MEMS Dielectrophoresis Device for Osteoblast Cell Stimulation

A fixed microelectrode device for cell stimulation has been designed and fabricated using micro-electromechanical systems (MEMS) technology. Dielectrophoretic forces obtained from non-uniform electric fields were used for manipulating and positioning osteoblasts. The experiments show that the osteoblasts experience positive dielectrophoresis (p-DEP) when suspended in iso-osmotic culture medium and exposed to AC fields at 5 MHz frequency. This work will help to investigate the mechanisms underlying Wolff’s law of bone growth dynamics at the cellular level. The methods used can also be developed to control osteoblast metabolism and ultimately enhance bone repair processes.

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Effects of a periosteal activation agent on bone repair, bone growth, and bone ingrowth into a porous material in the rabbit

10.31274/rtd-180814-6385 ◽

1982 ◽

Author(s):

L. Russell Alberts

Keyword(s):

Porous Material ◽

Bone Repair ◽

Bone Growth ◽

Bone Ingrowth

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Growth dynamics of the Arabidopsis fruit is mediated by cell expansion

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1914096116 ◽

2019 ◽

Vol 116 (50) ◽

pp. 25333-25342 ◽

Cited By ~ 4

Author(s):

Juan-José Ripoll ◽

Mingyuan Zhu ◽

Stephanie Brocke ◽

Cindy T. Hon ◽

Martin F. Yanofsky ◽

...

Keyword(s):

Computational Modeling ◽

Cell Expansion ◽

Growth Dynamics ◽

Spatial Separation ◽

Cellular Level ◽

Fruit Growth ◽

Signaling Cascades ◽

Comprehensive Understanding ◽

Cellular Mechanisms ◽

Plant Reproductive Success

Fruit have evolved a sophisticated tissue and cellular architecture to secure plant reproductive success. Postfertilization growth is perhaps the most dramatic event during fruit morphogenesis. Several studies have proposed that fertilized ovules and developing seeds initiate signaling cascades to coordinate and promote the growth of the accompanying fruit tissues. This dynamic process allows the fruit to conspicuously increase its size and acquire its final shape and means for seed dispersal. All these features are key for plant survival and crop yield. Despite its importance, we lack a high-resolution spatiotemporal map of how postfertilization fruit growth proceeds at the cellular level. In this study, we have combined live imaging, mutant backgrounds in which fertilization can be controlled, and computational modeling to monitor and predict postfertilization fruit growth in Arabidopsis. We have uncovered that, unlike leaves, sepals, or roots, fruit do not exhibit a spatial separation of cell division and expansion domains; instead, there is a separation into temporal stages with fertilization as the trigger for transitioning to cell expansion, which drives postfertilization fruit growth. We quantified the coordination between fertilization and fruit growth by imaging no transmitting tract (ntt) mutants, in which fertilization fails in the bottom half of the fruit. By combining our experimental data with computational modeling, we delineated the mobility properties of the seed-derived signaling cascades promoting growth in the fruit. Our study provides the basis for generating a comprehensive understanding of the molecular and cellular mechanisms governing fruit growth and shape.

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Electrically Switchable Liquid Crystal Polymer Rod Actuators

MRS Proceedings ◽

10.1557/proc-1096-ff03-07 ◽

2008 ◽

Vol 1096 ◽

Author(s):

Matthew Shafran ◽

Konstantinos Sierros ◽

Wade Huebsch ◽

Darran Cairns

Keyword(s):

Liquid Crystal ◽

Electric Fields ◽

Uv Light ◽

Orientational Order ◽

Photo Polymerization ◽

Translational Movement ◽

Crystal Polymer ◽

Stimulus Responsive ◽

Rod Structures ◽

Ac Fields

AbstractStimulus responsive liquid crystal nanorods, 60 μm in length and 200 nm in diameter, were fabricated by a template synthesis technique. The liquid crystal, RM 257, is a reactive monomer which polymerizes with the application of UV light. After polymerization the liquid crystal's orientational order is permanently “frozen”. Therefore, the subsequent structures are temperature independent after curing. In this study the liquid crystal was confined in the pores of Anopore membranes before curing, which results in rod structures after photo-polymerization. After fabrication, the rods were observed under the application of both AC and DC electric fields. DC fields were noted by either up and down or translational movement of the rods. Application of AC fields resulted in random movement of the rods.

