Fluorescent and electrochemical dual-mode detection of Chikungunya virus E1 protein using fluorophore-embedded and redox probe-encapsulated liposomes.

The critical goal of sensitive virus detection should apply in the early stage of infection, which may increase the probable survival rate. To achieve the low detection limit for the early stage where a small number of viruses are present in the sample, proper amplified signals from a sensor can make readable and reliable detection. In this work, a new model of fluorescent and electrochemical dual-mode detection system has been developed to detect virus, taking recombinant Chikungunya virus E1 protein (CHIK-VP) as an example. The hydrophobic quantum dots (QDs) embedded in the lipid bilayer of liposome and methylene blue (MB) encapsulated in the inner core of liposomes played a role of dual-signaling modulator. After CHIK-VP addition, the nanocomposites and APTES-coated Fe3O4 nanoparticles (Fe3O4 NPs) were conjugated with antibodies to form a sandwich structure and separated from the medium magnetically. The nanoconjugates have been burst out by chloroform as surfactant, and both the QDs and MB are released from the liposome and were then monitored through changes in the fluorescence and electrochemical signals, respectively. These two fluorometric and electrochemical signals alteration quantified the CHIK-VP in the range of femtogram to nanogram per milliliter level with a LOD of 32 fg mL-1, making this liposomal system a potential matrix in a virus detection platform. Graphical abstract.