Portable real-time colorimetric LAMP-device for rapid quantitative detection of nucleic acids in crude samples

Papadakis, G.; Pantazis, A. K.; Fikas, N.; Chatziioannidou, S.; Tsiakalou, V.; Michaelidou, K.; Pogka, V.; Megariti, M.; Vardaki, M.; Giarentis, K.; Heaney, J.; Nastouli, E.; Karamitros, T.; Mentis, A.; Zafiropoulos, A.; Sourvinos, G.; Agelaki, S.; Gizeli, E.

Loop-mediated isothermal amplification is known for its high sensitivity, specificity and tolerance to inhibiting-substances. We developed a device for performing real-time colorimetric LAMP combining the accuracy of lab-based quantitative molecular diagnosis with the simplicity of point-of-care testing. This handheld device employs a single reaction-pot for amplification and a mini-camera for detection. Competitive features are the rapid analysis (<30min), quantification over 9 log-units, crude sample-compatibility (saliva, tissue, swabs), low detection limit (<5copies/reaction), smartphone-operation and fast prototyping (3D-printing). The device’s clinical utility is demonstrated in cancer-mutations and COVID-19 testing. Excellent performance includes: detection of 0.01% of BRAF-V600E-to-wild-type molecules; 97% sensitivity to SARS-CoV-2 RNA detection (89 samples); 83% (Ct<34), 98% (Ct<30) and 100% (Ct<25) to 163 nasopharyngeal-swabs; 100% specificity in all cases. The device high technology-readiness-level makes it a suitable platform for performing any colorimetric LAMP assay; moreover, its simple and inexpensive fabrication holds promise for fast deployment and application in global diagnostics.