A Graphene Oxide-Organic Dye Ionic Complex with DNA-Sensing and Optical-Limiting Properties
A Graphene Oxide-Organic Dye Ionic Complex with DNA-Sensing and Optical-Limiting Properties
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DOI：
10.1002/anie.201001004
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发表时间：
2010-01-01
影响因子：
16.6
通讯作者：
Loh, Kian Ping
中科院分区：
文献类型：
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作者：
Balapanuru, Janardhan;Yang, Jia-Xiang;Loh, Kian Ping
氧化石墨烯（GO）是一种非化学计量的二维碳片，由石墨的酸剥离产生，为化学研究提供了一种新型的溶液分散的多芳香平台。氧化石墨烯基面两侧有共价结合的环氧化物（1,2 -醚）和羟基官能团，而羧基位于边缘位置由于存在芳香结构域和官能团，氧化石墨烯与溶液中的不同分子发生复杂的离子和非离子相互作用。[2-6]氧化石墨烯可被认为是一种弱酸性阳离子交换树脂，因为其可电离的羧基允许与金属阳离子或带正电的有机分子进行离子交换。受功能化氧化石墨烯在生物传感和药物递送中的应用的启发，我们报道了一种简单的离子交换策略，用于氧化石墨烯与合成染料的静电络合，形成能量或电荷转移络合物。[2,4,9]我们发现这种氧化石墨烯有机染料电荷转移配合物具有增强的生物传感和光学限制性能。芘衍生物以其与π-富电子框架分子的非共价相互作用而闻名。[4,9]为了将其应用于生物传感，我们设计了一种水溶性带正电的染料，即4-（1-芘基乙烯基）- n -丁基溴化吡啶（PNPB），晶体结构见图S1。这种带正电的染料可以与带负电的氧化石墨烯相互作用，形成荧光猝灭的电荷转移复合物，下文称为PNP+GOÀ （Scheme1）。PNP+GOÀ的FTIR光谱显示，GO和PNPB中都存在可分配给官能团的振动特征（Supporting Information, S2），因此证明它们之间成功耦合。PNP+GOÀ的原子力显微镜成像显示可以形成单层膜（Supporting Information, S3），这反映了PNP+GOÀ良好的单层分散性。的工作原理
Graphene oxide (GO), a nonstoichiometric, two-dimensional carbon sheet resulting from acid exfoliation of graphite, offers a new class of solution-dispersible polyaromatic platform for performing chemistry. Graphene oxide bears covalently bound epoxide (1, 2-ether) and hydroxyl functional groups on either side of its basal plane, while carboxyl groups are located at the edge sites.[1] Due to the presence of aromatic domains and functional groups, GO undergoes a complex interplay of ionic and nonionic interactions with different molecules in solution.[2–6] Graphene oxide can be considered to be a weak acid cation exchange resin because of the ionizable carboxyl groups, which allow ion exchange with metal cations or positively charged organic molecules. Motivated by the applications of functionalized GO in biosensing [7] and drug delivery,[8] we report a simple ionexchange strategy for electrostatic complexation of GO with a synthetic dye to form an energy-or charge-transfer complex.[2, 4, 9] We found that this GO–organic dye charge-transfer complex exhibits enhanced properties for biosensing and optical limiting.Pyrene derivatives are well known for their noncovalent interactions with molecules having π-electron-rich frameworks.[4, 9] To apply them in biosensing, we designed a watersoluble and positively charged dye, namely, 4-(1-pyrenylvinyl)-N-butylpyridinium bromide (PNPB; for crystal structure, see Supporting Information, Figure S1). This positively charged dye can interact with negatively charged GO to form a fluorescence-quenched charge-transfer complex, named hereafter PNP+GOÀ (Scheme1). The FTIR spectrum of PNP+GOÀ shows the presence of vibrational features assignable to the functional groups in both GO and PNPB (Supporting Information, S2), and thus attests to successful coupling between them. Atomic force microscopy imaging of PNP+GOÀ shows that a monolayer film can be formed (Supporting Information, S3), which reflects the good monolayer dispersion of PNP+GOÀ. The operating principle of the