Direct biopsy screening of colorectal cancer by electrochemical biosensor

We propose and demonstrate feasibility of a new electrochemical assay performed directly on slices of fresh tumor biopsies. An amperometric biosensor was used to screen for colon cancer on the basis of electrochemical distinction between cancerous and normal epithelia. This observation is based on the known down-regulation of the enzyme Alkaline Phosphatase in cancerous cells. Biopsy samples removed from tumors induced in mice were compared to biopsies samples simultaneously collected from the small and large intestine (colon) of same mice. The samples were suspended in an especially designed multichamber electrochemical sensor. Upon the addition of a suitable substrate current signals were recorded. Significant differences in current signal were observed for biopsies removed from tumors comparing to samples removed from the corresponding healthy tissue. Reproducibility was demonstrated. The new technology allows a direct assay carried out on small volume biopsies without the need of sample transfer to cell culture, thus eliminating the need for pretreatment and labor intensive preparative steps. This approach offers rapid and straightforward detection directly affected within minutes of biopsy removal.