1 research outputs found
Scalable Fabrication Framework of Implantable Ultrathin and Flexible Probes with Biodegradable Sacrificial Layers
For long-term biocompatibility
and performance, implanted probes
need to further reduce their size and mechanical stiffness to match
that of the surrounding cells, which, however, makes accurate and
minimally invasive insertion operations difficult due to lack of rigidity
and brings additional complications in assembling and surgery. Here,
we report a scalable fabrication framework of implantable probes utilizing
biodegradable sacrificial layers to address this challenge. Briefly,
the integrated biodegradable sacrificial layer can dissolve in physiological
fluids shortly after implantation, which allows the in situ formation
of functional ultrathin film structures off of the initial small and
rigid supporting backbone. We show that the dissolution of this layer
does not affect the viability and excitability of neuron cells in
vitro. We have demonstrated two types of probes that can be used out
of the box, including (1) a compact probe that spontaneously forms
three-dimensional bend-up devices only after implantation and (2)
an ultraflexible probe as thin as 2 μm attached to a small silicon
shaft that can be accurately delivered into the tissue and then get
fully released in situ without altering its shape and position because
the support is fully retracted. We have obtained a >93% yield of
the
bend-up structure, and its geometry and stiffness can be systematically
tuned. The robustness of the ultraflexible probe has been tested in
tissue-mimicking agarose gels with <1% fluctuation in the test
resistance. Our work provides a general strategy to prepare ultrasmall
and flexible implantable probes that allow high insertion accuracy
and minimal surgical damages with the best biocompatibility