Application of graphene quantum dots functionalized with thymine and thymine-appended zinc phthalocyanine as novel photoluminescent nanoprobes
Application of graphene quantum dots functionalized with thymine and thymine-appended zinc phthalocyanine as novel photoluminescent nanoprobes
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DOI：
10.1039/c6nj03285k
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发表时间：
2017-02-21
影响因子：
3.3
通讯作者：
Nyokong, Tebello
中科院分区：
文献类型：
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作者：
Achadu, Ojodomo J.;Nyokong, Tebello
用胸腺嘧啶分别修饰石墨烯量子点（GQDs）和酞菁锌（ZnPc），得到了胸腺嘧啶功能化的石墨烯量子点（T-GQDs）和石墨烯量子点（T-ZnPc）。采用原始GQDs（表示为纯净GQDs-T-ZnPc）或T-GQDs（表示为T-GQDs-T-ZnPc）的T-GQDs和T-ZnPc纳米偶联物作为荧光探针检测汞（II）离子（Hg2+）。由于T-GQDs上胸腺嘧啶功能与Hg2+之间的特异性相互作用，仅合成的T-GQDs对Hg2+检测表现出高度敏感和选择性的荧光“关闭”过程。另一方面，原始GQDs和T-GQDs的荧光在与T-ZnPc配合后被猝灭（“关闭”）。然而，在Hg2+存在的情况下，荧光发射选择性恢复（“开启”过程），导致Hg2+在纳摩尔浓度范围内（检测限为0.05 nM，对于原始GQDs-T-ZnPc探针）的敏感检测。与单独的T-GQDs或T-GQDs-T-ZnPc探针相比，含有原始GQDs和T-ZnPc复合物的探针对Hg2+具有更高的特异性和敏感性，这归因于前者的荧光“开启”过程。通过对不同金属离子和反离子的筛选，证明该探针特别适合于Hg2+的检测。
Graphene quantum dots (GQDs) and zinc phthalocyanine (ZnPc) were separately modified with thymine to obtain thymine-functionalized GQDs (T-GQDs) and ZnPc (T-ZnPc). T-GQDs and nanoconjugates of T-ZnPc with pristine GQDs (represented as pristine GQDs-T-ZnPc) or T-GQDs (represented as T-GQDs-T-ZnPc) were employed as fluorescent probes for the detection of mercury(II) ions (Hg2+). The as-synthesized T-GQDs alone demonstrated a highly sensitive and selective fluorescence "turn-OFF'' process for Hg2+ detection due to the specific interaction between the thymine functionality on the T-GQDs with Hg2+. On the other hand, the fluorescence of pristine GQDs and T-GQDs was quenched ("turn-OFF'') upon coordination with T-ZnPc. However, the fluorescence emission was selectively restored ("turn-ON'' process) in the presence of Hg2+ resulting in the sensitive detection of Hg2+ in the nanomolar concentration range (limit of detection = 0.05 nM, for the pristine GQDs-T-ZnPc probe). The probe containing pristine GQDs and the T-ZnPc complex demonstrated a higher specific and sensitive recognition of Hg2+ as compared to the T-GQDs alone or T-GQDs-T-ZnPc probes which are ascribed to the fluorescence "turn-ON'' process of the former. Screening of different metal ions and counter ions proved that the probes are specifically suited for Hg2+ detection.