Silica-coated liposomes loaded with quantum dots as labels for multiplex fluorescent immunoassay

• Silica coverage ensured the stability of liposomes during storage and application.
• The fluorescent labeled multiplex immunoassay was developed and validated.
• Silica-coated liposomes loaded with quantum dots were used as a fluorescent label.
• The technique resulted in a significant increase of the assay sensitivity.

This manuscript describes synthesis and followed application of silica-coated liposomes loaded with quantum dots as a perspective label for immunoaasay. The hollow spherical structure of liposomes makes them an attractive package material for encapsulation of multiple water-insoluble quantum dots and amplifying the analytical signal. Silica coverage ensures the stability of the loaded liposomes against fusion and internal leakage during storage, transporting, application and also provides groups for bioconugation. For the first time these nanostructures were employed for the sensitive multiplex immunochemical determination of two analytes. As a model system mycotoxins zearalenone and aflatoxin B1 were detected in cereals. For simplification of multiassay results’ evaluation the silanized liposomed loaded with QDs of different colors were used. The IC50 values for the simultaneous determination of zearalenone and aflatoxin B1 were 16.2 and 18 µg kg−1 for zearalenone and 2.2 and 2.6 µg kg−1 for aflatoxin B1 in wheat and maize, respectively. As confirmatory method, liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) was used.

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