posted on 2024-02-21, 05:03authored byYali Mu, Xiaowen Wang, Xiaoxue Du, Ping-Ping He, Weiwei Guo
Due to their programmable stimuli-responsiveness,
excellent biocompatibility,
and water-rich and soft structures similar to biological tissues,
smart DNA hydrogels hold great promise for biosensing and biomedical
applications. However, most DNA hydrogels developed to date are composed
of randomly oriented and isotropic polymer networks, and the resulting
slow response to biotargets and lack of anisotropic properties similar
to those of biological tissues have limited their extensive applications.
Herein, anisotropic DNA hydrogels consisting of unidirectional void
channels internally oriented up to macroscopic length scales were
constructed by a directional cryopolymerization method, as exemplified
by a DNA-incorporated covalently cross-linked DNA cryogel and a DNA
duplex structure noncovalently cross-linked DNA cryogel. Results showed
that the formation of unidirectional channels significantly improved
the responsiveness of the gel matrix to biomacromolecular substances
and further endowed the DNA cryogels with anisotropic properties,
including anisotropic mechanical properties, anisotropic swelling/shrinking
behaviors, and anisotropic responsiveness to specific biotargets.
Moreover, the abundant oriented and long macroporous channels in the
gel matrix facilitated the migration of cells, and through the introduction
of aptamer structures and thermosensitive polymers, an anisotropic
DNA cryogel-based platform was further constructed to achieve the
highly efficient capture and release of specific cells. These anisotropic
DNA hydrogels may provide new opportunities for the development of
anisotropic separation and biosensing systems.