Flexible 3D Nanonetworked Silica Film as a Polymer‐Free Drug‐Eluting Stent Platform to Effectively Suppress Tissue Hyperplasia in Rat Esophagus

Abstract

Loading and eluting drugs on self‐expandable metallic stents (SEMSs) can be challenging in terms of fabrication, mechanical stability, and therapeutic effects. In this study, a flexible 3D nanonetworked silica film (NSF) capable of withstanding mechanical stress during dynamic expansion is constructed to function as a drug delivery platform on an entire SEMS surface. Despite covering a broad curved area, the synthesized NSF is defect‐free and thin enough to increase the stent strut diameter (110 µm) by only 0.4 percent (110.45 µm). The hydrophobic modification of the surface enables loading of 4.7 times the sirolimus (SRL) concentration in NSF than Cypher, polymer‐coated commercial stent, which is based on the same thickness of coating layer. Furthermore, SRL‐loaded NSF exhibits a twofold delay in release compared to the control group without NSF. The SRL‐loaded NSF SEMS significantly suppresses stent‐induced tissue hyperplasia than the control SEMS in the rat esophagus (all variables, p < 0.05). Thus, the developed NSF is a promising polymer‐free drug delivery platform to efficiently treat esophageal stricture.

3D-printed versatile biliary stents with nanoengineered surface for anti-hyperplasia and antibiofilm formation

“…Fibroblast cell line was used to compare the ability of the inhibiting hyperplasia, as portal fibroblasts in bile duct epithelia, which is associated with biliary fibrosis, are similar to other fibroblast [ 118 , 119 ]. The adhesion and viability of fibroblasts on the surfaces of 3D-printed stents were compared after culturing for 24 h and 3 and 5 d, respectively.…”

Radiofrequency ablation via an implanted self-expandable metallic stent to treat in-stent restenosis in a rat gastric outlet obstruction model

“…RFA was performed at 4 weeks to evaluate the therapeutic effects of in-stent restenosis after granulation tissue formation had already occurred. It is well known that in-stent restenosis caused by stent-induced tissue hyperplasia of non-vascular luminal organs, such as the esophagus, urethra, biliary duct, and gastric outlet, occurs as an excessive proliferative response within 4 weeks after mechanical injury due to stent placement (Jun et al, 2017;Kim et al, 2018;Park et al, 2018;Park et al, 2020;Jeon et al, 2022;Park et al, 2022). Our current findings support the fact that the local SEMS-mediated RFA is an effective therapeutic option for the treatment of stentinduced granulation tissue formation in the rat GOO model.…”

“…However, a high risk of progressive tissue ingrowth or overgrowth through the stent meshes has been reported, and these situations are still considered significant obstacles to successful stent placement (Wadhwa et al, 2003;Kim et al, 2014;Jeong, 2016). To treat tissue hyperplasia or tumor growth adjacent to the implanted SEMS in non-vascular luminal organs, various functionalized stents with the use of antiproliferative or anticancer drugs, small interfering RNA, nanomaterials, and shape modifications have been developed and investigated (Lee et al, 2009;Van Hooft et al, 2011;Kim et al, 2014;Park et al, 2014;Jun et al, 2017;Jeon et al, 2022;Park et al, 2022). However, it remains an unresolved problem in the clinic, and a standard therapeutic strategy has not been established (Park et al, 2019).…”

Localized Photodynamic Therapy Using a Chlorin e6-Embedded Silicone-Covered Self-Expandable Metallic Stent as a Palliative Treatment for Malignant Esophageal Strictures

“…The long-term toxicity of the nanomaterials and polymers used on the stent surface for coating or as a covering membrane also needs to be evaluated. 20 PDT was introduced as an ablation technique for treating esophageal cancer and Barrett's esophagus. 21,22 Photosensitizers (PSs) generate highly reactive oxygen species (ROS) upon appropriate irradiation.…”

“…Despite recent advances in the development of multifunctionalized stents for local and direct therapeutic strategies, further investigation is required to verify the efficacy and safety using human disease models in preclinical trials. The long-term toxicity of the nanomaterials and polymers used on the stent surface for coating or as a covering membrane also needs to be evaluated …”