Rapid, sensitive, and highly specific detection of monkeypox virus by CRISPR-based diagnostic platform

Two-Dimensional Nanozyme-Catalyzed Colorimetric CRISPR Assay for the Microfluidic Detection of Monkeypox Virus

The recent monkeypox epidemic outbreaks worldwide highlight the urgent need for fast and precise diagnostic solutions, especially in resource-limited settings. Here, a two-dimensional nanozyme-catalyzed colorimetric CRISPR assay for the microfluidic detection of the monkeypox virus (MPXV) was established. We utilized graphene oxide as a substrate for the adsorption of gold seeds and the deposition of a porous Pt shell to prepare high-performance two-dimensional GO@Pt nanomaterials. The viral nucleic acids released from clinical samples initiated a single-step recombinase polymerase amplification-CRISPR/Cas13a for the trans-cleavage of ssRNA reporters labeled with FAM and biotin. These reporters can be recognized by FAM antibody-conjugated GO@Pt nanozymes and streptavidin-coated magnetic beads. The formed sandwich immunocomplexes can catalyze the oxidation of a colorless 3,3',5,5'-tetramethylbenzidine substrate with a distinct color change. The proposed GO@Pt-catalyzed colorimetric CRISPR assay exhibited a limit of detection of 1 copy/μL of MPXV in 60 min. Forty clinical samples, including rash fluid swabs and oral swabs, were tested with 100% agreement with the real-time PCR. These results indicate the excellent potential of GO@Pt-catalyzed colorimetric CRISPR for the sensitive and accurate testing of MPXV under resource-constrained conditions.

A rapid identification system for vaginal fluid stains based on nested recombinant polymerase amplification and lateral flow dipstick

In forensic practice, identifying the species of unknown bodily fluid stains can provide assistance in the qualitative analysis and investigation of cases, and vaginal fluid stains, as one of the common bodily fluid stains, are most commonly seen at the scene of sexual assault. At present, the commonly used vaginal peptidase or microscopic detection methods currently have drawbacks such as high false negative rates, poor sensitivity, and high requirements for sample integrity and background color. However, in forensic investigations, the test materials have specificity and scarcity, making it difficult to ensure their quantity and quality. Thus, in order to achieve rapid and sensitive detection of vaginal fluid stains, in this study, we combined nested PCR and isothermal amplification technology to construct a rapid detection system for suspicious vaginal fluid stains using lateral flow dipstick. This system achieves detection by detecting the specific marker microbial community Lactobacillus crispatus in vaginal fluid, and has a high sensitivity and accuracy, which can achieve detection at template quantities as low as 2.31 copies. More importantly, the system can achieve detection at a constant temperature of 37 °C without the need for complex instruments. It can provide rapid and sensitive identification results, providing assistance for subsequent forensic material extraction and individual identification.

Advancements and Challenges in Addressing Zoonotic Viral Infections with Epidemic and Pandemic Threats

Zoonotic viruses have significant pandemic potential, as evidenced by the coronavirus pandemic, which underscores that zoonotic infections have historically caused numerous outbreaks and millions of deaths over centuries. Zoonotic viruses induce numerous types of illnesses in their natural hosts. These viruses are transmitted to humans via biological vectors, direct contact with infected animals or their bites, and aerosols. Zoonotic viruses continuously evolve and adapt to human hosts, resulting in devastating consequences. It is very important to understand pathogenesis pathways associated with zoonotic viral infections across various hosts and develop countermeasure strategies accordingly. In this review, we briefly discuss advancements in diagnostics and therapeutics for zoonotic viral infections. It provides insight into recent outbreaks, viral dynamics, licensed vaccines, as well as vaccine candidates progressing to clinical investigations. Despite advancements, challenges persist in combating zoonotic viruses due to immune evasion, unpredicted outbreaks, and the complexity of the immune responses. Most of these viruses lack effective treatments and vaccines, relying entirely on supportive care and preventive measures. Exposure to animal reservoirs, limited vaccine access, and insufficient coverage further pose challenges to preventive efforts. This review highlights the critical need for ongoing interdisciplinary research and collaboration to strengthen preparedness and response strategies against emerging infectious threats.

