scholarly journals Novel diamond shuttle to deliver flexible bioelectronics with reduced tissue compression

2018 ◽  
Author(s):  
Kyounghwan Na ◽  
Zachariah J. Sperry ◽  
Jiaao Lu ◽  
Mihaly Vöröslakos ◽  
Saman S. Parizi ◽  
...  
Keyword(s):  
Nervous System ◽  
Dura Mater ◽  
Design Space ◽  
Three Dimensional ◽  
Neural Engineering ◽  
Cross Sectional ◽  
Vertical Support ◽  
Important Challenge ◽  
Tissue Compression

AbstractThe ability to deliver flexible biosensors through the toughest membranes of the central and peripheral nervous system is an important challenge in neuroscience and neural engineering. Bioelectronic devices implanted through dura mater and thick epineurium would ideally create minimal compression and acute damage as they reach the neurons of interest. We demonstrate that a three-dimensional diamond shuttle can be easily made with a vertical support to deliver ultra-compliant polymer microelectrodes (4.5 μm thick) in-vivo through dura mater and thick epineurium. The diamond shuttle has 54% less cross-sectional area than an equivalently stiff silicon shuttle, which we simulated will result in a 37% reduction in blood vessel damage. We also discovered that higher frequency oscillation of the shuttle (200 Hz) significantly reduced tissue compression regardless of the insertion speed, while slow speeds also independently reduced tissue compression. Insertion and recording performance are demonstrated in rat and feline models, but the large design space of these tools are suitable for research in a variety of animal models and nervous system targets.

Scalable submicrometer additive manufacturing

Science ◽  
2019 ◽  
Vol 366 (6461) ◽  
pp. 105-109 ◽  
Author(s):  
Sourabh K. Saha ◽  
Dien Wang ◽  
Vu H. Nguyen ◽  
Yina Chang ◽  
James S. Oakdale ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Design Space ◽  
Three Dimensional ◽  
Complex Structures ◽  
Layer By Layer ◽  
Promising Candidate ◽  
Single Digit ◽  
Cross Sectional ◽  
Two Photon ◽  
Nanoscale Features

High-throughput fabrication techniques for generating arbitrarily complex three-dimensional structures with nanoscale features are desirable across a broad range of applications. Two-photon lithography (TPL)–based submicrometer additive manufacturing is a promising candidate to fill this gap. However, the serial point-by-point writing scheme of TPL is too slow for many applications. Attempts at parallelization either do not have submicrometer resolution or cannot pattern complex structures. We overcome these difficulties by spatially and temporally focusing an ultrafast laser to implement a projection-based layer-by-layer parallelization. This increases the throughput up to three orders of magnitude and expands the geometric design space. We demonstrate this by printing, within single-digit millisecond time scales, nanowires with widths smaller than 175 nanometers over an area one million times larger than the cross-sectional area.

scholarly journals Three-dimensional geometrical changes of the human tibialis anterior muscle and its central aponeurosis measured with three-dimensional ultrasound during isometric contractions

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2260 ◽  
Author(s):  
Brent J. Raiteri ◽  
Andrew G. Cresswell ◽  
Glen A. Lichtwark
Keyword(s):  
Three Dimensional ◽  
Muscle Length ◽  
Pennation Angle ◽  
Human Muscle ◽  
Muscle Fibres ◽  
Isometric Contractions ◽  
Fascicle Length ◽  
Cross Sectional ◽  
Shape Changes

