On-Demand Modifications of Thin-Film Transistors for Label-Free Biosensing Applications

Thin film transistors are ubiquitous from displays to detectors. However, their use in biosensing is limited by a lack of techniques to functionalise the transistors. In this talk, the foundation of employing them as cost-effective portable biosensors by modifying the surface functionality will be discussed. One common functionalisation method is based on dropcasting which is to modify the whole chip surface with organofunctional molecules and antibody for the immobilisation of the specific biomolecule. But this method normally allows only one type of biomolecules to be detected at one time due to the spread of the molecule droplet over the sample surface. In this study, we use additive electrohydrodynamic printing to locally functionalise thin film transistors. The local functionalisation is achieved by printing features using microscale nozzles, enabling different surface functionalities on each transistor. This presents a unique method to create portable biosensors that are able to detect more than one biomolecule simultaneously, facilitating the diagnosis of human diseases.