Main - Information - Contact

Cellular Microencapsulation by Sasha Bakhru

Polymeric microcapsules provide a unique means to investigate the in?uence of physical and biochemical cues on cells in three dimensional microenvironments in vitro. Capsule parameters, such as permeability, size, and composition, can in?uence the viability, proliferation and fate of the cells cultured inside microcapsules (Fig. 1.3). A major advantage three-dimensional sca?olds have over their two-dimensional counterparts is that they can more closely mimic the natural cellular niche in terms of secreted factor presentation, cell-cell interaction, and cellsubstrate interaction. The three-dimensional sca?old is able to provide improved cell-cell contact, cell-ECM contact, and dispersion of secreted factors by having the cells surround each other in the extracellular space (Fig. 1.4) (Orive et. al., 2003). 2D sca?olds result in polar cell signaling, inplane cellcell contact, and directional cellsubstrate interaction, atypical of soft tissue architecture.


1.2.1 History of Cellular Microencapsulation

Cellular microencapsulation was ?rst developed for the purpose of immunoisolating allogenic and xenogenic cells following in vivo implantation for a variety of therapeutic applications. Encapsulation of pancreatic islets to provide a sustainable insulin depot for diabetic patients was among the most widely publicized. Type I diabetes is an autoimmune disorder in which the patient's own immune system attacks the islet cells that produce insulin. Encapsulation of the cultured islet cells in a thin shell is safe from the immune response but is permeable to insulin, nutrients, and other metabolic necessities (Orive et. al., 2003).

A second important application of cell encapsulation involves hepatocytes, among the most di?cult cells to culture. In lieu of allotransplantation, individuals su?ering from acute liver failure have limited options. Bioarti?cial Liver Assist Devices (BLAD) have been developed for the purpose of aiding a failing liver via perfusion of blood plasma through an extracorporeal device in which hepatocytes are encapsulated within a threedimensional microenvironment, promoting normal functions such as detoxi?cation, excretion, and metabolism. First generation BLADs were hollow cartridges housing hepatocytes cultured in the luminal space. Recently, there have been e?orts to encapsulate hepatocytes (Patzer et al. 2001) as the base for BLADs. Microcapsules serve to immunoisolate the cells within, and improves mass transfer with circulating blood.

Other Sites/Articles by Sasha Bakhru:

Sasha Bakru's Main Page
Sasha Bakhru: Polymeric Microcapsules - Introduction and Background

Recommended Sites:
Belfordhighschool - Online Highschool -
Losangelessalestraining - Sales Management School -