December 4, 2020
by Thomas Porter
In the last update, there was a roadblock in the erasable fluorescent cell labeling. We replaced the polymer and dye used in the DNA cage structure as well as fixing the system used to make the particles. We have been able to get the system working again, though we have more non-specific on the cells than desired right now. Due to this trouble with the non-specific binding, the erasing efficiency is not as high as in past studies.
Figure 1. Fluorescent labeling of U87 cells for actin and integrin. A) Negative control with primary antibodies not conjugated to DNA. Cells labeled using primary antibodies conjugated to DNA and fluorescent secondary antibodies targeting B) actin and C) β1 integrin. Cells labeled using primary antibodies conjugated to DNA and fluorescent DNA cages targeting B) actin and C) β1 integrin.
Also, in the last update we had shown attempts at non-specifically staining tissue slices. Those attempts were unsuccessful since the DNA cages were not concentrated enough. Since then, we have non-specifically stained the tissue with red and blue colored DNA cages as well as severely limiting this non-specific binding using different blocking buffers.
Figure 2. Colormetric labeling of mouse brain tissue non-specifically. A) Unstained tissue and B) tissue stained with red dye loaded DNA cages showing that the dye concentration is sufficient enough for labeling. Tissue C) before and D) after staining red dye loaded cages in 0.1% BSA and 1% goat serum showing that a change in blocking buffer reduces non-specific binding.