Three indolenine-based barbiturate squaraine dyes were synthesized, characterized and subjected to photophysical studies, including their affinity with human serum albumin and bovine serum albumin as protein models in phosphate buffer solution. All dyes successfully interact with both proteins with high affinity binding constants. It was found that dyes with hydrophobic substituents had superior binding constants with both proteins. The fluorescence intensity of all dyes increased in the presence of both proteins which allowed the determination of detection and quantifications limits in the tens of nanomolar, using a protein concentration of 0–3.5 μM. Concerning to the study on the binding sites of the synthesized dyes using the warfarin and ibuprofen markers, the results of this study suggest that, one dye binds to both BSA binding sites while the two others dyes binds only to site I, and that all three dyes bind to both HSA binding sites.

合成，表征了三种基于假吲哚的巴比妥酸酯方酸染料，并进行了光物理研究，包括它们与人血清白蛋白和作为蛋白质模型的牛血清白蛋白在磷酸盐缓冲溶液中的亲和力。所有染料均以高亲和力结合常数成功地与两种蛋白质相互作用。发现具有疏水性取代基的染料与两种蛋白质具有优异的结合常数。在两种蛋白质均存在的情况下，所有染料的荧光强度均增加，这使得可以使用浓度为0-3.5μM的几十纳摩尔来确定检测限和定量限。关于使用华法林和布洛芬标记物对合成染料结合位点的研究，该研究结果表明，