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Gloves
Published in Robert N. Phalen, Howard I. Maibach, Protective Gloves for Occupational Use, 2023
Marie-Noëlle Crépy, Pierre Hoerner
Polyurethanes are probably the polymers offering one the highest versatility. They can be designed to fit with the intended usage. TPU normally possesses a very good abrasion resistance and high resistance at the break. However, it is sensitive to degradation by alcohols, which is a major limitation, for example in medical settings. While TPUs can be made having improved alcohol resistance, they tend to produce relatively stiff films, which is problematic for most applications. TPU is mainly processed in solution, particularly in N,N-dimethylformamide (DMF), which is a toxic solvent. TPU latex dispersions developed for the glove and condom dipping industry have recently been introduced in the marketplace.16
Designing Biomaterials for Regenerative Medicine: State-of-the-Art and Future Perspectives
Published in Naznin Sultana, Sanchita Bandyopadhyay-Ghosh, Chin Fhong Soon, Tissue Engineering Strategies for Organ Regeneration, 2020
Zohreh Arabpour, Mansour Youseffi, Chin Fhong Soon, Naznin Sultana, Mohammad Reza Bazgeir, Mozafari Masoud, Farshid Sefat
Polyurethanes (PUs) are popular because of their hardness, durability, biocompatibility, and stability in biological systems. In addition, Polyurethanes were demonstrated to improve cell adhesion and proliferation without any side effects (Phan et al. 2005). Conventionally, PUs have been used as permanent and inert materials in catheters, heart valves and vascular grafts (Santerre et al. 2005).
Enteral nutrition
Published in David Westaby, Martin Lombard, Therapeutic Gastrointestinal Endoscopy A problem-oriented approach, 2019
A bewildering variety of tubes have arrived on the market in recent years, but they differ from one another in only a few important respects: tube diameter, the materials from which they are made, the external fixing device and, most important, the type of internal retention device used. In general, thinner diameter tubes (down to 9 F) have a similar blockage rate to larger ones and are preferred for their better tolerability. The choice of material is chiefly between silicone elastomers and polyurethane. The former is softer, but such a tube has a larger external diameter in relation to its lumen. Both materials are durable; polyurethane tends to split if left kinked for long periods, whereas silicon can become stretched and distorted with time. Experience with polyurethane tubes indicates that they can last up to 6 years. External fixation is achieved with either a simple disc or a more sophisticated device which positions the tube at a 90° angle, keeping it flat against the abdominal wall.
Antithrombogenic peripherally inserted central catheters: overview of efficacy and safety
Published in Expert Review of Medical Devices, 2019
Amanda J. Ullman, AndreW. C. Bulmer, Tim R. Dargaville, Claire M. Rickard, Vineet Chopra
PICCs have evolved substantially since their introduction in the 1970s by Verne Hoshal and Millie Lawson [10]. Key changes include improvement in catheter material, design, and configuration. The first-generation PICCs were made of silicone-based polymers – thought to be more durable and dependable than non-silicone rubbers. However, this was not the case and silicone PICCs exhibited many problems including rupture of the catheter wall and local reactions along the vessel wall. These local reactions – ranging from mild irritation to phlebitis – often led to premature device removal and painful complications for patients [11]. In the early 1980s, polyurethane-based materials were introduced as a means to reduce these complications. However, first-generation polyurethane devices were associated with many of these same complications including phlebitis and venous irritation. Third-generation polyurethane materials (currently used in most PICCs) have provided the optimal blend of patient acceptance and durability. These materials, in turn, can also withstand high-pressure injections – leading to the term ‘POWER PICCs’ being used for devices compatible with radiographic injectors, for example [12].
Dural sealants for the management of cerebrospinal fluid leakage after intradural surgery: current status and future perspectives
Published in Expert Review of Medical Devices, 2019
Ahmet Kinaci, Tristan P.C. Van Doormaal
Polyurethanes are synthetic polymers in which the mechanical properties, biocompatibility, and biodegradability are determined by its composition. Polyurethanes are formed via a reaction between a diisocyanate and a diol. Isocyanates adhesives adhere covalently to the underlying tissue in the presence of water through the formation of urea bond with amines available in the underlying tissue [8]. The major disadvantage of the commonly used polyurethanes is that they are toxic and not readily biodegradable. However, the use of aliphatic isocyanates instead of aromatic isocyanates eliminates toxicity. By incorporating hydrolytically degradable esters bonds by using monomers such as lactic acid or caprolactone enables the development of biodegradable polyurethanes [22,23].
Does antimicrobial coating and impregnation of urinary catheters prevent catheter-associated urinary tract infection? A review of clinical and preclinical studies
Published in Expert Review of Medical Devices, 2019
Aneela Majeed, Fnu Sagar, Azka Latif, Hamza Hassan, Ahmad Iftikhar, Rabih O. Darouiche, Mayar Al Mohajer
Modification of polyurethane has shown positive effects in some studies. Polyurethane surfaces are much more versatile than other polymers. They are also biocompatible and hemocompatible, and can be processed in several ways including injection molding, extrusion, film blowing, and solution dipping [29]. N-halamine precursors are compounds consisting of nitrogen-halogen covalent bonds. The halogenation of amide, imide, or amine groups forms these compounds. Their antimicrobial activity involves a halogen exchange reaction that causes bacterial cell death. In an in vitro study, an N-halamine precursor, 5,5-dimethyl hydantoin, was covalently linked to a polyurethane surface with 1,6-hexamethylene diisocyanate as the coupling agent. The antimicrobial effects of this surface were compared with those of untreated original polyurethane films as negative controls against S. aureus, E. coli, MRSA, vancomycin-resistant enterococci (VRE), and C. albicans. The authors observed a 4 log reduction in S. aureus in 60 min, a 4 log reduction in E. coli in 30 min, and a 4 log reduction in MRSA and VRE in 30 min, and this antimicrobial effect remained stable for >6 months. On the other hand, the original polyurethane films provided a 90% reduction of the same bacteria only after 8 h of contact [57]. Similarly, salicylic acid-releasing polyurethane acrylate polymers caused a reduction of biofilm growth in 5-day experiments for both P. aeruginosa and E. coli in an in vitro study [58]. This coating showed a biofilm inhibition rate of 60% over 11 days for E. coli and 50% over 5 days for P. aeruginosa.