Institutionen för teknikvetenskaper

Diagnostik med magnetiska nanopartiklar: VAM-NDA metoden

The overall aim is to develop a sensitive technology platform for diagnostics that is inexpensive enough to be employed at local doctors offices and at home, allowing for simple individual healthcare solutions as well as more advanced clinical analysis procedures. The project combines a detection principle relying on Changes in Brownian rotation dynamics as biomolecules bind to functionalised magnetic nanobeads and the diagnostic principle in which the target DNA in a test sample is rolling circle amplified to large coils.

Figure caption: Schematic illustration of the volume-amplified magnetic nanobead detection assay. A collection of single-stranded target DNA molecules are indicated in blue. After addition of matching padlock probes (grey), circularized padlock probes form upon hybridization and the ends of the padlock probe molecules are joined together by ligation. The circularized padlock probes are then amplified by the RCA mechanism, creating random-coiled DNA macromolecules. To detect the presence of RCA products, single-stranded oligonucleotidefunctionalized magnetic beads (brown) are added, which are incorporated by base pair hybridization to the RCA coils. The bead incorporation results in a spectrum of the complex magnetization (positive sample, blue magnetization curve) substantially different from the response of a sample containing free beads only, i.e., the absence of RCA products (negative sample, green magnetization curve). The two relaxation events in the blue curve have been resolved (bold black curves) using a Cole–Cole fitting procedure, and the peak frequency values are indicated.