DNA Cleared Plasma

Free DNA is undetectable in DNA Cleared Plasma

Bioanalyzer analysis demonstrates the absence of detectable free DNA in DNA Cleared Plasma, making it a suitable blank baseline control that is ideal for liquid biopsy studies (Figure 1).

DNA Cleared Plasma has a similar composition to untreated plasma

Analysis of DNA Cleared Plasma shows that it is compositionally similar to natural human plasma (Table 1) with comparable amounts of extracellular vesicles (EVs) (Figure 2) that are morphologically normal (Figure 3).

Figure 2. DNA Cleared Plasma has similar abundance of EVs as untreated plasma as determined using SBI’s EXOCET Exosome

DNA Cleared Plasma is better than synthetic plasma for spike-in studies

To demonstrate the excellent stability of spiked-in reference DNA in DNA Cleared Plasma, we added either a synthetic DNA fragment (blue circles) or fragmented nucleosomal DNA (yellow squares) to DNA Cleared Plasma for up to 270 days at 2-8°C (Figure 4). At 0, 2, 4, 90, 180, and 270 days, we extracted the spiked-in DNA and used qPCR to measure the number of copies of the fragments. Similar amounts of  recovery was observed at all time points.

Figure 4. Reference spiked-in DNA remains stable in DNA Cleared Plasma for at least 270 days at 2-8°C.

DNA Cleared Plasma also better replicates the DNA extraction properties of natural human plasma than either synthetic plasma or buffer (Figure 5). We spiked-in a known amount of a synthetic DNA fragment into either buffer (light gray diamonds), synthetic plasma (medium gray squares), untreated plasma (dark gray triangles) or DNA Cleared Plasma (blue circles), and then extracted the DNA and compared the observed versus the expected number of copies/mL, as measured by qPCR. Of the different matrices, the DNA Cleared Plasma behaved most similarly to untreated plasma, demonstrating its suitability as a control matrix for cfDNA studies.

Figure 5. DNA Cleared Plasma better replicates untreated plasma than buffer or synthetic plasma for DNA extraction studies.

DNA Cleared Plasma is an excellent matrix for comparing different cfDNA extraction kits

A known amount of reference DNA was spiked into DNA Cleared Plasma and used as the starting material for a study comparing the extraction efficiency (Figure 6) and sensitivity (Figure 7) of different cfDNA isolation kits. The amount of recovered cfDNA was evaluated using qPCR, enabling quantitative comparison of the different cfDNA isolation kits. Thus, DNA Cleared Plasma can be used as a validation tool for different cfDNA isolation kits and/or cfDNA isolation method development.