Current continuous subcutaneous insulin infusion (CSII) systems for treatment of type 1 diabetes (T1D) remain limited by conventional infusion cannulas, which possess substantial mechanical mismatch relative to surrounding soft tissue that may contribute to tissue irritation and chronic foreign body responses, and can have reduced long-term insulin delivery reliability due to cannula blockage. To address these limitations, this study investigated a porous electrospun zwitterionic polyurethane (ZPU) fiber-tube based soft cannula designed to improve tissue compatibility while enabling diffusion-mediated insulin transport through the porous cannula wall during clogged conditions.
Porous electrospun ZPU soft cannulas were fabricated through a modified wire-mandrel electrospinning approach. Because the electrospun structures lacked sufficient rigidity for direct tissue penetration, a retractable needle-sheath insertion platform was additionally developed to support the cannula during implantation while allowing only the soft porous electrospun structure to remain implanted following needle withdrawal. Preliminary implantation studies were performed using rat cadaver dorsal skin, while computational modeling studies investigated insulin transport behavior under unclogged and partially clogged conditions.
Implantation studies demonstrated successful insertion and retention of the porous electrospun ZPU cannulas within tissue using the retractable insertion platform. Computational modeling further demonstrated competent insulin transport capability across the porous wall during partially clogged conditions. Collectively, these findings demonstrate the fabrication feasibility, implantation capability, and alternative transport potential in clogged scenarios of porous electrospun ZPU soft cannulas for improved pump-based insulin delivery systems. Future studies include investigating long-term in vivo performance as well as therapeutic insulin delivery functionality in diabetic animal models.