scholarly journals Localized mechanical stimulation of single cells with engineered spatio-temporal profile

Lab on a Chip ◽  
2018 ◽  
Vol 18 (19) ◽  
pp. 2955-2965 ◽  
Author(s):  
M. Monticelli ◽  
D. S. Jokhun ◽  
D. Petti ◽  
G. V. Shivashankar ◽  
R. Bertacco

We introduce a new platform for mechanobiology based on active substrates, made of Fe-coated polymeric micropillars, capable to apply mechanical stimuli with tunable spatio-temporal profile on a cell culture.

2003 ◽  
Vol 773 ◽  
Author(s):  
James D. Kubicek ◽  
Stephanie Brelsford ◽  
Philip R. LeDuc

AbstractMechanical stimulation of single cells has been shown to affect cellular behavior from the molecular scale to ultimate cell fate including apoptosis and proliferation. In this, the ability to control the spatiotemporal application of force on cells through their extracellular matrix connections is critical to understand the cellular response of mechanotransduction. Here, we develop and utilize a novel pressure-driven equibiaxial cell stretching device (PECS) combined with an elastomeric material to control specifically the mechanical stimulation on single cells. Cells were cultured on silicone membranes coated with molecular matrices and then a uniform pressure was introduced to the opposite surface of the membrane to stretch single cells equibiaxially. This allowed us to apply mechanical deformation to investigate the complex nature of cell shape and structure. These results will enhance our knowledge of cellular and molecular function as well as provide insights into fields including biomechanics, tissue engineering, and drug discovery.


Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 474
Author(s):  
Silvia Todros ◽  
Silvia Spadoni ◽  
Edoardo Maghin ◽  
Martina Piccoli ◽  
Piero G. Pavan

Muscular tissue regeneration may be enhanced in vitro by means of mechanical stimulation, inducing cellular alignment and the growth of functional fibers. In this work, a novel bioreactor is designed for the radial stimulation of porcine-derived diaphragmatic scaffolds aiming at the development of clinically relevant tissue patches. A Finite Element (FE) model of the bioreactor membrane is developed, considering two different methods for gripping muscular tissue patch during the stimulation, i.e., suturing and clamping with pliers. Tensile tests are carried out on fresh and decellularized samples of porcine diaphragmatic tissue, and a fiber-reinforced hyperelastic constitutive model is assumed to describe the mechanical behavior of tissue patches. Numerical analyses are carried out by applying pressure to the bioreactor membrane and evaluating tissue strain during the stimulation phase. The bioreactor designed in this work allows one to mechanically stimulate tissue patches in a radial direction by uniformly applying up to 30% strain. This can be achieved by adopting pliers for tissue clamping. Contrarily, the use of sutures is not advisable, since high strain levels are reached in suturing points, exceeding the physiological strain range and possibly leading to tissue laceration. FE analysis allows the optimization of the bioreactor configuration in order to ensure an efficient transduction of mechanical stimuli while preventing tissue damage.


2014 ◽  
Vol 78 ◽  
pp. 131-140 ◽  
Author(s):  
Francesca Antoniolli ◽  
Stefano Maggiolino ◽  
Nicola Scuor ◽  
Paolo Gallina ◽  
Orfeo Sbaizero

1992 ◽  
Vol 67 (6) ◽  
pp. 1509-1527 ◽  
Author(s):  
C. M. Owens ◽  
D. Zhang ◽  
W. D. Willis

1. The responses of a population of 318 spinothalamic tract (STT) cells to mechanical stimulation of the skin were recorded in anesthetized macaque monkeys by several teams of investigators. The responses were subjected to k-means cluster analysis, a multivariate statistical procedure. 2. For an analysis that pertained to the responsiveness of the neurons, the mean responses to four standard mechanical stimuli (Brush, Pressure, Pinch, and Squeeze) were used. Although no true clusters were found, the cells could be partitioned into four groups (called clusters a, b, c, and d) that responded progressively more vigorously to the stimuli. 3. For an analysis that pertained to the selectivity of the cells for various stimulus intensities, from innocuous to highly noxious, the data were normalized by taking the ratio of the mean response evoked by each stimulus to the sum of the responses and multiplying by 100. This procedure does not have a bias toward selection of any particular number of clusters and resulted in three clusters of STT cells. 4. Cluster 1 STT cells responded best to Brush. Cluster 2 cells responded weakly to Brush and Pressure and maximally to Pinch. Cluster 3 cells responded weakly to Brush, Pressure, and Pinch and maximally to Squeeze. 5. The response states of STT cells with respect to mechanical stimulation of the skin can be defined by their cluster assignments on the basis of the responsiveness (clusters a-d) and selectivity (clusters 1-3) of the cells. The response states of newly recorded STT cells can be determined by discriminant analysis from the nearest centroids of the two types of clusters in the reference population of STT cells. 6. No consistent changes in response state were detected when a second series of mechanical stimuli was applied 1 cm from the site stimulated initially or when the stimulus series was alternately repeated at the initial site and at progressively more proximal sites. However, when the stimulus series was applied five times to the initial site, the response state of five of eight cells tested showed a change. Although a change in response state required repetitive damage, even a single stimulus series increased background activity and responses to Brush at undamaged sites. 7. The background activity and responses to Brush and Pressure of all five STT cells recorded in the superficial laminae increased after repeated testing. The background activity of five STT cells recorded in the nucleus proprius also increased, but the responses of only three of the cells to Brush and Pressure increased.(ABSTRACT TRUNCATED AT 400 WORDS)


