In this work, we have prepared peptide-functionalized metal-organic frameworks (MOFs) as signal-amplifying tags for the detection of secreted protein acidic and rich in cysteine (SPARC). Furthermore, enzyme-MOF nanocomposites are fabricated via a coprecipitation strategy between horse radish peroxidase (HRP) and ZIF-90, where ZIF-90 is used as a protective support for HRP immobilization. Meanwhile, the peptide sequence has been designed as SPARC-binding peptide, which imparts biorecognition functionality to HRP@ZIF-90 for performing a colorimetric sensor. Therefore, during the test, HRP molecules can be quickly released from nanocomposites by acidic condition to catalyze chromogenic reaction, enabling the ultrasensitive detection of SPARC with a low detection limit of 30 fg/mL. Moreover, the content of SPARC in colon cancer tissues with different degrees of differentiation can be determined with this sensor, demonstrating that the expression of SPARC is closely related to the occurrence, invasion and metastasis of human colon cancer. These results may show the potential applications of this biosensor in SPARC fundamental research as well as clinical diagnosis in the future.

在这项工作中，我们准备了肽功能化的金属有机框架（MOF）作为信号放大标签，用于检测酸性和富含半胱氨酸的分泌蛋白（SPARC）。此外，酶-MOF纳米复合材料是通过辣根过氧化物酶（HRP）和ZIF-90之间的共沉淀策略制备的，其中ZIF-90用作HRP固定化的保护性支持物。同时，该肽序列被设计为SPARC结合肽，可为HRP @ ZIF-90赋予生物识别功能，以执行比色传感器。因此，在测试过程中，HRP分子可以在酸性条件下从纳米复合材料中快速释放出来，以催化显色反应，从而能够以30 fg / mL的低检测限对SPARC进行超灵敏的检测。此外，该传感器可以测定不同分化程度的结肠癌组织中SPARC的含量，证明SPARC的表达与人结肠癌的发生，侵袭和转移密切相关。这些结果可能表明该生物传感器在SPARC基础研究以及未来的临床诊断中的潜在应用。