scholarly journals New Approach toward Laser-Assisted Modification of Biocompatible Polymers Relevant to Neural Interfacing Technologies

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 3004
Author(s):  
Nadya Stankova ◽  
Anastas Nikolov ◽  
Ekaterina Iordanova ◽  
Georgi Yankov ◽  
Nikolay Nedyalkov ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Neurological Diseases ◽  
Chemical Activation ◽  
Multielectrode Arrays ◽  
Platinum Black ◽  
Homogeneous Microstructure ◽  
New Approach ◽  
Tight Contact ◽  
Medical Grade ◽  
Neural Interfacing

We report on a new approach toward a laser-assisted modification of biocompatible polydimethylsiloxane (PDMS) elastomers relevant to the fabrication of stretchable multielectrode arrays (MEAs) devices for neural interfacing technologies. These applications require high-density electrode packaging to provide a high-resolution integrating system for neural stimulation and/or recording. Medical grade PDMS elastomers are highly flexible with low Young’s modulus < 1 MPa, which are similar to soft tissue (nerve, brain, muscles) among the other known biopolymers, and can easily adjust to the soft tissue curvatures. This property ensures tight contact between the electrodes and tissue and promotes intensive development of PDMS-based MEAs interfacing devices in the basic neuroscience, neural prosthetics, and hybrid bionic systems, connecting the human nervous system with electronic or robotic prostheses for restoring and treating neurological diseases. By using the UV harmonics 266 and 355 nm of Nd:YAG laser medical grade PDMS elastomer is modified by ns-laser ablation of in water. A new approach of processing is proposed to (i) activate the surface and to obtain tracks with (ii) symmetric U-shaped profiles and (iii) homogeneous microstructure This technology provides miniaturization of the device and successful functionalization by electroless metallization of the tracks with platinum (Pt) without preliminary sensitization by tin (Sn) and chemical activation by palladium (Pd). As a result, platinum black layers with a cauliflower-like structure with low values of sheet resistance between 1 and 8 Ω/sq are obtained.

scholarly journals Rehydration of Dried-Out Specimens: a New Approach

2020 ◽  
Vol 34 (1) ◽  
pp. 73-86
Author(s):  
F. Neisskenwirth
Keyword(s):  
Water Vapor ◽  
Soft Tissue ◽  
Second Step ◽  
Phosphate Solution ◽  
Glycerol Solution ◽  
New Approach ◽  
The Third ◽  
Demineralized Water ◽  
Chemically Induced

Abstract Different procedures are proposed in the literature for the rehydration of dried-out specimens. These procedures vary greatly in their efficiency and application. This work describes a new procedure that is inspired by the literature but that avoids heating the specimens. This method was applied to reconditioning dried-out specimens from a historical collection (Swiss freshwater fishes, bird brains, and bird eyes), stored at the Naturhistorisches Museum Bern in Switzerland. The procedure consists of five steps. The first step is the softening of hardened soft tissue with benzaldehyde and demineralized water. The second step is an indirect rehydration with water vapor. The third step is a chemically induced direct hydration using a trisodium phosphate solution that allows the specimen to swell in size before being washed with water to remove all additives. Finally, the rehydrated specimen is transferred into new preserving fluid. Because the dehydrating properties of ethanol as a preservative are problematic, this paper presents the results of an experimental case study using a glycerol solution as a preservation fluid.

scholarly journals Optimizing the neuron-electrode interface for chronic bioelectronic interfacing

2020 ◽  
Vol 49 (1) ◽  
pp. E7
Author(s):  
Conor Keogh
Keyword(s):  
Electrode Materials ◽  
Neurological Diseases ◽  
Tissue Reaction ◽  
Biological Interactions ◽  
Implanted Electrodes ◽  
Tissue Integration ◽  
Closed Loop Systems ◽  
Electrode Interface ◽  
Neural Interfacing