1975 ◽  
Vol 38 (1) ◽  
pp. 132-145 ◽  
Author(s):  
R. D. Foreman ◽  
A. E. Applebaum ◽  
J. E. Beall ◽  
D. L. Trevino ◽  
W. D. Willis

The responses of spinothalamic tract neurons were studied by extra- and intracellular recordings from the lumbosacral spinal cord in anesthetized rhesus monkeys (Macaca mulatta). The neurons were identified by antidromic activation from the contralateral diencephalon. They were then classified by the mildest form of mechanical stimulation applied to the ipsilateral hindlimb. The effects of electrical stimulation of the nerve(s) supplying the receptive field were investigated. Graded electrical stimulation revealed that the threshold responses of spinothalamic tract neurons excited by weak mechanical stimuli occurred when the largest afferent fibers were activated. On the other hand, neurons that required intense mechanical stimulation for their excitation tended to have higher thresholds to electrical stimulation. Some spinothalamic tract cells were shown to receive monosynaptic excitatory connections from peripheral nerve fibers, although polysynaptic connections may generally be more important. An input from unmyelinated afferent fibers was demonstrated. It is concluded the primate spinothalamic tract neurons receive a rich convergent input from a variety of cutaneous receptors. The experiments provide some evidence for the most likely types of receptors.


Author(s):  
Jennifer Blundo ◽  
Gretchen Chua ◽  
Oscar Abilez ◽  
Yong-Lae Park ◽  
Ali Rastegar ◽  
...  

A BioMEMS platform was designed and fabricated to enable electromechanical stimulation of cell cultures. The device consists of a stretchable microelectrode array embedded in a biocompatible elastomeric polymer, which is deformed by vacuum over a glass baseplate. The entire device is optically transparent and ∼1mm thick. Four cell culture wells apply electrical and/or mechanical stimulation in the range of 1–10 V/cm and 0–10% equibiaxial strain. Studies of electromechanical stimulation of cardiac myocyte precursors on this platform are proposed to elucidate mechanisms of differentiation.


1992 ◽  
Vol 169 (1) ◽  
pp. 181-206 ◽  
Author(s):  
DANIEL CATTAERT ◽  
JEAN-YVES BARTHE ◽  
DOUGLAS M. NEIL ◽  
FRANCOIS CLARAC

1. An isolated preparation of the crayfish nervous system, comprising both the thoracic and the abdominal ganglia together with their nerve roots, has been used to study the influence of a single leg proprioceptor, the coxo-basal chordotonal organ (CBCO), on the fictive swimmeret beating consistently expressed in this preparation. Both mechanical stimulation of the CBCO and electrical stimulation of its nerve were used. 2. In preparations not displaying rhythmic activity, electrical or mechanical stimulations evoked excitatory postsynaptic potentials (EPSPs) in about 30 % of the studied motor neurones with a fairly short and regular delay, suggesting an oligosynaptic pathway. Such stimulation could evoke rhythmic activity in swimmeret motor nerves. The evoked swimmeret rhythm often continued for several seconds after the stimulus period. 3. When the swimmeret rhythm was well established, electrical and mechanical stimuli modified it in a number of ways. Limited mechanical or weak electrical stimuli produced a small increase in swimmeret beat frequency, while more extreme movements of the CBCO or strong electrical stimuli had a disruptive effect on the rhythm. 4. The effect of low-intensity stimulation on existing swimmeret beating was phase-dependent: it shortened the beat cycle when applied during the powerstroke phase and lengthened it when applied during the retumstroke phase. 5. Rhythmic mechanical stimulation of CBCO or electrical stimulation of the CBCO nerve entrained the swimmeret rhythm within a limited range in relative or absolute coordination. Note: To whom reprint requests should be sent.


