scholarly journals Valley Vortex Assisted and Topological Protected Microparticles Manipulation with Complicated 2D Patterns in a Star-Like Sonic Crystal

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 4939
Author(s):  
Jian Zhu ◽  
Tianning Chen ◽  
Chen Chen ◽  
Wei Ding
Keyword(s):  
Tissue Engineering ◽  
Large Scale ◽  
Edge State ◽  
Sharp Corner ◽  
Microfluidic Systems ◽  
Cluster Aggregation ◽  
Sonic Crystal ◽  
Complicated Pattern ◽  
Sonic Crystals

Arranging microparticles into desired patterns, especially in a complicated pattern with a reliable and tunable manner, is challenging but highly desirable in the fields such as biomedicine and tissue engineering. To overcome these limitations, here, by using the concept of topology in acoustics, the valley vortex is utilized to manipulate particles on a large scale with complicated 2D patterns in the star-like sonic crystals at different frequencies. A topologically protected edge state is obtained at the interface of the crystals with different valley Hall phases, which shows the ability of reliable microparticles control along the sharp corner and the capability of robust particles cluster aggregation in a defective system. The results may provide intriguing resources for future microfluidic systems in a complicated and brittle environment.

scholarly journals GAKTpore: Stereological Characterisation Methods for Porous Foams in Biomedical Applications

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1269
Author(s):  
Gareth Sheppard ◽  
Karl Tassenberg ◽  
Bogdan Nenchev ◽  
Joel Strickland ◽  
Ramy Mesalam ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Biomedical Applications ◽  
Large Scale ◽  
Collagen Scaffold ◽  
Porous Structures ◽  
Tissue Engineering Scaffolds ◽  
Biological Responses ◽  
Sem Micrograph ◽  
Cell Adhesion And Proliferation ◽  
Characterisation Methods

In tissue engineering, scaffolds are a key component that possess a highly elaborate pore structure. Careful characterisation of such porous structures enables the prediction of a variety of large-scale biological responses. In this work, a rapid, efficient, and accurate methodology for 2D bulk porous structure analysis is proposed. The algorithm, “GAKTpore”, creates a morphology map allowing quantification and visualisation of spatial feature variation. The software achieves 99.6% and 99.1% mean accuracy for pore diameter and shape factor identification, respectively. There are two main algorithm novelties within this work: (1) feature-dependant homogeneity map; (2) a new waviness function providing insights into the convexity/concavity of pores, important for understanding the influence on cell adhesion and proliferation. The algorithm is applied to foam structures, providing a full characterisation of a 10 mm diameter SEM micrograph (14,784 × 14,915 px) with 190,249 pores in ~9 min and has elucidated new insights into collagen scaffold formation by relating microstructural formation to the bulk formation environment. This novel porosity characterisation algorithm demonstrates its versatility, where accuracy, repeatability, and time are paramount. Thus, GAKTpore offers enormous potential to optimise and enhance scaffolds within tissue engineering.

scholarly journals The Arteriovenous Loop: Engineering of Axially Vascularized Tissue

2018 ◽  
Vol 59 (3-4) ◽  
pp. 286-299 ◽  
Author(s):  
Annika Weigand ◽  
Raymund E. Horch ◽  
Anja M. Boos ◽  
Justus P. Beier ◽  
Andreas Arkudas
Keyword(s):  
Tissue Engineering ◽  
Large Scale ◽  
Treatment Options ◽  
Current Treatment ◽  
Loop Model ◽  
Engineering Approach ◽  
In Vivo Tissue Engineering ◽  
Tissue Engineering Approach ◽  
Tissue Defects

Background: Most of the current treatment options for large-scale tissue defects represent a serious burden for the patients, are often not satisfying, and can be associated with significant side effects. Although major achievements have already been made in the field of tissue engineering, the clinical translation in case of extensive tissue defects is only in its early stages. The main challenge and reason for the failure of most tissue engineering approaches is the missing vascularization within large-scale transplants. Summary: The arteriovenous (AV) loop model is an in vivo tissue engineering strategy for generating axially vascularized tissues using the own body as a bioreactor. A superficial artery and vein are anastomosed to create an AV loop. This AV loop is placed into an implantation chamber for prevascularization of the chamber inside, e.g., a scaffold, cells, and growth factors. Subsequently, the generated tissue can be transplanted with its vascular axis into the defect site and anastomosed to the local vasculature. Since the blood supply of the growing tissue is based on the AV loop, it will be immediately perfused with blood in the recipient site leading to optimal healing conditions even in the case of poorly vascularized defects. Using this tissue engineering approach, a multitude of different axially vascularized tissues could be generated, such as bone, skeletal or heart muscle, or lymphatic tissues. Upscaling from the small animal AV loop model into a preclinical large animal model could pave the way for the first successful attempt in clinical application. Key Messages: The AV loop model is a powerful tool for the generation of different axially vascularized replacement tissues. Due to minimal donor site morbidity and the possibility to generate patient-specific tissues variable in type and size, this in vivo tissue engineering approach can be considered as a promising alternative therapy to current treatment options of large-scale defects.

