Comparison of biodegradable poly(glycolide-ɛ-caprolactone) and poly(glycolide-ɛ-caprolactone-d,l-lactide) coatings enriched with ciprofloxacin formed on Ti6Al4V alloy

Chloride Ions-Responsive Intelligent Coatings for the Active Protection of Degradable Biomedical Mg Alloys

In this work, the hydroxyapatite (HA) microspheres are utilized as carriers for 8-hydroxyquinoline (8-HQ) inhibitors with a sodium alginate-silver nitrate layer (Ag-SA) added to confer chloride-responsive properties. These 8-HQ@Ag-SA-HA microspheres are subsequently integrated into poly(lactic acid) (PLA) coatings to produce biocompatible coatings. The resulting 8-HQ@Ag-SA-HA microsphere exhibits a spherical structure with a diameter of 3.16 μm. Thermogravimetric analysis indicates that the encapsulated 8-HQ inhibitors are approximately 11.83 wt %. Furthermore, the incorporation of these microspheres fills the micropores within the PLA coating, leading to a denser coating surface, enhanced wettability (contact angle value = 88°), and improved adhesion strength, thereby reinforcing the physical barrier effect. Corrosion tests reveal that the coatings exhibit increased resistance to corrosion in simulated body fluid (SBF) solutions. The released 8-HQ inhibitors in response to chloride ions form a protective layer of Mg(HQ)2, providing the coatings with self-healing properties and ensuring their durability in the SBF environment. Additionally, the cell test demonstrates a significant presence of MG-63 cells, accompanied by a low hemolysis rate of 3.81%, confirming the exceptional biocompatibility of the coatings. These findings offer valuable insights into the development of stimuli-responsive biocompatible coatings for effectively protecting Mg alloys.

Functional Properties of Polyurethane Ureteral Stents with PLGA and Papaverine Hydrochloride Coating

Despite the obvious benefits of using ureteral stents to drain the ureters, there is also a risk of complications from 80-90%. The presence of a foreign body in the human body causes disturbances in its proper functioning. It can lead to biofilm formation on the stent surface, which may favor the development of urinary tract infections or the formation of encrustation, as well as stent fragmentation, complicating its subsequent removal. In this work, the effect of the polymeric coating containing the active substance-papaverine hydrochloride on the functional properties of ureteral stents significant for clinical practice were assessed. Methods: The most commonly clinically used polyurethane ureteral Double-J stent was selected for the study. Using the dip-coating method, the surface of the stent was coated with a poly(D,L-lactide-glycolide) (PLGA) coating containing the papaverine hydrochloride (PAP). In particular, strength properties, retention strength of the stent ends, dynamic frictional force, and the fluoroscopic visibility of the stent during X-ray imaging were determined. Results: The analysis of the test results indicates the usefulness of a biodegradable polymer coating containing the active substance for the modification of the surface of polyurethane ureteral stents. The stents coated with PLGA+PAP coating compared to polyurethane stents are characterized by more favorable strength properties, the smaller value of the dynamic frictional force, without reducing the fluoroscopic visibility.

Electrospun paclitaxel delivery system based on PGCL/PLGA in local therapy combined with brachytherapy

The local administration of different drugs in anticancer therapy continue to attract attention. Thus, the idea of local delivery of cytostatics from nonwoven-structured polyesters seems to be highly desirable. It could reduce systemic drug levels and provide high local concentration of the chemotherapeutics at the tumor site and contribute to enhance the efficiency of the anticancer therapy. Poly(glycolide-ɛ-caprolactone) (PGCL) and poly(D,L-lactide-co-glycolide) (PLGA) synthesized with zirconium-based initiator have been used to prepare electrospun, drug-eluting patches since they possess very good fiber-forming ability. Well-known chemotherapeutic drug-paclitaxel has been loaded into fibrous structure as a model anticancer agent in order to obtain drug delivery systems for local administration. The drug dose in obtained nonwovens might be regulated by the thickness and total area of the implanted patches. Electrospinning of PGCL/PLGA blend allowed to obtain soft and flexible implantable materials. Flexibility has been important factor since it ensures convenient use when covering a tumor or filling a resection cavity. The effectiveness of designed nonwovens presented in the study has been tested in vivo on mouse model of breast cancer. The growth of the tumors was slowed down during in vivo study in comparison with drug-free nonwovens- The volume of the tumor was 40% lower. Drug-loaded electrospun systems implanted locally to the tumor site was further combined with brachytherapy which improved the effectiveness of the therapy in about 18%. Detailed analysis of the nonwovens before and during degradation process has been performed by means of Scanning Electron Microscopy, Differential Scanning Calorimetry, Nuclear Magnetic Resonance, Gel Permeation Chromatography, X-ray Diffraction. The molar mass changes of the nonwoven were quite rapid contrary to changes of comonomer unit content, thermal properties and morphology of the fiber.

Development of antibacterial, ciprofloxacin-eluting biodegradable coatings on Ti6Al7Nb implants to prevent peri-implant infections

Various types of biodegradable polymers containing lactide, glycolide, caprolactone, and trimethylene carbonate units have been used to obtain ciprofloxacin (CFX)-enriched coatings developed on the Ti6Al7Nb alloy, intended for short-term therapy. In the first step, the surface of the Ti6Al7Nb alloy was modified, mostly according to sandblasting and anodic oxidation to obtain the TiO₂ layer. Anodizing can be an effective method for preparing TiO₂ coatings with osteoconductive properties. The polymer containing CFX molecules was deposited on the modified alloy, and Polymer + CFX/TiO ₂ /Ti6Al7Nb systems were developed. CFX-enriched coatings adhered well to the surface of the previously modified alloy. Polymer layers maintain the topography of the alloy due to the development of the surface during the sandblasting method. As polymers intended for the study possess degradation ability, they are capable of releasing the incorporated drug. Antibacterial activity of CFX-enriched coatings was examined to verify the functionality of designed Polymer + CFX/TiO ₂ /Ti6Al7Nb systems, and the bactericidal effect was confirmed for all cases. The presented study is an extension of previous, initial research and creates an overview of polyester or polyestercarbonate CFX-eluting coatings.