Biology subjects

Ria, N.

Publications and source records attributed to Ria, N..

4 recordsLinked to original sources

bioRxiv2026

Advances in Thin-Film Graphene Neurotechnology for Chronic Nerve Stimulation and Recording

Neurotechnology is being explored for restoring sensorimotor functions after paralysis or amputation, which requires peripheral nerve interfaces that are selective, bidirectional, and chronically stable. Reduced graphene oxide (rGO)-based microelectrodes offer low impedance and a high charge-injection limit; however, long-term in vivo performance has been limited by the durability of encapsulation. Here, we introduce a 10 {micro}m-thick transverse intrafascicular multichannel electrode (TIME) with a hybrid polyimide-Al2O3 encapsulation engineered to improve fabrication yield, electrode-to-electrode uniformity, and device stability. In vitro, devices maintained near-ideal capacitive behaviour after accelerated ageing (3 months in PBS at 57 {degrees}C) and sustained 109 biphasic stimulation pulses without detectable electrochemical degradation. In vivo, the arrays recorded compound nerve action potentials after one month and enabled selective activation of distinct peripheral nerve fibres with comparatively low current thresholds during four months of follow-up, remaining below the device maximum injectable current. Together, these results demonstrate that combining graphene microelectrodes with a thin hybrid encapsulation improves chronic reliability of intraneural thin-film interfaces and helps to close the gap between laboratory prototypes and clinically relevant neuroprosthetic systems.

bioengineering↗

bioRxiv2025

An artefact-resilient wide bandwidth bidirectional graphene neural interface

The ability to simultaneously record and modulate neural activity is critical for next-generation bidirectional neural interfaces aiming to enable adaptive neuromodulation therapies for neurological disorders. Active graphene transistor technologies are particularly promising for neural recordings, as they extend the ability to monitor brain activity at very low frequencies and support multiplexed operation for high-density neural interfaces. However, their limited charge injection capacity makes them unsuitable for stimulation. In this work, we present a bidirectional neural interface that combines nanoporous reduced graphene oxide (rGO) microelectrodes for high charge injection focal stimulation and graphene solution-gated field-effect transistors (gSGFETs) for brain activity monitoring, exploiting the advantages of both technologies in one single device. Using scalable cleanroom microfabrication techniques, we monolithically integrate these two graphene-based technologies into fully flexible probes. We evaluate the performance of the hybrid devices both in saline and in vivo, with a particular focus on transistor performance during stimulation. Our results demonstrate that the recording capability of this bidirectional neural interface, including the monitoring of infraslow and local field potential activity, is not compromised during stimulation. This work highlights the potential of this hybrid neural interface for both basic neurophysiological and clinical translation use.

neuroscience↗

bioRxiv2024

Flexible graphene-based neurotechnology for high-precision deep brain mapping and neuromodulation in Parkinsonian rats

Deep brain stimulation (DBS) is a neuroelectronic therapy for the treatment of a broad range of neurological disorders, including Parkinsons disease. Current DBS technologies face important limitations that impact their efficacy, such as large electrode size, invasiveness, and lack of adaptive therapy based on biomarker monitoring. The use of novel electrode materials is expected to contribute to overcome these limitations. In a previous study, we reported that nanoporous reduced graphene oxide (rGO) is a promising electrode material due to its high charge injection capacity and low impedance. Here, we investigate the potential benefits of using the rGO technology in DBS. To this end, we implant a flexible high-density array of rGO microelectrodes in the subthalamic nucleus (STN) of healthy and hemi-parkinsonian rats to investigate specific electrophysiological Parkinsonian biomarkers and to assess the effect of microscale stimulation. We demonstrate that these microelectrodes record action potentials with high signal-to-noise ratios (SNR > 6), allowing the precise localization of deep brain structures like the STN, and the tracking of multiunit-based biomarkers such as STN bursts. The bidirectional capability to deliver high-density focal stimulation and to record high-fidelity signals unlocks the visualization of the local neuromodulation of the multiunit biomarker. These findings demonstrate the potential of bidirectional high-resolution neural interfaces to investigate the mechanisms around DBS in preclinical models and suggest new avenues for the use of adaptive closed-loop operation based on electrophysiological biomarkers monitoring.

bioengineering↗

bioRxiv2022

Graphene-based thin film microelectrode technology for in vivo high resolution neural recording and stimulation

Neuroprosthetic technology aims to restore nervous system functionality in cases of severe damage or degeneration by recording and stimulating the electrical activity of the neural tissue. One of the key factors determining the quality of the neuroprostheses is the electrode material used to establish electrical communication with the neural tissue, which is subject to strict electrical, electrochemical, and mechanical specifications as well as biological and microfabrication compatibility requirements. This work presents a nanoporous graphene-based thin film technology and its engineering to form flexible neural implants. Bench measurements show that the developed microelectrodes offer low impedance and high charge injection capacity throughout millions of pulses. In vivo electrode performance was assessed in rodents both from brain surface and intracortically showing high-fidelity recording performance, while stimulation performance was assessed with an intrafascicular implant that demonstrated low current thresholds and high selectivity for activating subsets of axons within the sciatic nerve. Furthermore, the tissue biocompatibility of the devices was validated by chronic epicortical and intraneural implantation. Overall, this works describes a novel graphene-based thin film microelectrode technology and demonstrates its potential for high-precision neural interfacing in both recording and stimulation applications.

bioengineering↗