Solid state fluid transport and sensing based on printed and embedded cellulose-polymer composites: the next level of paper-based microfluidics

In this contribution we present a further development of so-called paper-based microfluidics [1]. Instead of defining fluid conducting paths in paper by printing wax or other hydrophobic substances on the paper, we prepare cellulose/polymer composites that can be printed directly on, in principle, arbitrary surfaces. In this way, with respect to geometry and properties, well defined fluid conducting structures based on cellulose can be realized. Moreover, the composite can, prior to the printing step, be doped with a functional component, which facilitates the realization of printed, cellulose-based analytical devices. In this sense, the proposed technology can be seen as a further development of paper-based microfluidics, which may find application in specific bio-chemical assays embedded in the surface of everyday necessities or commodities. Especially lateral flow immunoassays, which, due to the pandemic, are currently needed in large quantities, may embody a future application field of the presented technology.