Biohybrid systems

2018 ◽  
Author(s):  
Nathan F. Lepora
Keyword(s):  
Synthetic Biology ◽  
Cochlear Implants ◽  
Memory Function ◽  
Neural Tissue ◽  
Sensory Organ ◽  
Tactile Sensing ◽  
Brain Machine Interfaces ◽  
Non Invasive

This chapter introduces the “biohybrid systems” section of the Handbook of Living Machines and briefly reviews some important examples of systems formed by coupling biological to engineered components. These include brain–machine interfaces, both non-invasive, using different external measurement and scanning devices, and invasive approaches focusing on implantable probes. Next we consider fabrication methods for micro- and nanobiohybrid systems and an example of a biohybrid system at the organism level, in the form of a robot–animal biohybrid, developed using methods from synthetic biology. There are many application for biohybrid systems in healthcare: we include exemplar chapters describing intelligent prostheses such as artificial hands with tactile sensing capabilities, sensory organ–chip hybrids in the form of cochlear implants, and artificial implants designed to replace damaged neural tissue and restore lost memory function.

scholarly journals Neural Tissue Degeneration in Rosenthal’s Canal and Its Impact on Electrical Stimulation of the Auditory Nerve by Cochlear Implants: An Image-Based Modeling Study

2020 ◽  
Vol 21 (22) ◽  
pp. 8511
Author(s):  
Kiran Kumar Sriperumbudur ◽  
Revathi Appali ◽  
Anthony W. Gummer ◽  
Ursula van Rienen
Keyword(s):  
Cochlear Implant ◽  
Cochlear Implants ◽  
Auditory Nerve ◽  
Ganglion Cells ◽  
Spiral Ganglion ◽  
Sensorineural Deafness ◽  
Neural Tissue ◽  
Neural Degeneration ◽  
Tissue Degeneration ◽  
Ganglion Neurons

Sensorineural deafness is caused by the loss of peripheral neural input to the auditory nerve, which may result from peripheral neural degeneration and/or a loss of inner hair cells. Provided spiral ganglion cells and their central processes are patent, cochlear implants can be used to electrically stimulate the auditory nerve to facilitate hearing in the deaf or severely hard-of-hearing. Neural degeneration is a crucial impediment to the functional success of a cochlear implant. The present, first-of-its-kind two-dimensional finite-element model investigates how the depletion of neural tissues might alter the electrically induced transmembrane potential of spiral ganglion neurons. The study suggests that even as little as 10% of neural tissue degeneration could lead to a disproportionate change in the stimulation profile of the auditory nerve. This result implies that apart from encapsulation layer formation around the cochlear implant electrode, tissue degeneration could also be an essential reason for the apparent inconsistencies in the functionality of cochlear implants.

scholarly journals Non-invasive on-skin sensors for brain machine interfaces with epitaxial graphene

2021 ◽  
Author(s):  
Shaikh Faisal ◽  
Mojtaba Amjadipour ◽  
Kimi Izzo ◽  
James Singer ◽  
Avi Bendavid ◽  
...  
Keyword(s):  
Surface Film ◽  
High Sensitivity ◽  
Epitaxial Graphene ◽  
Neural Signals ◽  
Brain Machine Interfaces ◽  
Contact Impedance ◽  
Invasive Approach ◽  
Non Invasive ◽  
Skin Contact ◽  
Prolonged Contact

Abstract Brain-machine interfaces are key components for the development of hands-free, brain -controlled devices. Electroencephalogram (EEG) electrodes are particularly attractive for harvesting the neural signals in a non-invasive fashion. Here, we explore the use of epitaxial graphene grown on silicon carbide on silicon for detecting the electroencephalogram signals with high sensitivity. This dry and non-invasive approach exhibits a markedly improved skin contact impedance when benchmarked to commercial dry electrodes, as well as superior robustness, allowing prolonged and repeated use also in a highly saline environment. In addition, we report the newly -observed phenomenon of surface conditioning of the epitaxial graphene electrodes. The prolonged contact of the epitaxial graphene with the skin electrolytes functionalize the grain boundaries of the graphene, leading to the formation of a thin surface film of water through physisorption and consequently reducing its contact impedance by more than 75%. This effect is primed in highly saline environments, and could be also further tailored as pre-conditioning to enhance the performance and reliability of the epitaxial graphene sensors.

