Glucose-Sensitive Biohybrid Roots for Supercapacitive Bioanodes.

Plants as living organisms, as well as their material-structural components and physiological processes, offer promising elements for developing more sustainable technologies. Previously, we demonstrated that plants could acquire electronic functionality, as their enzymatic activity catalyzes the in vivo polymerization of water-soluble conjugated oligomers. We then leveraged plant-integrated conductors to develop biohybrid energy storage devices and circuits.

NeuroRoots, a bio-inspired, seamless brain machine interface for long-term recording in delicate brain regions.

Scalable electronic brain implants with long-term stability and low biological perturbation are crucial technologies for high-quality brain-machine interfaces that can seamlessly access delicate and hard-to-reach regions of the brain. Here, we created "NeuroRoots," a biomimetic multi-channel implant with similar dimensions (7 m wide and 1.5 m thick), mechanical compliance, and spatial distribution as axons in the brain.

Stretchable Tissue-Like Gold Nanowire Composites with Long-Term Stability for Neural Interfaces.

Soft and stretchable nanocomposites can match the mechanical properties of neural tissue, thereby minimizing foreign body reactions to provide optimal stimulation and recording specificity. Soft materials for neural interfaces should simultaneously fulfill a wide range of requirements, including low Young's modulus (<<1 MPa), stretchability (≥30%), high conductivity (>> 1000 S cm), biocompatibility, and chronic stability (>> 1 year). Current nanocomposites do not fulfill the above requirements, in particular not the combination of softness and high conductivity.

Vertical organic electrochemical transistor platforms for efficient electropolymerization of thiophene based oligomers.

Organic electrochemical transistors (OECTs) have emerged as promising candidates for various fields, including bioelectronics, neuromorphic computing, biosensors, and wearable electronics. OECTs operate in aqueous solutions, exhibit high amplification properties, and offer ion-to-electron signal transduction. The OECT channel consists of a conducting polymer, with PEDOT:PSS receiving the most attention to date.

Obstructive sleep apnea improves with non-invasive hypoglossal nerve stimulation using temporal interference.

Background: Peripheral nerve stimulation is used in both clinical and fundamental research for therapy and exploration. At present, non-invasive peripheral nerve stimulation still lacks the penetration depth to reach deep nerve targets and the stimulation focality to offer selectivity. It is therefore rarely employed as the primary selected nerve stimulation method.

Investigating the electrode-electrolyte interface modelling in cochlear implants.

Objective: Proposing a good electrode-electrolyte interface (EEI) model and properly identifying relevant parameters may help designing safer and more optimized auditory nerve fiber stimulation and recording in cochlear implants (CI). However, in the literature EEI model parameter values exhibit large variability. We aim to explain some root causes of this variability using the Cole model and its simpler form, the Basic RC model.

Downsizing the Channel Length of Vertical Organic Electrochemical Transistors.

Organic electrochemical transistors (OECTs) are promising building blocks for bioelectronic devices such as sensors and neural interfaces. While the majority of OECTs use simple planar geometry, there is interest in exploring how these devices operate with much shorter channels on the submicron scale. Here, we show a practical route toward the minimization of the channel length of the transistor using traditional photolithography, enabling large-scale utilization.

A Biologically Interfaced Evolvable Organic Pattern Classifier.

Future brain-computer interfaces will require local and highly individualized signal processing of fully integrated electronic circuits within the nervous system and other living tissue. New devices will need to be developed that can receive data from a sensor array, process these data into meaningful information, and translate that information into a format that can be interpreted by living systems. Here, the first example of interfacing a hardware-based pattern classifier with a biological nerve is reported.

Metabolite-induced in vivo fabrication of substrate-free organic bioelectronics.

Interfacing electronics with neural tissue is crucial for understanding complex biological functions, but conventional bioelectronics consist of rigid electrodes fundamentally incompatible with living systems. The difference between static solid-state electronics and dynamic biological matter makes seamless integration of the two challenging. To address this incompatibility, we developed a method to dynamically create soft substrate-free conducting materials within the biological environment.

Ion-tunable antiambipolarity in mixed ion-electron conducting polymers enables biorealistic organic electrochemical neurons.

Biointegrated neuromorphic hardware holds promise for new protocols to record/regulate signalling in biological systems. Making such artificial neural circuits successful requires minimal device/circuit complexity and ion-based operating mechanisms akin to those found in biology. Artificial spiking neurons, based on silicon-based complementary metal-oxide semiconductors or negative differential resistance device circuits, can emulate several neural features but are complicated to fabricate, not biocompatible and lack ion-/chemical-based modulation features.

Virtual audiometric testing using smartphone mobile applications to detect hearing loss.

Objective: The COVID-19 pandemic drove the need for remote audiometric testing in the form of mobile applications for hearing assessment. This study sought to determine the accuracy of two smartphone-based hearing assessment applications, Mimi and uHear, against the gold standard of in-clinic audiometric testing.

Methods: One hundred patients that presented to clinic for hearing assessment were randomly assigned to take either the Mimi or uHear hearing test alongside standard audiometric testing.

Wireless optoelectronic devices for vagus nerve stimulation in mice.

Vagus nerve stimulation (VNS) is a promising approach for the treatment of a wide variety of debilitating conditions, including autoimmune diseases and intractable epilepsy. Much remains to be learned about the molecular mechanisms involved in vagus nerve regulation of organ function. Despite an abundance of well-characterized rodent models of common chronic diseases, currently available technologies are rarely suitable for the required long-term experiments in freely moving animals, particularly experimental mice.