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Positive dielectrophoresis and heterogeneous aggregation in high-gradient ac electric fields

Journal of Applied Physics ◽

10.1063/1.1495534 ◽

2002 ◽

Vol 92 (5) ◽

pp. 2829-2843 ◽

Cited By ~ 26

Author(s):

Zhiyong Qiu ◽

Nikolai Markarian ◽

Boris Khusid ◽

Andreas Acrivos

Keyword(s):

Electric Fields ◽

High Gradient ◽

Ac Electric Fields ◽

Positive Dielectrophoresis

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Inactivation of Mycobacterium paratuberculosis by Pulsed Electric Fields

Applied and Environmental Microbiology ◽

10.1128/aem.67.6.2833-2836.2001 ◽

2001 ◽

Vol 67 (6) ◽

pp. 2833-2836 ◽

Cited By ~ 49

Author(s):

Neil J. Rowan ◽

Scott J. MacGregor ◽

John G. Anderson ◽

Douglas Cameron ◽

Owen Farish

Keyword(s):

Electric Fields ◽

Pulsed Electric Fields ◽

Cellular Level ◽

Treatment Temperature ◽

Cow’S Milk ◽

Mycobacterium Paratuberculosis ◽

Cow's Milk ◽

High Temperature Short Time ◽

Peptone Water ◽

Short Time

ABSTRACT The influence of treatment temperature and pulsed electric fields (PEF) on the viability of Mycobacterium paratuberculosiscells suspended in 0.1% (wt/vol) peptone water and in sterilized cow's milk was assessed by direct viable counts and by transmission electron microscopy (TEM). PEF treatment at 50°C (2,500 pulses at 30 kV/cm) reduced the level of viable M. paratuberculosis cells by approximately 5.3 and 5.9 log10 CFU/ml in 0.1% peptone water and in cow's milk, respectively, while PEF treatment of M. paratuberculosisat lower temperatures resulted in less lethality. Heating alone at 50°C for 25 min or at 72°C for 25 s (extended high-temperature, short-time pasteurization) resulted in reductions ofM. paratuberculosis of approximately 0.01 and 2.4 log10 CFU/ml, respectively. TEM studies revealed that exposure to PEF treatment resulted in substantial damage at the cellular level to M. paratuberculosis.

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Bone remodelling in Neanderthal mandibles from the El Sidrón site (Asturias, Spain)

Biology Letters ◽

10.1098/rsbl.2010.1188 ◽

2011 ◽

Vol 7 (4) ◽

pp. 593-596 ◽

Cited By ~ 17

Author(s):

Cayetana Martinez-Maza ◽

Antonio Rosas ◽

Samuel García-Vargas ◽

Almudena Estalrrich ◽

Marco de la Rasilla

Keyword(s):

Morphological Traits ◽

Bone Growth ◽

Bone Remodelling ◽

Histological Study ◽

Growth Dynamics ◽

Mental Foramen ◽

Primate Species ◽

Bone Surface ◽

Skull Morphology

Skull morphology results from the bone remodelling mechanism that underlies the specific bone growth dynamics. Histological study of the bone surface from Neanderthal mandible specimens of El Sidrón (Spain) provides information about the distribution of the remodelling fields (bone remodelling patterns or BRP) indicative of the bone growth directions. In comparison with other primate species, BRP shows that Neanderthal mandibles from the El Sidrón (Spain) sample present a specific BRP. The interpretation of this map allows inferences concerning the growth directions that explain specific morphological traits of the Neanderthal mandible, such as its quadrangular shape and the posterior location of the mental foramen.

