Conditional DNA‐Protein Interactions Confer Stimulus‐Sensing Properties to Biohybrid Materials

Abstract

Interactive materials that specifically respond to environmental stimuli hold high promise as energy‐autonomous sensors and actuators in biomedicine, analytics or microsystems engineering. However, the implementation of materials specifically responsive to a given small molecule has so far been hampered by a lack of generically applicable stimulus sensors. In this study, a novel and likely general strategy for the synthesis of biohybrid materials with desired stimulus specificity is established. The strategy is based on allosterically regulated DNA‐binding proteins, a conserved protein family that has evolved in prokaryotes to sense and respond to most diverse molecules in order to enable bacterial survival in a changing environment. The novel hydrogel design concept is demonstrated with the example of single‐chain TetR, a protein that binds the tetO DNA motif and dissociates thereof in the presence of the antibiotic tetracycline. Therefore, linear polyacrylamide is crosslinked via the TetR/tetO interaction to a biohybrid material that can subsequently be dissolved by tetracycline in a dose‐dependent manner. This drug‐induced dissolution is applied for the adjustable release of the cytokine interleukin 4 in a tetracycline‐dependent manner. The design concept developed in this study might serve as a blueprint for the synthesis of biohybrid materials responsive to drugs, metabolites or toxins by replacing TetR/tetO with another protein/DNA pair showing the desired stimulus specificity.

Biofunctionalized Materials Featuring Feedforward and Feedback Circuits Exemplified by the Detection of Botulinum Toxin A

“…[15,28,32] The incorporation of biological building blocks into polymer materials enabled the modular assembly of biohybrid circuits featuring positive feedforward and positive feedback loop motifs.…”

Responsive DNA‐Based Hydrogels and Their Applications

“…The proof-of-principle work was demonstrated by Christen et al with the tetracycline repressor (TetR) protein and its cognate tetO DNA operator [62] (Figure 2b). The hydrogel was constructed with two types of linear polyacrylamide: one electrostatically coupled to TetR proteins and the other covalently functionalized with tetO DNAs.…”

“…The hydrogel contained a Deinococcus radiodurans -derived urate repressor (HucR) that binds to its cognate operator sequence hucO at low urate concentrations, while it dissociates from the DNA sequence at elevated concentration. The HucR protein was coupled to polyacrylamides via an established method [62] . HucR- binding multimeric hucO DNA sequences were used to crosslink HucR-incorporated polymers.…”

DNA Block Copolymers: Functional Materials for Nanoscience and Biomedicine

“…In respect to self-assembled structures, hybridization with cDNA can be used for facile and specific functionalization; facilitating templated reactions, particle recognition, and the alignment of DNA-functionalized nanomaterials like SWNTs. Upcoming concepts from molecular biology like next generation methods for DNA assembly 44 or the design of adaptive materials by combination of DNA and organic polymers with specific DNA binding proteins 45 will have a distinct impact on the field of DBC materials. In combination with advanced analytical tools (like F € orster related energy transfer) and visualization techniques (e.g., AFM, superresolution optical microscopy, and TEM), DBCs will give access to new functional materials and deliver insight into self-assembly processes of DNA nanomaterials.…”