Background.Muscles not only shorten during contraction to perform mechanical work, but they also bulge radially because of the isovolumetric constraint on muscle fibres. Muscle bulging may have important implications for muscle performance, however quantifying three-dimensional (3D) muscle shape changes in human muscle is problematic because of difficulties with sustaining contractions for the duration of anin vivoscan. Although two-dimensional ultrasound imaging is useful for measuring local muscle deformations, assumptions must be made about global muscle shape changes, which could lead to errors in fully understanding the mechanical behaviour of muscle and its surrounding connective tissues, such as aponeurosis. Therefore, the aims of this investigation were (a) to determine the intra-session reliability of a novel 3D ultrasound (3DUS) imaging method for measuringin vivohuman muscle and aponeurosis deformations and (b) to examine how contraction intensity influencesin vivohuman muscle and aponeurosis strains during isometric contractions.Methods.Participants (n= 12) were seated in a reclined position with their left knee extended and ankle at 90° and performed isometric dorsiflexion contractions up to 50% of maximal voluntary contraction. 3DUS scans of the tibialis anterior (TA) muscle belly were performed during the contractions and at rest to assess muscle volume, muscle length, muscle cross-sectional area, muscle thickness and width, fascicle length and pennation angle, and central aponeurosis width and length. The 3DUS scan involved synchronous B-mode ultrasound imaging and 3D motion capture of the position and orientation of the ultrasound transducer, while successive cross-sectional slices were captured by sweeping the transducer along the muscle.Results.3DUS was shown to be highly reliable across measures of muscle volume, muscle length, fascicle length and central aponeurosis length (ICC ≥ 0.98, CV < 1%). The TA remained isovolumetric across contraction conditions and progressively shortened along its line of action as contraction intensity increased. This caused the muscle to bulge centrally, predominantly in thickness, while muscle fascicles shortened and pennation angle increased as a function of contraction intensity. This resulted in central aponeurosis strains in both the transverse and longitudinal directions increasing with contraction intensity.Discussion.3DUS is a reliable and viable method for quantifying multidirectional muscle and aponeurosis strains during isometric contractions within the same session. Contracting muscle fibres do work in directions along and orthogonal to the muscle’s line of action and central aponeurosis length and width appear to be a function of muscle fascicle shortening and transverse expansion of the muscle fibres, which is dependent on contraction intensity. How factors other than muscle force change the elastic mechanical behaviour of the aponeurosis requires further investigation.

scholarly journals Injectable Hydrogels in Repairing Central Nervous System Injuries

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Huiyan Sun ◽  
Limin Zhang ◽  
Wei Cheng ◽  
Fengxia Hao ◽  
Liyan Zhou ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Experimental Studies ◽  
Three Dimensional ◽  
New Materials ◽  
Injectable Hydrogels ◽  
Clinical Challenge ◽  
Complex Surgery

The injured central nervous system (CNS) can hardly regenerate. In vitro engineering of brain tissue hits technical bottlenecks. Also, the compaction and complexity of anatomical structure defy the accurate positioning for lesion sites in intracranial injuries. Therefore, repairing injured CNS remains a significant clinical challenge. Various recent in vivo and in vitro experiments have demonstrated the excellent effect of tissue engineering on repairing central nerve cells and tissues through implanting new materials and engineered cells. Except for porous three-dimensional structures able to pad lesions in various shapes and simulate the natural extracellular matrix with nutrients for cell proliferation, hydrogels incorporate high biocompatibility. Injectable hydrogels with the merits of avoiding complex surgery on large wounds, filling irregular gaps, delivering drugs, and others, are of growing interest. This review focuses on the experimental studies regarding injectable hydrogels, especially applying various injectable hydrogels to repair brain damage.

Axonal Regulation of Central Nervous System Myelination: Structure and Function

2017 ◽  
Vol 24 (1) ◽  
pp. 7-21 ◽  
Author(s):  
Anna Klingseisen ◽  
David A. Lyons
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Adult Life ◽  
Structure And Function ◽  
Myelinated Axons ◽  
Cross Sectional ◽  
Recent Advances ◽  
Cross Sectional Size ◽  
And Function

Approximately half of the human brain consists of myelinated axons. Central nervous system (CNS) myelin is made by oligodendrocytes and is essential for nervous system formation, health, and function. Once thought simply as a static insulator that facilitated rapid impulse conduction, myelin is now known to be made and remodeled in to adult life. Oligodendrocytes have a remarkable capacity to differentiate by default, but many aspects of their development can be influenced by axons. However, how axons and oligodendrocytes interact and cooperate to regulate myelination in the CNS remains unclear. Here, we review recent advances in our understanding of how such interactions generate the complexity of myelination known to exist in vivo. We highlight intriguing results that indicate that the cross-sectional size of an axon alone may regulate myelination to a surprising degree. We also review new studies, which have highlighted diversity in the myelination of axons of different neuronal subtypes and circuits, and structure-function relationships, which suggest that myelinated axons can be exquisitely fine-tuned to mediate precise conduction needs. We also discuss recent advances in our understanding of how neuronal activity regulates CNS myelination, and aim to provide an integrated overview of how axon-oligodendrocyte interactions sculpt neuronal circuit structure and function.

