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Nanometer zinc oxide (Nano-ZnO) has been widely applied in many fields such as rubber,ceramics,textile,cosmetics,etc.due to its excellent physical,chemical and biological properties.In recent years,its applications in biomedicine have been paid more and more attention.This paper introduces the unique optical,chemical,mechanical,semi-conducting and biological properties of Nano-ZnO.Meanwhile,the applications of Nano-ZnO in bio-sensing and detection,biological nutrition,medical treatment,biological imaging,drug delivery,tumor cells targeted killing and translational medicine are also reviewed,and the brief outlook on the applications is presented.
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BACKGROUND:RACK1 is strongly associated with the occurrence and development of oral squamous cel carcinoma. However, the occurrence and development of tumor do not depend on a gene or protein, but a long-term complex process of a network structure of multiple genes and multiple molecules, multi-step, multi-stage joint action. Synergism between tumor genes promotes the formation and development of tumor cel s. Therefore, we cannot limit on a single gene or protein to discover the action mechanism of oral squamous cel carcinoma, but should pay attention on signaling network path related to differential protein or gene, investigate the alterations in related protein or gene expression in the whole signaling pathway, and analyze the action mechanism of the interaction of these molecules. OBJECTIVE:To screen differential genes related to oral squamous cel carcinoma, construct an interaction network through bioinformatics using STRING database, and provide clues for future tests. METHODS:In accordance with our previous classic proteomics results and microarray results of oral squamous cel carcinoma, genes with consistent expression and big differences were selected as differential genes. The differential genes were inputted into the database of STRING to find the possible relationship among the protein subunits and to construct network structure of their interaction. RESULTS AND CONCLUSION:The 19 differential proteins of oral squamous cel carcinoma construct a complicated net work, and the differential proteins interact through these networks. GNB2L1-encoded RACK1 is a node protein and interacts with other differential proteins via WD40 repeated protein (number COG2319) andβ-G protein subunit (number KOG0279). WD40 repeated protein (number COG2319) interacts with 5 differential proteins directly and constructs 10 interacting pathways.β-G protein subunit (number KOG0279) interacts with 8 differential proteins directly, which has 11 interacting pathways. We make a network structure picture based on the interaction of these 19 differential genes by the analysis of the STRING database. The results show that the two subunits of RACK1 protein have direct interaction with 8 differential proteins and have 18 interaction pathways on the picture. As a result, RACK1 is the core protein of the network, suggesting RACK1 is the key node protein in oral squamous cel carcinoma.
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BACKGROUND:Tissue engineering bone application for repairing critical-size segmental defects is stil in research stage. The ideal construction methods have not yet been found. OBJECTIVE:To review the research literatures on tissue engineering bone scaffold material, its shape and effect on the loading of seeding cells, seek appropriate engineered bone scaffolds which are capable of loading a large number of cells effectively and probably, and provide a new way of repairing segmental bone defects. METHODS:The first author performed a data retrieval of PubMed and Wanfang databases from 1994 to 2013, to search the articles addressing the construction method of tissue engineering bone scaffold, and reviewed the literatures systematical y. RESULTS AND CONCLUSION:A total of 379 references were retrieved, including 161 articles in Chinese and 218 articles in English. According to the inclusion and exclusion criteria, 53 articles were final y involved in the analysis. The analysis results indicated that, the needed volume of bone tissue engineering scaffolds for critical-sized section bone defect reconstruction is big, which needs to load a huge number of seed cells. If there is no suitable forms and shapes for celladhesion, the property of so-cal ed engineered bone is similar to pure artificial bone implants. The effective load of seed cells on engineering bone scaffold material and keeping the activity is the first step in clinical practice, as wel as the important guarantee for loading bioactive seed cells. Hence, a more simple and accurate detection method for loading cellquantity is needed. Looking into the retrieved content, effective load cellquantity and its bioactivity are detected by indirect methods, supporting the effectiveness of cellseeding. Some methods can guarantee the cellquantity and seeding pattern, the real load is unknown as wel as the activity. Fabricating engineering bone scaffold into special form and shape are easy to effective seeding, proliferation and maintaining the biomechanical performance, inducing osteogenesis, and final y detecting the load cellquantity and activity on the scaffold through the simple and direct method.
