Viscous, non‐aqueous liquid comprising stoichiometric conjugates of polymer surfactant‐bovine serum albumin (PSpBSA) is used as a host matrix for the dispersion of chemically distinct hydrophilic dyes. Using a combination of bright field polarized optical microscopy and fluorescence spectroscopy, we investigate the dispersion of dry and powdered cationic (Rhodamine 6G; Rh6G) and anionic (Fluorescein; FL) dyes in the PSpBSA liquid at room temperature. As the dyes disperse and dissolve in the PSpBSA liquid, it results in a pronounced increase in emission intensity of the former. Interestingly, a shift from 571 to 582 nm is observed in the emission maxima of Rh6G as it disperses in the PSpBSA solvent. Whilst no such red shift is found for the Rh6G dispersion in the aqueous solutions of either native BSA or polymer‐surfactant conjugated BSA, a similar shift occurs when Rh6G is dispersed in neat polymer‐surfactant (PS), suggesting the interaction of the dye with the PS chains. In the case of anionic FL, no shift is observed in its emission maximum as it disperses in the PSpBSA liquid. Furthermore, within 120 minutes of FL dispersion in the PSpBSA liquid, we observe a ≈26 % decrease in the tryptophan emission intensity (λ_exc.=285 nm; λ_emi.=330 nm) of BSA, which could be attributed to both static and dynamic quenching. Our findings provide a proof of concept of an alternative non‐aqueous solvent matrix which can dissolve and disperse charged fluorescent dyes, provide suitable binding sites, and show substantial photoluminescence. Thus, it can be envisaged for utilization as an alternative solvent medium for lasing dyes and related applications.

中文翻译：

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带电荷的荧光染料在基于蛋白质聚合物表面活性剂的非水液体中的分散和相互作用。

包含聚合物表面活性剂-牛血清白蛋白（PSpBSA）的化学计量共轭物的粘性非水液体用作分散化学性质不同的亲水性染料的基质。结合使用明场偏振光学显微镜和荧光光谱，我们研究了室温下干粉和粉状阳离子染料（若丹明6G； Rh6G）和阴离子染料（荧光素； FL）在PSpBSA液体中的分散性。当染料分散并溶解在PSpBSA液体中时，会导致前者的发射强度显着增加。有趣的是，当Rh6G分散在PSpBSA溶剂中时，在其发射最大值中观察到了从571 nm到582 nm的位移。虽然在天然BSA或聚合物-表面活性剂共轭BSA的水溶液中Rh6G分散液均未发现这种红移，当Rh6G分散在纯聚合物表面活性剂（PS）中时，也会发生类似的变化，这表明染料与PS链之间存在相互作用。在阴离子型FL的情况下，由于其分散在PSpBSA液体中，因此在其最大发射量中未观察到偏移。此外，在FL分散在PSpBSA液体中的120分钟内，我们观察到色氨酸发射强度（λ_排除 = 285纳米；λ _EMI。= 330 nm）的BSA，可以归因于静态和动态淬灭。我们的发现为替代性的非水溶剂基质提供了概念证明，该基质可以溶解和分散带电的荧光染料，提供合适的结合位点，并显示出大量的光致发光。因此，可以设想将其用作激光染料和相关应用的替代溶剂介质。