This work demonstrates for the first time rapid, real-time Mie scatter sensing of colloidal emulsion nucleic acid amplification directly from emulsion droplets. Loop-mediated isothermal amplification is used in this study, and, to our knowledge, has not previously been used in a colloidal emulsion platform. Interfacial tension values (γ) associated with bulk protein adsorption and denaturation at the oil–water interface exhibit characteristic changes in the absence or presence of amplification. In the presence of target and amplicon, emulsions maintain a constant 300–400 nm diameter, whereas emulsions formed with no target control show a rapid decrease in droplet diameter to <100 nm over the first 20 min of incubation. This method is validated using whole bacteria (Staphylococcus aureus MSSA and Escherichia coli O157:H7) and whole virus (Potato virus Y and Zika virus) samples suspended in water, buffer, or serum-like matrices. Short-term formation of colloidal emulsion is quantified via 60° scatter monitoring, where the initial slope of scattering intensity is utilized to confirm target amplification in less than 5 min. The unique benefits of this method render it more cost-effective and field-deployable than existing methods, while being adaptable to a multitude of targets, sample matrices, and nucleic acid amplification tests.
- Mie scatter
- loop-mediated isothermal amplification
- real-time quantification
- w/o emulsions
ASJC Scopus subject areas
- Biomedical Engineering
- General Biochemistry, Genetics and Molecular Biology