犬胆总管内置可降解支架并行激光焊接的安全性及胆总管组织学变化

目的：探讨犬胆总管(CBD)探查后内置可降解支架并行激光焊接的可行性及其临床应用价值。方法：用30条本地杂种犬模拟胆总管探查术（CBDE）,将其随机分为3组:单一激光焊接组（对照组Ⅰ,n=10）,CBD内置可降解支架后行I期缝合组（对照组Ⅱ,n=10）,以及CBD内置可降解支架后行激光焊接组（实验组,n=10）。观察各组手术前后CBD内径的变化,记录缝合时间和总手术时间, 观察术后1～3 d胆漏的发生率、支架降解情况,术后6周取胆总管及肝组织做病理学检查。结果：对照组Ⅰ术后胆漏的发生率（6/10）显著高于实验组（0/10）和对照组Ⅱ（0/10）;对照组Ⅱ的缝合时间［(7.20±2.88)min］多于实验组［(2.02±1.03)min］。术后第6周胆总管及肝组织病理学显示,实验组胆总管的内膜已修复,炎症反应轻,无明显肉芽肿形成,部分焊接区域几乎无纤维瘢痕,明显优于对照组Ⅱ;对照组Ⅱ与实验组术后均无肝损伤表现,CBD内径均无增宽或变窄。结论：胆总管探查术后内置可降解支架并行激光焊接的方法在动物实验中是安全有效的,且优于线缝合组。     

基质金属蛋白酶抑制剂的研究进展

牙本质粘接混合层的长期稳定性不佳,基质金属蛋白酶等内源性酶降解胶原是导致混合层破坏的重要因素。使用酶抑制剂抑制胶原降解,维持胶原结构的完整性,是提高混合层稳定性的关键。本文重点总结了基质金属蛋白酶抑制剂（包括氯己定、乙二胺四乙酸、季铵盐类、锌离子和氧化锌、四环素类及其衍生物、异羟肟酸类抑制剂、二磷酸盐衍生物、交联剂等）的研究进展,并对未来的发展进行展望。     

Hybrid polycaprolactone/polyethylene oxide scaffolds with tunable fiber surface morphology,improved hydrophilicity and biodegradability for bone tissue engineering applications

In the present study, we attempt to modify Polycaprolactone (PCL) by blending it with a water soluble polymer Polyethyleneoxide (PEO) having two different molecular weights (Mv ~1,00,000 and 6,00,000) using electrospinning technique. The effect of PEO molecular weight and blend ratio on fiber morphology, porosity, surface wettability, static and dynamic mechanical properties of PCL was investigated. In vitro degradation studies in phosphate buffer saline (PBS) at 37 °C demonstrated formation of pores on fiber surface especially in blend scaffolds with 50:50 ratios. In vitro studies using human osteoblast sarcoma (hOS) cell lines on blend scaffolds showed improved cellular response with good cell adhesion, viability and proliferation. The study revealed that incorporation of PEO on PCL scaffolds complemented the properties of PCL and facilitated fabrication of scaffolds with improved hydrophilicity, mechanical property and tunable degradation profile with better cell viability which makes it an ideal candidate for bone tissue engineering applications.     

Novel collagen scaffolds prepared by using unnatural D-amino acids assisted EDC/NHS crosslinking

This work discusses the preparation and characterization of novel collagen scaffolds by using unnatural D-amino acids (Coll-D-AAs)-assisted 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC)/N-hydroxyl succinimide(NHS)-initiated crosslinking. The mechanical strength, hydrothermal and structural stability, resistance to biodegradation and the biocompatibility of Coll-D-AAs matrices were investigated. The results from Thermo mechanical analysis, Differential scanning calorimetric analysis and Thermo gravimetric analysis of the Coll-D-AAs matrices indicate a significant increase in the tensile strength (TS, 180?±?3), % elongation (% E, 80?±?9), elastic modulus (E, 170?±?4) denaturation temperature (T _d, 108?±?4) and a significant decrease in decomposition rate (T _g, 64?±?6). Scanning electron microscopic and Atomic force microscopic analyses revealed a well-ordered with properly oriented and well-aligned structure of the Coll-D-AAs matrices. FT-IR results suggest that the incorporation of D-AAs favours the molecular stability of collagen matrix. The D-AAs stabilizing the collagen matrices against degradation by collagenase would have been brought about by protecting the active sites in collagen. The Coll-D-AAs matrices have good biocompatibility when compared with native collagen matrix. Molecular docking studies also indicate better understanding of bonding pattern of collagen with D-AAs. These Coll-D-AAs matrices have been produced in high mechanical strength, thermally and biologically stable, and highly biocompatible forms that can be further manipulated into the functional matrix suitable in designing scaffolds for tissue engineering and regenerative medical applications.     

