合成了三种新型液晶甲基丙烯酸酯,并表征为在光固化牙科树脂基复合材料中作为共聚单体进行测试。选定的配方由甲基丙烯酸烷基铵或胆甾醇型氨基甲酸酯和2,2-双[4-(2-羟基-3-甲基丙烯酰氧基丙基)苯基]丙烷(BisGMA)或经甲基丙烯酸氨基甲酸酯基团改性的BisGMA衍生物组成,并进一步用三乙二醇二甲基丙烯酸酯稀释(TEGDMA),并用70%的填料(硅酸锆纳米粉,硅烷化填料)增强。这项研究解决了LC单体结构,光聚合速率(通过差示扫描光度法)和牙科树脂复合材料的特定性能(体积收缩率,吸水率,水溶性和疏水性)之间的关系。通过差示扫描量热法和偏光显微镜对LC性能的研究表明,LC中间相对室温(阳离子单体)或40°C(甲基丙烯酸胆固醇酯)稳定。发现与BisGMA / TEGDMA结合使用的LC氨基甲酸酯甲基丙烯酸酯的聚合速率为(0.122-0.136 s-1)高于单独的介晶单体(0.085-0.107 s
Effect of Hydrophobic Interactions on Properties and Stability of DNA−Polyelectrolyte Complexes
作者:Sergey K. Filippov、Čestmír Koňák、Pavla Kopečková、Larisa Starovoytova、Milena Špírková、Petr Štěpánek
DOI:10.1021/la9036716
日期:2010.4.6
Polyplexes are polyelectrolyte complexes of DNA and polycations, designed for potential gene delivery. We investigated the properties of new polyplexes formed from cholesterol-modified polycations and DNA. Three complexes were tested; their cholesterol contents were 1.4, 6.3, and 8.7 mol %. UV spectroscopy and fluorescence assay using ethidium bromide proved the formation of polyplexes. The kinetics of turbidity of polyplexes solutions in physiological solution showed that the colloid stability of polyplexes increases with increasing content of cholesterol in polycations. Dynamic, static, and electrophoretic light scattering, small-angle X-ray scattering, and atomic force microscopy were used for characterization of polyplexes. The observed hydrodynamic radii of polyplexes were in the range of 30-60 nm; they were related to the polycation/DNA ratio and hydrophobicity of the used polycations (the cholesterol content). The properties of polyplex particles depend, in addition to polycation structure, on the rate of polycation addition to DNA solutions.
Synthesis and properties of liquid crystalline urethane methacrylates for dental composite applications
作者:Tinca Buruiana、Violeta Melinte、George Costin、Emil C. Buruiana
DOI:10.1002/pola.24693
日期:2011.6.15
urethane methacrylate and 2,2‐bis[4‐(2‐hydroxy‐3‐methacryloyloxypropyl)phenyl]propane (BisGMA) or a BisGMA derivate modified with urethane methacrylate groups, further diluted with triethyleneglycol dimethacrylate (TEGDMA) and reinforced with 70% filler (zirconium silicate nanopowder, silanized filler). This study addresses the relationships between the LC monomer structure, photopolymerization rates (by
合成了三种新型液晶甲基丙烯酸酯,并表征为在光固化牙科树脂基复合材料中作为共聚单体进行测试。选定的配方由甲基丙烯酸烷基铵或胆甾醇型氨基甲酸酯和2,2-双[4-(2-羟基-3-甲基丙烯酰氧基丙基)苯基]丙烷(BisGMA)或经甲基丙烯酸氨基甲酸酯基团改性的BisGMA衍生物组成,并进一步用三乙二醇二甲基丙烯酸酯稀释(TEGDMA),并用70%的填料(硅酸锆纳米粉,硅烷化填料)增强。这项研究解决了LC单体结构,光聚合速率(通过差示扫描光度法)和牙科树脂复合材料的特定性能(体积收缩率,吸水率,水溶性和疏水性)之间的关系。通过差示扫描量热法和偏光显微镜对LC性能的研究表明,LC中间相对室温(阳离子单体)或40°C(甲基丙烯酸胆固醇酯)稳定。发现与BisGMA / TEGDMA结合使用的LC氨基甲酸酯甲基丙烯酸酯的聚合速率为(0.122-0.136 s-1)高于单独的介晶单体(0.085-0.107 s