Association Between Default Number of Opioid Doses in Electronic Health Record Systems and Opioid Prescribing to Adolescents and Young Adults Undergoing Tonsillectomy.

Importance: In prior studies, decreasing the default number of doses in opioid prescriptions written in electronic health record systems reduced opioid prescribing. However, these studies did not rigorously assess patient-reported outcomes, and few included pediatric patients.

Objective: To evaluate the association between decreasing the default number of doses in opioid prescriptions written in electronic health record systems and opioid prescribing and patient-reported outcomes among adolescents and young adults undergoing tonsillectomy.

Noninvasive Stimulation of Peripheral Nerves using Temporally-Interfering Electrical Fields.

Electrical stimulation of peripheral nerves is a cornerstone of bioelectronic medicine. Effective ways to accomplish peripheral nerve stimulation (PNS) noninvasively without surgically implanted devices are enabling for fundamental research and clinical translation. Here, it is demonstrated how relatively high-frequency sine-wave carriers (3 kHz) emitted by two pairs of cutaneous electrodes can temporally interfere at deep peripheral nerve targets.

Vertical Organic Electrochemical Transistors and Electronics for Low Amplitude Micro-Organ Signals.

Electrical signals are fundamental to key biological events such as brain activity, heartbeat, or vital hormone secretion. Their capture and analysis provide insight into cell or organ physiology and a number of bioelectronic medical devices aim to improve signal acquisition. Organic electrochemical transistors (OECT) have proven their capacity to capture neuronal and cardiac signals with high fidelity and amplification.

Biostack: Nontoxic Metabolite Detection from Live Tissue.

There is increasing demand for direct in situ metabolite monitoring from cell cultures and in vivo using implantable devices. Electrochemical biosensors are commonly preferred due to their low-cost, high sensitivity, and low complexity. Metabolite detection, however, in cultured cells or sensitive tissue is rarely shown.

Multimodal Characterization of Neural Networks Using Highly Transparent Electrode Arrays.

Transparent and flexible materials are attractive for a wide range of emerging bioelectronic applications. These include neural interfacing devices for both recording and stimulation, where low electrochemical electrode impedance is valuable. Here the conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is used to fabricate electrodes that are small enough to allow unencumbered optical access for imaging a large cell population with two-photon (2P) microscopy, yet provide low impedance for simultaneous high quality recordings of neural activity .

A bilayered PVA/PLGA-bioresorbable shuttle to improve the implantation of flexible neural probes.

Objective: Neural electrophysiology is often conducted with traditional, rigid depth probes. The mechanical mismatch between these probes and soft brain tissue is unfavorable for tissue interfacing. Making probes compliant can improve biocompatibility, but as a consequence, they become more difficult to insert into the brain.

The Role of the Side Chain on the Performance of N-type Conjugated Polymers in Aqueous Electrolytes.

We report a design strategy that allows the preparation of solution processable n-type materials from low boiling point solvents for organic electrochemical transistors (OECTs). The polymer backbone is based on NDI-T2 copolymers where a branched alkyl side chain is gradually exchanged for a linear ethylene glycol-based side chain. A series of random copolymers was prepared with glycol side chain percentages of 0, 10, 25, 50, 75, 90, and 100 with respect to the alkyl side chains.

High-Performance Vertical Organic Electrochemical Transistors.

Organic electrochemical transistors (OECTs) are promising transducers for biointerfacing due to their high transconductance, biocompatibility, and availability in a variety of form factors. Most OECTs reported to date, however, utilize rather large channels, limiting the transistor performance and resulting in a low transistor density. This is typically a consequence of limitations associated with traditional fabrication methods and with 2D substrates.

A Microfluidic Ion Pump for In Vivo Drug Delivery.

Implantable devices offer an alternative to systemic delivery of drugs for the treatment of neurological disorders. A microfluidic ion pump (µFIP), capable of delivering a drug without the solvent through electrophoresis, is developed. The device is characterized in vitro by delivering γ-amino butyric acid to a target solution, and demonstrates low-voltage operation, high drug-delivery capacity, and high ON/OFF ratio.

N-type organic electrochemical transistors with stability in water.

Organic electrochemical transistors (OECTs) are receiving significant attention due to their ability to efficiently transduce biological signals. A major limitation of this technology is that only p-type materials have been reported, which precludes the development of complementary circuits, and limits sensor technologies. Here, we report the first ever n-type OECT, with relatively balanced ambipolar charge transport characteristics based on a polymer that supports both hole and electron transport along its backbone when doped through an aqueous electrolyte and in the presence of oxygen.

Microsecond Response in Organic Electrochemical Transistors: Exceeding the Ionic Speed Limit.

Organic electrochemical transistors (OECTs) are transistors that can have extrinsic transconductances as high as 400 S m , but they typically have response times on the order of 1 ms or longer. These response speeds are limited by ion transport. It is shown that OECTs can exceed the ionic response speed by a factor of 30 when operated in a high-speed bias regime.

Organic Transistor Arrays Integrated with Finger-Powered Microfluidics for Multianalyte Saliva Testing.

A compact multianalyte biosensing platform is reported, composed of an organic electrochemical transistor (OECT) microarray integrated with a pumpless "finger-powered" microfluidic, for quantitative screening of glucose, lactate, and cholesterol levels. A biofunctionalization method is designed, which provides selectivity towards specific metabolites as well as minimization of any background interference. In addition, a simple method is developed to facilitate multi-analyte sensing and avoid electrical crosstalk between the different transistors by electrically isolating the individual devices.