scholarly journals Signal Generation, Acquisition, and Processing in Brain Machine Interfaces: A Unified Review

2021 ◽  
Vol 15 ◽  
Author(s):  
Usman Salahuddin ◽  
Pu-Xian Gao
Keyword(s):  
Signal Generation ◽  
Signal Acquisition ◽  
Brain Machine Interfaces ◽  
Prosthetic Devices ◽  
Hybrid Techniques ◽  
Non Invasive ◽  
Computer Interfaces ◽  
Commercial Market ◽  
Neural Signaling ◽  
The Brain

Brain machine interfaces (BMIs), or brain computer interfaces (BCIs), are devices that act as a medium for communications between the brain and the computer. It is an emerging field with numerous applications in domains of prosthetic devices, robotics, communication technology, gaming, education, and security. It is noted in such a multidisciplinary field, many reviews have surveyed on various focused subfields of interest, such as neural signaling, microelectrode fabrication, and signal classification algorithms. A unified review is lacking to cover and link all the relevant areas in this field. Herein, this review intends to connect on the relevant areas that circumscribe BMIs to present a unified script that may help enhance our understanding of BMIs. Specifically, this article discusses signal generation within the cortex, signal acquisition using invasive, non-invasive, or hybrid techniques, and the signal processing domain. The latest development is surveyed in this field, particularly in the last decade, with discussions regarding the challenges and possible solutions to allow swift disruption of BMI products in the commercial market.

scholarly journals CTX-CNF1 Recombinant Protein Selectively Targets Glioma Cells In Vivo

Toxins ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 194
Author(s):  
Eleonora Vannini ◽  
Elisabetta Mori ◽  
Elena Tantillo ◽  
Gudula Schmidt ◽  
Matteo Caleo ◽  
...  
Keyword(s):  
Chimeric Protein ◽  
Glioma Cells ◽  
Neural Tissue ◽  
Bacterial Protein ◽  
Non Invasive ◽  
Novel Approaches ◽  
Cytotoxic Necrotizing Factor 1 ◽  
Tumoral Cells ◽  
The Brain

Current strategies for glioma treatment are only partly effective because of the poor selectivity for tumoral cells. Hence, the necessity to identify novel approaches is urgent. Recent studies highlighted the effectiveness of the bacterial protein cytotoxic necrotizing factor 1 (CNF1) in reducing tumoral mass, increasing survival of glioma-bearing mice and protecting peritumoral neural tissue from dysfunction. However, native CNF1 needs to be delivered into the brain, because of its incapacity to cross the blood–brain barrier (BBB) per se, thus hampering its clinical translation. To allow a non-invasive administration of CNF1, we here developed a chimeric protein (CTX-CNF1) conjugating CNF1 with chlorotoxin (CTX), a peptide already employed in clinics due to its ability of passing the BBB and selectively binding glioma cells. After systemic administration, we found that CTX-CNF1 is able to target glioma cells and significantly prolong survival of glioma-bearing mice. Our data point out the potentiality of CTX-CNF1 as a novel effective tool to treat gliomas.

scholarly journals Psychophysical measures of tonotopic selectivity in cats and humans

2021 ◽  
Author(s):  
Robert P. Carlyon ◽  
John C. Middlebrooks ◽  
Matthew L. Richardson ◽  
Robin Gransier ◽  
François Guérit ◽  
...  
Keyword(s):  
Cochlear Implants ◽  
Pure Tone ◽  
Electrophysiological Study ◽  
Center Frequency ◽  
Auditory Prosthesis ◽  
Auditory Filter ◽  
Non Invasive ◽  
Spread Of Excitation ◽  
Novel Approaches ◽  
Electrophysiological Methods