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Bacterial handling under the influence of non-uniform electric fields: dielectrophoretic and electrohydrodynamic effects

Anais da Academia Brasileira de Ciências ◽

10.1590/s0001-37652008000400004 ◽

2008 ◽

Vol 80 (4) ◽

pp. 627-638 ◽

Cited By ~ 7

Author(s):

Flavio H. Fernádez-Morales ◽

Julio E. Duarte ◽

Josep Samitier-Martí

Keyword(s):

Electric Fields ◽

Microelectrode Array ◽

Viscous Drag ◽

Liquid Motion ◽

Dielectrophoretic Force ◽

Electrode Surfaces ◽

Biological Objects ◽

Viscous Drag Force ◽

Lift Off ◽

Positive Dielectrophoresis

This paper describes the modeling and experimental verification of a castellated microelectrode array intended tohandle biocells, based on common dielectrophoresis. The proposed microsystem was developed employing platinumelectrodes deposited by lift-off, silicon micromachining, and photoresin patterning techniques. Having fabricated the microdevice it was tested employing Escherichia coli as bioparticle model. Positive dielectrophoresis could be verified with the selected cells for frequencies above 100 kHz, and electrohydrodynamic effects were observed as the dominant phenomena when working at lower frequencies. As a result, negative dielectrophoresis could not be observed because its occurrence overlaps with electrohydrodynamic effects; i.e. the viscous drag force acting on the particles is greater than the dielectrophoretic force at frequencies where negative dielectrophoresis should occur. The experiments illustrate the convenience of this kind of microdevices to micro handling biological objects, opening the possibility for using these microarrays with other bioparticles. Additionally, liquid motion as a result of electrohydrodynamic effects must be taken into account when designing bioparticle micromanipulators, and could be used as mechanism to clean the electrode surfaces, that is one of the most important problems related to this kind of devices.

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Author response: Altered bone growth dynamics prefigure craniosynostosis in a zebrafish model of Saethre-Chotzen syndrome

10.7554/elife.37024.041 ◽

2018 ◽

Cited By ~ 1

Author(s):

Camilla S Teng ◽

Man-chun Ting ◽

D'Juan T Farmer ◽

Mia Brockop ◽

Robert E Maxson ◽

...

Keyword(s):

Bone Growth ◽

Growth Dynamics ◽

Author Response ◽

Zebrafish Model

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Living fast in the Triassic: New data on life history in Lystrosaurus (Therapsida: Dicynodontia) from northeastern Pangea

PLoS ONE ◽

10.1371/journal.pone.0259369 ◽

2021 ◽

Vol 16 (11) ◽

pp. e0259369

Author(s):

Zoe T. Kulik ◽

Jacqueline K. Lungmus ◽

Kenneth D. Angielczyk ◽

Christian A. Sidor

Keyword(s):

South African ◽

Mass Extinction ◽

Bone Growth ◽

Growth Dynamics ◽

Maximum Size ◽

Long Bone ◽

African Species ◽

Geometric Morphometric ◽

Chinese Sample ◽

Average Body

Lystrosaurus was one of the few tetrapods to survive the Permo-Triassic mass extinction, the most profound biotic crisis in Earth’s history. The wide paleolatitudinal range and high abundance of Lystrosaurus during the Early Triassic provide a unique opportunity to investigate changes in growth dynamics and longevity following the mass extinction, yet most studies have focused only on species that lived in the southern hemisphere. Here, we present the long bone histology from twenty Lystrosaurus skeletal elements spanning a range of sizes that were collected in the Jiucaiyuan Formation of northwestern China. In addition, we compare the average body size of northern and southern Pangean Triassic-aged species and conduct cranial geometric morphometric analyses of southern and northern taxa to begin investigating whether specimens from China are likely to be taxonomically distinct from South African specimens. We demonstrate that Lystrosaurus from China have larger average body sizes than their southern Pangean relatives and that their cranial morphologies are distinctive. The osteohistological examination revealed sustained, rapid osteogenesis punctuated by growth marks in some, but not all, immature individuals from China. We find that the osteohistology of Chinese Lystrosaurus shares a similar growth pattern with South African species that show sustained growth until death. However, bone growth arrests more frequently in the Chinese sample. Nevertheless, none of the long bones sampled here indicate that maximum or asymptotic size was reached, suggesting that the maximum size of Lystrosaurus from the Jiucaiyuan Formation remains unknown.

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