scholarly journals Microfluidic systems for stem cell-based neural tissue engineering

Lab on a Chip ◽  
2016 ◽  
Vol 16 (14) ◽  
pp. 2551-2571 ◽  
Author(s):  
Mahdi Karimi ◽  
Sajad Bahrami ◽  
Hamed Mirshekari ◽  
Seyed Masoud Moosavi Basri ◽  
Amirala Bakhshian Nik ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Cell Culture ◽  
Stem Cell ◽  
Neural Tissue ◽  
Microfluidic Systems ◽  
Neural Tissue Engineering ◽  
Stem Cell Culture ◽  
Stem Cell Derivation

Overall process of stem cell derivation and isolation, as well as microfluidic stem cell culture and neural tissue engineering.

Square-root-like higher-order topological states in three-dimensional sonic crystals

2021 ◽  
Author(s):  
Zhiguo Geng ◽  
Huanzhao Lv ◽  
Zhan Xiong ◽  
Yu-Gui Peng ◽  
Zhaojiang Chen ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Surface States ◽  
Higher Order ◽  
Square Root ◽  
Root Lattice ◽  
Third Order ◽  
Topological Materials ◽  
Topological States ◽  
Sonic Crystal ◽  
Sonic Crystals

Abstract The square-root descendants of higher-order topological insulators were proposed recently, whose topological property is inherited from the squared Hamiltonian. Here we present a three-dimensional (3D) square-root-like sonic crystal by stacking the 2D square-root lattice in the normal (z) direction. With the nontrivial intralayer couplings, the opened degeneracy at the K-H direction induces the emergence of multiple acoustic localized modes, i.e., the extended 2D surface states and 1D hinge states, which originate from the square-root nature of the system. The square-root-like higher order topological states can be tunable and designed by optionally removing the cavities at the boundaries. We further propose a third-order topological corner state in the 3D sonic crystal by introducing the staggered interlayer couplings on each square-root layer, which leads to a nontrivial bulk polarization in the z direction. Our work sheds light on the high-dimensional square-root topological materials, and have the potentials in designing advanced functional devices with sound trapping and acoustic sensing.

Numerical study for increasement of low frequency sound insulation of double-panel structure using sonic crystals with distributed Helmholtz resonators

2019 ◽  
Vol 33 (14) ◽  
pp. 1950138
Author(s):  
Myong-Jin Kim
Keyword(s):  
Free Space ◽  
Transmission Loss ◽  
Numerical Study ◽  
Low Frequency ◽  
Helmholtz Resonator ◽  
Sound Insulation ◽  
The Finite Element Method ◽  
Helmholtz Resonators ◽  
Sonic Crystal ◽  
Sonic Crystals

Numerical simulations of the sound transmission loss (STL) of a double-panel structure (DPS) with sonic crystal (SC) comprised of distributed local resonators are presented. The Local Resonant Sonic Crystal (LRSC) consists of “C”-shaped Helmholtz resonator columns with different resonant frequencies. The finite element method is used to calculate the STL of such a DPS. First, the STLs of LRSC in free space and the DPS with LRSC are calculated and compared. It is shown that the sound insulations of the local resonators inserted in the double panel are higher than that in free space for the same size of the SCs and the same number of columns. Next, STL of the DPS in which the SC composed of three columns of local resonators having the same outer and inner diameters but different slot widths are calculated, and a reasonable arrangement order is determined. Finally, the soundproofing performances of DPS with distributed LRSC are compared with the case of insertion of general cylindrical SC for SC embedded in glass wool and not. The results show that the sound insulation of the DPS can be significantly improved in the low frequency range while reducing the total mass without increasing the thickness.

