The Experts below are selected from a list of 1128 Experts worldwide ranked by ideXlab platform

Paci Claudia - One of the best experts on this subject based on the ideXlab platform.

  • 3D bioprinting di idrogeli nanocompositi piezoelettrici e mioblasti per l'ingegnerizzazione del muscolo scheletrico
    'Pisa University Press', 2091
    Co-Authors: Paci Claudia
    Abstract:

    3D bioprinting has the potential for becoming a future breakthrough method in the implementation of skeletal muscle tissue engineering. In this domain, the physico-chemical properties of bioinks constitute a crucial aspect that can drive an appropriate cell differentiation. Material chemical Cues and mechanical properties have been widely investigated in the last decade. Less explored, yet intriguing, can be the incorporation of exogenous factors (e.g., Electrical, magnetic or mechanical stimulation) to further boost cell differentiative processes. Piezoelectric nanomaterials have been used as nanoscale transducers able to convert mechanically-induced deformation into an Electrical Cue when invested by an ultrasound wave (acting as a wireless source of mechanical energy). This paradigm has shown beneficial effects on different cell types, in particular accelerating the differentiation of neural and muscle precursors. However, no research groups have explored the inclusion of piezoelectric nanoparticles in a bioink used for 3D bioprinting of skeletal muscle cells so far. The aim of this Thesis is to verify the hypothesis that piezoelectric nanoparticles, stimulated with ultrasound, are able to accelerate the differentiation of myoblasts loaded within a nanocomposite hydrogel and printed to form a 3D construct. The idea is to exploit ultrasound as a wireless source of mechanical energy, to locally deform the piezoelectric nanoparticles (in particular, barium titanate nanoparticles) and to verify the effects that this indirect Electrical stimulus can have on the differentiation of myoblasts C2C12, encapsulated in constructs generated by controlled pneumatic extrusion. In the Thesis, a DLS characterization of PGA-coated barium titanate nanoparticles has been carried out and the bioink has been analyzed with DSC and FT-IR. Then 3D constructs loaded with different nanoparticle concentrations have been analyzed with SEM imaging and EDX spectroscopy. Biological analyses have been carried out to evaluate cell viability, proliferation and differentiation (with and without ultrasound stimulation) in the 3D constructs

Juliana Guerra Hühne - One of the best experts on this subject based on the ideXlab platform.

  • Fotoreceptores em campo elétrico
    2017
    Co-Authors: Juliana Guerra Hühne
    Abstract:

    Resumo: Estudos anteriores e evidências experimentais sugerem um papel importante dos campos elétricos endógenos no direcionamento da migração celular, no desenvolvimento e na regeneração celular e na cicatrização de feridas. Em culturas de células, campos elétricos de corrente contínua influenciam a divisão celular, a polaridade, a forma e a motilidade das células. As distrofias das células fotoreceptoras são uma das principais causas de cegueira hereditária no mundo ocidental; a aplicação de campo elétrico poderia ser usada como um sinal direcional para o crescimento das células fotoreceptoras na direção do tecido danificado. Neste estudo, investigamos os efeitos do campo elétrico no estabelecimento da polaridade celular de fotoreceptores e na polarização de estruturas intracelulares, a fim de demonstrar que são regulados por um sinal elétrico externo. Utilizando um ensaio de migração bem estabelecido, células fotoreceptoras de retina de camundongos do tipo cone, 661W, foram estimuladas durante 5 horas com campo eléctrico de 5 V/cm. Através de técnicas de imunofluorescência, investigamos mudanças na posição de organelas importantes após a estimulação, como o núcleo e o complexo de Golgi (GA), e também de proteínas do citoesqueleto, tais como actina, microtúbulos e o centro organizador dos microtúbulos (MTOC). Além disso, investigamos também alterações no potencial da membrana plasmática e mitocondrial utilizando corantes específicos, na presença e ausência de campo elétrico aplicado. Em resposta ao estímulo direcional, as células 661W estenderam protuberâncias de membrana no sentido do catodo; elas se alongaram perpendicularmente ao campo elétrico e formaram uma borda frontal. Ocorreu migração significativa na direção do catodo. O centro organizador dos microtúbulos, o complexo de Golgi e actina foram reorientados na direcção da borda frontal das células (catodo), enquanto os microtúbulos se acumularam na borda traseira das células (anodo) e o núcleo foi translocado para a parte de trás das células, também na borda traseira. Após exposição ao campo elétrico, ambos os potenciais de membrana, plasmático e mitocondrial, se despolarizaram, especialmente no lado do catodo das células. Esse estudo contribuiu para uma melhor compreensão dos mecanismos de migração direcional devido ao campo elétrico das células 661W, que depende da despolarização das membranas plasmática e mitocondrial e da polarização induzida do citoequeleto de actina e microtúbulos, com subsequente polarização do núcleo, MTOC e GA.Abstract: Previous studies and experimental evidences suggest an important role for endogenous electric fields in directing cell migration in wound healing, development and regeneration. In cultures, applied direct current electric field (dcEF) influences cell division, polarity, shape and motility. Photoreceptors dystrophies are one of the major causes of inherited blindness in the western world; application of EF could be used as a Cue to direct photoreceptors cells to growth towards the damaged tissue. In this study we investigate the effects of dcEF in the establishment of photoreceptor cell polarity and polarization of intracellular structures, in order to demonstrate that they are regulated by an extracellular Electrical Cue. Using a well established migration assay, photoreceptors cone-like 661W mouse retinal cells were stimulated for 5 h with 5 V/cm electric field. Using immunofluorescence techniques we have investigated changes in position of important organelles after the stimulation, like Golgi Apparatus (GA) and nucleus, and also cytoskeletal proteins, such as the Microtubules Organizing Center (MTOC), actin and Microtubules (MT). Furthermore, we investigated changes in plasma and mitochondrial membrane potentials using ion reporter dyes in the presence and absence of an applied dcEF. In response to the directional stimulus, 661W cells have extended membrane protrusions towards cathode; they got elongated perpendicular to the dcEF and have formed a leading edge towards the direction of Cues. Directional migration has occurred towards cathode. MTOC, GA and actin were reoriented in the direction of the leading edge of the cells (cathode), while the MT accumulated in the rear edge of the cells (anode) and the nucleus was translocated to the back of the cells, also in the rear edge. After dcEF exposure, both plasma and mitochondrial membranes were depolarized, especially in the cathode side of the cells. This study extended an understanding of the mechanism of the dcEF-directed 661W cell migration, which depends on plasma and mitochondrial membrane depolarization and an induced polarization of actin cytoskeleton and microtubules with subsequent polarization of nucleus, MTOC and GA