Midas Touch: Engineering Activity of Metal–Organic Frameworks via Coordination for Biosensing
作者:Chao Peng、Yuan Xue、Xinyang Zhu、Yongchao Fan、Jing Li、Erkang Wang
DOI:10.1021/acs.analchem.1c05007
日期:2022.1.18
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。