戊二醛交联对壳聚糖/羟基磷灰石-庆大霉素缓释材料性能的影响

背景：交联是骨组织工程材料改性的一种常用方法,但目前仍缺乏交联剂对载药人工骨材料性能影响的相关研究与报道。 目的：研究戊二醛交联对壳聚糖/羟基磷灰石-庆大霉素载药人工骨材料力学性能、降解性能及体外药物缓释行为的影响。 方法：分别制备壳聚糖质量分数为10%,20%,30%的壳聚糖/羟基磷灰石-庆大霉素载药人工骨材料与戊二醛交联壳聚糖/羟基磷灰石-庆大霉素载药人工骨材料,检测各组材料的机械强度、吸水率、降解率及体外药物释放行为。 结果与结论：壳聚糖含量为10%,20%,30%壳聚糖/羟基磷灰石-庆大霉素的抗压强度分别为(10.16±1.17),(28.40±0.64),(23.28±1.30) MPa,经戊二醛交联后材料的抗压强度分别增大至(36.30±1.20),(51.60±2.08),(36.90±3.22) MPa。壳聚糖含量为10%,20%,30%壳聚糖/羟基磷灰石-庆大霉素交联后的吸水率与降解率均低于交联前。在体外缓释的第1天,30%壳聚糖/羟基磷灰石-庆大霉素的药物释放量为42.2%,材料经戊二醛交联处理后药物释放量降至33.6%,在随后的9 d,交联壳聚糖/羟基磷灰石-庆大霉素的总释放量均低于壳聚糖/羟基磷灰石-庆大霉素。表明戊二醛交联赋予了材料更好的生物稳定性,减缓了材料降解速率,显著改善了药物突释现象。中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程全文链接：     

Relationship between Biodegradation Rate and Grain Size Itself Excluding Other Structural Factors Caused by Alloying Additions and Deformation Processing for Pure Mg

This work studied the relationship between biodegradation rate and grain size itself, excluding other structural factors such as segregations, impure inclusions, second phase particles, sub-structures, internal stresses and textures caused by alloying additions and deformation processing for pure Mg. A spectrum of grain size was obtained by annealing through changing the annealing temperature. Grain boundary influenced the hardness and the biodegradation behavior. The hardness was grain size-dependent, following a typical Hall–Petch relation: HV=18.45+92.31d−12. The biodegradation rate decreased with decreasing grain size, following a similar Hall–Petch relation: Pi=0.17−0.68d−12 or Pw=1.34−6.17d−12. This work should be helpful for better controlling biodegradation performance of biodegradable Mg alloys through varying their grain size.     

Exploration on the Enhancement of Detoxification Ability of Zearalenone and Its Degradation Products of Aspergillus niger FS10 under Directional Stress of Zearalenone

Zearalenone (ZEN) is one of the most common mycotoxin contaminants in food. For food safety, an efficient and environmental-friendly approach to ZEN degradation is significant. In this study, an Aspergillus niger strain, FS10, was stimulated with 1.0 μg/mL ZEN for 24 h, repeating 5 times to obtain a stressed strain, Zearalenone-Stressed-FS10 (ZEN-S-FS10), with high degradation efficiency. The results show that the degradation rate of ZEN-S-FS10 to ZEN can be stabilized above 95%. Through metabolomics analysis of the metabolome difference of FS10 before and after ZEN stimulation, it was found that the change of metabolic profile may be the main reason for the increase in the degradation rate of ZEN. The optimization results of degradation conditions of ZEN-S-FS10 show that the degradation efficiency is the highest with a concentration of 10⁴ CFU/mL and a period of 28 h. Finally, we analyzed the degradation products by UPLC-q-TOF, which shows that ZEN was degraded into two low-toxicity products: C₁₈H₂₂O₈S (Zearalenone 4-sulfate) and C₁₈H₂₂O₅ ((E)-Zearalenone). This provides a wide range of possibilities for the industrial application of this strain.     

