准确检测癌症相关mRNA对于早期癌症的诊断和潜在治疗具有益处。在此，我们首次开发了一种新型的CRISPR/Cas12a驱动的电化学/荧光（EC/FL）双模式控释均相生物传感器用于mRNA检测。我们合成了功能化的P2引发的Fe3O4-NH2带有亚甲基蓝(P2 @ MB-Fe3O4-NH2)的单链DNA作为信号探针，且选择survivin mRNA作为目标RNA。在靶mRNA的存在下，启动切割内切酶介导的滚动环形扩增（NEM-RCA）将产生大量的单链DNA，激活Cas12a对周围的单链DNA的并行活性。因此，完全与P2单链DNA互补的P1单链DNA被剪切，导致Fe3O4-NH2上的P2生物阀门由于静电相互作用而无法打开。因此，磁分离后上清液中没有或只有少量的MB，并且测得的EC/FL信号非常微弱。相反，P2生物阀门被打开，使得MB被释放到上清液中，并产生明显的EC/FL信号。由于EC/FL双模交叉验证的准确性，NEM-RCA和CRISPR/Cas12a的高扩增效率和高特异性以及载量高的介孔Fe3O4-NH2对信号分子的负载，该策略显示出亚摩尔级的灵敏度和单碱基错配特异性。更重要的是，此双模式策略在复杂的血清环境和肿瘤细胞裂解物中经过了实际的应用验证，为开发一种强大的疾病诊断工具提供了一种新途径。

Accurate detection of cancer-associated mRNAs is beneficial to early diagnosis and potential treatment of cancer. Herein, for the first time, we developed a novel CRISPR/Cas12a-powered electrochemical/fluorescent (EC/FL) dual-mode controlled-release homogeneous biosensor for mRNA detection. A functionalized ssDNA P2-capped Fe3O4-NH2 loaded with methylene blue (P2@MB-Fe3O4-NH2) was synthesized as the signal probe, while survivin mRNA was chosen as the target RNA. In the presence of the target mRNA, the nicking endonuclease-mediated rolling circle amplification (NEM-RCA) was triggered to produce significant amounts of ssDNA, activating the collateral activity of Cas12a toward the surrounding single-stranded DNA. Thus, the ssDNA P1 completely complementary to ssDNA P2 was cleaved, resulting in that the ssDNA P2 bio-gate on Fe3O4-NH2 could not be opened due to electrostatic interactions. As a result, there was no or only a little MB in the supernatant after magnetic separation, and the measured EC/FL signal was exceedingly weak. On the contrary, the ssDNA P2 bio-gate was opened, enabling MB to be released into the supernatant, and generating an obvious EC/FL signal. Benefiting from the accuracy of EC/FL dual-mode cross-verification, high amplification efficiency, high specificity of NEM-RCA and CRISPR/Cas12a, and high loading of mesoporous Fe3O4-NH2 on signal molecules, the strategy shows aM-level sensitivity and single-base mismatch specificity. More importantly, the practical applicability of this dual-mode strategy was confirmed by mRNA quantification in complex serum environments and tumor cell lysates, providing a new way for developing a powerful disease diagnosis tool.