Biosensors with Printed Active Layer
Felippe J. Pavinatto
Biosensors are thriving in the detection and precise quantification of a plethora of analytes ranging from water contaminants to biologicals inside the human body. This kind of bioelectronic device has at its heart a thin film with a biomolecule in its composition (active layer), which interacts with the sample to be analyzed and confers specificity and sensitivity to the devices. Here, we review the use of printing techniques to deposit the active layer, emphasizing the advantages and remarkable outcomes of this procedure. After an initial introduction of the main concepts, we discuss the most important aspects of the formulation of bioinks suitable for printing bioactive films. It is stressed that a proper choice of additives is vital for both attaining good printability and preserving functionality of the biomolecules. Moreover, printing conditions must be controlled to avoid further damage to the biological materials. The choice of the printing method depends on the requirements for the target device architecture. For instance, inkjet printing is the method of choice when high resolution features are sought. However, for fast, high throughput fabrication of large-area devices, roll-to-roll (R2R)-compatible mastered methods from the graphics industry (flexography and gravure) are more adequate. Several examples of application are given, and the advantages of using a specific printing method are highlighted in terms of devices performance. Overall, our goal is to illustrate how printing is versatile and effective to fabricate high-end devices through simple and technologically viable processes.
Keywords: Bioelectronics, Biosensors, Biomolecules, Printed Electronics, Inkjet, Rotogravure