Molecular association between biocompatible dendritic polymers, dendrigraft poly-l-lysines (DGLs), and an anionic fluorescent probe, 8-anilino-1-naphthalenesulfonate (ANS^–), was studied at the polarized water|1,2-dichloroethane (DCE) interface. The fluorescence intensity of ANS measured in aqueous solution was enhanced by the coexistence of DGLs over a wide pH range (2 < pH < 10), where ANS and DGL exist as a monoanionic form and a polycation, respectively. The voltammetric responses indicated that the positively charged DGLs were adsorbed at the water|DCE interface, whereas ANS^– was transferred across the interface accompanied by the adsorption process. The interfacial behavior of the DGL–ANS associates was analyzed by potential-modulated fluorescence (PMF) spectroscopy. The PMF results demonstrated that the ion association between DGLs and ANS at the water|DCE interface is strongly affected by the applied potential and the dendritic generation of DGL. By applying appropriate potentials, the ANS anion was dissociated from its ion associate with DGLs at the interface and transferred into the organic phase, whereas DGLs remained in the aqueous phase. The Gibbs free energy of ion association (ΔG_D···ANS) was estimated for the second–fourth generation DGLs (DGL-G2–G4) and the G4 polyamidoamine (PAMAM) dendrimer as a control. The highest stability of the DGL-G4–ANS associate manifested itself through ΔG_D···ANS: DGL-G4–ANS (>G4 PAMAM dendrimer–ANS) > DGL-G3–ANS > DGL-G2–ANS. The results elucidated the efficient anion-binding ability of higher generation DGLs and its potential dependence at the liquid|liquid interface.

中文翻译：

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枝晶接枝聚赖氨酸与8-苯胺-1-萘磺酸在液-液界面的离子缔合机理

生物相容的树枝状聚合物之间的分子缔合，状高支化聚升-lysines（DGLs），和阴离子荧光探针，8-苯胺基-1-萘磺酸（ANS ^- ）时，在偏振水进行了研究| 1,2-二氯乙烷（DCE）界面。在宽的pH范围（2 <pH <10）下，DGL的共存增强了水溶液中ANS的荧光强度，其中ANS和DGL分别以单阴离子形式和聚阳离子形式存在。伏安响应表明，带正电荷的DGL被吸附在水| DCE界面上，而ANS ^–伴随着吸附过程被转移到整个界面上。DGL-ANS缔合物的界面行为通过电势调制荧光（PMF）光谱进行了分析。PMF结果表明，DGL和ANS在水| DCE界面之间的离子缔合受到DGL的施加电势和枝状生成的强烈影响。通过施加适当的电势，ANS阴离子在界面处从与DGL的离子缔合中解离并转移到有机相中，而DGL保留在水相中。离子缔合的吉布斯自由能（ΔG _D···ANS）被估计为第二代第四代DGL（DGL-G2-G4）和G4聚酰胺基胺（PAMAM）树状大分子作为对照。DGL-G4-ANS的最高稳定性通过ΔG _D··ANS表现出来：DGL-G4-ANS（> G4 PAMAM树状聚合物-ANS）> DGL-G3-ANS> DGL-G2-ANS。结果阐明了更高世代的DGL的有效的阴离子结合能力及其在液界面上的电势依赖性。