Novel bioresorbable stent coating for drug release in congenital heart disease applications

Abstract

A novel double opposed helical poly-l-lactic acid (PLLA) bioresorbable stent has been designed for use in pediatrics. The aim was to test the PLLA stent biocompatibility. The PLLA stent was immersed into whole pig's blood in a closed loop circuit then fibrin and platelet association was assessed via enzyme-linked immunosorbent assay. D-Dimer was valued at 0.2 ± 0.002 ng/mL and P-selectin 0.43 ± 00.01 ng/mL indicating limited association of fibrin and platelets on the stent. To improve biocompatibility by targeting inflammatory cells, dexamethasone was incorporated on PLLA fibers with two coating methods. Both coatings were poly(l-lactide-co-glycolide) acid (PLGA) but one was made porous with sucrose while the other remained nonporous. There was no change in mechanical properties of the fiber with either coating of PLGA polymer. The total amount of dexamethasone released was then determined for each coating. The cumulative drug release for the porous fiber was significantly higher (∼100%) over 8 weeks than the nonporous fiber (40%). Surface examination of the fiber with scanning electron microscopy showed more surface microfracturing in coatings that contain pores. The biocompatibility of this novel stent was demonstrated. Mechanical properties of the fiber were not altered by coating with PLGA polymer. Anti-inflammatory drug release was optimized using a porous PLGA polymer.

Catheter-based Intramyocardial Injection of FGF1 or NRG1-loaded MPs Improves Cardiac Function in a Preclinical Model of Ischemia-Reperfusion

“…Of particular interest in the field of regenerative medicine are synthetic polymers like the polyesters poly(lactic-co-glycolic acid) (PLGA), which have reached FDA approval for clinical application in tissue repair 18 with a demonstrated track record as vehicles for protein delivery. Significant research has been carried out on the development of bioresorbable stent scaffolds 19 20 21 and drug delivery systems 22 23 using PLGA polymer for heart tissue engineering applications. Interestingly, PLGA can be shaped/processed into delivery systems like microparticles (MPs), which can be injected through cardiac catheters allowing controlled local delivery of proteins directly in relevant areas of the heart 24 25 26 .…”

Poly(gadodiamide fumaric acid): A Bioresorbable, Radiopaque, and MRI-Visible Polymer for Biomedical Applications

“…Some biopolymers such as PLLA degrade by bulk degradation in which autocatalysis of the center of the polymer degrades prior to the outer surface. Others such as PLGA, PFA, and PGFA undergo surface degradation in which the polymer chains exposed at the exterior surface degrade at a rate that exceeds the degradation of the center . The release of oligomers and monomers leads to a decrease in molecular weight and weight loss of the polymer structure.…”

“…39 There are many different ways in which polymer degradation can occurs: photo-, thermal-, mechanical, and chemical degradation. 40 All biodegradable polymers contain hydrolyzable bonds. Chemical degradation via hydrolysis or enzyme catalyzed hydrolysis is the most important degradation mechanism.…”

Bioactive Electrospun Fibers: Fabrication Strategies and a Critical Review of Surface-Sensitive Characterization and Quantification

“…Goodfriend et al investigated the fibrin and platelet deposition on a PLLA stent with ELISA . Another group analyzed the effect of the PEG concentration on the amount of the adsorbed model protein FN together with a FN antibody.…”