Creation of a lab-on-card based on electrical impedance spectroscopy

Abstract

The purpose of this paper was to create an electrical impedance platform that can harbour different receptors such as molecularly imprinted polymers (MIPs), DNA and proteins. The current detection techniques are expensive and require laboratory equipment and skilled personnel. These requirements are difficult to meet in developing countries, where agriculture and livestock are the biggest source of income. Microfluidics can solve these problems by their low-cost manufacturing, ease of use and effectiveness. In this paper, a lab-on-card (LOC) is made because a large working space is necessary. These cards were made from alternating layers of PET and double-sided tape. MIPs and NIPs were used as receptors. LOCs are a multi-purpose tool due to their layering technique. This property sparked the idea to incorporate an immunoassay into this type of sensor. Antigens were used as detection tool for enzyme-tagged antibodies. Initially, an LOC was created that used molecularly imprinted polymers and non-imprinted polymers (NIPs), sandwiched between two paper layers, to detect nicotine. A card was successfully constructed where a stable impedance signal could be recorded with aluminium contacts. Due to the layering technique, the focus was shifted to the implementation of an immunoassay into an electrical impedance platform. A change in impedance was observed when the antigens and blocking agents were introduced. Once this combination is realised it can be used for the detection of numerous molecules.