The ever-increasing attention on the highly sensitive biosensors pushes people to explore functional nanomaterials for signal amplification. To endow inert metal–organic frameworks (MOFs) with enzyme mimicking activity, a simple strategy of introducing Cu2+ via coordination with 2,2′-bipyridine ligands of Zr-MOF, just like “Midas touch,” is proposed. More details on the coordination environment of Cu active sites in Zr-MOF-Cu are disclosed via electron paramagnetic resonance and synchrotron-radiation-based X-ray absorption fine structure analyses. The as-prepared Zr-MOF-Cu exhibits unparalleled catalytic ability, which can catalyze ascorbic acid (AA) to dehydroascorbic acid and further stimulate the reaction with o-phenylenediamine to produce fluorescent signal probes with 8-fold signal amplification. On the basis of catalyzing the dephosphorylation process of l-ascorbic acid-2-phosphate to yield AA via alkaline phosphatase (ALP) and AA-dependent signal responses, a universal fluorescent system has been successfully constructed for quantitative measurement of the activity of ALP and the ALP-related enzyme-linked immunosorbent assay with carcinoembryonic antigen as a model. Moreover, the stable loading of Cu active sites endows the sensing platform with anti-inference capacity and enables its reuse without loss of catalytic activity after 6 months.
对高灵敏
生物传感器的日益关注促使人们探索用于信号放大的功能纳米材料。为了赋予惰性
金属有机框架(MOF)模拟酶活性,提出了一种通过与Zr-MOF的2,2′-联
吡啶配体配位来引入Cu2+的简单策略,就像“点石成
金”一样。通过电子顺磁共振和基于同步辐射的 X 射线吸收精细结构分析,揭示了 Zr-MOF-Cu 中 Cu 活性位点配位环境的更多细节。所制备的Zr-MOF-Cu表现出无与伦比的催化能力,可以催化
抗坏血酸(
AA)生成
脱氢抗坏血酸,并进一步刺激与
邻苯二胺的反应,产生信号放大8倍的荧光信号探针。在通过碱性
磷酸酶(ALP)和
AA依赖性信号响应催化L-
抗坏血酸-2-
磷酸去
磷酸化产生
AA的过程的基础上,成功构建了用于定量测量ALP和
AA活性的通用荧光系统。以癌胚抗原为模型的ALP相关酶联免疫吸附试验。此外,Cu活性位点的稳定负载赋予了传感平台抗干扰能力,并使其能够在6个月后重复使用而不会丧失催化活性。