Medical Devices and Adolescents: Points to Consider

Materials for Implantable Surface Electrode Arrays: Current Status and Future Directions

Surface electrode arrays are mainly fabricated from rigid or elastic materials, and precisely manipulated ductile metal films, which offer limited stretchability. However, the living tissues to which they are applied are nonlinear viscoelastic materials, which can undergo significant mechanical deformation in dynamic biological environments. Further, the same arrays and compositions are often repurposed for vastly different tissues rather than optimizing the materials and mechanical properties of the implant for the target application. By first characterizing the desired biological environment, and then designing a technology for a particular organ, surface electrode arrays may be more conformable, and offer better interfaces to tissues while causing less damage. Here, the various materials used in each component of a surface electrode array are first reviewed, and then electrically active implants in three specific biological systems, the nervous system, the muscular system, and skin, are described. Finally, the fabrication of next-generation surface arrays that overcome current limitations is discussed.

Digital Health Technologies in Pediatric Trials

BACKGROUND

Advances in the miniaturization of sensors and other technologies provide opportunities to collect physiological and/or functional data directly from patients participating in clinical trials. The use of such technologies in children is particularly promising. Objective, quantifiable measurements made by these technologies, often on a continuous or frequent basis, may provide more robust data than the episodic reports from caregivers that are used in traditional pediatric trials.

METHODS

We reviewed the pros and cons of these technologies for use in a variety of pediatric diseases, including seizure and neuromuscular disorders, cardiorespiratory diseases, and metabolic disorders.

RESULTS

Correlation between sensor measurements and patient observations or traditional clinical measurements varied depending on the disease being evaluated. There was a notable dearth of reports on the use of digital health technology in pediatric patients. Given the range of sensors and measurements that can be made by DHTs, selection of the design, metrics and types of sensors best suited to disease evaluation presents challenges for adoption of these technologies in clinical trials.

CONCLUSION

Traditional measurements of drug effects are often deficient, particularly in the evaluation of infants and young children. The opportunity to make objective, frequent measurements may increase our power to detect and quantify responses to therapy in these populations. Further research and evaluation are needed to realize the full scientific potential of remote monitoring in pediatric clinical trials.

Conjugated Polymer for Implantable Electronics toward Clinical Application

Owing to their excellent mechanical flexibility, mixed-conducting electrical property, and extraordinary chemical turnability, conjugated polymers have been demonstrated to be an ideal bioelectronic interface to deliver therapeutic effect in many different chronic diseases. This review article summarizes the latest advances in implantable electronics using conjugated polymers as electroactive materials and identifies remaining challenges and opportunities for developing electronic medicine. Examples of conjugated polymer-based bioelectronic devices are selectively reviewed in human clinical studies or animal studies with the potential for clinical adoption. The unique properties of conjugated polymers are highlighted and exemplified as potential solutions to address the specific challenges in electronic medicine.

How is flexible electronics advancing neuroscience research?

Innovative neurotechnology must be leveraged to experimentally answer the multitude of pressing questions in modern neuroscience. Driven by the desire to address the existing neuroscience problems with newly engineered tools, we discuss in this review the benefits of flexible electronics for neuroscience studies. We first introduce the concept and define the properties of flexible and stretchable electronics. We then categorize the four dimensions where flexible electronics meets the demands of modern neuroscience: chronic stability, interfacing multiple structures, multi-modal compatibility, and neuron-type-specific recording. Specifically, with the bending stiffness now approaching that of neural tissue, implanted flexible electronic devices produce little shear motion, minimizing chronic immune responses and enabling recording and stimulation for months, and even years. The unique mechanical properties of flexible electronics also allow for intimate conformation to the brain, the spinal cord, peripheral nerves, and the retina. Moreover, flexible electronics enables optogenetic stimulation, microfluidic drug delivery, and neural activity imaging during electrical stimulation and recording. Finally, flexible electronics can enable neuron-type identification through analysis of high-fidelity recorded action potentials facilitated by its seamless integration with the neural circuitry. We argue that flexible electronics will play an increasingly important role in neuroscience studies and neurological therapies via the fabrication of neuromorphic devices on flexible substrates and the development of enhanced methods of neuronal interpenetration.

Morphing electronics enable neuromodulation in growing tissue

Bioelectronics for modulating the nervous system have shown promise in treating neurological diseases^1-3. However, their fixed dimensions cannot accommodate rapid tissue growth^4,5 and may impair development⁶. For infants, children and adolescents, once implanted devices are outgrown, additional surgeries are often needed for device replacement, leading to repeated interventions and complications^6-8. Here, we address this limitation with morphing electronics, which adapt to in vivo nerve tissue growth with minimal mechanical constraint. We design and fabricate multilayered morphing electronics, consisting of viscoplastic electrodes and a strain sensor that eliminate the stress at the interface between the electronics and growing tissue. The ability of morphing electronics to self-heal during implantation surgery allows a reconfigurable and seamless neural interface. During the fastest growth period in rats, morphing electronics caused minimal damage to the rat nerve, which grows 2.4-fold in diameter, and allowed chronic electrical stimulation and monitoring for 2 months without disruption of functional behavior. Morphing electronics offers a path toward growth-adaptive pediatric electronic medicine.

Morphing electronics enable neuromodulation in growing tissue

Bioelectronics for modulating the nervous system have shown promise in treating neurological diseases^1-3. However, their fixed dimensions cannot accommodate rapid tissue growth^4,5 and may impair development⁶. For infants, children and adolescents, once implanted devices are outgrown, additional surgeries are often needed for device replacement, leading to repeated interventions and complications^6-8. Here, we address this limitation with morphing electronics, which adapt to in vivo nerve tissue growth with minimal mechanical constraint. We design and fabricate multilayered morphing electronics, consisting of viscoplastic electrodes and a strain sensor that eliminate the stress at the interface between the electronics and growing tissue. The ability of morphing electronics to self-heal during implantation surgery allows a reconfigurable and seamless neural interface. During the fastest growth period in rats, morphing electronics caused minimal damage to the rat nerve, which grows 2.4-fold in diameter, and allowed chronic electrical stimulation and monitoring for 2 months without disruption of functional behavior. Morphing electronics offers a path toward growth-adaptive pediatric electronic medicine.