Traumatic brain injury accompanied by intracranial hypertension remains one of the most fatal injuries worldwide. Usually, patients must undergo two surgeries, craniectomy and cranioplasty, to reduce the intracranial pressure and then repair the skull. Traditional biomaterials, such as autologous bones and titanium meshes, which have poor stretchability and very high Young's modulus values up to hundreds of GPa, tend to constrain intracranial tissue and cannot be implanted directly after craniectomy. Thus far, finding elastic and degradable biomaterials to be immediately implanted after a craniectomy has remained a great challenge, which should not only repair cranial defects but also avoid secondary surgery and reduce the risk of complications, has remained a great challenge. Herein, a 3D printable bioactive hydrogel scaffold with high elasticity that can protect brain tissue, adapt to intracranial pressure changes, allow for the transport of nutrients and the proliferation and osteogenic differentiation of bone mesenchymal stem cells is presented. As indicated by in vivo experiments, the hydrogel scaffold helps to treat traumatic brain injury within 8 weeks and degrades safely. With these advantages, this material shows the potential to open up new horizons for cranioplasty and to help patients survive traumatic brain injury.
Development
of smart switchable surfaces to solve the inevitable
bacteria attachment and colonization has attracted much attention;
however, it proves very challenging to achieve on-demand regeneration
for noncontaminated surfaces. We herein report a smart, host–guest
interaction-mediated photo/temperature dual-controlled antibacterial
surface, topologically combining stimuli-responsive polymers with
nanobactericide. From the point of view of long-chain polymer design,
the peculiar hydration layer generated by hydrophilic poly(2-hydroxyethyl
methacrylate) (polyHEMA) segments severs the route of initial bacterial
attachment and subsequent proliferation, while the synergistic effect
on chain conformation transformation poly(N-isopropylacrylamide)
(polyNIPAM) and guest complex dissociation azobenzene/cyclodextrin
(Azo/CD) complex greatly promotes the on-demand bacterial release
in response to the switch of temperature and UV light. Therefore,
the resulting surface exhibits triple successive antimicrobial functions
simultaneously: (i) resists ∼84.9% of initial bacterial attachment,
(ii) kills ∼93.2% of inevitable bacteria attack, and (iii)
releases over 94.9% of killed bacteria even after three cycles. The
detailed results not only present a potential and promising strategy
to develop renewable antibacterial surfaces with successive antimicrobial
functions but also contribute a new antimicrobial platform to biomedical
or surgical applications.
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