ABSTRACT
Polymeric hydrogels have gained major importance as functional materials. By their hydrophilic nature, crosslinked gels are well suited for applications in moist and liquid environments as in hygiene products, wound dressings, contact lenses, and drug delivery systems. The wide range of resources and structuring possibilities also makesthemvery attractive for sensor systems. Especially in the fields of biosensing, lab-on-a-chip technologies, and diagnostics hydrogelsare important building blocks. This chapter provides an overview of the main fabrication technologies and operation modes. The different microstructuring techniques are of fundamental importance to design a gel in the desired shape with the required mechanical stability, biocompatibility, and pore size. The main functions in sensors include responsive hydrogels, size exclusion membranes, and (bio)chemical reactors. Responsive gels are utilized in temperature, pH, and chemical sensors with a variety of transducing principles. In addition, porous gel matrices find manifold applications for flow control, analyte sieving, and immobilization. Each application field is illustrated by a selection of relevant examples.
