Matrix assisted pulsed laser evaporation processing of triacetate-pullulan polysaccharide thin films for drug delivery systems

We report the first successful deposition of triacetate-pullulan polysaccharide thin films by matrix assisted pulsed laser evaporation. We used a KrF* excimer laser source (λ = 248 nm, τ ≈ 20 ns) operated at a repetition rate of 10 Hz. We demonstrated by FTIR that our thin films are composed of triacetate-pullulan maintaining its chemical structure and functionality. The dependence on incident laser fluence of the induced surface morphology is analysed.     

Allyl protecting group mediated intramolecular aglycon delivery (IAD): synthesis of α-glucofuranosides and β-rhamnopyranosides

The use of allyl protecting group mediated intramolecular aglycon delivery (IAD) as a strategy for intramolecular glycosylation has been extended to allow the stereoselective synthesis of α-glucofuranosides and β-rhamnopyranosides, in a totally stereoselective fashion. The efficiency of intramolecular glycosylation is dependent on the protecting group pattern of the glycosyl donor, and on the steric bulk of the glycosyl acceptor.     

温度及pH敏感的树枝状高分子衍生物合成及药物控制释放研究

对合成的系列聚酰胺-胺型(PAMAM)树枝状高分子进行端基的羟基化和氯乙酰化两步修饰,使PAMAM最外层接上烷基氯.以修饰产物为引发剂,通过原子转移自由基引发甲基丙烯酸N,N-二甲氨基乙酯(DMAEMA)聚合得到树枝状PAMAM高分子衍生物,并对其结构用FTIR、1H-NMR和粒径分析进行了表征.紫外可见分光光度仪测定证实此高分子具有温度及pH敏感性.通过对小分子药物控制释放研究表明,此树枝状高分子衍生物通过环境pH值可有效地控制小分子药物的释放.     

傅立叶变换红外光谱对灰指甲组织结构的研究

对健康指甲和灰指甲的红外光谱特征吸收峰进行了指认,并对其相应官能团的吸收峰进行了对比分析.结果表明,灰指甲增厚、变脆的原因系α-角蛋白螺旋结构遭到破坏,肽链伸展并发生断裂,形成了不同化学环境的氨基酸,同时蛋白质分子的有序排列也发生了改变.     

无机层状复合氢氧化物中顺铂-DNA模型分子的选择性插入

药物分子的选择性包裹和控制释放是药物研究领域中具有挑战性的研究方向。本文研究表明:顺铂-DNA模型分子cis-[Pt(NH₃)₂(5′-GMP)₂](5′-GMP 5′-单磷酸鸟苷)可插入无机层状复合氢氧化物[Zn_0.68Al_0.32(OH)₂](NO₃)_0.32·mH₂O。但另一种层状复合氢氧化物[LiAl₂(OH)₆]Cl·H₂O由于其阳离子层中正电荷密度较高、阳离子层与层间阴离子之间静电作用较强,因而顺铂-DNA模型分子不能通过离子交换方式插入其层间。光谱数据证实插入层间的顺铂-DNA模型分子结构不变。这可能为铂-DNA分子的传递提供新的方法。     

赖氨酸修饰壳聚糖磁性超微载体的制备和表征

本文设计并合成了良好水溶性的赖氨酸修饰壳聚糖,并对制备工艺进行了优化.产物通过红外(FTIR)和核磁(1H-NMR)进行了表征,并将其作为壳层材料制备了赖氨酸修饰壳聚糖磁性超微载体.通过光电能谱(XPS)、透射(TEM)、激光粒度仪、X射线衍射(XRD)、磁性能测试(VSM)对载体进行了表征.结果表明,制备的赖氨酸修饰壳聚糖磁性超微载体表面带有大量的氨基(-NH2),粒径分布较为均一(100nm左右),形貌较为规则,并具有良好的超顺磁性,因而该载体具有更加良好的性能.     

Synthesis and peptide-binding properties of a luminescent pyrimidine zinc(II) complex

The synthesis and peptide-binding properties of a Zn(II)nitrilotriacetate complex substituted with pyrimidine hydrazine amides are reported. The metal complex provides millimolar binding affinity in aqueous buffer to peptides bearing N-terminal His. The pyrimidine heterocycles intermolecularly interact with the bound peptide and quench the emission of nearby Trp residues by energy transfer.     

Racemization in stepwise solid-phase peptide synthesis at elevated temperatures

The present work is an attempt to assess racemization in stepwise solid-phase peptide synthesis at elevated temperatures (SPPS-ET), a high-speed approach in which peptide elongation occurs at 55-75 °C. This attempt was based on the notion that a high propensity for this side reaction would hamper employment of this alternative approach and would dampen interest in its further development. Simple peptide models were synthesized using customized protocols for classical SPPS or SPPS-ET. Systematic analyses of the resulting crude peptides by reversed-phase HPLC, ion-exchange HPLC, capillary electrophoresis and electrospray ionization mass spectrometry revealed low diastereomeric byproduct contents. These results indicate that, from the standpoint of racemization, classical SPPS and SPPS-ET protocols were equivalent. Therefore, further studies employing SPPS-ET protocols are justified.