Stretchable wearable devices for the continuous monitoring of physiological signals from deep tissues are constrained by the depth of signal penetration and by difficulties in resolving signals from ...specific tissues. Here, we report the development and testing of a prototype skin-conformal ultrasonic phased array for the monitoring of haemodynamic signals from tissues up to 14 cm beneath the skin. The device allows for active focusing and steering of ultrasound beams over a range of incident angles so as to target regions of interest. In healthy volunteers, we show that the phased array can be used to monitor Doppler spectra from cardiac tissues, record central blood flow waveforms and estimate cerebral blood supply in real time. Stretchable and conformal skin-worn ultrasonic phased arrays may open up opportunities for wearable diagnostics.
Precise monitoring of neurotransmitters, such as dopamine (DA), is critical for understanding brain function and treating neurological disorders since dysregulation of DA implicates in a range of ...disorders, including Parkinson's disease (PD), schizophrenia, and addiction. This study proposes a multi‐deformable double‐sided (MDD) DA‐sensing probe with the three‐electrode system in all‐in‐one form for reliable real‐time monitoring of DA dynamics by integrating working, reference, and counter electrodes on a single probe. The proposed probe achieves high DA sensitivity and selectivity in virtue of enzyme immobilization on the 3D nanostructures grown on working electrode. Also, the serpentine design is employed for the electrodes to withstand in various deformations by achieving high stretchability and manage the stress induced on the probe. Experimental and computational analysis demonstrates an effective reduction in induced‐stress on the electrodes. The MDD DA‐sensing probe is implanted into the brain with success to enable real‐time, in vivo monitoring of DA levels in rodents. Furthermore, DA dynamic changes are monitored before and after treatment with L‐DOPA in hemi‐PD mice. This extremely deformable implantable probe has the potential for use in the study and treatment of neurodegenerative diseases, providing reliable monitoring of DA dynamics with minimal damage to brain tissue.
A multi‐deformable double‐sided (MDD) probe facilitates real‐time dopamine monitoring in the brain. The all‐in‐one probe integrates working, reference, and counter electrodes, achieving high sensitivity and selectivity through enzyme immobilization on ZnO Nanorods. Its serpentine design ensures stretchability and stress management. Successful rodent implantation enables reliable in‐vivo monitoring of dopamine dynamics, including assessing L‐DOPA treatment effects in hemi‐PD mice.
Based on their high applicability to wearable electronics, fiber-based stretchable electronics have been developed via different strategies. However, the electrical conductivity of a fiber electrode ...is severely degraded, following deformation upon stretching. Despite the introduction of conductive buckled structures to resolve this issue, there still exist limitations regarding the simultaneous realizations of high conductivity and stretchability. Here, we exploit the dense distribution of the Ag nanoparticle (AgNP) network in polyurethane (PU) to fabricate a strain-insensitive stretchable fiber conductor comprising highly conductive buckled shells via a facile chemical process. These buckled AgNPs/PU fibers exhibit stable and reliable electrical responses across a wide range (tensile strain = ∼200%), in addition to their high electrical conductivity (26,128 S/m) and quality factor (Q = 2.29). Particularly, the negligible electrical hysteresis and excellent durability (>10,000 stretching–releasing cycles) of the fibers demonstrate their high applicability to wearable electronics. Furthermore, we develop buckled fiber-based pH sensors exhibiting stable, repeatable, and highly distinguishable responses (changing pH is from 4 to 8, response time is 5–6 s) even under 100% tensile strain. The buckled AgNPs/PU fibers represent a facile strategy for maintaining the stable electrical performances of fiber electrodes across the strain range of human motion for wearable applications.
BACKGROUNDPrevious studies have reported that deep neuromuscular block (posttetanic-count 1 to 2 twitches) improves surgical conditions during laparoscopy compared with moderate block (train-of-four ...count1 to 2 twitches). However, comparisons of surgical conditions were made using different scales and assessment intervals with variable results.
OBJECTIVETo explore the heterogeneity of previous comparisons between deep and moderate neuromuscular block.
DESIGNSystematic review and meta-analysis of randomised controlled trials (RCTs).
DATA SOURCESMedline, EMBASE and Cochrane Central Register of Controlled Trials were searched from inception to October 2017.
ELIGIBILITY CRITERIAOur meta-analysis included RCTs comparing the effects of deep with moderate neuromuscular block on surgical field conditions during laparoscopic surgery. The frequency of excellent or good operating conditions on a surgical rating scale was compared. Heterogeneity was assessed by subgroup analyses.
RESULTSEleven RCTs involving 844 patients were included. On the surgical rating scale, the frequency of excellent or good operating conditions was higher with deep block compared with a moderate block (odds ratio 2.83, 95% confidence interval 1.34 to 5.99, P = 0.007, I = 59%). We analysed surgical rating according to the number of assessments made. There was a significant difference in surgical rating with multiple assessments, but no difference when the assessment was made on only one occasion. A significant difference in rating was noted with variable abdominal pressures; there was no significant difference with the same fixed abdominal pressure. Trial sequential analysis demonstrated that the cumulative z-curve crossed the O′Brien–Fleming significance boundary. However, required information size was not achieved.
