Figure 1.

Fluorescence microscopy detection of beads and co-localization principle. Red fluorescent beads (RBs) are 5.9 µm in size, surface modified with streptavidin and including magnetite for magnetic separation. Green fluorescent beads (GBs) are 1 µm in size and surface modified with avidin. (A) Fluorescent microscopic images of GB, RB and a mixture of the two. (B) Illustration of target sequence detection by two bead/PNA complexes through target hybridization via the PNA probes. Fluorescent beads were complexed with biotin-labeled PNA 3533 and PNA 3534 respectively for GB and RB. These two bead/PNA complexes were incubated with target nucleic acids. Two beads show proximity location upon the hybridization of two PNAs to their target sequences.