title: Bioresorbable ureteral stents from natural origin polymers.
abstract: In this work, stents were produced from natural origin polysaccharides. Alginate, gellan gum, and a blend of these with gelatin were used to produce hollow tube (stents) following a combination of templated gelation and critical point carbon dioxide drying. Morphological analysis of the surface of the stents was carried out by scanning electron microscopy. Indwelling time, encrustation, and stability of the stents in artificial urine solution was carried out up to 60 days of immersion. In vitro studies carried out with simulated urine demonstrated that the tubes present a high fluid uptake ability, about 1000%. Despite this, the materials are able to maintain their shape and do not present an extensive swelling behavior. The bioresorption profile was observed to be highly dependent on the composition of the stent and it can be tuned. Complete dissolution of the materials may occur between 14 and 60 days. Additionally, no encrustation was observed within the tested timeframe. The ability to resist bacterial adherence was evaluated with Gram-positive Staphylococcus aureus and two Gram-negatives Escherichia coli DH5 alpha and Klebsiella oxytoca. For K. oxytoca, no differences were observed in comparison with a commercial stent (Biosoft(®) duo, Porges), although, for S. aureus all tested compositions had a higher inhibition of bacterial adhesion compared to the commercial stents. In case of E. coli, the addition of gelatin to the formulations reduced the bacterial adhesion in a highly significant manner compared to the commercial stents. The stents produced by the developed technology fulfill the requirements for ureteral stents and will contribute in the development of biocompatible and bioresorbable urinary stents.
authors: 3B's Research Group-Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark, 4806-909, Taipas, Guimarães, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.
authors: Alexandre A
authors: AA
authors: Barros
authors: Ana
authors: A
authors: Rita
authors: C
authors: C
authors: Duarte
authors: Ricardo A
authors: RA
authors: Pires
authors: Belém
authors: B
authors: Sampaio-Marques
authors: Paula
authors: P
authors: Ludovico
authors: Estevão
authors: E
authors: Lima
authors: João F
authors: JF
authors: Mano
authors: Rui L
authors: RL
authors: Reis
mesh_terms: D020341:Absorbable Implants / Q000382:microbiology; D065966:Absorption, Physicochemical; D000327:Adsorption; D000464:Alginates / Q000633:toxicity; D000818:Animals; D001422:Bacterial Adhesion; D003460:Crystallization; D004926:Escherichia coli / Q000502:physiology; D005780:Gelatin / Q000633:toxicity; D020723:Glucuronic Acid / Q000633:toxicity; D006603:Hexuronic Acids / Q000633:toxicity; D041121:Klebsiella oxytoca / Q000502:physiology; D007739:L Cells; D008422:Materials Testing; D051379:Mice; D008855:Microscopy, Electron, Scanning; D011135:Polysaccharides, Bacterial / Q000633:toxicity; D013211:Staphylococcus aureus / Q000502:physiology; D015607:Stents / Q000382:microbiology; D013718:Tensile Strength; D014513:Ureter
chemical_list: D000464:Alginates; D006603:Hexuronic Acids; D011135:Polysaccharides, Bacterial; C048288:gellan gum; D020723:Glucuronic Acid; D005780:Gelatin
keywords: aerogel/hydrogel; bioresorbable polymers; kidney stones; natural polymers; supercritical fluid technology; ureteral stents