Surface-Primed qPCR on Metal-Organic Frameworks for Extraction-Free Diagnostic Detection of Feline Calicivirus

Feline calicivirus (FCV) is a significant pathogen in cats, causing severe oral and respiratory diseases that threaten feline health. It is essential to find an efficient and rapid method for detecting FCV. Current detection methods, such as reverse transcription-quantitative polymerase chain reaction (RT-qPCR), are often labor-intensive and time-consuming. To overcome these limitations, this study developed a simplified mRNA detection method leveraging the multiadsorption properties of aptamers on metal-organic frameworks (MOFs). In this approach, RT-qPCR was performed on UiO-66 functionalized with reverse transcription (RT) primers that selectively hybridize to FCV RNA in biosamples. Nucleic acid amplification was initiated directly on the MOF surface, enabling quantitative analysis without prior RNA extraction. This method, termed surface-primed quantitative polymerase chain reaction (SP-qPCR), offers simple operation, ideal specificity, and high sensitivity with a limit of detection (LOD) of 1.91 copies/μL FCV in 90 min and excellent reproducibility (intra-assay and inter-assay coefficients of variation both less than 5%). Compared to commercial kits, SP-qPCR was faster and more cost-effective, eliminating the need for nucleic acid extraction. By integrating MOF-based sensing with qPCR, this strategy provides a rapid, efficient, and low-cost tool for FCV detection, with broad potential for clinical diagnostics.