Au-nanoprobe based quantification of BRC-ABL fusion mRNA directly in total RNA extracted from K562 cell line. Nanoprobe aggregation as measured by ratio of AUC500 nm-560 nm/AUC570 nm-630 nm for increasing concentrations of total RNA from a BCR-ABL positive cell line (K562) - 10 to 60 ng/μl. (Inset) Real-Time RT-PCR vs. Au-Nanoprobe Assays. A linear association (R2 = 0.9171) was found between the two methods. The error bars represent the standard deviation from three independent assays.