克服水溶性药物的突释现象,可减少给药次数,提高疗效.本研究以卡托普利为模型药物,壳聚糖为载体,采用耦合的方法,设计合成了壳聚糖-卡托普利和壳聚糖-赖氨酰-卡托普利两种新的键连型壳聚糖基载药体系,产物结构经IR、1 H NMR和MS表征;并测试了两种化合物在PBS缓冲溶液(pH=7.4)和HCl-KCl缓冲溶液(pH=1.2)中72h的累积释药率:壳聚糖-卡托普利的累积释药率分别为59.2%和78.4%,壳聚糖-赖氨酰-卡托普利的累积释药率分别为55.2%和76.4%.结果表明,两种键连型载药体系均消除了突释现象,具有很好的缓释效果,这将有望成为水溶性药物的理想载药体系.
Main observation and conclusion An enzyme-free amperometric sensor based on a heptadecapeptide possessing an electroactive ferrocene(Fc)linker as ferrocene-Gly-Gly-Gly-Gly-Phe-Gly-His-Ile-His-Glu-Gly-Tyr-Gly-Gly-Gly-Gly-Lys-(CH_(2))_(4)-dithiocyclopentane self-assembled on gold substrate was designed and fabricated for specific determination of L-arginine(L-Arg).The detection mechanism is based on conformational change of surface-immobilized peptide induced by the target L-Arg,which was confirmed via SEM,TEM,AFM,XPS,and SPR studies.The binding affinity and the recognition feasibility of immobilized specific and non-specific peptides were also assessed using electrochemical impedance spectroscopy(EIS),cyclic voltammetry(CV),and differential pulse voltammetry(DPV).The proposed method can serve as“signal-on”sensor for detection of L-Arg down to 31 pmol/L with broad linear range(0.0001 to 10μmol/L).Furthermore,the Fc-conjugated specific peptide sensor was successfully applied to the determination of L-Arg in pig serums with a recovery rate of 97.5%—106.9%,and its test results are in good agreement with that of chromatographic instrument,evidencing that the oligopeptide-based sensor can be served as a simple and enzyme-free biosensing platform towards L-Arg for future application.
该工作以富含大量胸腺嘧啶（Thymine，T）核酸单链为识别分子，SYBR Green I （SG）为荧光基团，建立了一种简单、灵敏的荧光增强法检测Hg2＋。由于T-Hg2＋-T键的形成，富T单链自我折叠或者两两配对形成双链DNA结构，当溶液中的SG嵌入DNA双链中时，SG荧光强度显著增强。实验结果表明，SG荧光强度随着Hg2＋浓度的增加而增加。在最优实验条件下，SG的荧光强度与Hg2＋的浓度在4．000×10-7~2．000×10-6 mol/L范围内呈线性关系，检出限为3．900×10-8 mol/L。该方法在含5．0％湘江水实际样品中获得的回收率为98．72％~104．5％，因此该传感器可用于实际湘江水样品中Hg2＋的测量。
