Targeting Efficiency and Biodistribution of Zoledronate Conjugated Docetaxel Loaded Pegylated PBCA Nanoparticles for Bone Metastasis

In an attempt to improve tumor localization of docetaxel (DTX)‐loaded nanoparticles (NPs), zoledronic acid (ZOL) is used as a ligand to target bone metastasis. DTX‐loaded ZOL‐conjugated polyethylene glycol (PEG)ylated polybutyl cyanoacrylate (PBCA) NPs are prepared using an anionic polymerization technique. PBCA‐PEG‐ZOL NPs are subjected to cytotoxic assay in both BO2 and MCF‐7 cell lines. Cell cycle arrest and apoptosis induced by the PBCA‐PEG‐ZOL NPs are studied. Quantitative cellular uptake, NP uptake route characterization, confocal microscopy and IPP/ApppI levels are performed. PBCA‐PEG‐ZOL NPs show an enhanced cytotoxic effect in both BO2 as well as MCF‐7 cell lines due to higher uptake following ZOL‐mediated endocytosis. The molecular basis of apoptosis reveals the involvement of a cytoplasmic protein in activating the programmed cell death pathway. Route characterization studies reveal that PBCA‐PEG‐ZOL NPs uptake is not completely blocked even by using both inhibitors (genistein and phenyl arsinoxide) simultaneously, conferring that uptake is not entirely based upon clathrin or caveolae. PBCA‐PEG‐ZOL NPs showed 7 and 5.3 times increase in IPP and ApppI production, in comparison to ZOL treatment, and 138 times higher than the control group in MCF‐7 cell line. In BO2 cell line, after treatment with NPs, IPP was 5.35 times higher than ZOL solution. No ApppI in BO2 cell line after treatment with NPs and ZOL solution was found. NP distribution in tumor infected bone is also significantly high in comparison to the normal bone at any time point. It is concluded that ZOL‐conjugated NPs provide an efficient and targeted delivery of DTX, with synergistic effects. Thus, these NPs present a promising treatment in the near future, by actively targeting metastatic tumor.     

Cell Generator: A Self‐Sustaining Biohybrid System Based on Energy Harvesting from Engineered Cardiac Microtissues

Biohybrid soft robotic devices present unique advantages for designing biologically active machines that can dynamically sense and interact with complex bioelectrical signals. Here, a controllable cell‐based machine is developed that harvests energy from arrays of beating cardiomyocytes to generate electricity for biomedical microscale robotic applications. The “Cell Generator” device is based on an array of piezoelectric microcantilevers wrapped with 3D patterned cardiac cells. Spontaneous contraction of the engineered cardiac constructs provides the source of mechanical energy for electricity generation. It is demonstrated that a single “Cell Generator” unit with 40 cantilevers can output peak voltages of ≈70 mV, and a larger array of 540 cantilevers can directly generate a pulsed output as high as ≈1 V. When integrated with an electrical rectification and storage circuit, it is further shown that the “Cell Generator” can provide functional outputs and work as a self‐powered neural stimulator to evoke action potentials in cultured neuronal networks. This demonstration of “Cell Generator” technology provides an innovative perspective of exploiting live biological powering system on biomedical microscale robotic devices in the human body.     

Bone Plate Composed of a Ternary Nanohydroxyapatite/Polyamide 66/Glass Fiber Composite: Biocompatibility In Vivo and Internal Fixation for Canine Femur Fractures

Bone plates have been applied to fix fractures for over a hundred years. Metal plates are the gold standard. However, an increasing number of clinical practices and animal experiments have shown that metal plates have had incidents of failure due to their rigid fixation and long‐term complications. Degradable composites present the advantages of a lower elastic modulus and absorbable properties but are unsuitable for load‐bearing applications. Nondegradable bone plates composed of a nanohydroxyapatite/polyamide 66/glass fiber (n‐HA/PA66/GF) composite are prepared, which have enough strength and a low elastic modulus for an internal fixation device. To better assess its function as a bone plate, animal experiments are conducted using a canine load‐bearing femur fracture model. The results show that the n‐HA/PA66/GF plate can fix fractures effectively. Gross observation, radiographic films, and histological analysis all show that the n‐HA/PA66/GF plate leads to a secondary (indirect) union with obvious callus formation, whereas the titanium plate leads to primary (direct) union due to rigid fixation. Furthermore, the histological results reveal that new bone grows at the interface and that the n‐HA/PA66/GF plate can integrate with native bone tissue. Consequently, the n‐HA/PA66/GF composite shows good potential as a bone plate to fix loading‐bearing bone fractures.     

