College of Life and Health Science, Northeastern University, Shenyang 110819, PR China.
School of Public Health, Jilin University, Changchun 130021, PR China.
J Colloid Interface Sci. 2022 Nov;625:257-263. doi: 10.1016/j.jcis.2022.06.027. Epub 2022 Jun 7.
Salmonella typhimurium (S. typhimurium) infection is one of leading causes of severe foodborne illness, which poses grievous threats to public health. Thus, the detection with ultra-sensitivity is highly demanded for timely prevention and diagnosis of S. typhimurium. In this study, we developed a novel detection machinery based on DNA walker and CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats)-Cas12a technologies. Mechanistically, the S. typhimurium specific sequence triggers Nt.AlwI nicking endonuclease and produces particular signaling nucleotide, which further activates Cas12a for strong fluorescence signal output. This cascade amplification strategy exhibits excellent specificity and successfully decreases the limit of detection (LOD) of DNA walker by 2,000 folds to 5 CFU/mL. Collectively, this combinatorial approach offers great promises to effectively reduce foodborne diseases by ultrasensitive detection of S. typhimurium. As a proof of concept, this innovative design also shows prominent potential in detections of other biomolecules, cells and pathogens.
鼠伤寒沙门氏菌（S. typhimurium）感染是严重食源性疾病的主要原因之一，对公众健康构成严重威胁。因此，超敏检测对于及时预防和诊断鼠伤寒沙门氏菌非常重要。在本研究中，我们开发了一种基于 DNA walker 和 CRISPR（Clustered Regularly Interspaced Short Palindromic Repeats）-Cas12a 技术的新型检测机制。从机制上讲，鼠伤寒沙门氏菌特异性序列触发 Nt.AlwI 核酸内切酶切割并产生特定的信号核苷酸，进一步激活 Cas12a 产生强烈的荧光信号输出。这种级联放大策略具有出色的特异性，并成功将 DNA walker 的检测限（LOD）降低了 2000 倍，达到 5 CFU/mL。总的来说，这种组合方法通过超灵敏检测鼠伤寒沙门氏菌，为有效减少食源性疾病提供了巨大的前景。作为概念验证，这种创新设计在检测其他生物分子、细胞和病原体方面也显示出了显著的潜力。
