Fully Printed, Wireless, Stretchable Implantable Biosystem toward Batteryless, Real‐Time Monitoring of Cerebral Aneurysm Hemodynamics

Abstract

This study introduces a high‐throughput, large‐scale manufacturing method that uses aerosol jet 3D printing for a fully printed stretchable, wireless electronics. A comprehensive study of nanoink preparation and parameter optimization enables a low‐profile, multilayer printing of a high‐performance, capacitance flow sensor. The core printing process involves direct, microstructured patterning of biocompatible silver nanoparticles and polyimide. The optimized fabrication approach allows for transfer of highly conductive, patterned silver nanoparticle films to a soft elastomeric substrate. Stretchable mechanics modeling and seamless integration with an implantable stent display a highly stretchable and flexible sensor, deployable by a catheter for extremely low‐profile, conformal insertion in a blood vessel. Optimization of a transient, wireless inductive coupling method allows for wireless detection of biomimetic cerebral aneurysm hemodynamics with the maximum readout distance of 6 cm through meat. In vitro demonstrations include wireless monitoring of flow rates (0.05–1 m s−1) in highly contoured and narrow human neurovascular models. Collectively, this work shows the potential of the printed biosystem to offer a high throughput, additive manufacturing of stretchable electronics with advances toward batteryless, real‐time wireless monitoring of cerebral aneurysm hemodynamics.

Advanced Nanomaterials, Printing Processes, and Applications for Flexible Hybrid Electronics

“…Introduce elastomer substrates [23] Utilize open-mesh, serpentine structures [23] Durability Mechanical robustness against long-time and continuous bending, stretching, and slipping movement.…”

“…Optimize sintering temperature [145] Add a suitable binder, which prevents cracks [16] Reduce the tensile strength [40] Use self-healing polymer [174,175] Use the encapsulation layer of elastomer to protect patterns [23] For contact printing technologies, many endeavors are devoted to making more sophisticated stencils or engraved cells [11,141]. Hyun et al introduced a thin silicon stencil made from conventional lithography techniques [70].…”

“…With the use of open-mesh structure, conformal skin contact was achieved to measure high-quality electroencephalograms (EEG) [29]. Serpentine structure of AgNP-printed sensor, encapsulated by Si elastomer, accommodates a high stretchability of up to 250% of radial stretching and a cyclic bending [23].…”

“…The continuous incoming blood flow to the ballooned section of the vessel may cause rupture or even more serious damage [ 198 , 199 ]. To address this issue, a highly stretchable nanomembrane system for wireless monitoring was developed, which can conformally be integrated onto a medical stent and deployed into a blood vessel via the conventional catheter procedure [ 23 ]. The aerosol-printed, nanostructured sensor shows an exceptional stretchability of 250% and flexibility of 180° bending ( Figure 10 j), which captures the device’s ability to be placed around highly contoured and narrow cerebral arteries.…”

Artificial Biosystems by Printing Biology

“…In general, the choice of the ink formulation for 3D printing depends on the viscosity of the printing solution/composite. In this regard, dichloromethane is a common choice due to the low boiling point and ease to be removed from the final material; [235] higher boiling point solvents, such as DMSO [236] or 1methyl-2-pyrrolidinone, [237] are selected when expected deposition from hot solution or an annealing step has to be performed. Nonetheless, aqueous inks are needed for printing artificial biosystems, within narrow windows of pH and ionic strength.…”