Device Processing Challenges for Miniaturized Sensing Systems Targeting Biological Fluids

This article presents a review of device processing technologies used in the fabrication of biomedical systems, and highlights
the requirements of advanced manufacturing technology. We focus on biomedical systems that perform diagnostics
of fluidic specimens, with analytes that are in the liquid phase. In the introduction, we define biomedical systems as well as
their versatile applications and the essential current trends. The paper gives an overview of the most important biomolecules
that typically must be detected or analyzed in several applications. The paper is structured as follows. First, the conventional
architecture and construction of a biosensing system is introduced. We provide an overview of the most common biosensing
methods that are currently used for the detection of biomolecules and its analysis. We present an overview of reported biochips,
and explain the technology of biofunctionalization and detection principles, including their corresponding advantages
and disadvantages. Next, we introduce microfluidics as a method for delivery of the specimen to the biochip sensing area.
A special focus lies on material requirements and on manufacturing technology for fabricating microfluidic systems, both
for niche and mass-scale production segments. We formulate requirements and constraints for integrating the biochips and
microfluidic systems. The possible impacts of the conventional microassembly techniques and processing methods on the
entire biomedical system and its specific parts are also described. On that basis, we explain the need for alternative microassembly
technologies to enable the integration of biochips and microfluidic systems into fully functional systems.