Stitches, dissolving

Polylactic acid (PLA) has been produced for many years as a high-value material for use in medical applications such as dissolvable stitches and controlled release devices, because of the high production costs. The very low toxicity and biodegradability within the body made PLA the polymer of choice for such applications. In theory PLA should be relatively simple to produce by simple condensation polymerization of lactic acid. Unfortunately, in practice, a competing depolymerization process takes place to produce the cyclic lactide (Scheme 6.10). As the degree of polymerization increases the rate slows down until the rates of depolymerization and polymerization are the same. This equilibrium is achieved before commercially useful molecular weights of PLA have been formed. 

Figure 7.5 Stitched TEM images of Nanocyl NC7000 dissolved from PC composites containing 3 wt% MWCNT including lines to show the length of selected highlighted nanotubes.

CHEMICAL CONNECTIONS 16A Stitches That Dissolve 16B Paper or Plastic ... 

Catgut is a traditional monofilament used to stitch wounds together, but there are now many alternative fibrous materials available. Another natural product, braided silk fibre can also be used, and individual doctors make a choice appropriate for each particular type of wound. Stitches that dissolve... 

In decorative embroidery, elaborate stitching is sewn onto a base fabric. In order to make a free-standing 3D structure, the base fabric is dissolved away. An example, which is used in reconstractive shoulder surgery (McQuaid, 2005), is shown in Figure 1.12. The product was designed by Peter Butcher and manufactured by Ellis Developments Ltd. 

Section 29.5 Chemical Connections Stitches That Dissolve Section 29.6 Chemical Connections Organic Polymers That Conduct Electricity MCAT Practice The Chemistry of Superglue... 

Dexon (below) is a polyester that is spun into fibers and used for surgical stitches that dissolve overtime, eliminating the need for a follow-up procedure to remove the stitches. The ester moieties are slowly hydrolyzed by enzymes present in the body, and in this way, the stitches are dissolved over a period of several months. Hydrolysis of the polymer produces glycolic acid, which is readily metabolized by the body. Draw the structure of glycolic acid. Identify a systematic name for glycolic acid. 

After the surgery, Maureen applies Indermil, which is a type of liquid bandage, to Robert s incision sites. Liquid bandages are tissue adhesives that seal surgical or wound incisions on a patient. Stitches and staples are not required and scarring is minimal. The polymer in a liquid bandage is typically dissolved in an alcohol-based solvent. The alcohol also acts as an antiseptic. 

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