Parametric Study on Rectangular Sonic Crystal

2012 ◽  
Vol 152-154 ◽  
pp. 281-286 ◽  
Author(s):  
Arpan Gupta ◽  
Kian Meng Lim ◽  
Chye Heng Chew
Keyword(s):  
Band Gap ◽  
Periodic Structure ◽  
Parametric Study ◽  
Sound Propagation ◽  
Periodic Structures ◽  
Sound Attenuation ◽  
Experimental Results ◽  
Center Frequency ◽  
Sonic Crystal ◽  
Sonic Crystals

Sonic crystals are periodic structures made of sound hard scatterers which attenuate sound in a range of frequencies. For an infinite periodic structure, this range of frequencies is known as band gap, and is determined by the geometric arrangement of the scatterers. In this paper, a parametric study on rectangular sonic crystal is presented. It is found that geometric spacing between the scatterers in the direction of sound propagation affects the center frequency of the band gap. Reducing the geometric spacing between the scatterers in the direction perpendicular to the sound propagation helps in better sound attenuation. Such rectangular arrangement of scatterers gives better sound attenuation than the regular square arrangement of scatterers. The model for parametric study is also supported by some experimental results.

scholarly journals A Customizable, Low-Cost Perfusion System for Sustaining Tissue Constructs

2018 ◽  
Vol 23 (6) ◽  
pp. 592-598
Author(s):  
Brian J. O’Grady ◽  
Jason X. Wang ◽  
Shannon L. Faley ◽  
Daniel A. Balikov ◽  
Ethan S. Lippmann ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Cell Viability ◽  
Large Scale ◽  
Low Cost ◽  
Three Dimensional ◽  
Tissue Scaffolds ◽  
Perfusion System ◽  
Pump System ◽  
Tissue Constructs ◽  
Engineered Tissue

The fabrication of engineered vascularized tissues and organs requiring sustained, controlled perfusion has been facilitated by the development of several pump systems. Currently, researchers in the field of tissue engineering require the use of pump systems that are in general large, expensive, and generically designed. Overall, these pumps often fail to meet the unique demands of perfusing clinically useful tissue constructs. Here, we describe a pumping platform that overcomes these limitations and enables scalable perfusion of large, three-dimensional hydrogels. We demonstrate the ability to perfuse multiple separate channels inside hydrogel slabs using a preprogrammed schedule that dictates pumping speed and time. The use of this pump system to perfuse channels in large-scale engineered tissue scaffolds sustained cell viability over several weeks.

Bioinspired Growth of Hydroxyapatite Nanocrystals on PLGA- (PEG- ASP)n Scaffolds Modified with Oligopeptide Derived from BMP-2

2007 ◽  
Vol 334-335 ◽  
pp. 1261-1264 ◽  
Author(s):  
Quan Yuan ◽  
Xiao Dong Guo ◽  
Qi Xin Zheng ◽  
Ming Zhao ◽  
Zheng Qi Pan ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Active Sites ◽  
Large Scale ◽  
Organic Matrix ◽  
Sem Analysis ◽  
Bone Morphogenetic Protein 2 ◽  
Intimate Contact ◽  
Simple Method ◽  
Natural Bone

Natural bone is a typical example of an “organic matrix-mediated” biomineralization process which constituted of hydroxyapatite(HA) nanocrystals orderly grown in intimate contact with collagen fibers. Bone morphogenetic protein 2 (BMP2) is the most powerful osteogenic factor. But it is extremely difficult to be manufactured in large scale. In previous study, we have designed a novel oligopeptide (P24) derived from BMP2 knuckle epitope and it contained abundant Asp(aspartic acid) and phosphorylated Ser(serine) which may be helpful for self-assambly biomineralization and osteogenesis. Previous In vivo experiments have shown that this novel oligopeptide had excellent osteoinductive and ectopic bone formation property which was similar to that of BMP2. In this study, PLGA-(PEG-ASP)n scaffolds were modified with P24 and a new biomimetic bone tissue engineering scaffold material with enhanced bioactivity was synthesized by a biologically inspired mineralization approach. Peptide P24 was introduced into PLGA-(PEG-ASP)n scaffolds using cross-linkers. Then the P24 modified scaffolds and the simple PLGA-(PEG-ASP)n scaffolds were incubated in modified simulated body fluid (mSBF) for 10 days. Growth of HA nanocrystals on the materials was confirmed by observation SEM and measurements EDS and XRD. SEM analysis demonstrated the well growth of bonelike HA nanocrystals on P24 modified PLGA-(PEG-ASP)n scaffolds than that of the control scaffolds. The main component of mineral of the P24 modified scaffolds was hydroxyapatite containing low crystalline nanocrystals, and the Ca/P ratio was nearly 1.60, similar to that of natural bone, while that of the control scaffolds was 1.52. The introduction of peptide P24 into PLGA- (PEG- ASP)n copolymer provides abundant active sites to mediate the nucleation and self- ssembling of HA nanocrystals in mSBF. the resulted peptide P24 modified- HA/PLGA- (PEG- ASP)n composite shows some features of natural bone both in main composition and and hierarchical microstructure. This biomimetic treatment provides a simple method for surface functionalization and subsequent biomineralization on biodegradable polymer scaffolds for tissue engineering.

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