Page 667 - Carrahers_Polymer_Chemistry,_Eighth_Edition

630 Carraher’s Polymer Chemistry

G1; Growth and preparation of
M; Mitosis the chromosomes for
replication

G2; Preparation for mitosis S; Synthesis of DNA

FIGURE 19.6 Cell growth cycle.

touch another cell and then stop reproduction. This is called contact inhibition. Finally, cancer cells
are normally in a growth mode whereas healthy cells are generally in a rest mode. For most situations,
drug action takes advantage of the cancer cells being in a growth mode needing an intake of various
materials to keep growing. Thus, any cell that is growing at the time a chemo drug is administered
will get a dose of the chemo drug, most likely a lethal dose. Since the cancer cells are almost always in
the growth mode, they will be most affected. Recently, we have found a family of organotin polymers
that inhibit a variety of cancer cells but do not affect the growth cycle of healthy cells. This points out

another possible avenue to create cancer cell specific drugs. Healthy cells have their autoimmune sys-
tem in tack, whereas cancer cells have damaged autoimmune systems. These organotin polymers may
be warded off by the healthy cells, whereas the cancer cells, are inhibited by them.

19.5 SYNTHETIC BIOMEDICAL POLYMERS

Synthetic polymers have been studied for some time for their use in the general field of medicine.

Initial results were average. More recently, because of a better understanding of the importance of
surface, avoidance of contaminants, control of molecular weight and molecular weight distribution the
use of synthetic polymers in the biomedical sciences is increasing. Polymers are viewed as important
biomedical materials for a number of reasons, some of which appear contradictory—but only because
different uses require different properties. Some of the important properties are the ability to tailor-
make structures, surface control, strength, flexibility, rigidity, inertness/reactivity, light weight, ease

of fabrication, ability to achieve a high degree of purity, lack of and because of their water solubility/
compatibility, bioerodability, and the ability of some of them to withstand long-term exposure to the
human body—a truly hostile environment. Fighting against some of the biomaterials are their limited
(by volume) use—thus, researchers are often limited to using commercial materials made for other
applications, but as the use of these important materials increases, manufactures will become more
interested in tailormaking materials if for no other reason than the high cost per unit volume.
Long-term inertness without loss of strength, fl exibility, or other necessary physical property is
needed for use in artificial organs, prostheses, skeletal joints, and so on. Bioerodability is needed

9/14/2010 3:44:00 PM
K10478.indb 630 9/14/2010 3:44:00 PM
K10478.indb 630