Label-Free Cross-Priming Amplification Coupled With Endonuclease Restriction and Nanoparticles-Based Biosensor for Simultaneous Detection of Nucleic Acids and Prevention of Carryover Contamination

Research Progress of Nucleic Acid Detection Technology for Genetically Modified Maize

Genetically modified (GM) maize is one of the earliest GM crops to have achieved large-scale commercial cultivation globally, and it is of great significance to excel in the development and implementation of safety policy regarding GM, and in its technical oversight. This article describes the general situation regarding genetically modified maize, including its varieties, applications, relevant laws and regulations, and so on. From a technical point of view, we summarize and critically analyze the existing methods for detecting nucleic acid levels in genetically modified maize. The nucleic acid extraction technology used for maize is explained, and the introduction of traditional detection techniques, which cover variable-temperature and isothermal amplification detection technology and gene chip technology, applications in maize are described. Moreover, new technologies are proposed, with special attention paid to nucleic acid detection methods using sensors. Finally, we review the current limitations and challenges of GM maize nucleic acid testing and share our vision for the future direction of this field.

Lateral Flow Recombinase Polymerase Amplification Assays for the Detection of Human Plasmodium Species

This study highlights the development of two lateral flow recombinase polymerase amplification assays for the diagnosis of human malaria. The lateral flow cassettes contained test lines that captured biotin-, 6-carboxyfluorescein, digoxigenin-, cyanine 5-, and dinitrophenyl-labeled amplicons. The overall process can be completed in 30 minutes. Recombinase polymerase amplification coupled with lateral flow had a detection limit of 1 copy/µL for Plasmodium knowlesi, Plasmodium vivax, and Plasmodium falciparum. No cross-reactivity was observed among nonhuman malaria parasites such as Plasmodium coatneyi, Plasmodium cynomolgi, Plasmodium brasilanium, Plasmodium inui, Plasmodium fragile, Toxoplasma gondii, Sarcocystis spp., Brugia spp., and 20 healthy donors. It is rapid, highly sensitive, robust, and easy to use. The result can be read without the need for special equipment and thus has the potential to serve as an effective alternative to polymerase chain reaction methods for the diagnosis of malaria.

CRISPR/Cas12a-Enhanced Loop-Mediated Isothermal Amplification for the Visual Detection of Shigella flexneri

Shigella flexneri is a serious threat to global public health, and a rapid detection method is urgently needed. The CRISPR/Cas (clustered regularly interspaced short palindromic repeats/CRISPR-associated) system is widely used in gene editing, gene therapy, and in vitro diagnosis. Here, we combined loop-mediated isothermal amplification (LAMP) and CRISPR/Cas12a to develop a novel diagnostic test (CRISPR/Cas12a-E-LAMP) for the diagnosis of S. flexneri. The CRISPR/Cas12a-E-LAMP protocol conducts LAMP reaction for S. flexneri templates followed by CRISPR/Cas12a detection of predefined target sequences. LAMP primers and sgRNAs were designed to the highly conserved gene hypothetical protein (accession: AE014073, region: 4170556–4171,068) of S. flexneri. After the LAMP reaction at 60°C for 20 min, the pre-loaded CRISPR/Cas12a regents were mixed with the LAMP products in one tube at 37°C for 20 min, and the final results can be viewed by naked eyes with a total time of 40 min. The sensitivity of CRISPR/Cas12a-E-LAMP to detect S. flexneri was 4 × 10⁰ copies/μl plasmids and without cross-reaction with other six closely related non-S. flexneri. Therefore, the CRISPR/Cas12a-E-LAMP assay is a useful method for the reliable and quick diagnosis of S. flexneri and may be applied in other pathogen infection detection.

Development of Solid-Phase RPA on a Lateral Flow Device for the Detection of Pathogens Related to Sepsis

Population extended life expectancy has significantly increased the risk of septic shock in an ageing population. Sepsis affects roughly 20 million people every year, resulting in over 11 million deaths. The need for faster more accurate diagnostics and better management is therefore paramount in the fight to prevent these avoidable deaths. Here we report the development of a POC device with the ability to identify a broad range of pathogens on a lateral flow platform. Namely Gram-positive and Gram-negative bacteria. The simple to use laboratory device has the potential to be automated, thus enabling an operator to carry out solid-phase lysis and room temperature RPA in situ, providing accurate results in hours rather than days. Results show there is a potential for a fully automated device in which concepts described in this paper can be integrated into a lateral flow device.