Source: Peiman Shahbeigi-Roodposhti and Sina Shahbazmohamadi, Biomedical Engineering Department, University of Connecticut, Storrs, Connecticut

For over 4000 years, sutures have been used as a medical intervention. The earliest records indicate linen was the biomaterial of choice. Catgut, which is still in use today, was reportedly used to treat gladiators around 150 AD. Today, there are numerous materials being used for sutures. Sutures are classified by their composition (natural or synthetic) and their absorption (non-resorbable or resorbable).

Resorbable (or absorbable) sutures degrade in the body through either enzymatic degradation or programmed degradation caused by the interaction of water with specific groups in the polymer chain. These sutures are often created from synthetic materials, such as polyglycolic acid, polydioxanone, and polycaprolactone, or natural biomaterials, such as silk. They are usually used for certain internal procedures, like general surgery. Resorbable sutures will hold the wound together for a time frame long enough for healing, but then they eventually disintegrate by the body. On the other hand, non-resorbable sutures do not degrade and must be extracted. They are usually derived from polypropylene, nylon, and stainless-steel. These sutures are usually implemented for orthopedic and cardiac surgery and require a medical professional to remove them at a later date.

Here, the tensile strength of two types of resorbable sutures will be tested after exposing them to neutral, acidic, and alkaline solutions, which correspond to the different pH environments found within the human body. The test will consist of two parts. First, control samples will be prepared and analyzed via tensile testing. Then, samples will be tested after the continuous exposure to solutions of varying pH over the course of several weeks.

1. Sample preparation

1. Create six labels containing the information below, and attach the labels onto screw-top test tubes.
   1. Date: month and day
   2. Sample type: polyglyconate or polydioxanone
   3. Solution type:  acidic (A), alkaline (B), or neutral (N) solution with pH ranging between 2-14.
2. Open the suture packaging and remove the suture. Cut off the needle and discard it into the sharps container.
3. Cut the suture into 3 pieces that are approximat

Over the course of five weeks, all treated specimens were tested and analyzed. From the overall trials, the average tensile strengths were calculated using Equation 1:

   (1)

The standard deviations of all the forces at failure with respect to suture type and solution

In this experiment, the tensile strength of sutures in different pH environments were evaluated. Over five weeks, the tensile strengths of two different types of sutures were explored after exposure to acidic, alkaline, and neutral solutions. The results overwhelmingly indicate that bioabsorbable sutures will degrade over time in any pH environment.

Although the polyglyconate sutures degrade at a faster rate, the remain stronger compared to the polydioxanone sutures. The experimental results a

1. Wise, Donald L., et al. Encyclopedic Handbook of Biomaterials and Bioengineering. Marcel Dekker, Inc., New York. 1995. 567-569.
2. Dattilo, P.P., King, M.W., Cassill, N.L., et al. Medical Textiles: Application of an Absorbable Barbed Bi-directional Surgical Suture. J. Text. & App., Tech. & Mgmt. 2002, 2, 1