"Graphene applications in tissue engineering and in regenerative medicine"

Abstract

The stem cells have the ability to divide asymmetrical (but also symmetrical), leading in generation in daughter cells identical to original cell and appropriate for specific differentiation, as progenitor cell. This cell called Transit Amplifying Cell or TAC. Transit ammplyfying cells eventually become incapacitated for multiplication and are ultimately transformed into terminally differentiated TD cells.The stem cells have the ability to divide asymmetrical (but also symmetrical), leading in generation in daughter cells identical to original cell and appropriate for specific differentiation, as progenitor cell. This cell called Transit Amplifying Cell or TAC. Transit ammplyfying cells eventually become incapacitated for multiplication and are ultimately transformed into terminally differentiated TD cells.

The symmetrical division of stem cells provides a mechanism to increase the population of stem cells after their loss. But it can potentially to cause an uncontrolled escalation number of stem cells. Alternatively, lack appropriate signals may lead to stem cell depletion. Two basic mechanisms appear to govern asymmetric cell division (a) the asymmetric distribution of intracellular and (b) asymmetric orientation; contact of daughter cells with light- or with extraneous signals. In stem cell cultures the addition of agents that induce EMT (such as TGF-β, Snail or Twist) maintains stem cells in an undifferentiated situation.

Researchers have focused on the therapeutic simulation of three types of stem cells: stem cell, adult or physical stem cells and induced multiples. The embryonic stem cells are derived from eggs fertilized in vitro and dispensed for investigation after written consent. The human fetal stem cells are 4-5 days and presume from the9blastocyst. The blastocyst pen the internal cell mass, a group of cells from which the moss. The embryonic stem cells are cultured (theoretically indefinitely, but practically for months) and self-renewed while remaining undifferentiated.

They are characterized by specific superficial ones markers and transcription factors, which and disable genes at the right time dot. The most important are Nanog, OCT4 and SOX2. Adult or somatic stem cells can be differentiated by acquiring trained cells, participating in tissue homeostasis and repair. In the 1950s, bone marrow was found to be included at least two types of adult stem cells: hematopoietic and non-hematopoietic stem cells of the marrow layer, which are also called Squamous cells (MSCs).

Since 2004 and the isolation of the 2D crystal of graphene, an intense effort hasbeen devoted by the scientific community, to integrate graphene into a variety ofapplications. Graphene is a material with unique electrical properties and it appears to have high mobility of charge carriers. In addition, grapheneexhibits excellent mechanical properties,such as high mechanical strength and flexibility, as well as high thermal conductivity. All these quality properties make graphene an excellent candidate for many nanotechnology applications and hence scientists believe that it will gradually replace silicon. Among the many applications of graphene, the most important is the use of graphene and especially the use of RGO (Reduced Graphene Oxide) in order to develop flexible optoelectronic devices as field emitters.

DOTSIKAS Evangelos