Electrochemical biosensor for point of care cancer and disease detection
Abstract
The first sign of growth of a malignant tumour within the body is indicated by the presence of protein markers in the bloodstream. Current detection methods, based on turbidity and fluorescent parameters, require the use of bench top optical read out systems which offer no portability. By combining electrochemical techniques and electronic miniaturization, low cost, on site, biosensors are being realized.
Protein detection is based on our ability to identify selective molecular binding between the targeted protein and the biorecognition element. When the reaction occurs and the targeted protein binds to the biorecognition element, several attributes of the molecular chain change. It is this change that is indicative of the cancer marker’s presence. Correctly identifying the occurrence of this reaction is highly dependent on the selectivity of the molecules binding to the targeted proteins in question.
In this work we plan to achieve high specificity and reliability of protein detection by using aptamers. An aptamer is a nucleic acid receptor that can bind tightly to its target molecule and with high selectivity due to its three dimensional shape. When the target molecule has bound to the aptamer, the electrochemical current path of the molecular chain is changed, and this modulation can be measured directly using cyclic voltammetry. We have built a potentiostat circuit for this purpose, which sweeps a voltage across two electrodes while measuring the induced current across a third electrode. We are exploring different miniaturization methods of the electrodes which will be addressed in the presentation.