Engineering approaches have vast potential to improve the treatment of disease. Brain-machine interfaces have become a well-established means of treating some otherwise medically refractory neurological diseases, and they have shown promise in many more areas. More widespread use of implanted stimulating and recording electrodes for long-term intervention is, however, limited by the difficulty in maintaining a stable interface between implanted electrodes and the local tissue for reliable recording and stimulation.This loss of performance at the neuron-electrode interface is due to a combination of inflammation and glial scar formation in response to the implanted material, as well as electrical factors contributing to a reduction in function over time. An increasing understanding of the factors at play at the neural interface has led to greater focus on the optimization of this neuron-electrode interface in order to maintain long-term implant viability.A wide variety of approaches to improving device interfacing have emerged, targeting the mechanical, electrical, and biological interactions between implanted electrodes and the neural tissue. These approaches are aimed at reducing the initial trauma and long-term tissue reaction through device coatings, optimization of mechanical characteristics for maximal biocompatibility, and implantation techniques. Improved electrode features, optimized stimulation parameters, and novel electrode materials further aim to stabilize the electrical interface, while the integration of biological interventions to reduce inflammation and improve tissue integration has also shown promise.Optimization of the neuron-electrode interface allows the use of long-term, high-resolution stimulation and recording, opening the door to responsive closed-loop systems with highly selective modulation. These new approaches and technologies offer a broad range of options for neural interfacing, representing the possibility of developing specific implant technologies tailor-made to a given task, allowing truly personalized, optimized implant technology for chronic neural interfacing.

Long-lasting bioresorbable poly(lactic acid) (PLA94) mesh: a new approach for soft tissue reinforcement based on an experimental pilot study

2007 ◽  
Vol 18 (9) ◽  
pp. 1007-1014 ◽  
Author(s):  
Renaud de Tayrac ◽  
Marie-Claire Oliva-Lauraire ◽  
Isabelle Guiraud ◽  
Laurent Henry ◽  
Michel Vert ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Pilot Study ◽  
Soft Tissue ◽  
Poly Lactic Acid ◽  
New Approach

Surface modification of medical-grade polyurethane by cyanurchloride-activated tetraether lipid (a new approach for bacterial antiadhesion)

2008 ◽  
Vol 84A (3) ◽  
pp. 672-681 ◽  
Author(s):  
Ananthu Sateesh ◽  
Jürgen Vogel ◽  
Evelyn Dayss ◽  
Beate Fricke ◽  
Karin Dölling ◽  
...  
Keyword(s):  
Surface Modification ◽  
Lipid A ◽  
New Approach ◽  
Tetraether Lipid ◽  
Medical Grade

First U-Pb dating of fossilized soft tissue using a new approach to paleontological chronometry

Geology ◽  
2021 ◽  
Author(s):  
Heriberto Rochín-Bañaga ◽  
Donald W. Davis ◽  
Tobias Schwennicke
Keyword(s):  
Soft Tissue ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Uranium Content ◽  
New Approach ◽  
Inductively Coupled ◽  
Shark Teeth ◽  
Inductively Coupled Mass Spectrometry ◽  
Late Diagenesis ◽  
Three Dimensional Space

Previous U-Pb dating of fossils has had only limited success because of low uranium content and abundance of common Pb as well as element mobility during late diagenesis. We report the first accurate U-Pb dating of fossilized soft tissue from a Pliocene phosphatized bivalve mold using laser ablation–inductively coupled mass spectrometry (LA-ICPMS). The fossilized soft tissue yields a diagenetic U-Pb age of 3.16 ± 0.08 Ma, which is consistent with its late Pliocene stratigraphy and similar to the oldest U-Pb age measured on accompanying shark teeth. Phosphate extraclasts give a distinctly older age of 5.1 ± 1.7 Ma, indicating that they are likely detrital and may have furnished P, promoting phosphatization of the mold. The U-Pb ages reported here along with stratigraphic constraints suggest that diagenesis occurred shortly after the death of the bivalve and that the U-Pb system in the bivalve mold remained closed until the present. Shark teeth collected from the same horizon show variable resetting due to late diagenesis. Data were acquired as line scans in order to exploit the maximum Pb/U variation and were regressed as counts, rather than ratios, in three-dimensional space using a Bayesian statistical method.

Sign in / Sign up

Export Citation Format

Share Document