In vitro point-of-care assay method/process using combination of bioactivated non-magnetic and magnetic quantum dots for rapid immuno-optomagnetic detection of serum biomarkers in free solution

A method for detecting and quantifying a target analyte in a test sample for a central nervous system disease, comprising steps of:

• providing a free/colloidal bioactivated multi-colored CdSe/CdS/ZnS non-magnetic quantum dot (QD) functionalised with a first analyte specific reagent,
• providing a plurality of optomagnetic magnetic quantum dots (MQDs) functionalised with a second analyte specific reagent, capable of binding to the target analyte followed by the first analyte specific reagent,
• providing both the first analyte specific reagent and the second analyte specific reagent capable of binding to the target analyte from different sides,
• contacting the free/colloidal bioactivated multi-colored CdSe/CdS/ZnS non-magnetic quantum dot (QD) with the target analyte and forming a QD nanocrystals first analyte specific reagent-target analyte complex, wherein the QD nanocrystals-first analyte specific reagent-target analyte complex is a first complex,
• forming a sandwich complex between the first complex and the plurality of optomagnetic magnetic quantum dots (MQDs) functionalised with the second analyte specific reagent, wherein the sandwich complex is a second complex,
• detecting a diagnostic signal originating from a color change after a binding of the target analyte with two different colors (wavelengths) of biofunctionalized MQDs (λ1) and bioactivated QDs (λ2),
• separating the second complex from non-magnetic unbound QDs by a magnetic separation method,
• visualizing the diagnostic signal generated by a naked eye in real-time using an ultraviolet (UV)-torch.