Biology subjects

Robledo, A.

Publications and source records attributed to Robledo, A..

3 recordsLinked to original sources

bioRxiv2023

Endocisternal interfaces for minimally invasive neural stimulation and recording of the brain and spinal cord

Minimally invasive neural interfaces can be used to diagnose, manage, and treat many disorders with substantially reduced risks of surgical complications. Endovascular neural interfaces implanted in the veins or arteries is one approach, but it requires prescriptions of anti-thrombotic medication and are likely not explantable after endothelialization. More critically, the approach is limited by the small size and location of blood vessels, such that many important cortical, subcortical, spinal targets cannot be reached. Here, we demonstrate a chronic endocisternal neural interface that approaches brain and spinal cord targets through inner and outer cerebral spinal fluid (CSF) spaces. These spaces surround the nervous system and lack the tortuosity of the circulatory system, giving us access to the entire brain convexity, deep brain structures within the ventricles, and the spinal cord from the spinal subarachnoid space. Combined with miniature magnetoelectric-powered bioelectronics, the entire wireless system is deployable through a percutaneous procedure. The flexible catheter electrodes can be freely navigated throughout the body from the spinal to cranial subarachnoid space, and from the cranial subarachnoid space to the ventricles. We show in a large animal model that we can also reposition the recording and stimulation electrodes or explant the neural interface after chronic implantation. This enables applications in therapies that require transient or permanent brain/machine interface such as stroke rehabilitation and epilepsy monitoring and opens a new class of minimally invasive endocisternal bioelectronics.

bioengineering↗

bioRxiv2023

Garments that measure EEG: Evaluation of an EEG sensor layer fully implemented with smart textiles

This paper presents the first garment capable of measuring EEG activity with accuracy comparable to state-of-the art dry EEG systems. The main innovation is an EEG sensor layer (i.e., the electrodes, the signal transmission, and the cap support) fully implemented as a garment, using threads, fabrics and smart textiles, without relying on any metal or plastic materials. The garment is interfaced via a connector to a mobile EEG amplifier to complete the measurement system. The new EEG system (Garment-EEG) has been characterized with respect to a state-of-the-art Ag/AgCl dry-EEG system (Dry-EEG) over the forehead area of healthy participants in terms of: (1) skin-electrode impedance; (2) electrophysiological measurements (spontaneous and evoked EEG activity); (3) artifacts; and (4) user ergonomics and comfort. The results show that the Garment-EEG system provides comparable recordings to Dry-EEG, but it is more prone to getting affected by artifacts in adverse recording conditions due to poorer contact impedances. Ergonomics and comfort favor the textile-based sensor layer with respect to its metal-based counterpart. User acceptance is the main obstacle for EEG systems to democratize neurotechnology and non-invasive brain-computer interfaces. EEG sensor layers encapsulated in wearables have the potential to enable neurotechnology that is naturally accepted by people in their daily lives. Furthermore, by supporting the EEG implementation in the textile industry it is manufactured with lower cost and much less pollution compared to the metal and plastic industries.

neuroscience↗

bioRxiv2021

Wireless endovascular nerve stimulation with a millimeter-sized magnetoelectric implant

Implanted bioelectronic devices have the potential to treat disorders that are resistant to traditional pharmacological therapies; however, reaching many therapeutic nerve targets requires invasive surgeries and implantation of centimeter-sized devices. Here we show that it is possible to stimulate peripheral nerves from within blood vessels using a millimeter-sized wireless implant. By directing the stimulating leads through the blood vessels we can target specific nerves that are difficult to reach with traditional surgeries. Furthermore, we demonstrate this endovascular nerve stimulation (EVNS) with a millimeter sized wireless stimulator that can be delivered minimally invasively through a percutaneous catheter which would significantly lower the barrier to entry for neuromodulatory treatment approaches because of the reduced risk. This miniaturization is achieved by using magnetoelectric materials to efficiently deliver data and power through tissue to a digitally-programmable 0.8 mm2 CMOS system-on-a-chip. As a proof-of-principle we show wireless stimulation of peripheral nerve targets both directly and from within the blood vessels in rodent and porcine models. The wireless EVNS concept described here provides a path toward minimally invasive bioelectronics where mm-sized implants combined with endovascular stimulation enable access to a number of nerve targets without open surgery or implantation of battery-powered pulse generators.

bioengineering↗