PLAU and prostate cancer: Additional studies showed the detection of the prostate cancer biomarker, urokinase plasminogen activator (uPA), using DNA-SWCNTs conjugated to an anti-uPA antibody (Figure 2b) [124], and the detection of single RAP1 proteins secreted from individual Escherichia coli cells using SWCNTs functionalized with the RAP1 aptamer [126].