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BACKGROUND:The effects of engineered bone scaffold containing seeding cels with different shapes to repair bone defect are varied, while the loaded cellquantity is the important factor influencing the curative effect, but which is rarely reported. OBJECTIVE:By preparing self-made corrugated tissue-engineered bone scaffold and other three forms of bone tissue engineering scaffolds, to study the quantity of loaded cels on different scaffolds and osteogenesis of corrugated tissue-engineered bone scaffold so as to discuss the advantages and features of self-made corrugated tissue-engineered bone scaffold. METHODS: (1) Experimentin vitro: There were four kinds of scaffolds with the same volume and samples: calcium phosphate cement (CPC) corrugated surface scaffold group, smooth surface scaffold group, cylindrical scaffold group and porous cylindrical scaffold with holow tubes group, in which the latter three groups are control ones. A certain volume with same density of rabbit bone marrow mesenchymal stem cels (BMSCs) suspension after osteogenesis induction was seeded onto the scaffolds. After incubation, culture, digestion and colection, cellquantity was counted, absorbance value was finaly detected and cellactivity was proofed by alkaline phosphatase and alizarin red staining. (2) Experimentin vivo: New Zealand rabbits were randomly and equaly divided into recombinant human bone morphogenetic protein-2 (rhBMP-2)/CPC/BMSCs corrugated scaffold group, pure CPC corrugated scaffold group and cancelous bone implant group. Three kinds of scaffold implants with the same volume were inserted into the area between rabbit’s L5, 6 transverse processes bilateraly. At 4, 8, 12 weeks postoperatively, gross and histological observation was performed. RESULTS AND CONCLUSION:(1)Experimentin vitro: The drip of cellsuspension steadily stayed on the surface of corrugated scaffold because of corrugated shape groove and the surface tension of the liquid. The amount of cels per sample digested down from the CPC corrugated surface scaffold was significantly more than that from the other three groups (P 0.05). (2) Experimentin vivo: At each time point the osteogenesis quantity of rhBMP-2/CPC/BMSCs corrugated scaffold group was more than that of the pure CPC corrugated scaffold group (P 0.05). These findings indicate that the characteristics of the self-made corrugated engineered bone scaffold are beneficial to seed cellloading, which supports a large number of osteogenesis and provides feasibility to promote the healing of segmental bone defects.
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BACKGROUND: Many experiments indicate that the angiogenesis of tissue engineered bone graft plays a key role in the osteogenesis.OBJECTIVE: An experimental pattern was set up designed to prepare a kind of vascularized engineered-bone graft for repairing rhesus tibia defects and analyze the relation of angiogenesis and osteogenesis in vivo by rontgenographic and morphological approaches.DESIGN: Random controlled animal experiment.SETTING: Department of Orthopaedics and Traumatology, Nanfang Hospital, Southern Medical University.MATERIALS: The composite graft was constructed by seeding the induced bone marrow stem cells (BMSCs) on to a beta-tricalcium phosphate(3-TCP) scaffold in vitro, a circular cylinder (20 mm × 8 mm diameter) with a slit (width 2 mm and length 3 mm ) open to both ends and slot. Porosity 60% and pore diameter 100-150 μm. Twenty-nine healthy rhesuses aged 4-5 years and weighted 3.5-5 kg were adopted without gender limitation.METHODS: The experiment was conducted in the Department of Orthopaedics and Traumatology, Nanfan Hospital, Southern Medical University from October 2003 to July 2005. ①Bone-periosteum defect of 20 mm was made in the middle part of right tibia of the 27 rhesuses, and randomly divided into 3 groups equally. ②The defect gaps in fascia-blood vessel group (A) were plugged with in vitro engineered composites constructed by bone marrow stem cells and 3-TCP scaffold, which were totally hugged by a sheet of pedicled deep fascia and additionally a corresponding portion of saphenous artery and veins. The gaps in fascia group (B) and control group(C), however, were inserted with fascia-coated tissue engineered bone and tissue engineered bone only, respectively. Furthermore, two rhesuses without filling materials on the defect were picked up as blanks fixed by steel pins. ③The angiogenesis and osteogenesis for each treatment was assessed by radioactive imaging, roentgenographic analyses, blocking density and vaso-area image analysis at time intervals of 4, 8 and 12 weeks postoperative.MAIN OUTCOME MEASURE: The score of radioactive imaging,roentgenographic, morphological and vaso-area image analyses RESULTS: Totally 29 rhesuses were involved in the result analysis.① General observation of samples: In group A, all the surfaces of the implanted material and the central part were wholly wrapped up or replaced by bonelike tissues which were hard and could not be broken. And 2/3 materials had been absorbed; In group B and C, partial materials of the medial surface and the front were not coated or replaced by bonelike tissues, which could be broken with force, and 1/3 material had been absorbed.②Histological observation of scaffolds: With time passing, the scaffold materials were absorbed to different degrees in group A, B and C, among which, group A was most significant; Under the microscope, the implanted materials at 12 weeks were completely coated with the bonelike tissues, while the blood vessels structures in the materials were mostly alveoli alike and multi-braches. In group B, most of the materials at 12 weeks were wrapped up by the new bone, and few blood vessels could be seen in the center of the materials. In group C, the implanted materials at 12 weeks were slightly absorbed. The new bone and the vascular structures were both increased a little, but still very few.③Analyses of vaso-area: The vaso-areas of both central and peripheral parts in group A were significantly bigger than those of group B and C (P ＜ 0.05). Furthermore, it tended to increase with the time.④X-rays observation: At 12 weeks, group A's images presented obviously decreased density which was lower than that of the normal bone in individual areas and the continual bony callus manifested. Whereas group B and C's images showed slightly decreased density and the continual bony callus appeared on the sections. ⑤The roentgenographic scores of bone defects: The results indicates that the scores of group A was better than those of group B and C at 4, 8 and 12 weeks, respectively (P ＜ 0.05).CONCLUSION: ①This study shows that a feasible and effective angiogenesis approach of tissue engineered bone can accelerate osteogenesis in vivo. ②The absorption level is positively related to local angiogenesis.