Sound spectra are represented by patterns of activity along the tonotopic axis ofthe cochlea. Cochlear implants can transmit spectra by stimulating tonotopicallyappropriate electrodes, but fidelity is limited by intracochlear spread of excitation. We aim to better evaluate present-day experimental stimulation procedures and, potentially, to improve transmission of spectra with novel stimulation modalities. As a first step, we are developing non-invasive measures of tonotopic spread of excitation that can be compared between normal-hearing cats and humans. These measures include psychophysics in the present study and scalp-recorded electrophysiology in a companion study (Guérit et al., 2021). Cats and humans detected pure-tone probes presented in continuous 1/8- and 1-oct noise-band maskers. Masker bandwidths were readily discernable in both species by the dependence of masked thresholds on probe frequencies. Thresholds were largely constant across the bandwidth of the 1-oct masker, whereas thresholds dropped markedly at frequencies away from the center of the 1/8-oct masker. Cats and humans differed in that the feline auditory filter centered on 8 kHz, which we measured using a notched-noise procedure, was 22% wider than published values for humans at the same center frequency. Also, thresholds for the cats in the 1-octmasker condition consistently were 1.0 to 3.2 dB higher than expected based on the estimated masker power in the feline auditory filter. The present psychophysical results parallel those in our companion electrophysiological study, thereby providing perceptual validation for that study. These psychophysical and electrophysiological methods will be valuable for future investigations of novel approaches for auditory prosthesis.

scholarly journals Sensitivity to Haptic Sound-Localization Cues at Different Body Locations

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3770
Author(s):  
Mark D. Fletcher ◽  
Jana Zgheib ◽  
Samuel W. Perry
Keyword(s):  
Cochlear Implants ◽  
Sound Localization ◽  
Dynamic Range ◽  
Low Cost ◽  
Sound Intensity ◽  
Hearing Impaired ◽  
Localization Accuracy ◽  
Non Invasive ◽  
Intensity Information ◽  
Haptic Stimulation

Cochlear implants (CIs) recover hearing in severely to profoundly hearing-impaired people by electrically stimulating the cochlea. While they are extremely effective, spatial hearing is typically severely limited. Recent studies have shown that haptic stimulation can supplement the electrical CI signal (electro-haptic stimulation) and substantially improve sound localization. In haptic sound-localization studies, the signal is extracted from the audio received by behind-the-ear devices and delivered to each wrist. Localization is achieved using tactile intensity differences (TIDs) across the wrists, which match sound intensity differences across the ears (a key sound localization cue). The current study established sensitivity to across-limb TIDs at three candidate locations for a wearable haptic device, namely: the lower tricep and the palmar and dorsal wrist. At all locations, TID sensitivity was similar to the sensitivity to across-ear intensity differences for normal-hearing listeners. This suggests that greater haptic sound-localization accuracy than previously shown can be achieved. The dynamic range was also measured and far exceeded that available through electrical CI stimulation for all of the locations, suggesting that haptic stimulation could provide additional sound-intensity information. These results indicate that an effective haptic aid could be deployed for any of the candidate locations, and could offer a low-cost, non-invasive means of improving outcomes for hearing-impaired listeners.

Our understanding of neural codes rests on Shannon's foundations

2019 ◽  
Vol 42 ◽  
Author(s):  
Charles R. Gallistel
Keyword(s):  
Brain Structure ◽  
Neural Tissue ◽  
Neural Codes ◽  
Flow Of Information

Abstract Shannon's theory lays the foundation for understanding the flow of information from world into brain: There must be a set of possible messages. Brain structure determines what they are. Many messages convey quantitative facts (distances, directions, durations, etc.). It is impossible to consider how neural tissue processes these numbers without first considering how it encodes them.

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