High School Student Vestal Senior High School Vestal, New York, United States
Introduction: Primarily as a result of various cancers and tumors—malignant or nonmalignant alike—gastroduodenal outlet obstruction impedes the process in which the stomach empties, associated with persistent emesis and abdominal pains. This obstruction occurs in the stomach or in close proximity—the duodenum. Due to the obstruction, stenting may be applied to ameliorate such symptoms and complications. Stenting, viewed as a reliable and effective method of opening blockages, uses small, mesh metal tubes aimed at supporting body passages or, specifically in this case of study, clearing blockages in the gastrointestinal tract. In certain patient conditions, gastroduodenal stents require removal; this removal may be determined due to beneficial outcomes—relief of obstruction pain—or due to complications—stent migration. Removing such stents calls for additional medical attention, cost, and opening for further comorbidity. This study targets the process of stent removal, replacing the common stent material of carbon, iron, nickel, and chromium alloys with zinc, implementing biodegradability.
Materials and
Methods: To measure the rate of dissolution of zinc in HCl, one plastic bucket was obtained to hold water. A 100 mL eudiometer with a variability of ± 0.1 mL was filled with water to 3.0 mL, secured to a retort clamp on a stand. The opening of the eudiometer was positioned toward the bucket bottom, leaving an opening for rubber tubing to enter. Filling a 20 mL glass test tube, 7.0 mL of 1.0 M HCl was measured using 10 mL graduated cylinders with uncertainties of ± 0.1 mL. This process of hydrogen gas collection confirms the dissolution of zinc in gastric acid and was performed at five varying temperatures (0.0°C, 10.0°C, 22.8°C, 50.0°C, 75.0°C) to simulate body temperature levels and methods of dissolution control. For all trials, the 20 mL test tube was placed in a 400 mL beaker filled with water to 200 mL. With contrasting temperature systems, the methods of water preparation varied, utilizing ice water or a hot plate to obtain the desired temperatures (Figure 1). Once experimental equipment and glassware were properly prepared, 0.5000 g of mossy zinc was massed using an analytical balance calibrated to an uncertainty of ± 0.0001 g. The zinc was then added to the test tube, beginning the gas collection procedure by attaching a rubber tubing stopper, connecting it to the eudiometer (Figure 2). With the reaction progression, gas was collected by water displacement for five minutes for each trial.
Results, Conclusions, and Discussions: A clear positive linear relationship is displayed between the two variables (Figure 4). The rates of reaction were determined—with respect to the HCl—as 0.016 mol L-1 min-1, 0.035 mol L-1 min-1, 0.065 mol L-1 min-1, 0.14 mol L-1 min-1, and 0.17 mol L-1 min-1 for each of the increasing temperatures, derived from individual hydrogen gas production volumes. At colder temperatures of 0.0°C and 10.0°C, gas production—observed through bubbling—occurred at comparatively slower rates (Figure 3A). At the experimental room temperature of 22.8°C, bubbles escaping the rubber tubing were larger in size, filling the circumference of the eudiometer (Figure 3B). At higher temperature conditions (50.0°C and 75.0°C), the reacting solution grew cloudy from rapid gas production and swirling movement (Figure 3C). Adhering to the general trend of most chemical reactions, the overall reaction rate displays a directly proportional relationship with temperature. Controlling the rates at which zinc stents degrade in gastrointestinal tracts proves possible through external heating or cooling devices, exploiting the demonstrated proportionality.
By resourcing zinc as the primary material for temporary stents, specifically in the gastrointestinal tract, removal procedures would be deemed unnecessary, replaced by the dissolution process of zinc in gastric acid, HCl. For patients and medical sectors alike, costs would diminish significantly, providing efficient methods of treatment for obstructions. This concept can be further applied to other body locations and systems, testing alternative stent metals for biodegradability in the body. Expanding to a greater extent, biodegradability can be applied to a variety of surgical items, including implants, bandages, and sealants. With the ongoing study of biodegradability in the medical field, the study of zinc stents provides proof and reason for additional study and attention.