scholarly journals Three-dimensional architecture of the whole human soleus muscle in vivo

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4610 ◽  
Author(s):  
Bart Bolsterlee ◽  
Taija Finni ◽  
Arkiev D’Souza ◽  
Junya Eguchi ◽  
Elizabeth C. Clarke ◽  
...  
Keyword(s):  
Soleus Muscle ◽  
Diffusion Tensor ◽  
Three Dimensional ◽  
Muscle Length ◽  
Fascicle Length ◽  
Cross Sectional ◽  
Quantitative Measurements ◽  
Muscle Fascicle ◽  
Total Muscle

Background Most data on the architecture of the human soleus muscle have been obtained from cadaveric dissection or two-dimensional ultrasound imaging. We present the first comprehensive, quantitative study on the three-dimensional anatomy of the human soleus muscle in vivo using diffusion tensor imaging (DTI) techniques. Methods We report three-dimensional fascicle lengths, pennation angles, fascicle curvatures, physiological cross-sectional areas and volumes in four compartments of the soleus at ankle joint angles of 69 ± 12° (plantarflexion, short muscle length; average ± SD across subjects) and 108 ± 7° (dorsiflexion, long muscle length) of six healthy young adults. Microdissection and three-dimensional digitisation on two cadaveric muscles corroborated the compartmentalised structure of the soleus, and confirmed the validity of DTI-based muscle fascicle reconstructions. Results The posterior compartments of the soleus comprised 80 ± 5% of the total muscle volume (356 ± 58 cm3). At the short muscle length, the average fascicle length, pennation angle and curvature was 37 ± 8 mm, 31 ± 3° and 17 ± 4 /m, respectively. We did not find differences in fascicle lengths between compartments. However, pennation angles were on average 12° larger (p < 0.01) in the posterior compartments than in the anterior compartments. For every centimetre that the muscle-tendon unit lengthened, fascicle lengths increased by 3.7 ± 0.8 mm, pennation angles decreased by −3.2 ± 0.9° and curvatures decreased by −2.7 ± 0.8 /m. Fascicles in the posterior compartments rotated almost twice as much as in the anterior compartments during passive lengthening. Discussion The homogeneity in fascicle lengths and inhomogeneity in pennation angles of the soleus may indicate a functionally different role for the anterior and posterior compartments. The data and techniques presented here demonstrate how DTI can be used to obtain detailed, quantitative measurements of the anatomy of complex skeletal muscles in living humans.

scholarly journals Innovative high-resolution microCT imaging of animal brain vasculature

2020 ◽  
Vol 225 (9) ◽  
pp. 2885-2895
Author(s):  
Ruslan Hlushchuk ◽  
David Haberthür ◽  
Petr Soukup ◽  
Sebastien F. Barré ◽  
Oleksiy-Zakhar Khoma ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Dura Mater ◽  
Vertebral Column ◽  
Ex Vivo ◽  
Basic Research ◽  
The Central Nervous System ◽  
Microct Imaging

AbstractAnalysis of the angioarchitecture and quantification of the conduit vessels and microvasculature is of paramount importance for understanding the physiological and pathological processes within the central nervous system (CNS). Most of the available in vivo imaging methods lack penetration depth and/or resolution. Some ex vivo methods may provide better resolution, but are mainly destructive, as they are designed for imaging the CNS tissues after their removal from the skull or vertebral column. The removal procedure inevitably alters the in situ relations of the investigated structures and damages the dura mater and leptomeninges. µAngiofil, a polymer-based contrast agent, permits a qualitatively novel postmortem microangio-computed tomography (microangioCT) approach with excellent resolution and, therefore, visualization of the smallest brain capillaries. The datasets obtained empower a rather straightforward quantitative analysis of the vascular tree, including the microvasculature. The µAngiofil has an excellent filling capacity as well as a radio-opacity higher than the one of bone tissue, which allows imaging the cerebral microvasculature even within the intact skull or vertebral column. This permits in situ visualization and thus investigation of the dura mater and leptomeningeal layers as well as their blood supply in their original geometry. Moreover, the methodology introduced here permits correlative approaches, i.e., microangioCT followed by classical histology, immunohistochemistry and even electron microscopy. The experimental approach presented here makes use of common desktop microCT scanners, rendering it a promising everyday tool for the evaluation of the (micro)vasculature of the central nervous system in preclinical and basic research.

