Intramolecularly Protein-Crosslinked DNA Gels: New Biohybrid Nanomaterials with Controllable Size and Catalytic Activity

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Intramolecularly Protein-Crosslinked DNA Gels: New Biohybrid Nanomaterials with Controllable Size and Catalytic Activity, Small 2017, 1700706

 

Besides its biological importance, DNA can be seen as a material that combines unique properties of biocompatibility and programmability. For instance, the use of DNA as a backbone for hydrogels has recently led to various fundamental studies and applications, such as molecular detection, drug or gene delivery, cell culture, and water detoxification. Such DNA hydrogels can be prepared by several methods, including covalent crosslinking between double-stranded DNA molecules, i-motif formation or hybridization between sticky ends of branched DNA nanostructures, and physical entangling between long DNA strands. For nanotechnological and biomedical applications, the reduction of the dimensions of such biocompatible materials is often a requisite, which has triggered a growing interest for nano- and microsized DNA gels. For instance, DNA nanogels of controllable size were prepared through hybridization between branched DNA nanostructures in the presence of DNA units able to inhibit the extension of the nanogel. Another strategy has relied on the intramolecular hybridization inside long, single-stranded DNA produced by the rolling circle amplification method.

 

 

In summary, we have described a new way to create crosslinks inside individual DNA molecules, by exploiting the strong yet noncovalent streptavidin–biotin interaction. We showed that streptavidin allowed us not only to control the crosslinking density of IPDGs, but also to incorporate various protein guests by using commercially available streptavidin–protein conjugates. This method can be readily extended to other proteins or to bring other functions to the DNA gels by using, for instance, streptavidin conjugated to other entities such as nanoparticles or signaling molecules. Another way to functionalize the IPDGs would consist in using biotinylated compounds that could be incorporated in the already formed gels by interacting with the free binding sites of the streptavidin crosslinks. We have also demonstrated the interest of using a reversible DNA condensation strategy to further actuate the IPDGs. This was shown here with the simple spermine/NaCl system but this principle could be extended to other types of DNA compaction processes. For instance, IPDGs could be photocontrolled by using photoreversible DNA compaction systems. Overall, this work provides insights for the design of novel nano- to microscale multifunctional DNA materials, offering promising perspectives for the development of hybrid DNA/protein-based sensors and reactors.

 

Consultez le communiqué de presse associé à cet article : Des microgels hybrides ADN-protéine

 

Résumé: 

Small 2017, 1700706

 

DNA micro- and nanogels—small-sized hydrogels made of a crosslinked DNA backbone—constitute new promising materials, but their functions have mainly been limited to those brought by DNA. Here a new way is described to prepare submicrometer-sized DNA gels of controllable crosslinking density that are able to embed novel functions, such as an enzymatic activity. It consists of using proteins, instead of traditional base-pairing assembly or covalent approaches, to form crosslinks inside individual DNA molecules, resulting in structures referred to as intramolecularly protein-crosslinked DNA gels (IPDGs). It is first shown that the addition of streptavidin to biotinylated T4DNA results in the successful formation of thermally stable IPDGs with a controllable crosslinking density, forming structures ranging from elongated to raspberry-shaped and pearl-necklace-like morphologies. Using reversible DNA condensation strategies, this paper shows that the gels can be reversibly actuated at a low crosslinking density, or further stabilized when they are highly crosslinked. Finally, by using streptavidin–protein conjugates, IPDGs with various enzymes are successfully functionalized. It is demonstrated that the enzymes keep their catalytic activity upon their incorporation into the gels, opening perspectives ranging from biotechnologies (e.g., enzyme manipulation) to nanomedicine (e.g., vectorization).

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Microfluidique
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Intramolecularly Protein-Crosslinked DNA Gels: New Biohybrid Nanomaterials with Controllable Size and Catalytic Activity

 

L. Zhou, M. Morel, S. Rudiuk and D. Baigl

 

Small 2017, 1700706

 

DOI: 10.1002/smll.201700706