Smart Microneedle Stent Seals Intestinal Surgery Sites and Delivers Drugs On Demand

Bowel resection — surgical removal of diseased intestinal segments — is among the most common and consequential abdominal procedures performed worldwide. Its success depends on two factors: a secure mechanical reconnection of the bowel ends (anastomosis) and control of post-surgical inflammation that can lead to leakage, infection, or cancer recurrence. Current approaches rely on hand-sewn or stapled anastomoses combined with systemic drug administration, an approach prone to dosing complications, off-target effects, and inadequate local drug concentrations.

Researchers from Zhejiang University developed a microneedle anastomotic stent (MAS) designed to solve both problems simultaneously. The device integrates a biodegradable polyglycolic acid stent — providing structural support and leak prevention — with a stimulus-responsive polyprodrug microneedle patch. The microneedles penetrate the mucosal layer of the intestine and release an anti-inflammatory drug payload specifically in response to the hyperinflammatory microenvironment at the anastomotic site, enabling precise on-demand therapy without systemic exposure.

In vitro testing confirmed minimal cytotoxicity and strong biocompatibility for both the MAS and its degradation products. Ex vivo experiments using actual patient tissue samples demonstrated effective mucosal penetration and inflammation-triggered drug release. In vivo validation was conducted in a murine radiation colitis model and in a minipig model of ischemic inflammatory bowel injury — the latter closely mimicking human surgical conditions — with both confirming the device's safety, feasibility, and therapeutic efficacy.

The MAS also demonstrated versatility as a drug delivery platform, showing potential to carry diverse therapeutic agents for more complex intestinal diseases such as colorectal cancer or Crohn's disease.

This technology could represent a significant step forward in minimally invasive gastrointestinal surgery. By eliminating sutures and enabling localized smart drug delivery, it may reduce anastomotic leak rates and systemic drug toxicity. However, human clinical trials are needed before this approach can be adopted in practice.