Extracellular proteolytic Cathepsin L (CTSL) serves an important role in regulating the metastatic potential of cancer. In this research, biotinylated full length histone H3 (BFLH3) treated extended gate (EG) field effect transistors (FETs) were used to detect extracellular activity of CTSL with 10<sup>4 </sup>times the sensitivity of fluorometric CTSL activity assays., The treated BFLH3 is cleaved after amino acid 21 upon active reaction by CTSL, inducing a significant change in charge on the EG surface due to the large size and charge of the cleaved BFLH3. FET can detect the change in EG surface charge, allowing the quantification of proteolytic extracellular CTSL activity. Furthermore, self-normalized quantification of CTSL activity was possible in heterogeneous LNCaP and PANC-1 cultured cell media, which accurately demonstrated higher CTSL levels in LNCaP derived from metastatic lesion of human prostatic adenocarcinoma. EG FET allows multiple measurements of CTSL activity with one FET and further investigation is possible to detect other proteolytic enzymes for cancer diagnosis and prognosis.

Detection of extracellular proteolytic cathepsin L activity using full length histone H3 conjugated electrochemical biosensor

2019 Spring National Meeting

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