Lab-on-Chip based diagnostic tools: Microfluidic structures on top of CMOS devices

The growing number of chronic diseases such as cancer, the absence of specific and efficient treatments for several viral and bacterial diseases and the absence of efficient and fast method of environmental monitoring has created the need of rapid identification and diagnosis. Laboratory on-Chip (LoC) is an advanced method to produce real-time, multiple and highly sensitive analysis at the point-of-care, providing the results for physicians and patients. This multidisciplinary research approach calls for an integration of heterogeneous structures including microelectronic and microfluidic technologies as well as conventional biochemistry techniques. Standard CMOS process is an excellent candidate to realize such LoC systems offering the advantages of well-studied circuits and embedded sensors/actuators. This tutorial presents an overview of recent advances in the design and implementation of hybrid microfluidic CMOS systems for LoC applications. A CMOS-based LoC can be divided in three parts : microfluidic structure, biofunctionalized layers and microelectronic circuitry. The microfluidic structure is required to direct the fluid toward the sensing/actuating sites, the biofunctionalized layers are formed to transduce the biological quantities to electrical changes or vice versa. After a long period of research on biological and chemical aspects of LoC, now the microelectronic circuits and systems design emerges as critical. In this tutorial, a brief overview of proposed methods in the literature for microfluidic packaging, functionalized layer and the relevant applications are firstly described. Thereafter, the recent progresses in dedicated circuits and systems design are put forward. CMOS process by offering an array of addressable coils or electrodes can play an essential role to generate programmable electrical or magnetic fields for dielectrophoresis, or magnetic manipulations. On the other hand, through this technology several embedded sensing techniques can be realized as reported in the literature. In this tutorial, the optical, thermal, ISFET, impedimetric and in particular capacitive sensors are presented for molecular/cellular applications.