Several microRNAs (miRNAs) are expressed at lower levels in specific tumors, e.g., miR-let-7a in non-small cell lung cancer (NSCLC). This makes it challenging to analyze their lower abundance versus specifically elevated miRNAs. Here, we describe a novel fluorescent biosensor for the highly selective and sensitive detection of miR-let-7a constructed by combining miRNA screening assisted by a duplex-specific nuclease (DSN) with CRISPR-Cas12a system signal amplification. We meticulously designed a mismatch in the first three to four bases at the 5'-end of the capture DNA to improve the signal-to-noise ratio of the CRISPR-Cas12a system. Within this "DSN-mismatched CRISPR" fluorescence strategy, miR-let-7a was accurately screened by DSN-assisted cleavage, and the mismatched capture DNA unbound to target miRNA could trigger the CRISPR-Cas12a system to produce a mass of trans-cleave fluorescence signals. This "turn-off" approach was suitable for detecting decreased levels of miRNAs. This approach can not only discriminate the single-base mismatched let-7 family but also reach a limit of detection at 64.17 fM as well as be quantified from 100 fM to 500 pM. The miR-let-7a levels were then measured in clinical serum samples from healthy volunteers and patients with NSCLC. This study holds promise for the development of a universal under-expressed miRNA assay for early diagnosis and treatment of cancers.
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http://dx.doi.org/10.1016/j.aca.2024.342273 | DOI Listing |
J Agric Food Chem
January 2025
School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China.
() is a major pathogenic bacterium responsible for bacterial foodborne diseases, making its rapid, specific, and accurate detection crucial. In this study, we develop a ratiometric biosensor based on the recombinase polymerase amplification-clustered regularly interspaced short palindromic repeats/CRISPR associated protein 12a (RPA-CRISPR/Cas12a) system and Eu-metal-organic framework (Eu-MOF) fluorescent nanomaterials for the high-sensitivity detection of , combining with RPA for efficient isothermal amplification, this sensor enhances specificity and sensitivity by utilizing the target activation of CRISPR/Cas12a. The Eu-MOF serves a dual function, providing stable red fluorescence as a reference signal and adsorbing FAM-labeled probes for fluorescence quenching, forming a dual-signal system that significantly reduces background interference.
View Article and Find Full Text PDFAnal Chim Acta
January 2025
Department of Laboratory Medicine, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan, People's Republic of China; Wuhan Research Center for Infectious Diseases and Cancer, Chinese Academy of Medical Sciences, Wuhan, People's Republic of China; Hubei Engineering Center for Infectious Disease Prevention, Control and Treatment, Wuhan, People's Republic of China. Electronic address:
Background: In current years, the CRISPR (clustered regularly interspaced short palindromic repeats) based strategies have emerged as the most promising molecular tool in the field of gene editing, intracellular imaging, transcriptional regulation and biosensing. However, the recent CRISPR-based diagnostic technologies still require the incorporation of other amplification strategies (such as polymerase chain reaction) to improve the cis/trans cleavage activity of Cas12a, which complicates the detection workflow and lack of a uniform compatible system to respond to the target in one pot.
Results: To better fully-functioning CRISPR/Cas12a, we reported a novel technique for straightforward nucleic acid detection by incorporating enzyme-responsive steric hindrance-based branched inhibitors with CRISPR/AsCas12a methodology.
Anal Chim Acta
January 2025
Department of Chemistry and Biochemistry, Utah State University, 0300 Old Main Hill, Logan, UT, 84322, USA; Department of Chemistry, University of Louisiana at Lafayette, 300 East St. Mary Blvd, Lafayette, LA, 70504, USA. Electronic address:
A rapid and accurate biosensor for detecting disease biomarkers at point-of-care is essential for early disease diagnosis and preventing pandemics. CRISPR-Cas12a is a promising recognition element for DNA biosensors due to its programmability, specificity, and deoxyribonuclease activity initiated in the presence of a biomarker. The current electrochemical CRISPR-Cas12a-based biosensors utilize the single-stranded DNA (ssDNA) self-assembled on an electrode surface and covalently modified with the redox indicator, usually methylene blue (MB).
View Article and Find Full Text PDFAnal Chim Acta
January 2025
Department of Quality Control Material R&D, Shanghai Center for Clinical Laboratory, Shanghai, PR China; Department of Molecular Biology, Shanghai Center for Clinical Laboratory, Shanghai, PR China; Department of Molecular Diagnostic Innovation Technology, Shanghai Academy of Experimental Medicine, Shanghai, PR China. Electronic address:
Background: The current pandemic of 2022 global mpox (formerly known as monkeypox), caused by infection with monkeypox virus (MPXV), has now reached over 120 countries. This constitutes a critical public health issue requiring effective disease management and surveillance. Rapid and reliable diagnosis is conducive to the control of infection, early intervention, and timely treatment.
View Article and Find Full Text PDFAnal Chem
January 2025
School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China.
The CRISPR-Cas12a system has shown tremendous potential for developing efficient biosensors. Albeit important, current CRISPR-Cas system-based diagnostic technologies (CRISPR-DX) highly rely on an additional preamplification procedure to obtain high sensitivity, inevitably leading to issues such as complicated assay workflow, cross-contamination, etc. Herein, a spherical protospacer-adjacent motif (PAM)-antenna-enhanced CRISPR-Cas12a system is fabricated for universal amplification-free nucleic acid detection with a detection limit of subfemtomolar.
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