Improving the antibacterial property of porcine small intestinal submucosa by nano-silver supplementation: a promising biological material to address the need for contaminated defect repair.

Objective: We hypothesize that introduction of nano-silver particles to porcine-derived small intestinal submucosa (NS-PSIS) would lead to significant enhancement in antibacterial property in repairing contaminated abdominal defect.

Background: Porcine-derived small intestinal submucosa (PSIS) is an acellular and xenogenic biological material intensively used in repairing and regenerating wounded and dysfunctional tissues. Surgical site infection (SSI) remains so far a serious problem and major challenge, particularly in contaminated tissue-deficient repairing.

Methods: Self-assembly was used to fabricate NS-PSIS. The antibacterial property was evaluated in vitro and in vivo by means of repairing full-thickness contaminated abdominal defect in rats. The native PSIS and polypropylene-oxidized regenerated cellulose were served as controls. In addition, changes in biomechanical resistance, morphology and immunohistochemistry for inflammatory reaction and neovasculation in the repaired abdominal wall were analyzed. Biosafety was investigated by pyrogen test, skin irritation test and silver measurement in vivo.

Results: NS-PSIS exhibited strong antibacterial activity against Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, and Pseudomonas aeruginosa on agar diffusion, with mean diameters of inhibition zone ranging from 11.9 to 23.5 mm. There were significantly lower SSI incidence and a tendency of better abdominal wall resistance in the NS-PSIS group as compared with the PSIS or polypropylene-oxidized regenerated cellulose group after repairing contaminated abdominal defect in rats. Nano-silver modified PSIS did not change the native PSIS property in the tissue recolonization, remodeling and neovascularization. NS-PSIS was not pyrogenic or skin irritated, without silver residual in vivo after repairing contaminated abdominal defect.

Conclusion: Nano-silver particles to PSIS lead to significant enhancements in antibacterial property in vitro and in vivo without decreasing its biomechanical resistance and biocompatibility. This study provides proof of concept for the use of nano-silver modified naturally derived PSIS as an ideal scaffold for SSI prevention in the contaminated tissue-deficient repair.