Allergic contact dermatitis to silicone in a continuous positive airway pressure mask

Effect of Different Amine Catalysts on the Thermomechanical and Cytotoxic Properties of 'Visco'-Type Polyurethane Foam for Biomedical Applications

Components for manufacturing polyurethane foams can adversely affect the human body, particularly if they are in contact with it for long periods. In applications where the foam is not placed directly into the body, the study of the product's effects is often neglected. In the case of human skin, distinguishing the increasingly frequent problems of skin atopy, more attention should be paid to this. This paper presents the influence of the different catalytic systems on cytotoxic and thermomechanical properties in polyurethane foams. Among others, foams were produced with the most popular catalysts on the market, DABCO and a metal-organic tin catalyst. The foams were characterized by thermomechanical properties and were subjected to a cytotoxicity test against human keratinocytes. In biocompatibility tests with skin cells, the results were highly variable. VAB 2 with a catalytic system consisting of commercial Diethanolamine and Addocat^®105 performed the best. However, with such a catalytic system, the mechanical properties have worsened.

Design, manufacture, and testing of customized sterilizable respirator

The respirator as one of the personal protective equipment is essential for industrial activities (e.g., mining, painting, woodcutting, manufacturing) for protection from contaminants in the air and during the Covid-19 pandemic to protect the wearer from infection. The respirators nowadays are commonly made of rigid plastic. They are expensive, cumbersome, and not comfortable to wear. The many components with complex structures prevent it from cleaning and reusing. We develop a practical and scalable strategy to create customized respirators with durability using computational modeling and 3D printing. It is shown that by morphing the shape according to the user's photo, the respirator is designed to fit a user's face without air leaks. Using a printing-mold-casting method, this respirator can be manufactured by silicone rubber with accuracy, which is highly durable, with its mechanics primarily not affected by sterilization. These features provide the current respirator adaptivity and convenience in carrying and storing, as well as more comfort for long-time wearing.