Luminescent Polyelectrolytes for use in Biosensors

用于生物传感器的发光聚电解质

• 批准号: 0099843
• 负责人: Alan Heeger
• 金额: $ 33万
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-05-01 至 2006-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0099843&HistoricalAwards=false
• 关键词: Luminescent; Polyelectrolytes; use; Biosensors

Luminescent polyelectrolytes exhibit enhanced fluorescence quenching ("superquenching") with very large Stern-Volmer quenching constants. The superquenching arises from a combination of two effects. First, it has been demonstrated that a single acceptor (functioning as an acceptor for photoinduced electron transfer) can quench the fluorescence emission from an entire macromolecule in aqueous solution. Second, in aqueous solution, such luminescent polyelectrolytes are charged. As a result, the positively charged acceptor and the anionic polymer form a weakly bound complex thereby enabling static superquenching. The superquenching of the photoluminescence (PL) can be used for sensing biomolecules with specificity and with high sensitivity. Thus, determining and controlling the magnitude of the Coulomb binding energy of the polymer/quencher complex is of particular importance to the use of luminescent polyelectrolytes in biosensor applications. If the binding between the ligand tethered to the quencher and the analyte is smaller than that between the quencher and the polymer, the quencher/ligand cannot be effectively pulled away from the luminescent polymer. In addition, the photoluminescence (PL) quantum efficiency is sensitive to the conformation of the polymer in solution. It is known that polyelectrolytes can form stable complexes with oppositely charged amphiphilc molecules (surfactants). Experiments have shown that addition of sufactant to solutions containing luminescent polyelectrolytes significantly increases the PL efficiency. Thus, studies of the chain conformation of luminescent polyelectrolytes is of clear scientific relevance and importance.%%% This project is directed toward determining the chain conformation of luminescent polyelectrolytes and the magnitude of the Coulomb binding energy of the polymer: quencher complexes. The luminescent polyelectrolytes to be studied include water soluble PPV derivatives and novel poly-lysine polymers (polypeptide chains with cyanine dyes in J-aggregate configuration attached as side-chains). A series of quenchers with different charges have been developed and are available for these studies. Quenching of PL will be studied by changing the ion concentration in buffered aqueous solutions, by changing the concentration of acceptors, and by varying the temperature. The chain conformation of the luminescent polyelectrolytes will be determined (with and without quencher, surfactant etc), as a function of the Debye screening length (ion concentration) and as a function of molecular weight using light scattering and neutron scattering.

发光聚电解质表现出增强的荧光猝灭（“超猝灭”），具有非常大的斯特恩-沃尔默猝灭常数。超淬火是由两种作用共同产生的。首先，它已经证明了单个受体（作为光诱导电子转移的受体）可以淬灭水溶液中整个大分子的荧光发射。其次，在水溶液中，这种发光的聚电解质是带电的。结果，带正电的受体和阴离子聚合物形成弱结合的配合物，从而实现静态超猝灭。光致发光（PL）的超猝灭特性可用于具有特异性和高灵敏度的生物分子传感。因此，确定和控制聚合物/猝灭络合物的库仑结合能的大小对于发光聚电解质在生物传感器中的应用具有特别重要的意义。如果与猝灭剂相连的配体与分析物之间的结合小于猝灭剂与聚合物之间的结合，则猝灭剂/配体不能有效地从发光聚合物中抽离。此外，光致发光（PL）量子效率对溶液中聚合物的构象很敏感。众所周知，聚电解质可以与带相反电荷的两亲分子（表面活性剂）形成稳定的配合物。实验表明，在含有发光聚电解质的溶液中加入表面活性剂可显著提高发光效率。因此，研究发光聚电解质的链构象具有明确的科学意义和重要性。这个项目是为了确定发光聚电解质的链构象和聚合物的库仑结合能的大小：猝灭剂配合物。所研究的发光聚电解质包括水溶性PPV衍生物和新型聚赖氨酸聚合物（带有j -聚集型菁染料的多肽链作为侧链附着）。已经开发了一系列不同装药量的淬灭器，可用于这些研究。将通过改变缓冲水溶液中的离子浓度、改变受体的浓度和改变温度来研究PL的猝灭。利用光散射和中子散射测定发光聚电解质的链构象（有或没有淬灭剂、表面活性剂等），作为德拜筛选长度（离子浓度）的函数和作为分子量的函数。