CONCLUSIONDeep block was associated with excellent or good surgical rating more frequently than moderate block. However, this finding was not consistent on subgroup analyses based on frequencies of assessment of surgical conditions and abdominal pressure. Further studies are required to address the heterogeneity and power shortage demonstrated by the trial sequential analysis.
Implantable bioelectronics capable of electrophysiological monitoring intimately interfacing with biological tissue have provided massive information for profound understanding of biological systems. ...However, their invasive nature induces a potential risk of acute tissue damage, limiting accurate and chronic monitoring of electrophysiological signals. To address this issue, advanced studies have developed effective strategies to engineer the soft, flexible device using preclinical animal models. In addition, the optional but innovative approaches to improve the device's function have been also explored. Herein, these strategies satisfying essential and supplemental requirements for engineering implantable bioelectronics are summarized. Three types of implantable devices, classified by their structural designs, are introduced to describe the approaches using suitable strategies for their specific purpose. In conclusion, the further advancement of engineering implantable bioelectronics addresses the remaining challenges. Such advancements have the potential to contribute to enhanced functionality, encouraging a more delicate understanding of the physiology of biological systems and further broadening the applicability of implantable bioelectronics in the field of biomedical technology.
Neural Probes
In article number 2311436, Yong‐Seok Oh, Kyung‐In Jang, and co‐workers present a multi‐deformable double‐sided (MDD) probe that facilitates real‐time dopamine monitoring in the brain. ...The all‐in‐one probe integrates working, reference, and counter electrodes, achieving high sensitivity and selectivity through enzyme immobilization on ZnO nanorods. Its serpentine design ensures stretchability and stress management. Successful rodent implantation enables reliable in‐vivo monitoring of dopamine dynamics, including assessing L‐DOPA treatment effects in hemi‐PD mice.
Simultaneous monitoring of electrophysiology and magnetic resonance imaging (MRI) could guide the innovative diagnosis and treatment of various neurodegenerative diseases that are previously ...impossible. However, this technique is difficult because the existing metal‐based implantable neural interface for electrophysiology is not free from signal distortions from its intrinsic magnetic susceptibility while performing an MRI of the implanted area of the neural interface. Moreover, brain tissue heating from neural implants generated by the radiofrequency field from MRI poses potential hazards for patients. Previous studies with soft polymer‐based electrode arrays provide relatively suitable MRI compatibility but does not guarantee high‐resolution electrophysiological signal acquisition and stimulation performance. Here, MRI compatible, optically transparent flexible implantable device capable of electrophysiological multichannel mapping and electrical stimulation is introduced. Using the device, neuropathic pain (NP) relief with a 30‐channel electrophysiological mapping of the somatosensory area before and after motor cortex stimulation (MCS) in allodynia rats after noxious stimulation is confirmed. Additionally, artifact‐free manganese‐enhanced MRI of dramatic relief of pain‐related region activity by MCS is demonstrated. Furthermore, artifact‐free optogenetics with transgenic mice is also investigated by recording light‐evoked potentials. These results suggest a promising neuro‐prosthetic for analyzing and modulating spatiotemporal neurodynamic without MRI or optical modality resolution constraints.
Integration of electrophysiology with magnetic resonance imaging (MRI) is achieved by MRI compatible, transparent Poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) neural implantable device. The neuropathic pain alleviation is demonstrated by this MRI compatible electrode array, simultaneously recording/stimulating the brain with manganese‐enhanced MRI. This work highlights a future technology that eliminates the potential risks and inconveniences of medical imaging of patients with conventional neural implants.
In this paper, we evaluate fiscal sustainability of five regional groups in the EU using the dataset of 26 countries for the period 1950–2014. To this end, we estimate their policy rules in which ...primary surpluses respond to public debt and examine whether estimated policy rules satisfy the conditions for fiscal solvency. In the baseline solvency tests with time-invariant marginal responses of primary surpluses, we find that estimated policy rules satisfy the solvency condition that the marginal response be positive for the Benelux, northern, and eastern groups but fail to do so for the western and southern groups. When estimating their policy rules separately for eurozone and non-eurozone countries, we find that long-term fiscal sustainability of eurozone countries is more questionable in the sense that non-eurozone countries in all regional groups have significantly positive marginal responses, whereas eurozone countries in most regional groups do not. Finally, more general solvency tests that allow time-varying marginal responses reveal that only the Southern group fails to satisfy the generalized solvency conditions that marginal responses be always nonnegative and positive infinitely often. These findings seem to be consistent with the fact that countries in the Southern group experienced severe fiscal crises.
In article number 1910026, Kyung‐In Jang, Taeyoon Lee, and co‐workers develop a highly stretchable and reliable 3D helical fiber to fabricate stretchable interconnects for wearable devices. The ...biaxially stretchable passive matrix light‐emitting diode display and skin‐mountable band‐type oximeter provide new insights into stretchable interconnects in wearable electronics and their biomedical applications.
PDF