scholarly journals Application of an Ultrasound Semi-Quantitative Assessment in the Degradation of Silk Fibroin Scaffolds In Vivo

2021 ◽  
Author(s):  
Lihui Cai ◽  
Nan Gao ◽  
Tingyu Sun ◽  
Ke Bi ◽  
Xin Chen ◽  
...  
Keyword(s):  
Silk Fibroin ◽  
Three Dimensional ◽  
Quantitative Detection ◽  
Sprague Dawley ◽  
Cross Sectional ◽  
Sprague Dawley Rats ◽  
The Cross ◽  
Scaffold Degradation ◽  
Living Organisms

Abstract Background: Research on the degradation of silk fibroin (SF) scaffolds in vivo lacks uniform and effective standards and experimental evaluation methods. This study aims to evaluate the application of ultrasound in assessing the degradation of SF scaffolds.Methods: Two groups of three-dimensional regenerated SF scaffolds (3D RSFs) were implanted subcutaneously into the backs of Sprague-Dawley rats. B-mode ultrasound and hematoxylin and eosin (HE) staining were performed on days 3, 7, 14, 28, 56, 84, 112, 140, and 196. The cross-sectional areas for two groups of 3D RSFs that were obtained using these methods were semi-quantitatively analyzed and compared to evaluate the biodegradation of the implanted RSFs.Results: Semi-quantitative analysis of the cross-sectional areas detected using B-mode ultrasound revealed that the degradations of the two 3D RSF groups were significantly different. The degradation rate of the SF-B group was found to be higher than that of the SF-A group. This was consistent with the semi-quantitative detection results for HE staining. Regression analysis showed that the results of the B-mode ultrasound and HE staining were correlated in both groups, indicating that B-mode ultrasound is a reliable method to evaluate the SF scaffold degradation in vivo. As the SF scaffold degraded, its echo gradually decreased. In the early stages of degradation, the echo of the SF scaffold was higher than that of the muscle. In the middle stage of degradation, the echo was equal to that of the muscle. In the later stage, the echo was lower than that of the muscle.Conclusions: This study suggests that B-mode ultrasound can clearly display the implanted SF scaffolds non-invasively and monitor the degradation of the different SF scaffolds after implantation in living organisms in real-time.

scholarly journals Proposed implementation of various imaging modes of OCT on FPGA

2021 ◽  
Author(s):  
Vitaliy Mykhaylychenko
Keyword(s):  
Real Time ◽  
Three Dimensional ◽  
Time Data ◽  
Cross Sectional ◽  
Color Flow ◽  
System Generator ◽  
Data Processor ◽  
Recorded Data ◽  
Time Acquisition

Optical Coherence Tomography (OCT) is three-dimensional imaging technique, capable of producing high resolution cross-sectional images through homogeneous samples, such as biological tissue. Real-time acquisition rates are a significant advantage in OCT. However, when images are generated by first acquiring data and then postprocessed on PC to extract information this advantage is cancelled out. In this project a system which can provide estimation of pixel values for three imaging modes: Structural, Color-flow Doppler and Velocity Variance is designed. The proposed system is standalone data processor using FPGA. The system was designed to process recorded data for verification purposes; however, it can be easily modified to process real-time data. Since the system has three modes of visualization it can be used for detecting in vivo blood flow. The proposed system was completed at MATLAB, Xilinx System Generator (XSG) and VHDL levels and the results show consistency between theoretical results, MATLAB, XSG and VHDL.

