Bioresorbable Zinc Staples for Anastomoses in the Digestive Tract

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Summary: For anastomoses in the digestive tract, titanium (Ti) staples are most-commonly used because of good mechanical strength and ductility but are not biodegradable. Their life-time presence may interfere with imaging examinations and impede growth especially in young patients. The long-term existence would also increase the chance of clinical complications such as leakage, stricture, chronic inflammation, foreign body response, bleeding and infection. A second revision/removal surgery must be performed if the situation gets worse. Biodegradable polymer materials such as PLA-PGA based staples are available but largely for subcuticular applications. Their poor mechanical properties restrain their applications in gastrointestinal (GI) anastomoses which need high closure strength. Thus, these identified inadequacies in the properties of Ti and polymer staples open opportunities for bioresorbable metal (i.e., zinc) as a new generation of anastomotic staples for the digestive tract. The use of metallic Zn as an alternative bioresorbable staple could offer some distinct advantages. The higher strength of Zn makes it ideal for GI anastomoses while its bioresorbable nature may minimize the chance of anastomotic leakage and stricture and will not impede growth or cause chronic inflammation, bleeding and infection. Plus, Zn is an essential and natural element for life, its toxicity should be of minimal concern. In fact, evidence showed that Zn implants could promote stem cell recruiting and differentiation. Zn is also a natural antimicrobial biomaterial that can minimize potential infection after surgical wound-closure as GI mucus is home to trillions of microbes. Additionally, their degradation speed and mechanical strength can be further manipulated through alloying. The goal hereby is to develop bioresorbable Zn-based staples for anastomoses in the digestive tract and to validate their efficacy in cells and animal models through biodegradation, biocompatibility, antimicrobial testing, stem cell differentiation, as well as wound healing including the GI mucus barrier regeneration.