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International Journal of Bioprinting Bioprinting for wearable tech and robot

capacitance of 44 μF/cm , and was cyclically stable for up on Polydimethylsiloxane (PDMS), transferred to parylene
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to 10,000 cycles. The reported technology can be employed films, and connected using a custom 3D-printed connector.
as a life-long power source for implantable bioelectronic The device successfully recorded brain signals in rat models
devices. Lei et al. developed a framework from printed (Figure 3c). Likewise, Xie et al. developed a bioconcrete
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neural networks for electric field imaging of cochlear bioink featuring electrosprayed cell-laden microgels as
implants. This approach facilitated the construction of an “aggregate” and GelMA as the “cement.” Portable and
tunable and customizable 3D-printed cochleae, which can easily prepared, this bioink enabled the pre-culturing of
emulate realistic scenarios at various stimulation levels. microgels into mini tissues. Its effectiveness in repairing
The system can identify the causes of current dispersion cranial defects demonstrated its clinical potential for in
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and measure in vivo cochlear tissue resistivity (estimated situ treatment (Figure 3d). The fusion of bioprinting with
average of 6.6 kΩ·cm). Furthermore, this technology can BAN constitutes a cutting-edge technological domain that
improve physical modeling and digital twin applications in could lead to next-generation healthcare with increased
neuromodulation implants (Figure 3b). Xu et al. proposed personalization and integrated therapeutic systems. This
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a synthesis method for creating complex polymer networks synergy promises to improve individual health outcomes
in biomimetic electroconductive liquid metal hydrogels. and advance more patient-centric systems.
By synthesizing four precursors within two steps, hydrogel
adhesives with strong adhesion, high electroconductivity, 4. Brain-machine interfaces
and excellent compatibility both in vitro and in vivo were 4.1. Bioprinted nerve conduits
produced. These hydrogels can self-heal and possess shear- In brain science and neural repair in clinical interventions,
thinning properties that may be suitable for minimally nerve conduits are instrumental in promoting the precise
invasive bioprinting in in vivo experiments. 93 and targeted regeneration of damaged neural pathways.
In the future, bioprinting is expected to revolutionize Peripheral and central (brain) nerves have complex
the development of implantable and wearable devices with interactions and differences in regenerative capacities.
integrated soft electronics. Advancements in scalability, The peripheral nervous system (PNS) has a greater
regulatory frameworks, and long-term functionality will ability to regenerate after injury, aided by the presence of
enable the widespread implementation of bioprinted Schwann cells, which support axonal growth and promote
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wearable devices. a more permissive environment. In contrast, the central
nervous system (CNS), which includes the brain and
3.3. Bioprinting of body area network spinal cord, has limited regeneration capability due to
Body area network (BAN) refers to a network of wearable inhibitory molecules. 98
devices within or on the human body. BAN elevates wearable Bioprinted nerve conduits have a significant impact
devices to the systemic level by integrating devices into a on studies of the PNS and CNS. For PNS, bioprinted
cohesive framework that enables sophisticated monitoring, nerve conduits provide a platform for the regeneration of
data collection, and communication interfaced with damaged nerve tissues that facilitate the effective repair of
physiological processes. The synergy between bioprinting traumatic nerve injuries. Furthermore, these conduits can
and BAN offers numerous research opportunities. For be tailored to match the diameter and length of damaged
instance, bioprinting facilitates the creation of personalized nerves, promoting successful regrowth and functional
prosthetic devices with BAN functionalities. These recovery. For CNS studies, bioprinted nerve conduits
biocompatible prostheses may interact with the patient’s have the potential to enhance tissue engineering and drug
nervous system, enhancing proprioceptive feedback and development for neural disorders, such as Alzheimer’s and
motor control for better quality of life and functionality. Parkinson’s disease. The ability to control the composition
Moreover, the capacity of bioprinting to produce and architecture of these conduits enables the creation of
personalized implantable devices that communicate models that mimic the complexity and functionality of
through BAN paves the way for monitoring platforms the CNS. Hu et al. utilized bioprinting to fabricate a bio-
and sophisticated drug delivery systems. For general conduit with cryo-polymerized GelMA (cryoGelMA)
healthcare, implantable sensors are used to monitor various and adipose-derived stem cells for peripheral nerve
biomarkers, such as glucose, electrolytes, and hormones. regeneration. This customizable and biodegradable
The incorporation of biosensors with BAN enables a remote conduit supported cell attachment, proliferation, and
monitoring system that alerts healthcare professionals to neurotrophic factor expression. After implantation in a rat
any deviations. Kim et al. created a 22-channel, highly sciatic nerve model, the bio-conduit effectively supported
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flexible electrocorticography microelectrode array on a re-innervation across a 10 mm gap (Figure 4a). Hsu et al.
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parylene film. The microelectrode patterns were printed introduced a conductive microporous hydrogel composed

Volume 10 Issue 6 (2024) 25 doi: 10.36922/ijb.3590