Porous ZnO/2–Hydroxyethyl Methacrylate Eluting Coatings for Ureteral Stent Applications

Marco Laurenti,Valentina Cauda,Marta Grochowicz

doi:10.3390/coatings8110376

Marco Laurenti, Valentina Cauda + Show 1 more

Open Access

https://doi.org/10.3390/coatings8110376

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Abstract

High-surface-area porous coatings represent an interesting option to fabricate eluting stents with additional functionalities, as controlled drug delivery and antibacterial resistance properties. ZnO is a biocompatible material available in various high-surface-area morphologies, with promising antibacterial properties. Hydrophilic 2-hydroxyethyl methacrylate (HEMA) polymers (pHEMA) have been widely investigated for their biomedical applications, thanks to their biocompatibility, absence of toxicity, and tunable swelling properties. This work aims to demonstrate the use of porous ZnO/polymer bilayer coatings for future drug eluting stent applications. Sputtered mesoporous ZnO layers were coated with pHEMA and p(HEMA-co-acrylic acid (AA)) films through vacuum infiltration and drop-casting methods. The last approach was found to be the most suitable one for achieving a good polymer infiltration within the ZnO matrix and to avoid the mechanical detachment of the porous film from the substrate. The corresponding release properties were evaluated by loading a fluorescent dye in the host ZnO matrix, before drop-casting the polymer coating. For pure ZnO, the release of the dye was completed after 2 h. For ZnO/pHEMA, the sustained release of the molecule was achieved with only 30% released after 2 h and 100% released after seven days. In this case, the pH-triggered delivery properties were also demonstrated by switching from neutral to acidic pH conditions. No significant changes were obtained for the ZnO/p(HEMA-co-AA) system, which exhibited a faster swelling behavior and a release profile similar to pure ZnO.

Highlights

IntroductionHigh-surface-area porous coatings for implantable biomedical devices represent an intriguing solution to confer the device additional functionalities with respect to the uncoated implant [1]
High-surface-area porous coatings for implantable biomedical devices represent an intriguing solution to confer the device additional functionalities with respect to the uncoated implant [1].In this regard, drug-releasing devices featuring biocompatibility, biostability, antibacterial resistance properties, efficient drug loading and delivery should be pursued
For the pure pHEMA, the absorption band derived from the hydroxyl group vibration is observed at 3400 cm−1

Summary

Introduction

High-surface-area porous coatings for implantable biomedical devices represent an intriguing solution to confer the device additional functionalities with respect to the uncoated implant [1] In this regard, drug-releasing devices featuring biocompatibility, biostability, antibacterial resistance properties, efficient drug loading and delivery should be pursued. Drug-releasing devices featuring biocompatibility, biostability, antibacterial resistance properties, efficient drug loading and delivery should be pursued For such purposes, the most commonly used materials are polymers [2]; new generation carbon-based materials, such as graphene and graphene oxide [3]; and other inorganic porous materials like anodized alumina [4], titania nanotubes [5], and porous silicon coatings [6]. One of the main limitation affecting ureteral stents’ operation is the formation of progressive encrustations due to inorganic salt deposition and bacteria biofilm formation, resulting in the total occlusion of the stent lumen in the worst case, especially for prolonged indwelling times.

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