The current status and future prospects of CRISPR-based detection of monkeypox virus: A review

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. Clinical laboratories use various conventional diagnostic methods for detecting MPXV, including PCR, which can be regarded as a gold-standard diagnostic method. However, the application of PCR is limited by its requirements for high-cost equipment, skilled professionals, and a laboratory setting.

RESULTS

Clustered regularly interspaced short palindromic repeats (CRISPR)-based diagnostic systems have provided promising prospects for the rapid, sensitive, and specific detection of infectious diseases, especially in point-of-care settings. Over the past 2 years, an increasing number of researchers have concentrated on the application of the CRISPR method to mpox diagnosis. In the majority of cases, a two-step method was chosen, with CRISPR/Cas12a and recombinase polymerase amplification (RPA) as pre-amplification methods, followed by a fluorescence readout. Different strategies have been applied to overcome the encountered limitations of CRISPR detection, but no consensus on an integrated solution has been achieved. Thus, the application of the CRISPR/Cas system in mpox detection requires further exploration and improvement.

SIGNIFICANCE

This review discusses contemporary studies on MPXV CRISPR detection systems and the strategies proposed to address the challenges faced by CRISPR diagnosis with the hope of helping the development of CRISPR detection methods and improving pathogen detection technologies.

CRISPR-based strategies for sample-to-answer monkeypox detection: current status and emerging opportunities

The global health threat posed by the Monkeypox virus (Mpox) requires swift, simple, and accurate detection methods for effective management, emphasizing the growing necessity for decentralized point-of-care (POC) diagnostic solutions. The clustered regularly interspaced short palindromic repeats (CRISPR), initially known for its effective nucleic acid detection abilities, presents itself as an attractive diagnostic strategy. CRISPR offers exceptional sensitivity, single-base specificity, and programmability. Here, we reviewed the latest developments in CRISPR-based POC devices and testing strategies for Mpox detection. We explored the crucial role of genetic sequencing in designing crRNA for CRISPR reaction and understanding Mpox transmission and mutations. Additionally, we showed the integration of CRISPR-Cas12 strategy with pre-amplification and amplification-free methods. Our study also focused on the significant role of Cas12 proteins and the effectiveness of Cas12 coupled with recombinase polymerase amplification (RPA) for Mpox detection. We envision the future prospects and challenges, positioning CRISPR-Cas12-based POC devices as a frontrunner in the next generation of molecular biosensing technologies.

A field diagnostic method for rapid and sensitive detection of mpox virus

The mpox outbreak has subdued with fewer reported cases at the present in high-income countries. It is known that mpox virus (MPXV) infection has been epidemic for more than 50 years in African countries. The ancestral MPXV strain has changed into multiple clades, indicating the ongoing evolution of MPXV, which reflects the historical neglect of mpox in Africa, especially after smallpox eradication, and bestows the danger of more severe mpox epidemics in the future. It is thus imperative to continue the development of mpox diagnostics and treatments so we can be prepared in the event of a new mpox epidemic. In this study, we have developed an MPXV detection tool that leverages the recombinase-aid amplification assay by integrating lateral flow strips (RAA-LF) and one-step sample DNA preparation, with visible readout, no need of laboratory instrument, and ready for field deployment. The detection limit reaches 10 copies per reaction. The performance of our RAA-FL assay in diagnosing mpox clinical samples is on par with that of the quantitative polymerase chain reaction (PCR) assay. Taken together, we have developed a point-of-care RAA-LF method of high accuracy and sensitivity, readily deployable for field detection of MPXV. This diagnostic tool is expected to improve and accelerate field- and self-diagnosis, allow timely isolation and treatment, reduce the spread of MPXV, thus effectively mitigate MPXV outbreak in the future.