An antibacterial and biocompatible multilayer biomedical coating capable of healing damages

Natural biopolymers in the fabrication and coating of ureteral stent: An overview

Ureteral stents are indwelling medical devices that are most commonly used in treating different urinary tract complications like ureteral obstruction, kidney stones, and strictures, and allow normal urine flow from the kidney to the bladder. Tremendous work has been done in ureteral stent technology to meet the clinical demands, however, till-date a gold standard material for ureteral stents has not yet been developed. Many materials such as metal, and synthetic polymers have been published, however, the role of natural biopolymers has not yet been summarized and discussed. There is no detailed review published to explain the role of natural biopolymers in ureteral stent technology. This is the first review that explains and summarizes the role of natural polymer in ureter stent technology. In this review alginate and chitosan polymers are discussed in detail in the fabrications and coating of ureteral stents. It was summarized that alginate polymer alone or in combination with other polymers have been successfully used by many researchers for the manufacturing of ureteral stents with satisfactory results in vitro, in vivo, and clinical trials. However, alginate is rarely used to coat the surface of ureteral stent. On the other hand, only two reports are available on chitosan polymers for the manufacturing of ureteral stents, however, chitosan is largely used to coat the existing ureteral stents owing to their good antibacterial characteristics. Coating procedures can inhibit encrustation and biofilm formation. Nevertheless, the lack of antibacterial efficiency and inadequate coating limit their applications, however, natural biopolymers like chitosan showed significant promises in coating. Overall, the renewable nature, abundant, biocompatible, and biodegradable potential of natural polymer can be established with significant aspects as the ideal ureteral stent. To fully utilize the potential of the natural biopolymers in the ureteral stent design or coatings, an in-depth study is required to understand and identify their performance both in vitro and in vivo in the urinary tract.

pH-response of protein-polysaccharide multilayers adsorbed on a flat gold surface: A surface plasmon resonance study

Polysaccharide-protein multilayers (PPMLs) consisting of bovine serum albumin (BSA) and chondroitin sulfate (CS) are assembled in acidic solution (pH 4.2) via layer-by-layer deposition method. The formation of PPMLs on gold surface and their responsiveness to pH change from 4.2 to 7 is investigated by Surface Plasmon Resonance Spectroscopy. The buildup of the multilayer at pH 4.2 exhibits non-linear growth while the formation of the first layers is strongly affected by the physicochemical properties of the gold surface. Neutral solution (pH 7) affects the interactions between the biopolymers and results in a partially disassemble (disintegration) of the multilayer film. On one hand, the single pair of layers, BSA-CS and the double pair of layers, (BSA-CS)2, assemblies are stable in neutral pH, a result that will be of interest for biomedical applications. On the other hand, multilayer films consisting of more than four layers that is (BSA-CS)2 Collapse

Key Words

• layer‐by‐layer
• multilayer
• pH‐responsiveness
• protein‐polysaccharide
• surface plasmon

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MESH Headings

• Gold/chemistry
• Surface Plasmon Resonance/methods
• Hydrogen-Ion Concentration
• Serum Albumin, Bovine/chemistry
• Adsorption
• Chondroitin Sulfates/chemistry
• Surface Properties
• Cattle
• Animals
• Polysaccharides/chemistry

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Grants Collapse

Affiliation(s)

Nikolitsa Katsenou Department of Physics, University of Patras, Patras, Greece
Nikolaos Spiliopoulos Department of Physics, University of Patras, Patras, Greece
Dimitrios L Anastassopoulos Department of Physics, University of Patras, Patras, Greece
Aristeidis Papagiannopoulos Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, Athens, Greece
Chris Toprakcioglu Department of Physics, University of Patras, Patras, Greece

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Research Progress in the Multilayer Hydrogels

Hydrogels have been widely used in many fields including biomedicine and water treatment. Significant achievements have been made in these fields due to the extraordinary properties of hydrogels, such as facile processability and tissue similarity. However, based on the in-depth study of the microstructures of hydrogels, as a result of the enhancement of biomedical requirements in drug delivery, cell encapsulation, cartilage regeneration, and other aspects, it is challenge for conventional homogeneous hydrogels to simultaneously meet different needs. Fortunately, heterogeneous multilayer hydrogels have emerged and become an important branch of hydrogels research. In this review, their main preparation processes and mechanisms as well as their composites from different resources and methods, are introduced. Moreover, the more recent achievements and potential applications are also highlighted, and their future development prospects are clarified and briefly discussed.