Figure 5

Performance metrics. (A) Resolution is defined as the width of the minimum dissectible area (a circle) generated by touching the rotating blade to the tissue without transverse movement (known as a point dissection). Each value is from five tests on each of five xScisors where the xScisor was removed and replaced into the collet after every dissection. Ave. = average, SD = Standard Deviation. (B) Accuracy is defined as the average distance between the intended boundary (using the digital overlay) and the actual boundary of dissection. The values shown are the percent of the linear distance around the circumference of the actual dissection boundary that was within 50 and 100 microns, or outside of 250 microns of the intended dissection boundary. This experiment was performed on a total of 14 AOIs from three different human liver tissue section samples. For each sample, the total circumference of the AOIs is shown. (C) Efficiency is measured by DNA quantitation using Pico Green following Proteinase K digestion; both mesodissection and manual dissection appear to be near 100% by visualization. Paraffinized tissue is efficiently aspirated using mineral oil, somewhat less efficiently using buffers containing SDS (but visualization is better), and not efficiently held in suspension by many aqueous buffers. (D) Purity is the percent of the recovered sample that is from the dissected area (a measure of potential contamination from adjacent undissected tissue). Purity was determined by dissecting immediately adjacent human and mouse 5 micron liver tissue sections at the indicated distances from the intersection, then testing by multiplex PCR containing one human and one mouse amplicon, or single amplicon qPCR as described in Results.