1990 ◽  
Vol 64 (1) ◽  
pp. 299-311 ◽  
Author(s):  
V. Neugebauer ◽  
H. G. Schaible

1. In the spinalized cat, nociceptive spinal neurons with knee input show enhanced responses to mechanical stimulation of that joint once an inflammation has developed in the knee. Enhanced responses may result from increased afferent inflow as well as from modifications of the nociceptive processing within the spinal cord. To examine the significance of these components, we tested in 30 chloralose-anesthetized, spinalized cats whether, during development of arthritis, changes of responsiveness in spinal neurons are restricted to stimulation of the inflamed joint or whether responsiveness in these neurons is altered in general. While continuously recording from a neuron, we injected kaolin and carrageenan into one knee and tested the responses to mechanical stimuli applied to the joint and to regions adjacent to and remote from the knee during the developing arthritis. In addition, in six cats we monitored the neurons' responses to electrical stimulation of the sural nerves and the rostral lumbar spinal cord. 2. Of 32 neurons in laminae VI, VII, and VIII of the lumbar spinal cord, 15 ascending and eight nonascending cells were driven by mechanical stimulation of one or both knee joint(s). Nine of these were nociceptive specific (NS), responding exclusively or predominantly to noxious compression of the knee and other deep tissue, and 12 were wide-dynamic-range (WDR) cells with graded responses to gentle and noxious stimuli applied to the knee joint(s), deep tissue, and skin. Two neurons with high ongoing discharges had some excitatory joint input but showed marked inhibition by most stimuli used (INH neurons). The majority of the neurons had receptive fields on both legs. Nine of the 32 neurons had no input from the knee(s). 3. All 23 neurons with joint input became sensitive or more responsive to movements and gentle compression of the inflamed knee once the inflammation had developed. In general, these neurons also showed enhanced responses to compression of the adjacent muscles in thigh and lower leg. In 20 neurons, response properties were even altered for stimuli applied to regions remote from the inflamed joint, including the contralateral leg in 18 cases. We found expansion of initially restricted receptive fields (mainly in NS cells), enhancement of preexisting responses, and/or lowering of threshold to mechanical stimuli applied to these regions; few neurons developed inhibitory reactions.(ABSTRACT TRUNCATED AT 400 WORDS)


1994 ◽  
Vol 72 (4) ◽  
pp. 1464-1475 ◽  
Author(s):  
P. M. Dougherty ◽  
J. Palecek ◽  
V. Paleckova ◽  
W. D. Willis

1. Activation of neurokinin receptors contributes to the excitation of many dorsal horn neurons by cutaneous sensory stimuli, particularly noxious stimuli. In the present study we investigate the role of neurokinin receptors in the activation of primate spinothalamic tract (STT) neurons by cutaneous mechanical stimuli and by intradermal injection of capsaicin. This was done by testing the responses of these neurons to a battery of cutaneous stimuli before and during infusion by microdialysis of antagonists selective for NK1 and NK2 receptors. 2. The NK1 receptor antagonists cis-3-(2-methoxybenzyl-amino-2-benzhydrylquinuclidine (CP96345) and D-Pro9-[Spiro-y-lactam]-Leu10,Trp11)-Physalaemin(1-11) (GR82334) did not significantly reduce the responses of STT cells to mechanical stimulation of the skin. Both NK1 antagonists did, however, produce a significant reduction in the responses of STT neurons to an intradermal injection of capsaicin. Finally, despite having no effects on responses to mechanical stimuli, both NK1 antagonists prevented the sensitization of the responses to cutaneous stimuli that is usually observed after intradermal injections of capsaicin. 3. The NK2 selective antagonists PhCO-Ala-Ala-D-Trp-Phe-D-Pro-Pro-Nle-NH2 (GR98400) and [Tyr5,D-Trp6,8,9,Lys10]-NKA (4–10) (MEN10376) had effects very similar to those of the NK1 antagonists, but with an important difference. Neither NK2 antagonist affected the responses of STT neurons to noxious or innocuous mechanical stimulation of the skin, but they did reduce the responses to intradermal capsaicin injections. These compounds failed to prevent capsaicin-induced sensitization. In fact, cells exposed to GR98400 or MEN10376 showed unusually sustained increases in the responses to mechanical stimuli after the first capsaicin injection, suggesting that these compounds actually induced sensitization. 4. These results support the contention that both neurokinin receptors participate in the processing of nociceptive information in the dorsal horn, especially responses to strong stimuli such as intradermal injection of capsaicin. NK1 receptors are also involved in the sensitization of STT neurons after peripheral injury. A clearer understanding of the role of NK2 receptors in sensitization requires further studies with improved antagonists.


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