This article focuses on the use of graphene oxide-polyaniline (GO-PANI) nanocomposite as fluorescent probe for sensing of adenine (A) and guanine (G). Swollen liquid crystalline mesophase were used for the synthesis of graphene oxide-polyaniline nanocomposite. GO-PANI nanocomposite showed enhanced fluorescent at 441 nm (ƛ excitation = 361 nm) on interaction of purines viz A and G solutions in dimethyl sulfoxide, GO exhibited quenching at 540 nm (ƛ excitation = 261 nm). The fluorescence emission spectra of GO-PANI nanocomposite and GO were recorded in the the pressence of A and G concentrations upto 1.2 × 10-4 M. The limits of detection (LOD) calculated from the concentration dependence study for GO-PANI nanocomposite and GO are 7.5 × 10-6 M and 13.4 × 10-6 M respectively. The LOD in the case of GO is identical for both A (13.0 × 10-6) and G (13.6 × 10-6 M). The binding constant (Kb) determined for GO-PANI with purines are in the range of 0.05-0.08 × 103 M-1 which is higher in the case of GO (2.42-7.52 × 103 M-1). The lifetime measurement demonstrates, an excited state interaction of GO-PANI nanocomposite and GO with purines. This is evident from the increasing lifetime from 4.3 ns to 29.2 ns for GO-PANI nanocomposite, while 17.5 ns to 37.2 ns for GO respectively. The relatively short lifetime of the GO-PANI nanocomposite in comparison with GO suggest an electronic charge dissipation of the excited state between polyaniline and graphene oxide possibly due to the alignment of polyaniline on the graphene oxide sheet. The photopysical properties of GO-PANI nanocomposite and GO observed in this study is new and has potential for application as fluorescent probe for the detection of purines.

中文翻译：

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溶胀的液晶中间相辅助合成GO-PANI纳米复合材料，作为嘌呤的荧光探针。

本文重点介绍使用氧化石墨烯-聚苯胺（GO-PANI）纳米复合材料作为荧光探针来检测腺嘌呤（A）和鸟嘌呤（G）。溶胀的液晶中间相用于氧化石墨烯-聚苯胺纳米复合材料的合成。GO-PANI纳米复合材料在嘌呤与A和G溶液在二甲亚砜中相互作用时，在441 nm处增强荧光（激发361 nm），GO在540 nm处激发淬灭（激发261 nm）。在A和G浓度高达1.2×10-4 M的压力下记录了GO-PANI纳米复合材料和GO的荧光发射光谱。根据GO-PANI纳米复合材料和GO的浓度依赖性研究计算的检测限（LOD）。分别为7.5×10-6 M和13.4×10-6M。GO的LOD对于A（13.0×10-6）和G（13。6×10-6 M）。GO-PANI与嘌呤的结合常数（Kb）在0.05-0.08×103 M-1的范围内，在GO的情况下更高（2.42-7.52×103 M-1）。寿命测量表明，GO-PANI纳米复合材料和GO与嘌呤的激发态相互作用。从GO-PANI纳米复合材料的寿命从4.3 ns延长到29.2 ns，而GO的寿命分别从17.5 ns到37.2 ns可以明显看出这一点。与GO相比，GO-PANI纳米复合材料的寿命相对较短，这表明聚苯胺和氧化石墨烯之间的激发态可能会由于聚苯胺在氧化石墨烯片材上的排列而耗散电子电荷。在这项研究中观察到的GO-PANI纳米复合材料和GO的光物理性质是新的，并且有潜力用作检测嘌呤的荧光探针。