Question

Q:Select one application of tissue engineering on different types of tissues other than cartilage, bone and vascular. Define the properties of the tissue and explain what type of materials would be potential to use. How would you fabricate this scaffold? What would be possible techniques that you do in order to increase your scaffolds’ regeneration capacity? You should always consider the host response and immune rejection while designing your ideal scaffold.

Answer 1

Tissue engineering is the use of a combination of cells, engineering, and materials methods, and suitable biochemical and physicochemical factors to improve or replace biological tissues. Tissue engineering involves the use of a tissue scaffold for the formation of new viable tissue for a medical purpose. Tissue engineering involves applications that repair or replace portions of or whole tissues. Often, the tissues involved require certain mechanical and structural properties for proper functioning.

Scaffolds are materials engineered to cause desirable cellular interactions to contribute to the formation of new functional tissues for medical purposes. Cells are often 'seeded' into these structures capable of supporting three-dimensional tissue formation. Scaffolds mimic the extracellular matrix of the native tissue, recapitulating the in vivo milieu and allowing cells to influence their own microenvironments. They usually serve purposes like : allow cell attachment and migration, deliver and retain cells and biochemical factors, enable diffusion of vital cell nutrients and expressed products, exert certain mechanical and biological influences to modify the behaviour of the cell phase.

Material used -

Many different materials (natural and synthetic, biodegradable and permanent) are used.  Most of these materials have been known in the medical field before and thus are being already employed as bioresorbable sutures. Examples of these materials are collagen and some polyesters

To achieve the goal of tissue reconstruction, scaffolds must meet some specific requirements. High porosity and adequate pore size are necessary to facilitate cell seeding and diffusion throughout the whole structure of both cells and nutrients. Biodegradability is often an essential factor since scaffolds should preferably be absorbed by the surrounding tissues without the necessity of surgical removal. The rate at which degradation occurs has to coincide as much as possible with the rate of tissue formation: this means that while cells are fabricating their own natural matrix structure around themselves, the scaffold is able to provide structural integrity within the body and eventually it will break down leaving the newly formed tissue which will take over the mechanical Load.

Techniques for scaffold formation - Nanofiber self-assembly, Textile technologies, Solvent casting and particulate leaching, gas foaming, Emulsification freeze-drying.