness test showed increased hardness for Ti-HAp composite with 10% of HAp regarding pure Ti. The bioactivity of Ti-HAp composites evaluated in simulated body fluid significantly improved with HAp content. The presence of HAp has lowered the cytotoxic effect of Ti-based composites on Hek293 cells.     

Bio-inspired low elastic biodegradable Mg-Zn-Mn-Si-HA alloy fabricated by spark plasma sintering

In this paper, biodegradable low elastic Mg-Zn-Mn-Si-HA alloys have been synthesized by element-alloying assisted spark plasma sintering (SPS) process. The main concern of the current investigation is to study the influence of the key SPS-process variables, such as, alloying element, milling/alloying time, sintering temperature, and pressure on the porosity and elastic modulus of the fabricated alloys. Following an L₂₇ OA-based on Taguchi method and accompanying the input parameters, a series of SPS experiments were carried out. Results indicated that sintering temperature and pressure were found to have a significant effect. The SEM observations showed that highest degree of porosity was observed at the lowest level of the parameters and the full dense compact was obtained at the highest level of the parameters. The alloying of HA and Si refined the grain structure and improved the brittleness of the composite. The SPS fabricated alloys exhibited an elastic modulus in the range between 16 and 38 GPa, that is proximate to bone and viably avoid stress-shielding. Moreover, various biocompatible phases, that is, CaMg, Mg-Si, Mn-CaO, Ca-Mn-O, and CaMgSi were observed in the alloy, which are expected to enhance its bioactivity and corrosion resistance. As-synthesized alloy would be considered potential biodegradable material for orthopedic applications.     

羟基磷灰石超长纳米线/植物纤维纳米复合“宣纸”及其防霉性能

宣纸是中国书画作品必不可少的载体, 具有优良的耐久性和防霉性能, 因此赢得了“纸中之王”的美誉。2009年, 宣纸被联合国教科文组织列入《人类非物质文化遗产代表作名录》。羟基磷灰石具有优良的生物相容性, 环境友好, 白度高, 是一种具有良好应用前景的生物材料。羟基磷灰石超长纳米线具有高柔韧性, 可用于构建具有不同功能的新型耐火纸。本研究发展了一种新型纳米复合“宣纸”, 由羟基磷灰石超长纳米线和植物纤维复合制成。所制备的纳米复合“宣纸”的白度随着羟基磷灰石超长纳米线含量增加而得到提高, 当羟基磷灰石超长纳米线重量比为25%时, 其白度为76.1%, 高于商品生宣纸(71.9%)或商品熟宣纸(70.3%)。采用三种霉菌(球毛壳霉菌、长枝木霉菌、黑曲霉菌)研究了新型纳米复合“宣纸”的抗霉菌性能。实验结果显示, 与传统宣纸相比, 所制备的纳米复合“宣纸”的防霉性能得到显著改善, 与空白样品和商品宣纸相比, 纳米复合“宣纸”对霉菌的生长具有更好的抑制能力, 在其表面三种霉菌的生长速率明显较低, 并且随着羟基磷灰石超长纳米线含量的增加而降低。在恒温恒湿箱内培养过程中, 商品宣纸表面生长出霉菌, 但是纳米复合“宣纸”表面上没有观察到明显的霉菌生长。预期所制备的纳米复合“宣纸”有助于书画艺术品的长久安全保存, 在书法和绘画艺术中具有良好的应用前景。     

磷灰石复合光催化剂降解异丁基黄药的实验研究

为研究磷灰石复合光催化剂光催化降解性能,选择球形羟基磷灰石(HAP)为基体材料与二氧化钛复合,制备磷灰石复合光催化剂处理异丁基黄药模拟废水,考察了p H值、光照时间、光照条件、初始质量浓度等条件对异丁基黄药催化降解效果。结果表明,初始质量浓度为50 mg/L,p H值为3.6且在紫外光下照射6 min,异丁基黄药降解率可达99.993%,残余质量浓度低于0.005 mg/L,达到国家地表水环境质量标准。     

Radiosensitization induced by zinc-doped hydroxyapatite nanoparticles in breast cancer cells

Zinc-doped hydroxyapatite (HA) nanoparticles were synthesized by microwave assisted method and used with ionizing radiation for inhibition of proliferation of breast cancer cells. Zinc-doped HAs were produced in four different compositions in order to determine the best doping rate in terms of physical and biological properties. Nanoparticle characterizations were performed with X-ray diffractometer, Fourier transform infrared spectroscopy, scanning electron microscopy, and inductively coupled plasma-mass spectrometry. Viability of MDA-MB-231(isolated at M D Anderson from a pleural effusion of a patient with invasive ductal carcinoma) cells treated with nano-HA particles and radiation were assessed by MTT assay. Caspase-7 and Poly (ADP-ribose) polymerase protein expressions in samples were examined by the Western blot. X-ray diffraction patterns of our samples were found to be in good correlation with the reference HA peaks. Notably, increasing zinc amount resulted in elevated percentage of β-tricalcium phosphate, phases. All formulations including pure HA particles were non-cytotoxic in MDA MB 231 cells. On the other hand, low rate Zn-doped HA particles showed significant anti-proliferation effect during irradiation. The combination of irradiation with Zn-doped HA particles also induced apoptosis, demonstrated as cleavage of caspase-7 and PARP proteins. In conclusion, low rate Zn-doped HA enhanced the radiation effect on breast cancer cells.