Summary
A research team led by Dr. Jaecheol Park and Dr. Hojun Kim at the Korea Institute of Science and Technology (KIST), in collaboration with Prof. Seung-Jung Ki of Chonnam National University Hospital, developed FUSION, an ultra-rapid diagnostic platform capable of selectively detecting infectious viruses within 5 minutes. The platform employs virus-targeting lipid nanoparticles (VEACON)1 loaded with CRISPR2 gene-editing components, enabling direct detection of viral RNA through simple mixing, without complex sample preparation. Using synchrotron X-ray analysis, the researchers revealed that membrane fusion is accelerated by electrostatic interactions, leading to highly enhanced CRISPR activity within a confined nanoscale volume. The platform demonstrated sensitive detection of multiple viruses, including SARS-CoV-2, influenza, and RSV, and was further adapted into a sprayable system for real-time visualization of viral contamination on surfaces.
Background
Rapid and accurate diagnosis of viral infections is essential for preventing the spread of infectious diseases. Polymerase Chain Reaction (PCR)3 is currently the most widely used diagnostic method. Although PCR is highly sensitive and capable of detecting even trace amounts of viral genetic material, it requires multiple sample preparation steps, including nucleic acid extraction4, which limits its suitability for rapid point-of-care testing. In addition, PCR may produce positive results from residual viral RNA fragments (RNA remnants) derived from noninfectious viruses, potentially leading to unnecessary isolation measures and associated socioeconomic costs. This study aimed to overcome these limitations of conventional diagnostic technologies. The researchers focused on membrane fusion5, a critical process through which viruses enter host cells. Based on this mechanism, they sought to develop a diagnostic platform capable of selectively recognizing intact, infectious viruses and autonomously generating detection signals. Ultimately, the goal was to establish a simple and rapid diagnostic method that enables virus detection by merely mixing a detection solution with a sample, without requiring complex sample preparation procedures.
Methodology
The research team developed VEACON (Virus Entry-Activated CRISPR Operating Nanoparticle), a 120 nm lipid-membrane6 nanoparticle functionalized with virus-specific receptors and loaded with CRISPR-Cas13a complexes7. To investigate the mechanism of virus detection, synchrotron small-angle X-ray scattering (SAXS) analysis8 at Pohang Accelerator Laboratory was employed to quantitatively monitor membrane fusion between VEACON and target viruses. The study revealed that increasing the proportion of cationic lipids on the nanoparticle surface enhanced membrane fusion through electrostatic interactions. The researchers further compared responses to infectious viruses and heat- or chemically inactivated viruses lacking fusion capability, confirming that signal generation occurred selectively through membrane fusion. In addition, the platform was validated using 100 nasopharyngeal swab9 clinical samples to assess its diagnostic performance under real-world conditions.
Read more on the Pohang Accelerator Laboratory website
Image: Schematic illustration of a sprayable membrane fusion-based detection system for visualizing viral contamination on surfaces