Monitoring biodegradation of creosote in soils using radiolabels,toxicity tests,and chemical analysis

Microbial acclimation to, and mineralization of polycyclic aromatic hydrocarbons (PAHs), was studied using four uncontaminated soils (designated HS, HC, GP, MS) spiked with creosote and ¹⁴C‐phenanthrene. The effects of nutrient amendments (nitrogen and phosphorus), temperature (10°C and 22°C), and moisture content (50 or 85% of water‐holding capacity, WHC) on mineralization were monitored by measuring evolution of ¹⁴CO₂ in microcosms. Acclimation and mineralization occurred more rapidly at 22°C than at 10°C and were enhanced by the P amendment, at 50% of WHC for GP soil and 85% of WHC for HC and MS soils. These conditions were applied to microcosms containing 1500 g soil and monitored for biodegradation of total petroleum hydrocarbons (TPHs) and PAHs using chemical analysis and six soil toxicity tests. Although 40% ¹⁴C was recovered as CO₂ within 35–45 days in the smaller microcosms, analytical and toxicity test data indicated that bioremediation in the larger microcosms was not successful after 130 days. The soil depth and high moisture content may have restricted oxygen diffusion into the soil, which was not stirred during the experiment. Variations in toxicity and contaminant concentrations were observed but were considered a consequence of the sampling protocol and insufficient mixing during spiking, which may have produced pockets of “hot” soil. The mineralization experiment was useful for confirming that indigenous soil microorganisms could degrade PAHs, but was not indicative of the success of the bioremediation protocol on a larger scale. © 2000 John Wiley & Sons, Inc. Environ Toxicol 15: 99–106, 2000     

生物可降解分子印迹聚合物的制备及评价

背景：交联剂是支撑分子印迹聚合物骨架的主要单元,分子印迹聚合物是否生物友好与交联剂的性能密不可分,但目前常用交联剂的生物相容性和生物降解性还不明确。 目的：制备新型生物可降解分子印迹聚合物,分析其吸附性能和可降解性能。 方法：以丙烯酰化的聚ε-己内酯为交联剂,以丙烯酸为功能单体,采用紫外光引发聚合法制备茶碱分子印迹聚合物,通过等温吸附、Scatchard分析和动力学曲线研究其吸附能力,在模拟人体生理环境体系中进行体外降解实验。 结果与结论：等温吸附曲线表明茶碱分子印迹聚合物和非分子印迹聚合物对模板分子茶碱均有吸附能力,但茶碱分子印迹聚合物的吸附量显著高于非分子印迹聚合物。茶碱分子印迹聚合物对茶碱的载药量为1.54%,包封率为12.48%,茶碱分子印迹聚合物和聚ε-己内酯二醇在观察时间内的体外降解率分别为6.60%和1.33%。制备的分子印迹聚合物不仅对目标分子有特异的吸附性能,而且具有良好的生物降解性能,可在模拟人体环境中进行降解。     

3D Printing of Cellulase-Laden Cellulose Nanofiber/Chitosan Hydrogel Composites: Towards Tissue Engineering Functional Biomaterials with Enzyme-Mediated Biodegradation

The 3D printing of a multifunctional hydrogel biomaterial with bioactivity for tissue engineering, good mechanical properties and a biodegradability mediated by free and encapsulated cellulase was proposed. Bioinks of cellulase-laden and cellulose nanofiber filled chitosan viscous suspensions were used to 3D print enzymatic biodegradable and biocompatible cellulose nanofiber (CNF) reinforced chitosan (CHI) hydrogels. The study of the kinetics of CNF enzymatic degradation was studied in situ in fibroblast cell culture. To preserve enzyme stability as well as to guarantee its sustained release, the cellulase was preliminarily encapsulated in chitosan–caseinate nanoparticles, which were further incorporated in the CNF/CHI viscous suspension before the 3D printing of the ink. The incorporation of the enzyme within the CHI/CNF hydrogel contributed to control the decrease of the CNF mechanical reinforcement in the long term while keeping the cell growth-promoting property of chitosan. The hydrolysis kinetics of cellulose in the 3D printed scaffolds showed a slow but sustained degradation of the CNFs with enzyme, with approximately 65% and 55% relative activities still obtained after 14 days of incubation for the encapsulated and free enzyme, respectively. The 3D printed composite hydrogels showed excellent cytocompatibility supporting fibroblast cell attachment, proliferation and growth. Ultimately, the concomitant cell growth and biodegradation of CNFs within the 3D printed CHI/CNF scaffolds highlights the remarkable potential of CHI/CNF composites in the design of tissue models for the development of 3D constructs with tailored in vitro/in vivo degradability for biomedical applications.