Thursday, March 15, 2007

Potential of Nanofiber Matrix as Tissue-Engineering Scaffolds

ZUWEI MA, Ph.D. MASAYA KOTAKI, Ph.D. RYUJI INAI,
and SEERAM RAMAKRISHNA, Ph.D.

It's been well documented that cell behaviors depends greatly on the surrounding ECM properties. So in order for a TE device to be successful ECM properties need to be taken into account. This paper explores the use of nanofibers to fulfill that need and the various techniques commonly used to manufacture nanofibers.

Of the 3 common nanofiber production techniques electrospinning is the most used and oldest technique. Although the technique is fairly successful at contructing various nanofibers ranging from biodegradable polymers to collagen, the harsh 10-20 kV condition during spinning. Good luck trying to embedd proteins or cells during the spinning process.

Various research groups have shown PLGA(poly lactic co glycolic acid), PCL(polycaprolactone) or collagen nanofibers can be used to successfully culture fibroblast, cartilage, mesenchymal stem cells, chondrocytes and smooth muscle cells while maintaining their "selfness". The nanofiber structure is capable of supporting cell attachment and proliferation.
Nanofiber's physical properties like fiber diameter, alignment, can be manipulated to match the native physical conditions of various cell's ECM. In cases like TE blood vessel, the nanofiber can be aligned in the direction of the blood flow to help prevent atherosclerosis(hardening of the blood vessel) and the surrouding scaffold for smooth muscles cells can be aligned in concentric circles to help withstand pressure.

For a TE device to perform properly inside a patients body, one can't just slap in the device with no regard for the ECM. This field still have alot of potential for future improvements. One future technique is mimicking spider silk spinning. Such a technique can enalbe TE devices to have time released shells filled with growth factors or nanofibers embedded with living cells.

6 comments:

annie said...

my paper also talks about electrospinning...i'm curious to know what the other 2 nanofiber production techniques are?

kzhang said...

you said that the nanofibers can provide direction and alignment, but i was wondering whether the other option that is being considered, PLGA, can also have alignment similar to nanofibers? i thought PLGA's cross-linking could trap cells or proteins in the polymer, but is there anyway to manufacture it to have similar physical properties as the nanofiber?

kwasi said...

If electrospinning is too harsh an environment to embed cells and proteins then why is it the most commonly used technique? Is there some other method to attach cells to electrospun nanofibers?

Henry Lu said...

kwasi: electrospinning is the most commonly used because its probably oldest and best known method and the equipment set up is much simpler and cheaper than the other methods. cells can be attached after the spinning process.

katherine: since research groups managed to successfully electrospin PLGA fibers I think its safe to assume they can be aligned in the spinning process.

terry: it can help prevent atherosclerosis by controlling the endothelial cell shape, in a study "Micro channel platform for the study of endothelial cell shape and function" they found atherosclerosis forms more near round shaped endothelial cells, so by elongating the endothelial cells through the scaffold they can help prevent atherosclerosis.

Annie: the other two production methods are phase separation and a self-assembly process.

Armodons said...

Did the authors simply discuss the three methods or was there a more in-depth look at the merits of each technique? I understand that fibers of 67% collagen I are best for fibroblast attachment and proliferation. Is there similar optimal conditions for the other types of fibers, and how do they compare?

etsay said...

Since electronspinning is the oldest naonfiber production technique, the other two techniques must have some kind of advantage over electrospinning. Did the authors explain the advantages these other techniques have over electrospinning and possibly their disadvantages?