Read the full article here: Macromolecules 54 (2021)
by C. Oluwadunsin Akintayo, G. Creusen, P. Straub and A. Walther
The use of DNA as a building block in synthetic polymer hydrogels promises high levels of programmability regarding sol/gel temperatures, tunable bond lifetimes, biocompatibility, and interaction with biological components (e.g., enzymes, cells, and growth factors). However, scalability and quantitative structure–property relationships for large-scale materials are still challenging to achieve. Building on our recently introduced and scalable one-pot liquid-phase oligonucleotide synthesis of DNA onto star-shaped poly(ethylene glycol) (PEG), we here report hydrogels based on starPEG-DNA conjugates together with divalent DNA linkers of tunable duplex hybridization length. By systematically varying parameters such as the duplex melting temperature, salinity, and building block concentrations, we establish the mechanical phase space of such hydrogels. We elucidate tunable mechanical properties ranging from a few Pa to the kPa regime and discuss time scales of self-healing and bond exchange, as well as tunable sol/gel transition temperatures. These comprehensive investigations shed some light on the future design principles for DNA hydrogel materials based on scalable building blocks, that allow for the formation of quasi-ideal networks due to their star-shaped and flexible building block topologies. Such materials can be useful in the field of biomedicine and cell culture.