A four-channel microelectronic system for neural signal regeneration

This paper presents a microelectronic system which is capable of making a signal record and functional electric stimulation of an injured spinal cord. As a requirement of implantable engineering for the regeneration microelectronic system, the system is of low noise, low power, small size and high performance. A front-end circuit and two high performance OPAs (operational amplifiers) have been designed for the system with different functions,and the two OPAs are a low-noise low-power two-stage OPA and a constant-g_m RTR input and output OPA. The system has been realized in CSMC 0.5-μm CMOS technology. The test results show that the system satisfies the demands of neuron signal regeneration.     

人骨髓间充质干细胞的超微结构

目的：分离培养人骨髓骨充质干细胞，进行超微结构观察。方法：冲洗出流产胎儿股骨髓内容物，梯度离心，取舍有骨髓间充质干细胞的低密度血小板层进行,立春 透射电镜，扫描电镜下进行超微结构的全面观察，结果：透射电镜下可见细胞有两种不同的形态结构，细胞间有许多缝隙连接；扫描电镜下可见细胞表面有短而粗的微绒毛突起，结论：培养的细胞有适宜作为组织工程种子细胞的形态学基础。     

Evaluation of Er, Cr:YSGG laser for hard tissue ablation: an in vitro study

The use of erbium,chromium:yttrium-scandium-gallium-garnet (Er, Cr:YSGG) laser with a wavelength of 2.78 μm for hard bone tissue ablation was evaluated. The surface morphology and microstructure changes of bone tissue treated with Er, Cr:YSGG were analyzed as compared to those treated with diamond drill.The influence of fluence on ablation rate and ablation efficiency as well as microstructure was also examined.The results show that Er, Cr:YSGG laser can perform bone perforation that is more fine and presented a lot of unique advantages compared to traditional methods. An approximately linear relationship was observed between the ablation rate/ablation efficiency and radiant exposure.Increasing the radiant exposure irradiated on bone tissue will produce stronger thermal injury around the crater and result in microstructure changing.     

畜骨在食品开发中的发展前景

说明了骨头的营养价值和骨糊的加工要点,同时也估算了生产骨糊的经济效益和发展前景     

Electrospun Fibrous Architectures for Drug Delivery,Tissue Engineering and Cancer Therapy

The versatile electrospinning technique is recognized as an efficient strategy to deliver active pharmaceutical ingredients and has gained tremendous progress in drug delivery, tissue engineering, cancer therapy, and disease diagnosis. Numerous drug delivery systems fabricated through electrospinning regarding the carrier compositions, drug incorporation techniques, release kinetics, and the subsequent therapeutic efficacy are presented herein. Targeting for distinct applications, the composition of drug carriers vary from natural/synthetic polymers/blends, inorganic materials, and even hybrids. Various drug incorporation approaches through electrospinning are thoroughly discussed with respect to the principles, benefits, and limitations. To meet the various requirements in actual sophisticated in vivo environments and to overcome the limitations of a single carrier system, feasible combinations of multiple drug‐inclusion processes via electrospinning could be employed to achieve programmed, multi‐staged, or stimuli‐triggered release of multiple drugs. The therapeutic efficacy of the designed electrospun drug‐eluting systems is further verified in multiple biomedical applications and is comprehensively overviewed, demonstrating promising potential to address a variety of clinical challenges.     

Direct‐Write Assembly of Microperiodic Silk Fibroin Scaffolds for Tissue Engineering Applications

Three–dimensional, microperiodic scaffolds of regenerated silk fibroin have been fabricated for tissue engineering by direct ink writing. The ink, which consisted of silk fibroin solution from the Bombyx mori silkworm, was deposited in a layer‐by‐layer fashion through a fine nozzle to produce a 3D array of silk fibers of diameter 5 µm. The extruded fibers crystallized when deposited into a methanol‐rich reservoir, retaining a pore structure necessary for media transport. The rheological properties of the silk fibroin solutions were investigated and the crystallized silk fibers were characterized for structure and mechanical properties by infrared spectroscopy and nanoindentation, respectively. The scaffolds supported human bone marrow‐derived mesenchymal stem cell (hMSC) adhesion, and growth. Cells cultured under chondrogenic conditions on these scaffolds supported enhanced chondrogenic differentiation based on increased glucosaminoglycan production compared to standard pellet culture. Our results suggest that 3D silk fibroin scaffolds may find potential application as tissue engineering constructs due to the precise control of their scaffold architecture and their biocompatibility.