A CRISPR/Cas12a-assisted array for Helicobacter pylori DNA analysis in saliva

Helicobacter pylori infection has become a threat to the world populations. This leads to an urgent need of an efficient and convenient approach to accurately diagnose H. pylori infection. Saliva-based diagnoses are particularly welcomed for their efficiency and convenience. Aiming at saliva sample analysis, we proposed a CRISPR/Cas12a-assisted array, which had integrated H. pylori concentration detection and genotype screening functions. Single-nucleotide variations (SNVs) could be distinguished using the screening array with different probes, and an isothermal cycling strategy was combined with the trans-cleavage activity of Cas12a for signal amplification to improve accuracy of the diagnosis. As a demonstration, the SNV screening array was fabricated by utilizing the hybridization efficiency difference caused by mismatched bases. The array was able to successfully distinguish between ten H. pylori genotypes, and combined with the successful SDA biosensing, it had a LOD of as low as 60 fM. It was also able to diagnose H. pylori infection in saliva samples from infected patients. Together, the developed array has a potential in large-scale clinical screening and is a promising tool for the diagnosis and prevention of H. pylori infection-related diseases.