Nanopores as communicating reaction spaces in silica-hybrid cotton thread networks and paper.

• Applicant: Professorin Dr. Annette Andrieu-Brunsen
• Subject Area: Synthesis and Properties of Functional Materials
• Term: since 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 422698725

Communicating reaction spaces are a prerequisite for the construction of complex systems. They are discussed in the context of so-called "life-like materials" but also for technological applications in sensor technology, e.g. for signal amplification. The necessary compartments are predominantly constructed from biological cells, polymersomes or similar components. One disadvantage is that in these "materials" the arrangement of pore spaces depends on the assembly processes. Another drawback is that transport between such pore spaces is based on diffusion and can be difficult to design in an adjustable manner. Here, functionalized papers or cotton threads with adjustable pore spaces and controllable fluid distributions offer new possibilities, but have not yet been investigated. Also, only a few examples of functionalized cotton threads and papers have been widely used in applications such as diagnostic test strips, despite the relatively large and growing number of research approaches to modified papers and potential demonstrator applications to date. In this context, pore spaces are crucial for applications of high-tech papers in the context of sensing or catalysis. In the first funding period (FP), we were able to show how adjustable pore spaces locally control fluid distribution and fluid flow in paper and cotton threads. The formation of nanoscale pores by mesoporous silica coatings in paper and cotton threads was controlled, the characterization of these processes was extended, and three-dimensional porous silica gradients, and thus e.g. three-dimensional adjustable fluid distribution, were designed in a paper. Thus, in addition to functional papers and cotton threads, we were able to contribute to the evaluation of models of fluid behavior in papers. An important finding was that fiber swelling but also the presence of nanoscale pores on the fiber play an important role, which is not considered in most models. In the second funding period, the control of fluid distribution in papers as well as the arrangement of different pore spaces in paper will be extended to adjustable pore sizes and complementary functionalization in order to make communicating reaction spaces and thus a new generation of functional papers accessible, e.g. in the context of sensor technology and "life-like materials". The enzyme cascade reactions of glucose oxidase (GOx) and myoglobin (MGB) will serve as a model reaction to study pore size and partitioning effects. In this process, GOx converts glucose to peroxide, which in turn reacts with MGB amplex red to form resorufin. By combining this reaction with the described cotton threads and paper, fundamental questions about the control of complex reactions by the design of reaction spaces, their arrangement as well as fluid distribution in papers and 3D linked thread networks become accessible and thus design criteria for sensor papers but also for "life-like" materials can be derived.

• DFG Programme: Research Grants
• International Connection: Argentina
• Co-Investigators: Professor Dr. Markus Biesalski; Professor Dr. Nico Bruns; Privatdozent Dr. Tobias Meckel; Professor Dr.-Ing. Samuel Schabel
• Cooperation Partner: Professor Dr. Marcelo Ceolin