Evaluation of the perforators of the anterior communicating artery (AComA) using routine cerebral 3D rotational angiography

2015 ◽  
Vol 8 (10) ◽  
pp. 1061-1066 ◽  
Author(s):  
Stephanie Lescher ◽  
Maja Zimmermann ◽  
Jürgen Konczalla ◽  
Thomas Deller ◽  
Luciana Porto ◽  
...  
Keyword(s):  
Imaging Techniques ◽  
Three Dimensional ◽  
Therapeutic Interventions ◽  
Anterior Communicating Artery ◽  
Interventional Treatment ◽  
Rotational Angiography ◽  
Cross Sectional ◽  
Therapy Assessment ◽  
Neurologic Deficits

BackgroundDamage to perforating branches of the anterior communicating artery (AComA) is a known complication of surgical or interventional treatment procedures for AComA aneurysm leading to neurologic deficits. In spite of the clinical relevance of these AComA branches, they have not been systematically analyzed using imaging techniques and most of our knowledge is based on post-mortem injection studies or neurosurgical reports. We therefore analyzed three-dimensional rotational angiography (3DRA) images of the AComA, and propose a first imaging definition of the microvascular structures surrounding the AComA.MethodsReconstructed 3D data derived from standard-of-care rotational angiography acquisitions (5 s DSA) were retrospectively analyzed. 20 patients undergoing selective cerebral angiography and 3DRA for therapy assessment were included in our study. 3DRA datasets were reconstructed and displayed using the volume rendering technique (VRT). Additionally, multiplanar reformatted CT-like cross-sectional images (MPR) were used to evaluate the number, size, and origin of the perforators of the AComA.ResultsPerforating branches of the AComA could be demonstrated in all cases with large interindividual variations in vessel visibility. MPRs appeared to be superior to total VRT volumes in the visualization of the perforating branches of the AComA.Conclusions3DRA can be used to visualize perforating branches of the AComA in vivo. Since damage to these perforators may result in neurologic deficits, visualization of these vessels prior to surgery or endovascular aneurysm treatment could help in the planning of therapeutic interventions. Further refinement of current imaging techniques will be necessary, however, to increase the reliability of small vessel angiography.

scholarly journals Application of an ultrasound semi-quantitative assessment in the degradation of silk fibroin scaffolds in vivo

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Lihui Cai ◽  
Nan Gao ◽  
TingYu Sun ◽  
Ke Bi ◽  
Xin Chen ◽  
...  
Keyword(s):  
Silk Fibroin ◽  
Three Dimensional ◽  
Quantitative Detection ◽  
Sprague Dawley ◽  
Cross Sectional ◽  
Sprague Dawley Rats ◽  
The Cross ◽  
Scaffold Degradation ◽  
Living Organisms

Abstract Background Research on the degradation of silk fibroin (SF) scaffolds in vivo lacks uniform and effective standards and experimental evaluation methods. This study aims to evaluate the application of ultrasound in assessing the degradation of SF scaffolds. Methods Two groups of three-dimensional regenerated SF scaffolds (3D RSFs) were implanted subcutaneously into the backs of Sprague-Dawley rats. B-mode ultrasound and hematoxylin and eosin (HE) staining were performed on days 3, 7, 14, 28, 56, 84, 112, 140, and 196. The cross-sectional areas for two groups of 3D RSFs that were obtained using these methods were semi-quantitatively analyzed and compared to evaluate the biodegradation of the implanted RSFs. Results The 3D RSFs in the SF-A group were wholly degraded at the 28th week after implantation. In contrast, the 3D RSFs in the SF-B group were completely degraded at the 16th week. Ultrasonic examination showed that the echoes of 3D RSFs in both groups gradually decreased with the increase of the implantation time. In the early stages of degradation, the echoes of the samples were higher than the echo of the muscle. In the middle of degeneration, the echoes were equal to the echo of the muscle. In the later stage, the echoes of the samples were lower than that of the muscle. The above changes in the SF-B group were earlier than those in the SF-A group. Semi-quantitative analysis of the cross-sectional areas detected using B-mode ultrasound revealed that the degradations of the two 3D RSF groups were significantly different. The degradation rate of the SF-B group was found to be higher than that of the SF-A group. This was consistent with the semi-quantitative detection results for HE staining. Regression analysis showed that the results of the B-mode ultrasound and HE staining were correlated in both groups, indicating that B-mode ultrasound is a reliable method to evaluate the SF scaffold degradation in vivo. Conclusions This study suggests that B-mode ultrasound can clearly display the implanted SF scaffolds non-invasively and monitor the degradation of the different SF scaffolds after implantation in living organisms in real-time.

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